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Hello k20a.org! Pardon the long post!

Short background:
Been driving VAG-based cars in various offroad competitions for over 5 years now. We have quite a reasonable amount of experience in engine building and tuning, however all of our experience has been with the VW/Audi 4cil platform. The past three seasons our cars have been running properly built N/A engines running on E85 with ITB's and DIY megasquirt EFI.

The amateur rally competition we're currently running in regulates N/A engines with a maximum of 4 cilinders, the regulations are pretty much free after that.

The problem we have with the VAG platform is that it's basically one of the worst bases to start a proper built engine from (but 90% of competitors drove em and parts were widely available, hence the original choice). We would like to built an engine that'll put out ~270 hp / 270Nm at the flywheel, which on a VAG platform will set you back at least $10K and some serious reliability issues.

The biggest problem we have with this is that the way we drive the cars in this rally class, there's a chance we'll make a big shunt about once a season, which more often than not trashes an engine beyond repair. (No ARP rod bolts or upgraded oil pump is gonna protect your engine from landing upside down in a road-side pond so to speak). So the cheaper it is to replace the engine with another spare one, the better.

Current situation:
After spending some time looking into 2.3L Ford Duratec engines, I spoke to an old buddy last weekend who told me to look into the k-series, which is what I've been doing here at k20a.org for the past few days. And I like what I see so far ;). So in just three days time I've read through quite some FAQs and dyno sheets, but most of the builts here seem to be starting at 250WHP and above!

Due to the amount of spare parts/LSD we have we will make an adapter plate to bolt our VAG transmission to whatever engine we use.

The K-serie plan:
-The main goal: 270hp/270nm flywheel, which should translate to somewhere around 235WHP / 235WNm (175WTQ lbft)
-I don't see many K20A2's available here in the Netherlands, but came across some K24A3's, which should have the same bottom end as the US K24A2 but with the "2 lobe" half-assed VTEC head right?
-We still have a set of Jenvey 45mm DCOE ITB's
-Still have two megasquirt2 systems, and are able to get a DTA S80Pro for a bargain

Planned setup:
-K24A3 block
-Wiseco 1:13,7 pistons
-K24A3 head, as bone stock as possible
-E85 fuel
-45mm ITB's, stacks, airbox, CAI
-adequate exhaust headers, 3" exhaust I guess?
-MS2 or DTA S60/S80 ECU
-eventually dry sump it
-revlimiter maximum 8000rpm

Questions:
-How close to our goal will the above "budget" setup get us?
-Will we be needing a set of rods?
-What intake manifold to get for the DCOE jenveys? I only seem to come across TODA-style complete intake sets that use four bolts per ITB for the intake mounting.
-If we don't reach our goal;
-Will we be needing a set (or only intake) cams?
-How big is the VTEC-E problem? Is it possible to lock the solenoid in place thus always engaging every intake valve from idle onwards? I've got no clue about what duration and lift those stock cams run....
-The K24A3 head doesn't have VTC right?
-Are we really required to mount a K20A2 head to get proper power? The reason I'd rather not do this this season is the availability of these heads, the price that comes along with building the frankenstein (and we'd need to source two to have a spare engine....). And as far as I can tell to use the VTC we would then need to swap the ECU to a Hondata K-Pro??
-If we keep the revlimiter at maximum 8000rpm, will the K24 oil pump hold or will we still need the K20A2 one? The plan is to dry-sump it later on (any advice on good dry-sump pumps?), but that $1000 pricetag might push that back a season.

Again, sorry for the long post and many questions, please school these Honda noobs and pursuade us into taking a K-series out rallying!

Thanks for all of your input!
 

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45mm throttles are far too small. Back in 2005 a member on this site or clubrsx, I cant remember, tested 48mm ITBs on a K20 with bolt ons and as far as I remember he lost power vs the already poor stock manifold..

The kind of power level you want can be done with ease. A North American K24a2 2006-2008 TSX longblock could make those kind of numbers with the appropriate "bolt ons". A set of rods. a piston with 13.7:1 compression and the correct cam and expect to see that number rise to the 280whp/210 ft/lb range. If built correctly with good parts and you keep it below 8000rpm I would expect it to live a long time
 

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you can use the A3 head with a VTEC killer setup. It has VTC and everything, so it will be like running in VTEC all the time. Sounds like it's not going to see low RPM's very often anyway, so that's what I would do. You don't need an A2 head to make the power in the upper half of the RPM range. 235 wheel horsepower is very very attainable with the stock bottom end... no aftermarket rods are required. K pro will probably be the ECU you would want to reach your goals...
 

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Your going to need bigger injectors for e85. Some 1000s should do the trick. I have a set for sale if your interested.
 

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Discussion Starter · #8 · (Edited)
Thanks for all the replies, love this forum. Lot of activity and informative posts!

you can use the A3 head with a VTEC killer setup. It has VTC and everything, so it will be like running in VTEC all the time. Sounds like it's not going to see low RPM's very often anyway, so that's what I would do. You don't need an A2 head to make the power in the upper half of the RPM range. 235 wheel horsepower is very very attainable with the stock bottom end... no aftermarket rods are required. K pro will probably be the ECU you would want to reach your goals...
edit: just found out the k24a3 runs the 25* VTC, I thought it had no VTC at all.

The VTEC killer will lock the vtec-e so it will always run on both intake valves? Will look up what this "killer" setup exactly means...
Have come accross some TODA rocker arm plugs for K20 heads, are these enough or does it involve swapping to different style cams as well?

RBC/RRC manifold should be good enough for your power goal
RBC is a OEM Honda manifold, and RRC is Aftermarket available through Honda dealerships as far as I understood. Is the RBC attached to a stock K24A3 or will that be a totally different manifold?
What TB size would I need to attach to it, 70mm?

the tsx int. cam can be reworked to .500" lift and 244 degrees and eliminate the primary lobes , use a dogbone rocker , i just did this and works well
Dogbone rocker currently doesn't ring any bells, will look that one up.

Your going to need bigger injectors for e85. Some 1000s should do the trick. I have a set for sale if your interested.
Injectors propably won't be the problem, we have a fair amount of injector sizes available from our previous E85 endeavours. Although by my calculations ~650-750cc injectors would be sufficient for up to 300flywheel HP on E85?

Thanks again for the replies, I'll just keep adding questions ;)
 

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Just wanted to mention that if you're planning on running the k24a3 and gonna rev to 8k rpm's i would highly suggest aftermarket valvetrain. If not keep it under 8k just to be safe. As far as p2v with those 13.7 wiseco's it's my understanding you should always clay the motor anyways to see how many degrees you can go. As far as injectors, i'd go with something like an Injector Dynamics 725cc. People are recommending them for a reason. RC's are based on an old Lucas based design and have a less optimal spray pattern. I'd recommend RDX injectors but with E85 i don't know if it could handle the power you're looking for...or could it?
 

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Yeah that setup with a proper cam is going to make WAY more power than your goals. I'd suggest since you're racing it the way you are that you don't rev over 8000 rpms.

if you don't want to change the VTC gear to one with 50 degrees of angle adjustment, just use a cam that prefers max VTC at 30 and you should make great power.

If you're running E85 that engine is going to need exactly what people above said for injectors, 725cc or larger.

No, RDX injectors can't handle a k20 at 230 whp with E85, so definitely not this setup.

You'd have to modify them (similar to OEM k injectors, which makes them piss like a garden hose...)
 

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The k24a3 (accord type-s in europe) is the same engine as the k24a2 from the Acura TSX in the states.

It does not have e-vtec, it has the proper i-vtec (dohc vtec + vtc). It can use the same cams and valvetrain as the K20A, but the head does not flow as much in stock form.

If you cant afford camshafts, valvetrain and such, don't buy ITBs. By the excessive manifold and cams instead :)

Also you should change to the type-r (k20a) oil pump, and make sure to get some baffles in the oil sump so the the pump does not starve in the corners. With this the engine can handle over 8000 (over 8500 with proper rods or just rod bolts).

Do you drive Rally or Rallycross?

I am building a K23A3 for a customer than will compete in the Norwegian Rallycross Championship.

If you have questions feel free to email me at: karl-kristian (at) nyborg-garage (dot) no
 

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Thanks for all the replies, love this forum. Lot of activity and informative posts!


edit: just found out the k24a3 runs the 25* VTC, I thought it had no VTC at all.

The VTEC killer will lock the vtec-e so it will always run on both intake valves? Will look up what this "killer" setup exactly means...
Have come accross some TODA rocker arm plugs for K20 heads, are these enough or does it involve swapping to different style cams as well?
yeah, VTEC killer essentially always runs your valves as if they're always in VTEC. You don't need the low RPM's anyway since you're racing. I believe you just need the full VTEC Cams... pretty cheap to source from a lotta different vehicles.
RBC is a OEM Honda manifold, and RRC is Aftermarket available through Honda dealerships as far as I understood. Is the RBC attached to a stock K24A3 or will that be a totally different manifold?
What TB size would I need to attach to it, 70mm?
Both RBC/RRC are OEM units. RBC comes from our USDM 06-11 Civic Si. The RRC came from the Japanese Civic Type-R. K24A3 has a manifold that is great for low end torque but is going to be pretty terrible for high end power.
One intake manifold that deserves some mention is the manifold from the Euro Civic Type-R FN2 chassis. It's the RSP chassis and has been shown to be pretty promising.

70mm TB would probably be a good upgrade to achieve the power you are wanting.

Here's a thread with some interesting material on vtec killer
http://www.k20a.org/forum/showthread.php?t=66643&page=34
 

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if your K24A3 is the equivalent of our K24A2 then you don't need much to achieve your power goals.

I achieved 237whp 187wtq with the following mods.
93 pump gas
12.5:1 supertech pistons
stock head with type-s cams
rbc manifold with port matched 70mm throttle body
R-crew header 3" exhaust
Type-s oil pump

from there to try E-85 I installed some import builders stage3 cams & ID1000cc injectors
and replaced the header with an ASP big tube 4-1 collector with megaphone
it makes 274WHP & 202WTQ.

as you see it's not hard to make power with K24 engines. just select the right compression pistons for your fuel,But your goals are achievable with pump gas. leave the head alone but change the intake manifold & throttle body to no less than 70mm, if you want the engine to make power on the top rpm. the oil pump must be changed to a type-s if you do not want to take chances past 7600rpm. or dry sump it.

my other engine is a K24a4 9:7.1 bone stock with type-s cams in vteckiller mode and 25 degree vtc to avoid piston to valve contact with the factory K24a3 pistons. I haven't dyno it, but it feels like it makes low 200whp or close to it maybe around the 180 whp torque. but it's a blast to drive there is plenty of torque every where thru the rpm range.

i wouldn't be surprised if your engine in it's current form gets really closed to your power goals by just replacing the oil pump so you can rev it to 8,000rpm & replacing the oem manifold & throttle body. i would give it a shot.
 

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Discussion Starter · #14 · (Edited)
thanks again for the replies guys, little update:

(We kinda bit the bullit!) If everything goes according to plan, we will be buying an slightly modded engine soon. Engine should be a good base for this project:

K24A3 stock bottom end
K20A2 oil pump
K24A3 stock head
K20A2 cams, 50* VTC
double valve springs+retainers K20A2
RRC intake manifold

Seeing all your reactions to our power goals, I'm thinking about running the revlimiter at 7500-7600 rather than the 8000 I mentioned above. I get the feeling this will still allow us to reach our power goals (and gearing shouldn't be a problem since final drive ratio will be chosen and mounted after engine is tested and built).
I want to do this since " torque doesn't kill engines, revs do".

Things on my to-do list as far as I'm aware right now:
-13:7 wiseco's
-new OEM crank/rod bearings (have to check out the whole color-thing)
-baffle the sump
-clay engine for VTC
-put "new style" dogbone exhaust rockers at inlet valves so all intake valves run on the center high lobe on K20A2 cam (any partnumbers for this, or am I understanding this wrong) what about vtec on exhaust side?
-70mm TB (adapt the RRC manifold to 70mm, check if it needs to be ported at head-side)
-injectors + fuel rail etc. (1000cc)
-exhaust header

Questions still remaining:
with this setup,
-will rods still be ok
-will k20a2 springs be ok
-what about the cam chain tensioner thing
-anything else I'm completely missing? please tell!
 

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The only thing that happens if you lock the engine in vtec mode is that you LOOSE tons of torque below where you would normal engage vtec (~4500rpm).

The guys that are talking about doing this and using k20a cams are talking about a different engine that do not have proper vtec.

Your engine have the same vtec system as the k20a "type-r" engine, except that it originally have only 25deg vtc.

Actually i'm not shure there even was a point of chaning out the the cams. I believe to have read that the TSX engine (k24a2) have a bigger exhaust cam than the k20a2(??).

I am not 100% (maybe 97%) sure that the K24A2 from the TSX and the K24A3 from the euro accord type-s are exactly the same. But they have the same casting on the block and head, they have the compression ratio, they have the same vtec system, and they have the same power output.

So I am 100% sure that it has the proper DOHC VTEC system, and not the economy version that some other honda engines have.

The 50deg will probably give you more midrange, but make sure you have enough clearance for it (valve to valve, and valve to piston clearance).

The OEM Honda chain tensioner is the safest choise.

7800rpm should not be a problem, even on stock rod bolts (this is what I would consider the weakest link on your build, with better rods (bolts) 8500rpm should be no problem).

Also, with 13.7:1 pistons and "small" k20a2 cams the dynamic compression will be very high before vtec engages, and maybe even in vtec mode. So that even on "pump" E85 fuel you might have to retard the ignition some to avoid knock/pinging. Off course for a professional tuner this is no problem.

I would not use any smaller cams that drag cartell 2.2 or 4piston road race cams, and cams like that should give you a lot more power than the stock "200hp" cams on this 2400cc high compression engine. On my similar build I am using MUCH bigger cams (and because of the i-vtec system i should not loose any torque/power because of this)

But off course this would cost quite a bit extra (cams and valvetrain is about $1500)

It been a while since I was reading up on the OEM intake manifolds, but I believe that at least a 72mm throttle body should not be a problem, and those two extra mm should equal to a few extra hp.
 

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The only thing that happens if you lock the engine in vtec mode is that you LOOSE tons of torque below where you would normal engage vtec (~4500rpm).

The guys that are talking about doing this and using k20a cams are talking about a different engine that do not have proper vtec.

Your engine have the same vtec system as the k20a "type-r" engine, except that it originally have only 25deg vtc.

Actually i'm not shure there even was a point of chaning out the the cams. I believe to have read that the TSX engine (k24a2) have a bigger exhaust cam than the k20a2(??).

I am not 100% (maybe 97%) sure that the K24A2 from the TSX and the K24A3 from the euro accord type-s are exactly the same. But they have the same casting on the block and head, they have the compression ratio, they have the same vtec system, and they have the same power output.

So I am 100% sure that it has the proper DOHC VTEC system, and not the economy version that some other honda engines have.

The 50deg will probably give you more midrange, but make sure you have enough clearance for it (valve to valve, and valve to piston clearance).

The OEM Honda chain tensioner is the safest choise.

7800rpm should not be a problem, even on stock rod bolts (this is what I would consider the weakest link on your build, with better rods (bolts) 8500rpm should be no problem).

Also, with 13.7:1 pistons and "small" k20a2 cams the dynamic compression will be very high before vtec engages, and maybe even in vtec mode. So that even on "pump" E85 fuel you might have to retard the ignition some to avoid knock/pinging. Off course for a professional tuner this is no problem.

I would not use any smaller cams that drag cartell 2.2 or 4piston road race cams, and cams like that should give you a lot more power than the stock "200hp" cams on this 2400cc high compression engine. On my similar build I am using MUCH bigger cams (and because of the i-vtec system i should not loose any torque/power because of this)

But off course this would cost quite a bit extra (cams and valvetrain is about $1500)

It been a while since I was reading up on the OEM intake manifolds, but I believe that at least a 72mm throttle body should not be a problem, and those two extra mm should equal to a few extra hp.
The K24A3 is not the same as teh K24A2. It has the single lobe exhaust cams... and running the K20A cams is the whole point to vtec killer. He doesn't need the extra torque under 4500 RPMs as it will stay above that point for most of racing, and it's not as if the torque is completely dead under it. It will have plenty, just not as much. He also stated that he will be claying the VTC for P2V clearance, so that would take care of him there also. I think he's headed in the right direction for what he's wanting to do.
 

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The only thing that happens if you lock the engine in vtec mode is that you LOOSE tons of torque below where you would normal engage vtec (~4500rpm).

The guys that are talking about doing this and using k20a cams are talking about a different engine that do not have proper vtec.

Your engine have the same vtec system as the k20a "type-r" engine, except that it originally have only 25deg vtc.

Actually i'm not shure there even was a point of chaning out the the cams. I believe to have read that the TSX engine (k24a2) have a bigger exhaust cam than the k20a2(??).

I am not 100% (maybe 97%) sure that the K24A2 from the TSX and the K24A3 from the euro accord type-s are exactly the same. But they have the same casting on the block and head, they have the compression ratio, they have the same vtec system, and they have the same power output.

So I am 100% sure that it has the proper DOHC VTEC system, and not the economy version that some other honda engines have.

The 50deg will probably give you more midrange, but make sure you have enough clearance for it (valve to valve, and valve to piston clearance).

The OEM Honda chain tensioner is the safest choise.

7800rpm should not be a problem, even on stock rod bolts (this is what I would consider the weakest link on your build, with better rods (bolts) 8500rpm should be no problem).

Also, with 13.7:1 pistons and "small" k20a2 cams the dynamic compression will be very high before vtec engages, and maybe even in vtec mode. So that even on "pump" E85 fuel you might have to retard the ignition some to avoid knock/pinging. Off course for a professional tuner this is no problem.

I would not use any smaller cams that drag cartell 2.2 or 4piston road race cams, and cams like that should give you a lot more power than the stock "200hp" cams on this 2400cc high compression engine. On my similar build I am using MUCH bigger cams (and because of the i-vtec system i should not loose any torque/power because of this)

But off course this would cost quite a bit extra (cams and valvetrain is about $1500)

It been a while since I was reading up on the OEM intake manifolds, but I believe that at least a 72mm throttle body should not be a problem, and those two extra mm should equal to a few extra hp.
I would never spin an oem k24 to 8500. Hell if I had a built bottom end I still wouldn't turn it past 8500
 

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The K24A3 is not the same as teh K24A2. It has the single lobe exhaust cams... and running the K20A cams is the whole point to vtec killer. He doesn't need the extra torque under 4500 RPMs as it will stay above that point for most of racing, and it's not as if the torque is completely dead under it. It will have plenty, just not as much. He also stated that he will be claying the VTC for P2V clearance, so that would take care of him there also. I think he's headed in the right direction for what he's wanting to do.
Do you have a euro spec K24A3 in your garage? Also, what car in the US came with a K24A3?

Here is mine: https://www.facebook.com/media/set/?set=a.10151237023882028.512041.285901672027&type=3

That sure looks like vtec on intake and exhaust to me.

I said the part about checking clearances because you can not check valve to valve with clay.

I agree that you would not loos that much torque, especially since he has so much compression for the small cams. But since I believe that he as dohc vtec, it would be extra work and money just to loose torque, which would be pointless.

Also i have spoke to a few rally and rallycross drivers that what as broad power band, and as much torque as possible down low with smooth and predictable power delivery all the way down to 2500rpm (without loosing to much up top) because they often drive on on track with so little grip (mud, snow, and so on) that they want to have the ability to run two gears higher than you normally would with good gip because the car is often easier to control this way. (you still have so much power that you are struggling with the grip because there is so little of it).

As far as the RPM goes I said 7800 for stock block with k20a oil pump, and 8500 with proper rods (preferably with 7/16 bolts).
I don't think it should be a problem since many are doing more than this, but maybe it is. I have not tested it, yet.

As for the original post, 270NM at the flywheel or 235nm at the wheels I think is a very good and realistic goal. But when you say you want 270hp, do you realize that this means that you want a nice flat torque curve up until 7121rpm, and then you want the torque to fall/dropp fast?

If the torque curve keeps on going relatively flat, and the engine can handle more than 7200rpm, there is no point in stopping there. It will only make the car faster, and this is because it allows you use the lower gear for a longer time.
 
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