....

 

Welcome to the forum! Can't wait to see more on this project in the future

 

Haha, I had my welcome a long time ago on here! 😅

I'll try and update regularly. Lots of diffent things going on right now with it so it's a bit all over the place but I'll post some stuff up soon enough. Chassis is going away end of the month for some work so I'll show where it's at now, what's happening to it and why. 😎

 

Well, you got a second welcome because I didn't check

 

Haha, I'm not bothered, it's nice to get a welcome back. 😁

 

Busy day....

Shell's now booked in with my fabricator (i wish i could weld!) for quite a few changes. I've learnt the hard way over the years to just go balls deep and push for end goal without too many steps on the way and decided now is the time to get all the details done so there's not much revisiting later on down the line. There's a mix of things going on, one side being weight reduction (F=MA) and on the other side getting functional items / systems put in / located.

This is the current state of the shell, OMP FIA certified FE(T)45 6 pt "bolt in" cage and 90% the way there for removing weight.

What's going to change...

Some fairly significant changes, all with purpose.

Below photo. At the front there's still 2x doubler plates on the floor, both of these will go. Drivers original transverse seat mount (front / rear) will come out, welded in seat rails will be installed and as far back as reasonably practicable. Seat is a Tillett B2 which is about as heavy as a bag of feathers but may need side mount extensions for height, will cross that bridge when we come to it.

AP floor mounted pedal box will be going in not only to suit seat position but there's no ABS, brakes will be balanced off the pedal box / prop (data logged for pressure), clutch is now hydraulic and intake is being changed to DBW.

Rear cage legs will be removed and new legs put in tied into the floor beside the strut tops. I've got zero interest in controlling any torsional / bending moments in a wheel arch but plenty of interest in controlling what happens with the suspension. Harness bar will be reinstated (2" 6pt).

Internal side panels will be cut. Class regs restrict any chassis modifications between the wheel centre lines (there are a few exceptions to this rule) so they'll be removed as per regs. Structural strength outside of the wheel CL's is of no importance apart from retaining body shape. The RF member between the struts will also go as the cage will provide more rigidity / opposition to torsion than that lump of steel will.

Spare wheel well will be removed from the rear up to the member the rear LCA's / ARB bolt onto. This will remove weight that sits outside of the 'axle' but will also make way for a centre exit exhaust. As mentioned, modifying the chassis between the wheel CL's is prohibited apart from certain circumstances. One of these happens to be for the passage of the exhaust so that's exactly what's going to happen in the white circle, exhaust will pass through there and out the rear. How big that hole will be is yet to be determined as the exhaust system still need's specified and will need to include a CAT and meet MSA regs for noise. The OEM fuel tank is gone so there's plenty of room to fit it all in. The full wheel well will be covered over by carbon sheet consisting of a Nomex layer which will meet regs regarding bulkheads / fire proofing & i'm considering putting additional underfloor bracing in from the b-pillar leg area to the rear LCA member. It's additional weight but it's also low down relative to CG.

Again, showing where exhaust will exit, also showing removal of spare wheel well. A diffuser will sit between the rear chassis legs and be supported by the legs and LCA/ARB main support. Not sure if i'll have time to fabricate that before i get out next season but i'll play it by ear, flat floor will be installed as well. This is aimed more at drag reduction than downforce but any downforce i can add will be welcome. Top speed will be sub 100mph mostly so consideration needs to be given for adding weight vs performance gain. Drag reduction doesn't need the same criteria as downforce to work....

Existing horizontal bar will be replaced. A stub was welded on for a dash panel which is overkill (understatement) for purpose and the OEM steering column assembly was also welded on in full. Easier to just replace the full tube rather than start chopping bits off it. Steering column will be replaced / extended to suit driver position. The tricky part is the column is made up of two shafts to accommodate the off centre wheel position relative to the bulkhead pass through. Using as single shaft shouldn't be too much of an issue regarding wheel angle / tilt but we'll need to have a play about with this one and see what works best. All front BHD holes will be sealed and any redundant studs / brackets removed. The upper dash panel will be covered in neoprene foam to prevent reflection on the windscreen.

Quite a major one, section highlighted will be cut out and an exhaust tunnel put in.

13.4.6. Localised alteration for the passage/clearance of the exhaust system.

Why? Two fold, weight distribution and drag reduction. The exhaust that was on it was 304L SS, can't remember exact weights of exhaust and manifold but i can be reduced. All that weight is on the drivers side (UK shell) and although side - side weight when balanced isn't too much of a big deal, it still has a big impact on weight transfer when cornering. So 1st objective / purpose being achieved regarding weight reduction (which would be done through different materials anyway) with better positioning (central rather than favouring one side of the chassis) and 2nd objective also achieved having a higher mounted exhaust along the floor allowing for a more complete flat floor to be installed. The higher mass to CG should be totally offset by the weight reduction (Inconel) and drag reduction.

Positioning. Car is running a dry sump and the tank is currently mounted in front of the gearbox. Not only does this put weight outside of the front axle it also makes the front end very cluttered with all of the associated pipework. Sump tank will be re-mounted inside the cabin in the footwell but as close to the chassis CL as possible to keep the hose lengths to a minimum. Sump pump is at the front of the engine so hoses will run along the BHD out through to / from pump, block & breather tank. Sump breather tank will also pick up the gearbox breather.

White outline will most likely be where the electronics sit, this will consist of ecu (Motec M130), PDM (PDM15) & isolation system. CAN keypad will be mounted above the exhaust tunnel.

Red outline is where the gearbox compressor & accumulator will sit (paddle shift).

Further rear outline is where the fuel tank will reside. This will be a 2 section / compartment tank with anti reversion / flow back incorporated and baffled not only to assist in the prevention of starvation but also to counter longitudinal load transfer. Tank capacity is approximately 8L including 1L lower compartment, gravity fed single pump including roll over protection.

All of the above will be covered by a fabricated aluminium box to meet fluid / bulkhead rules within the driver compartment and i'll end up using the aluminium box section as a pattern for a carbon / kevlar part, again with Nomex layer incorporated. Fuel lines will be PTFE lined and run underneath the oil tank through the BHD along side the air lines for the gearbox valve block.

Having the electronics / pneumatics between the tanks keeps the cover low in the middle which will complies to regs stating "5.2.4 Not have the space normally occupied by passengers encroached upon in such a way that may impede extrication of the driver from that side", the top of the fuel tank will sit below the cage RF bracing and also be easily accessed for filling through the passenger door way.

Rear boot lid is already carbon with polycarbonate screen. I've already cut out the guts of the OEM spoiler and the upper hinges will be replace with alu pins. Any weight reduction this high up on the chassis in relation to CG is welcome (IMO), it all adds up.

Front end will be seeing some attention as well but i'll cover that another day.

Front / rear distribution is on my mind right now but if the back end turns out to be too light i can always add ballast back in and more importantly choose where to add it, eg, under the floor rather than above it.

I've given all of this a fair bit of consideration and believe it will be optimum for weight distribution / reduction, allowing for drag reduction & doing it all whilst increasing chassis stiffness, and more importantly, safety aspects. Having said that, there's many ways to skin a cat and i'm always open to suggestion for improvement so feel free to pick and prod if you feel something can be done better!

 

Damn brother, I have to get over to my laptop so I can re-read this badass post man. I love the ideas. I have been hoping my buddy gets a wrecked DC5 so I can cut out the first section of the hump between the floorboard. The flip flop it around so it makes a dope tunnel for the exhaust... that would work flawlessly.

Once those ep3's/dc5's get down to 2600lbs they get faster. I love your race car. The inconel piping is sick stuff. Just badass

 

Damn brother, I have to get over to my laptop so I can re-read this badass post man. I love the ideas. I have been hoping my buddy gets a wrecked DC5 so I can cut out the first section of the hump between the floorboard. The flip flop it around so it makes a dope tunnel for the exhaust... that would work flawlessly.

Once those ep3's/dc5's get down to 2600lbs they get faster. I love your race car. The inconel piping is sick stuff. Just badass

I've been loosely following some AWD builds using EP3 so putting an exhaust tunnel in like they do for the propshaft seems quite simple. There should be plenty of room between the two main chassis rails either side of where it'll sit. What will need more thought is location of CAT / silencer(s) but with the OEM fuel tank gone there's a big space under the rear seats for shoving it all in.

No idea what dry weight will be once it's all done but anything less than 850kg and I'll be happy. We shall see....

 

I would ditch that sound proofing... I got over 25lbs I still have more to go. I love the sound of rocks it adds to the excitement 😄

Dry Ice or a powerful heat gun

 

Yep, all of that will get removed as well. Couple of years ago I took a wire wheel to the underside of the car all the way up to the engine then recoated. Was an absolute bitch of a job doing it on axle stands but took a decent bit of weight off and gave myself and nice clean chassis to work of for suspension. Just need to get the front done as well. Downside with driveway motorsport is weather, especially at this time of year!

Hoping to get the shell resprayed once all the fabrication is done and that'll be it good to go. Engines going to take a while to put together so should be able to get it done before running gear gets dropped back in. I also want a nice blank canvas to advertise some of the companies that are involved with it, firm believer in promoting a company that I put my trust in, which is far and few between!

Got a few other things I can share so I'll add to the thread over the weekend. My wife needs a new daily driver so today we're going car shopping, she quite likes a CR-V so might be bringing home another Honda. 😁

 

Little bit of time to kill so thought i'd go over suspension. With the shell now booked in i need to get it rolling so the past few days have been sorting out suspension components ready to bolt back on. I'm fairly methodical in what i do and like to have all parts for whatever job ready to go so this is where i'm at right now....

Starting at the rear, trailing arms were powder coated a long time ago. There's not really much scope for changing these out for something lighter and i don't want to make the back end too light. Keeping some weight down low there isn't a bad thing. These have been fitted with Upaclick spherical bearings completely removing compliance unlike a few alternatives that are available off the shelf. They do both press fit and bolt in, i've opted for the latter as it will mean servicing / replacing the bearing in future will be quite easy. These are lubricated with white lithium grease rather than silicone as there's no rubber boots. PCI do a rear trailing arm that is slightly light than stock but also changes the motion ratio by placing the strut on a 20deg incline by moving the lower connection further outboard and using a custom top hat. I did consider this but the top hat is not compatible with the rear Moton's so stock it is. Brian also use's JRZ which are a little bit different to Moton in stroke length...

ARB has recently been changed. I've had an ASR hollow bar before but it isn't very user friendly for exhaust routing. Now the exhaust will be routed centrally, i've gone and grabbed another. ASR description for suitable bar thickness is reasonably vague, none really pertain to what i'm using the car for but i've opted for a 0.198" thk bar doing some guess work. ASR also confirmed it should be good based on expected car weight but i won't really know until i get some baseline data from having it out on track.

Rear LCA are Hardrace with spherical bearings, hubs also powder coated with full Hardrace spherical bearings installed and rear camber arms are from Brian / Chris at Pro Car Innovations (PCI), i'm sure some of you over the pond will be quite familiar with PCI. The PCI arms are heavier than the spherical bearing Hardrace ones i had on but i'm keen to explore what difference they make with the further inboard mounting / longer link. All kinematics will be systematically checked before hitting the track so measuring dynamic toe, camber curves etc etc will be part and parcel of generating baseline data. Wheel studs have also been changed front / rear for Hardrace extended studs, obviously ARP do these as well but Hardrace were cheaper to they won!

Part of yesterdays job list was changing the studs on all 4 hubs and i think this took maybe 30 minutes at most. A couple of sacrificial nuts and a stud tool from Amazon is all that's needed...

I did weigh the front OEM studs and there's appox. 20g difference between stock and extended, this is even more so on the rear due to the shorter stock studs. That's an extra 100g minimum on each corner for unsprung weight and rotating mass. I'll need to decided if i value the convenience of the longer stud vs the additional weight.

I had originally intended to use Ti wheel nuts but after a re-read of the regs, these are prohibited and steel lug nuts must be used. Finding a good quality low weight steel nut is harder than you'd think as most these days are alloy. Ended up settling on Muteki nuts, short and open which means lighter!

Out with the old.....

And in with the new on a built up hub...

Moving forward....

Front end is a little different from the norm and that's mainly due to the bottom arms / knuckles. With the sequential box going in i now need to measure for driveshafts and this has given me the perfect opportunity to convert the front end to DC5 spec and increase track width by 20mm per side. I was already running tubed lower arms but these ones from PCI are made to DC5 Type R spec and give the extra track width. Having said that, i'm now in talks with a race engineer and there is scope to change these out for tubed arms again but to a different design spec that will net a whopping +55mm track width on the front vs stock EP3. Why is this so important? Load transfer, both lateral and diagonally. The whole overall performance of the car (ignoring driver for now) depends on the available grip, anything to improve this is priority and why despite having just received these lower arms, they maybe be changed out promptly as i don't want to have to measure and pay twice for driveshafts. The PCI arms are around 4kg per side, Brian did mention tubing these later on down the line but the potential replacements are around 3kg and I'm sure some holes could be cut in these 3mm steel plate these are made from to reduce mass. I've got DC5 knuckles away for powder coating right now and they'll be fitted with new hubs / bearings when they come back. I've also got a front brake assembly away back to my brake guy to machine new bells / carriers to suit the DC5 knuckle as the carrier offset is far greater than an EP3 knuckle to accommodate the stock DC5 Brembo calliper. Looks like someone will get a good setup when this lot goes up for sale. It's also got a knock on effect of making carbon wings / arches as i need to wait for it to be finalised / fitted and wheel offset determined by KPI / scrub before i know how much of an extension i need on the arches. Nothing is ever simple building race cars!

Front ARB again is a little different and this has come from PCI / Brian. I already had a bespoke ARB fitted but this was in the stock location under the subframe. It's now changed to hollow bar which will run through a CDS tube (will see if i can change this for T45) welded between inner wheel arches, very similar to BTCC location. It moves mass higher on the chassis but also means i can easily swap bars and the bar end will be perpendicular to the lower arm. Bar is 0.120" thk.

Steering rack is another area of focus. This is a facelift spec rack and i believe the only difference between this and pre facelift is the internal spring. Comparing part numbers for all components associated with the rack, this is the only part that differs, along with with PAS ECU (also have both pre and FL ECU's sat here). The intention is to investigate how the steering assist strength is controlled and setup a table within Motec software to allow this to be adjusted via a rotary switch. It's quite common to use Opel Corsa B/C PS in kit cars for this very reason so it should be a simple case of controlling voltage. An alternative is to try and fit a a variable proportioning valve in the rack but i don't think this will be an easy task. The racks been fully rebuilt now, PCI slider installed, TGS solid steering rack bushes (thanks Theodore!), mounting brackets have seen a Dremel to remove all casting marks / flashes to reduce weight and PCI steering arms will be used.

The PCI steering arms are nice. Bump steer is a big thing and it's a fine line between positive and negative results. Common for the EP3 when lowered is to use a rack riser which just moves the stock steering arm rack location up an inch or so. This is a fairly crude and inaccurate method and definitely isn't one fits all. Brain has made a setup which not only gives adjustable length arms with comparative weight to stock but also inboard height adjustment. If you've got a strut with a fixed pitman arm then this is a big win. I really like this setup and surprised nobody has made this before now.

Icing on the cake is a set of Moton 3 ways front / rear. These were an opportune purchase at the time a while back due to price, i don't really need 3 way struts for hill climbing but here were are. I had these rebuilt / checked over by Moton / AST, re-valved / sprung and 14mm shafts fitted vs 12mm. Current spring rates are 140/200nm but this will likely change to lower rates once the cars up and running. It's nigh on impossible to spec anything suspension related unless the cars already built so this will all get looked at once back together and i can weigh the car, check for CG position etc etc. One feature on these which is quite nice is the pitman arms are adjustable, i need to verify if that's just for height or also angle as well, i suspect both. That alone is quite a nice thing to have as not only does it help with bump steer but also potential to have a play about with Ackerman. Strut tops are from Area Motorsport and these are essential the same design that DVI / Davinci Racing came out with years ago. Not only do they allow for camber adjustment but also a healthy increase in caster. Whether these remain when the lower arms get changed out i don't know. All caster / camber will most likely be set using the arms and strut to knuckle but that's a chat for another time.

Lastly, wheels / tyres. Currently have two sets, one set of Braid Fullrace wheels which have additional lightening on the face and these are fitted with Pirelli SS 245/620, 17x8 square with +35. I've also got a set of Hart CP035 fitted with Avon A15 210/620, again 17x8 with similar offset (+32), these as superlight and helped shed a load of unsprung weight from each corner along with the brakes (more on that later). There's a high chance all of these will be used for rear's only or some cut as wets. Front may require more tyre than an 8" but as with most things suspension related i'll now be getting some guidance / advice from someone who actually knows what they're doing / full understanding of the whole system / kinematics instead of amateur best guess for what might work. Data (IMO) is an extremely useful tool no matter what your skill level is and the more i / we can acquire / run through certain software applications, the better understanding we have of what's happening as a system. If you watch stuff like HPA and their webinars, you'll soon come to realise that even at this level, all this stuff is quite accessible and useful, just need a little guidance on how to use it all. I'd also recommend grabbing a copy / reading Carroll Smith books, for a total newbie to kinematics, they've been an easy fast learning curve and quite an eye opener to what's quite a comprehensive topic in it's own right.

 

Lots of good information here on this thread... subscribed.

 

Thanks! Pretty sure there will be plenty of hurdles along the way so good to share experience and for myself to learn from others input!

Engine will be a whole other topic in itself and I'll be doing the spanner work so should be interesting to follow as well. Won't be able to go into too much detail about design / spec but I'll be able to talk about it to a certain extent and go through the whole build process.

 

Your in a cut-throat position racing a hill-climb, every little bit is every little bit gained. You are taking on a huge task, you will like how much sound deading comes out of the inside of the ep3/dc5. I got the jdm dc5 aluminum lower bpillar bar. I don't work on my car when I am here alone, if something happens I lower my chances of survival. I am about to go fart around on my engine and read the service manual to scan for things.

I don't need to know your engine specs... I am in your corner w/o worry...

 

Absolutely. I'm competing against cars that are almost entirely lighter than the EP3 chassis so no mean feat to get it running at the front. The main advantage will really be engine but EP3 is no slouch on the chassis side of life when tuned well. Any weight I can shave off, even if it's a few grams is going. Sum of all parts!

For sure, just saying that it'll l be quite an interesting part of the project as well.

 

Wow awesome thread. I don’t know how I didn’t get notified for the tag!! I will definitely be taking the time tonight to read through your updates as I only just got through the initial post.

Seems like we’ve got some real real nice parts going on here so I’m excited to follow along!

Loving the attitude so far as well. sometimes I get frustrated and just want to give up but pushing through all of that always ends up better

 

Love the motons and the asr bar. What a great bit of suspension there. Regarding the bar thickness, I believe they have 2 options. One more suitable for Autocross and lower-mid speed and one more suitable for road racing - higher speed tracks. I need to find this post again.

Some great info here. The weight reduction is awesome. I would love to take some more weight out of my car but class rules wouldn’t allow without more penalty.

The brake pressure logging is going to be a great bit of data as well. I’m considering adding a sensor in to my aim unit

 

Slightly off topic but yesterday was a success in more ways than one, Wife has a new car and I've potentially got 4WD for the civic if I wanted... 😅 Never expected her to go with a Honda, she was keen on an AMG but test drives can easily change a person's mind!

 

Wife has a new car and I've potentially got 4WD for the civic if I wanted...

Welcome. You will find some of the best in the world here. People capable of getting as technical as you can "imagine". I remember when you first started posting I got the impression that you are pointed and knowledgeable. I have read back and forth on this site and was wondering where you came from? Now I have a better idea. Thank you for your contributions and look forward to more of what you got. Speaking of gotovato he needs better hubs. Might you share if those can be had for him, they look aftermarket and he's made a waste land out of hubs.. I had to comment to get you in my stream. I will say if your planning on boosting the drive train out of your Wifes new car. This would be of great interest to me. I must know how that goes for you.

 

I use OEM hubs, NTN bearings (Front) and longer studs.

Toungue and cheek remark about the CRV drive train, it'll definitely be staying the the CRV.

 

Never expected her to go with a Honda, she was keen on an AMG but test drives can easily change a person's mind!

Now I am curious, what was here experience on both and what specific AMG it was, which lost against a Honda CRV.

 

A line Markus, G was a bit out of reach. 😅

 

Ah, good you didn't. The M133 engine and it successors are no easy engines for maintenance and cost to run it. Especially the turbo does seems to be a princess on the M133 versions, the M139 is still new, we will see how that princess comes out. I wonder how long the CAT survives on these engines.

In German, but think about, your wiifi would have drifted on the way to the grocery, for sure .

 

Ok, so moving on....brakes....

UK hillclimb is rather niche is a sense. All tracks are mostly on private ground which is completely different to the Euro stuff. Runs are relatively short, anything from around 30 seconds to a little over a minute. We don't need monster callipers / discs to cope with heat so the only real focus is having enough breaking force to stop the car from cold.

Quite some time ago i got in touch with AP for spec'ing brakes. I was totally oblivious at the time to what was required to do this properly and thought if i gave them a rough chassis weight / split and application they'd sort me out there and then. For those that don't know, there's far more to it to do this properly than you'd think. Static weight, dynamic weight, brake pad / tyre coefficients, tyre force, CG etc etc, best guess doesn't cut it.

At the time of getting in touch with AP i had stock rear callipers and Stoptech Trophy front BBK. Unfortunately i learned the hard way that a BBK on the front without any bias correction is a big no no and that's what put the car back on axle stands after finding out how easy it is to 180deg when stomping on the anchors. Getting all the correct measurements to spec the brakes at the time wasn't possible so i spoke to a brake specialist and had a set of front / rear brakes made based on expected weight / distribution.

The sexy Stoptechs that did nothing good....

And the replacements....

Criteria given to my brake guy was enough stopping power for a given weight / distribution whilst being mindful of unsprung weight. Handbrake isn't required by reg's for my class so there was a little more freedom with the rears than usual. Setup i've got now consists of Willwood calipers / discs / pads on all four corners and significantly reduced weight on each corner as well. Front is running Midlite calipers with 279*20 discs, rear's are 260x19mm discs with Powerlite calipers, BP10 pads all round. Custom bells were made for the fronts and all 4 corners have carriers machined to suit.

All of this was done pre COVID and the car's not been out since so it's all still to be proven!

This year i decided to pull the finger out and get it back on track for next year, with that decision has come a few intended modifications to get the car to where i want it as an end goal and leave very little on the table for future modifications other than seat time and setup. One of those changes is a serious focus on weight distribution / CG and that means moving my ass further back in the car. To do so means alteration to the steering column to extend it and also relocation of the pedals. Obviously that can't realistically be done with the OE pedal arrangement so i decided on an entry level AP pedal box (very relative, entry AP pedal box costs more than most others mid tier pedal boxes!). I spoke with the dealer about MC sizing and we both had similar thoughts so order was placed and this arrived a few days later......

Initially supplied for cable but i was keen to take advantage of the engine rebuild and move to DBW for various reasons so sensor is also sat on the shelf ready to go.

Despite all good intentions, when the car's rebuilt the braking system will be subject to change. I'm taking things seriously now rather than a go with the flow mentality so once i'm able to take all applicable measurements the system will be reviewed / revised and we can spec it specifically for the car. Might even be able to reduce weight further!

In my last post i talked about suspension. Confirmation of spec has been reached and ill be running DC5 rear hubs on EP3 knuckles (+15mm track width vs EP3), bespoke front arms whilst retaining EP3 knuckles rather than DC5 knuckles (lighter than DC5 knuckles and +55mm max track either side through the arms). The PCI stuff will be sold but i'll be retaining Brians front ARB. Existing front brake carriers will still be good but i'll need to send a rear knuckle / DC5 hub to my brake guy to machine new carriers for the rear. Wheel offset and width / tyre size to be discussed with my race engineer and that needs to happen sooner rather than later so i can start making molds for the wings / arches / fenders (call them what you want!). Weight / CG / Track width, all 3 boxes are being ticked.

Next up, gearbox, then onto the engine....

 

A friend updated his JRSC K20 Elise last year with a dual MC balance bar set-up.
He is very happy with the track performance as now bias can be dialed in to max stopping power without overbreaking the rear. Before he could only change disk sizes and pad compounds. This is much nicer to dial in.

 

Indeed, from what i can gather once the rest of the system is spec'd accordingly then it should be a winner. I've read lots of comments about people trying to use a pedal box and resorting back to stock due to issues sizing MC etc. Doing it the mathematical way rather than best guess hopefully will produce the required result. I know there's a split opinion on various topics regarding theory vs reality but pinnacle motorsport teams don't employ engineers "just because". Once the car's rebuilt, all measurements required will be taken then the system reviewed accordingly. I'll run sensors for bias so we'll be able to dial in braking through the data logs.

Off topic, i hate having conversations with people on a subject i largely know nothing about. I'm the type of person that want's to know the subject matter to make my own informed decisions and not be glossed over by a salesman selling ice to eskimos. Last week i enrolled myself on a Mech.Eng Higher National Certificate to get the ball rolling. It helps with my job but the real motivation is this. End goal is to get BEng/Masters then jump into a motorsports degree. Knowledge=fast lap times!

 

Drivetrain...

Plenty of options available for the K20. stock, OE LSD, MFactory kits, multitude of LSD's, FD options etc. I happened to to be in the right place at the right time a few years ago and bought a PPG 5 speed box from an ex drag racer which was fitted with a 4.3FD and quaife ATB. It had done 6 passes at Santa Pod (main UK 1/4 mile), dyno time and that's it. When it came into my ownership i changed the FD to a 5.83, sold off the ATB and installed an OS Giken spec X LSD. After a few conversations with the USA division of OS Giken the diff was set as per the honda works cars and fitted to the box.

Driving a dogbox was new to me. Making sure revs were matched to prevent kangerooing was foremost in my mind and i felt this distracted me from concentrating on braking / turn / accel. As you can probably tell by now, i've jumped in head first so i'm willing to accept any opportunity to make life easier when feasible. There's a few cars in my class that now run sequential boxes, the difference these make is absurdly apparent. On throttle accel through the gears is undeniably quicker than a std H pattern but there's also more perks to life than just that.

Changing to seq is a substantial investment, these boxes aren't cheap. You've got Quaife, Sadev, Beckert, XTrac etc, not one of them is an easy purchase for an amateur like myself. I've kept my eye on the classifieds for a few years tbh but most (especially Sadev) are bogus adverts. You've got to be really careful when perusing a deal, lot's of scammers about for stuff like this.

When i found out the engine needed a rebuild, i made the decision to invest in a sequential box. The remit was / is to build the car to the highest spec i can (within budget) within the regs.

Quaife was top of the list, mostly due to retaining the original casing (OE mounts) and i could keep the Giken diff. S/H unfortunately was always the wrong ratios or the wrong FD, new price was steep compared to the alternatives and ratios weren't ideal. I've been in touch with Sadev for a few years now and prices have gone up. They do offer a good package but price is at a premium now after Brexit. Xtrac i never looked into TBH but i already had a box in mind...

Over here in the UK there's a company called Satchell Engineering. Colin Satchell (owner) competes in the same class with a Peugeot 205 and has set many records. He's done remarkably well to the extent of getting an invite into the Hillclimb Masters a few years ago (go search on YT for vids). Not only has he designed a great car, he has an eye for quality products. Satchell happen to be the sole UK distributer for Beckert boxes so my ears were peaked. After a little further research, i decided that ratios would suit the application, i could get a 6 speed rather than a 5, the LSD was well proven / fully adjustable & reliability through various applications (Area Motorsport used this box in their circuit endurance build, Colin hillclimbing and various others with rally) was also proven. I had to dig deep but after a few weeks this arrived...

Beckert Evo 1 seq box. This is running their own LSD spec'd for hillclimb and Honda F2 homologated ratios. Top speed will be circa 130mph which i won't see on a UK hillclimb but it leaves the door open to other things, 1-5 is where all the action will be but having 6th won't be a bad thing and box weight of 5spd vs 6spd is insignificant. What matters the most is the gearing. With expected peak HP/TQ of the new engine it'll synchronise with the HP/TQ band nicely and keep the K20 "on the boil" as we say over here. They offer a few different ratios but i decided the Honda F2 ratios would suit best. I could state ratios but you can look this up yourself, it's all relevant to max rpm and that's not something i'll disclose at this point in time but it'll be circa 9.8krpm+. Box weight is 39kg IIRC but i've still to weigh it to confirm.

Downside is it needs bespoke mounts. Both the side mount and rear mount need to be fabricated. The rear is the easy job, it's basically a bushed turnbuckle that needs a mounting point welded to the subframe, the side mount is a little more complex and potentially involves chassis arm modification. The chassis is away to my fabricator next week for a small list of jobs to do and this will be one of them, we'll have a look at it together and decide the best course of action.

Beckert stipulate that all mounts (engine and box) use the same shore rating but after a chat with Satchell, this was really aimed at those who tried to solid mount one area (box side) and ran into issues. The rear turnbuckle and box mounts will fabricated to using Superpro inserts and the engine mount will be innovative 85a. I need to confirm the shore rating of the Superpro bushes but think we'll be good. This one might have to be proven by application rather than best endeavour.

Further to that, driveshafts are bespoke. Once the box is mounted i need to wait for the engine to be built / fitted and all suspension in place to measure for driveshaft length. One step forwards and two steps back in a way.

To make best use out of drivetrain and engine, i've decided to change to DBW. Having already had Kinslers, they were the 1st thought. Converting cable Kinslers to DBW isn't feasible and the new engine will most likely require a set of ITB's that use a smaller ID than Kinsler provide (57mm) and we may take advantage of different inj. position. This is all still TBD pending flow data of the head that will be used but it's highly likely that a set of Jenveys will be fitted. Either way, i decided to go for paddle shift vs stick and eliminate the clutch completely apart from getting off the line. There are a couple of options available on the market but Geartronics won the day. Geartronics has been proven for years, most seq setups here in the UK use them and already having the system controlled by Motec, the decision was a no brainer. Motec offer 3 different packages, GPA, GPR & GPRP, the latter being for paddle shift. Neil@Geartronics teamed up with RDS (Race Data Systems) and basically created their own GPRP package but with far better control. Paddles weigh less than a stick, i can keep both hands on the wheel and the software control is above what Motec can offer - Win win. Always remember, weight means everything...

Additionally, the AIM MXS (Link) Strada dash i had has been sold and i'll be using a Geartronics dash. It less cluttered than the Aim dash, gear position is primary with selectable secondaries, all data logging will be through the M130 which now has Lvl.3 logging enabled (1000hz) and it weighs less. Did i mention weight is key?

Beer coaster vs size of dash...

Clutch & flywheel are probably relevant to this now so i'll mention them as well. The Beckert box uses a Ford spline rather than Honda so a clutch change was required anyway. Previous was an Exedy stage 2(?) 3 puck sprung clutch plate with matching diaphragm combined with an Exedy Race flywheel. Total weight of this setup was over 9kg IIRC. I approached TTV over here in the UK and set out the criteria for clutch / FW spec. After a few conversations, measurements were taken (mostly relative to crank face, bolt height) and we agreed on a suitable setup. FW is their K20 race FW for a 140mm clutch which centralises mass (2.7KG total) and clutch is a 140mm twin plate paddle coming in at 1.89kg. 184mm was initially offered but i'd rather rather have reduced inertia even if the twin 140mm far exceeds the TQ rating of what the engine will be capable of producing. I don't pay lip service to inertia, it has pro's and con's but i'm in the mindset of i will learn to drive it correctly and i'd rather take the mechanical advantage and be forced to deal with it than take the easier route and sacrifice inertia for lack of driver ability.

Next topic is most likely engine and that's a whole other can of worms....

 

This thread is amazing. Thank you for the detailed posts. Keep up that great work!

 

Next topic is most likely engine and that's a whole other can of worms....

I welcome you and all your doing this is a serious car your building. Way beyond me but neat to see what the other half drives.

 

Knowledge=fast lap times!

Indeed, I would add realization of it, as I sometimes have a challenging time to find just the parts and built quality needed for the realization of that knowledge. Budget is not the only constrain, market or fabrication availability and timing is often also a constrain here. But sure knowledge is the basis for all the fab and buy action.

GB has concentrated a lot of racing schools and University courses as well as teams of a very high level and experience. That is an location advantage you have. I wanted to study combustion engines at the TU Munich, but that time there was even no Prof. active on the chair of ICE (headquarter of BMW). Anyway, I've decided to study the basics, thermodynamics and fluiddynamics as well as a lot of practical modeling and simulation as well as test rig development and measurement. I've gathered then further 9 years on an engine OE, which was quite helpfully and valuable.

I had a long way through study, doctorate, OE experience and still didn't know nothing about race engine design. Of course all the way helped me to understand every detail and enabled me to dive deep into all of them, but I think a shorter way should be possible. If I were in your situation, I would go top down, from system to as much details as possible, but always having the system as focus. Everything begin there, understanding details without that is useless, but it is a way of experience coming from top down to understand all the details.

FW is their K20 race FW for a 140mm clutch which centralises mass (2.7KG total) and clutch is a 140mm twin plate paddle coming in at 1.89kg.

Sounds like a progress, making the speed dynamic much more sensitive, which is good on a NA engine of 300+ hp and the need grip as well with your shift system. Durability will suffer, but racing is a compromise .

 

Absolutely Markus, knowledge is only half the battle. If I can utilise my spare time more effectively to achieve a better understanding of how each system works, then I can make better informed decisions myself rather than be solely reliant on what someone else is telling me. I'm in a fortunate position where hobby and work crossover to some extent so the benefit and motivation to do so is easy to see. Ploughing my way through all the maths stuff right now which is reasonably enjoyable in itself but looking forward to the more interesting stuff like thermo & fluid dynamics.


If the car was still going to run on cable and H pattern then I don't think I would have chosen a FW/Clutch setup of this weight, I think it would end up being quite a difficult car to drive. Changing to seq/dbw has opened the door for reducing inertia in this area IMO but I'll need to wait and see how it runs when back out. TQ rating of the clutch far exceeds the box and expected output but lifespan / fatifue and holding capacity are two totally different things I would think, it'll be interesting to see the wear on the plates after a full season...

 

it'll be interesting to see the wear on the plates after a full season...

That EXCEDY didn't seem to beat up. I will be watching this even if I can't afford a bit of it. I'll try to spend my 2 cents elsewhere as not to interrupt.

 

Very little use tbh, majority of its time was spent on the dyno. Very easy clutch to use and ideal for a K20, I think Tom / Gotovato has the same in his car (?).

One thing I didn't realise until the new setup had arrived and the box showed up is the requirement not to use a sprung clutch for the box. Ended up lucky in that regard as I wasn't aware that was a requirement until I read through some notes that came with the box!

 

Ok, so moving on....brakes....

UK hillclimb is rather niche is a sense. All tracks are mostly on private ground which is completely different to the Euro stuff. Runs are relatively short, anything from around 30 seconds to a little over a minute. We don't need monster callipers / discs to cope with heat so the only real focus is having enough breaking force to stop the car from cold.

Quite some time ago i got in touch with AP for spec'ing brakes. I was totally oblivious at the time to what was required to do this properly and thought if i gave them a rough chassis weight / split and application they'd sort me out there and then. For those that don't know, there's far more to it to do this properly than you'd think. Static weight, dynamic weight, brake pad / tyre coefficients, tyre force, CG etc etc, best guess doesn't cut it.

At the time of getting in touch with AP i had stock rear callipers and Stoptech Trophy front BBK. Unfortunately i learned the hard way that a BBK on the front without any bias correction is a big no no and that's what put the car back on axle stands after finding out how easy it is to 180deg when stomping on the anchors. Getting all the correct measurements to spec the brakes at the time wasn't possible so i spoke to a brake specialist and had a set of front / rear brakes made based on expected weight / distribution.

The sexy Stoptechs that did nothing good....

View attachment 114698

And the replacements....

View attachment 114699

View attachment 114700

View attachment 114701

Criteria given to my brake guy was enough stopping power for a given weight / distribution whilst being mindful of unsprung weight. Handbrake isn't required by reg's for my class so there was a little more freedom with the rears than usual. Setup i've got now consists of Willwood calipers / discs / pads on all four corners and significantly reduced weight on each corner as well. Front is running Midlite calipers with 279*20 discs, rear's are 260x19mm discs with Powerlite calipers, BP10 pads all round. Custom bells were made for the fronts and all 4 corners have carriers machined to suit.

All of this was done pre COVID and the car's not been out since so it's all still to be proven!

This year i decided to pull the finger out and get it back on track for next year, with that decision has come a few intended modifications to get the car to where i want it as an end goal and leave very little on the table for future modifications other than seat time and setup. One of those changes is a serious focus on weight distribution / CG and that means moving my ass further back in the car. To do so means alteration to the steering column to extend it and also relocation of the pedals. Obviously that can't realistically be done with the OE pedal arrangement so i decided on an entry level AP pedal box (very relative, entry AP pedal box costs more than most others mid tier pedal boxes!). I spoke with the dealer about MC sizing and we both had similar thoughts so order was placed and this arrived a few days later......

View attachment 114702

Initially supplied for cable but i was keen to take advantage of the engine rebuild and move to DBW for various reasons so sensor is also sat on the shelf ready to go.

Despite all good intentions, when the car's rebuilt the braking system will be subject to change. I'm taking things seriously now rather than a go with the flow mentality so once i'm able to take all applicable measurements the system will be reviewed / revised and we can spec it specifically for the car. Might even be able to reduce weight further!

In my last post i talked about suspension. Confirmation of spec has been reached and ill be running DC5 rear hubs on EP3 knuckles (+15mm track width vs EP3), bespoke front arms whilst retaining EP3 knuckles rather than DC5 knuckles (lighter than DC5 knuckles and +55mm max track either side through the arms). The PCI stuff will be sold but i'll be retaining Brians front ARB. Existing front brake carriers will still be good but i'll need to send a rear knuckle / DC5 hub to my brake guy to machine new carriers for the rear. Wheel offset and width / tyre size to be discussed with my race engineer and that needs to happen sooner rather than later so i can start making molds for the wings / arches / fenders (call them what you want!). Weight / CG / Track width, all 3 boxes are being ticked.

Next up, gearbox, then onto the engine....

Almost nothing inspires driver confidence like a responsive and consistent brake pedal. So many focus on "BBK" regardless of brake bias, pedal feel, MC sizing, any of it! I can really appreciate your in depth approach here. Races can be won or lost all over the brakes!

I look forward to hearing how the new setup works for you. With the runs you do that little wilwood kit should be good. Your car is light as well which is awesome.

I know you're ditching the stoptech setup but i must say i have been more then happy/impressed with my stoptech C43 kit. Bias is perfect, rotor sizing is "smaller" compared to other kits but the setup really is effective and light weight.

Much of your build to me screams "unlimited time attack spec" and im loving it. We dont see many NA builds of this caliber around here. Now to catch up with your lastest post...

 

Almost nothing inspires driver confidence like a responsive and consistent brake pedal. So many focus on "BBK" regardless of brake bias, pedal feel, MC sizing, any of it! I can really appreciate your in depth approach here. Races can be won or lost all over the brakes!

I look forward to hearing how the new setup works for you. With the runs you do that little wilwood kit should be good. Your car is light as well which is awesome.

I know you're ditching the stoptech setup but i must say i have been more then happy/impressed with my stoptech C43 kit. Bias is perfect, rotor sizing is "smaller" compared to other kits but the setup really is effective and light weight.

Much of your build to me screams "unlimited time attack spec" and im loving it. We dont see many NA builds of this caliber around here. Now to catch up with your lastest post...

The Stoptech kit I thought was really well made, it was my own fault for not thinking that I'd need to change the bias vs stock. Easiest lessons learned seem to come the hard way! On the plus side, between wheel / tyre change and brakes, I think I dropped around 20kg unsprung weight between all four corners. I think I'll be able to run smaller rear calipers / 2 pot but only time will tell.

I get the reference to TA but obviously there's some major differences. Aero, cc, etc. Whole approach to the car now is to get it to a state I'm happy with that I don't have to revisit areas in the future. Do it right - do it once. Setup / seat time / fun is the only focus I want once it's back up and running. Engine will require frequent inspection intervals but that's all part of the game. Really looking forward to getting back in it and hopefully this time it'll be plain sailing rather than issues!