Honda / Acura K20a K24a Engine Forum banner
1 - 14 of 14 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter · #1 ·
Hey Guys, I’m new to Honda motors and I may ask some dumb questions but I need help. I’m sick of the bike engine in my race car and I’ve decided to pick up a K24 with a boxster 5 speed transaxle and get the adapter plate from Kennedy. I’ve gotten this far and I need some help with the details. First off anyone who has a K24 in a race car or kit car and have gone through this please share your experience and let me know what may save me time and money.

first Q is about the ECU, should I get a factoryRSX ECU and get it running with that or should I get a stand alone ECU? My plan initially is to run NA with bolt ons then possibly turbo in the future.

little info on my car, it’s a formula Jedi formula 1000 chassis converted to a prototype body car. It weighs 800lbs wet. I’ve owned the car for 2 years and haven’t enjoyed more than 1lap under power due to clutch issues with the gsxr1000. I’m finished with the bike motor and ready for k24 power!
104179

104180
Tire Hood Automotive tire Vehicle Wheel
Vehicle Car Motor vehicle Automotive tire Hood
 

·
Premium Member
Joined
·
10,576 Posts
Ok, first and foremost, what's the budget here. If it's in there don't bother with a factory based ecu. Much more tuning control with a full stand alone. Personally I'd go with a company that will easily integrate into a dash display, lose analog gauges altogether at that point and have a pseudo can network to run with. With that sort of chassis, traction may or may not be an issue. I thought there were stand alones that can handle that as well.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #3 ·
Ok, first and foremost, what's the budget here. If it's in there don't bother with a factory based ecu. Much more tuning control with a full stand alone. Personally I'd go with a company that will easily integrate into a dash display, lose analog gauges altogether at that point and have a pseudo can network to run with. With that sort of chassis, traction may or may not be an issue. I thought there were stand alones that can handle that as well.
Great point. My budget isn’t huge. It’s more a matter of how fast can I get it running and on track vs spend more over longer periods of time. I eventually want to change over to the AIM formula wheel with the screen on it. Get rid of all other gauges. I don’t have the budget for motec. I can afford to do a hondata or something like that. I can’t see myself ever running TC. My goal is to make around 250whp then if I think it’s time to take it to the next level I may spend more over the long term.
 

·
Premium Member
Joined
·
10,576 Posts
I see a dash in there now, I'll do a bit more looking about to familiarize myself with the options. It's been too long now since I've had a look. I vaugely remember outputs for a dash in say the hondata stuff but I don't remember.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #5 ·
I see a dash in there now, I'll do a bit more looking about to familiarize myself with the options. It's been too long now since I've had a look. I vaugely remember outputs for a dash in say the hondata stuff but I don't remember.
Yes there is an AIM old school dash that works fine. I’ll probably use this initially. I’m thinking of getting the hybrid racing universal wire harness (electrical is my weakness). If I initially go with a Honda ECU can they still be flashed?
 

·
Premium Member
Joined
·
10,576 Posts
Yes, we'll sort of, but in different ways. Depends on the ecu you want to go with, either direct flashes or using a daughter board installed onto the factory board.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #7 ·
Yeah if I have to buy more stuff it makes more sense to buy a reasonable stand alone. My friend owns a performance shop with a dyno so I’ll ask him what platform his tuner uses
 

·
Arouse the DAMPFHAMMER!
Joined
·
8,024 Posts
Welcome on board Kgermanton!

little info on my car, it’s a formula Jedi formula 1000 chassis converted to a prototype body car. It weighs 800lbs wet. I’ve owned the car for 2 years and haven’t enjoyed more than 1lap under power due to clutch issues with the gsxr1000. I’m finished with the bike motor and ready for k24 power!
That is a very exciting race series. I love the sound of the high revving bike engines. The transmissions make issues on the torque "echo" from the axle due to the higher chassis weight and huge traction advantage compared to an 2-wheel bike. I was a developing an 1600 ccm K-series engine for a race series, in which normally 1600 ccm GSXR stroked engines are used, which showed after 2-4 races transmission issues. The cut out of that dependency of engine and gearbox was another 1600 ccm engine basis. The Honda B-series would be nice, but limited on the head. The K-series head is almost to big, but open for up to 280 hp, if right designed, a perfect circuit warrier. Anyway, I love that high revving stuff.

The K24 will have no issues on that light chassis, but I don't recommend it, especially if manual shifted. The maximum rational engine speed limit at around 7800 rpm for high speed circuit engines (forged internals, dry sump high flow pump) will be reached so easily that shifting time is the biggest concern during acceleration, when the gear ratios are matched for the track correctly. Not the rod bolt forces are the problem, which limit the redline, these are the side forces on the piston-liner-system and unbalanced forces of the crank drive, which makes no bigger issue in drag disciplines, but on continuous operation at that level. I would at least recommend using an 86x86 engine (2000 ccm) or even better the 87x84 (2000 ccm) to have more revving capability for rational time sequences between the shifts. The K-series head design is much better suited for the 500 ccm/cylinder of the 86 mm stroke engine as for the 99 mm stroke engine. Necessary port work makes it more expensive.

My colleague, with whom I do race engine development, did built a Yamaha-VAG-1-Liter-Hybrid NA engine with 200 hp/Liter, this gives the option to include that block with OEM flange brackets for FWD or RWD drivetrains and to open that weak link transmission thing. Just another option.

When K24, then only a fast acting double clutch or flat shift sequential, otherwise it won't be funny to drive that thing.

first Q is about the ECU, should I get a factoryRSX ECU and get it running with that or should I get a stand alone ECU? My plan initially is to run NA with bolt ons then possibly turbo in the future.
Depends on what you are demanding. I would highly recommend a standalone like AEM, MoTec or any other capable ECU with an VE based fuel model, a good transient fuel model and a capable anti-knock-method. The OEM Honda ECU is it definitely not for such a fast gearing setup. The stock lambda probe won't be fast enough to follow during shifts, the knock model isn't worth a penny as it acts as fuel quality model and the transient fuel model is a single factor, which need load, engine speed and ECT as inputs. The ECU and tuning is definitely not a place to safe money on such a car and application.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #9 ·
Welcome on board Kgermanton!

That is a very exciting race series. I love the sound of the high revving bike engines. The transmissions make issues on the torque "echo" from the axle due to the higher chassis weight and huge traction advantage compared to an 2-wheel bike. I was a developing an 1600 ccm K-series engine for a race series, in which normally 1600 ccm GSXR stroked engines are used, which showed after 2-4 races transmission issues. The cut out of that dependency of engine and gearbox was another 1600 ccm engine basis. The Honda B-series would be nice, but limited on the head. The K-series head is almost to big, but open for up to 280 hp, if right designed, a perfect circuit warrier. Anyway, I love that high revving stuff.

The K24 will have no issues on that light chassis, but I don't recommend it, especially if manual shifted. The maximum rational engine speed limit at around 7800 rpm for high speed circuit engines (forged internals, dry sump high flow pump) will be reached so easily that shifting time is the biggest concern during acceleration, when the gear ratios are matched for the track correctly. Not the rod bolt forces are the problem, which limit the redline, these are the side forces on the piston-liner-system and unbalanced forces of the crank drive, which makes no bigger issue in drag disciplines, but on continuous operation at that level. I would at least recommend using an 86x86 engine (2000 ccm) or even better the 87x84 (2000 ccm) to have more revving capability for rational time sequences between the shifts. The K-series head design is much better suited for the 500 ccm/cylinder of the 86 mm stroke engine as for the 99 mm stroke engine. Necessary port work makes it more expensive.

My colleague, with whom I do race engine development, did built a Yamaha-VAG-1-Liter-Hybrid NA engine with 200 hp/Liter, this gives the option to include that block with OEM flange brackets for FWD or RWD drivetrains and to open that weak link transmission thing. Just another option.

When K24, then only a fast acting double clutch or flat shift sequential, otherwise it won't be funny to drive that thing.

Depends on what you are demanding. I would highly recommend a standalone like AEM, MoTec or any other capable ECU with an VE based fuel model, a good transient fuel model and a capable anti-knock-method. The OEM Honda ECU is it definitely not for such a fast gearing setup. The stock lambda probe won't be fast enough to follow during shifts, the knock model isn't worth a penny as it acts as fuel quality model and the transient fuel model is a single factor, which need load, engine speed and ECT as inputs. The ECU and tuning is definitely not a place to safe money on such a car and application.
I should have Been more clear on what the car will be used for. I’m planning on doing time attack or NASATT super unlimited. I don’t plan on racing the car wheel to wheel, it’s simply too small. The K 24 performs fine for circuit racing. The only worry I have is oil starvation. The only two engines I can think of that will survive hi G forces stockAre the Honda K-series and the BMW motors. As for shifting I can’t afford a sequential so the Porsche manual transaxle is the only option.
 

·
Arouse the DAMPFHAMMER!
Joined
·
8,024 Posts
The K 24 performs fine for circuit racing
Sure it does, my point was elsewhere.

The only worry I have is oil starvation. The only two engines I can think of that will survive hi G forces stockAre the Honda K-series and the BMW motors.
There is no other easy going receipt against oil starvation then a dry sump oil system. No wet sump system can hold the acceleration forces of an formula engine with 1000 lbs and maybe the same in downforce. You can bring that oil starvation issue up in a simple Lotus Elise with semi slicks and no additional downforce as stock. I saw even Civic EP3, hill climb application, which had oil starvation with an baffle kit had in slow corners oil starvation, damaging the engine. Your worries are right. Dry sump kits costs above 2000 USD.

As for shifting I can’t afford a sequential so the Porsche manual transaxle is the only option.
VAG DQ250 or BMW DCT would be an option, just the SW integration has to be solved. Here in Europe some companies solved that already: MaxxECU, ECUMaster and so on...

From my experience, your budget should be more 7000 USD (w/o dry sump) for the good performing at least one season lasting system, based on a 100.000 miles K24A2, incl. overhaul (only OEM parts), blue printing, chassis engine integration, chassis harness integration all done yourself and external custom exhaust, standalone ECU and tuning. This would be typical to have something ready to race. As always complications came up the budget exceed bandwidth should be 2000 USD. If you let do it the DIY marked stuff external, then plus labor, which is around 2500 USD you should supply a budget of 9500-11500 USD (w/o dry sump kit).

My goal is to make around 250whp
Not based on a stock NA engine and the budget mentioned above. You need an higher CR and aftermarket cams, adding at least 2200 USD, labor is almost the same when overhauling it. Finally for ready to rumble fun to drive 250 whp K-series NA engine in that chassis you will throw 13700 USD, maybe with used parts for ECU, harness and dry sump kit 10500 USD. Far less is more effort and compromise on your side, and will be most likely less reliable.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #11 ·
Sure it does, my point was elsewhere.

There is no other easy going receipt against oil starvation then a dry sump oil system. No wet sump system can hold the acceleration forces of an formula engine with 1000 lbs and maybe the same in downforce. You can bring that oil starvation issue up in a simple Lotus Elise with semi slicks and no additional downforce as stock. I saw even Civic EP3, hill climb application, which had oil starvation with an baffle kit had in slow corners oil starvation, damaging the engine. Your worries are right. Dry sump kits costs above 2000 USD.

VAG DQ250 or BMW DCT would be an option, just the SW integration has to be solved. Here in Europe some companies solved that already: MaxxECU, ECUMaster and so on...

From my experience, your budget should be more 7000 USD (w/o dry sump) for the good performing at least one season lasting system, based on a 100.000 miles K24A2, incl. overhaul (only OEM parts), blue printing, chassis engine integration, chassis harness integration all done yourself and external custom exhaust, standalone ECU and tuning. This would be typical to have something ready to race. As always complications came up the budget exceed bandwidth should be 2000 USD. If you let do it the DIY marked stuff external, then plus labor, which is around 2500 USD you should supply a budget of 9500-11500 USD (w/o dry sump kit).

Not based on a stock NA engine and the budget mentioned above. You need an higher CR and aftermarket cams, adding at least 2200 USD, labor is almost the same when overhauling it. Finally for ready to rumble fun to drive 250 whp K-series NA engine in that chassis you will throw 13700 USD, maybe with used parts for ECU, harness and dry sump kit 10500 USD. Far less is more effort and compromise on your side, and will be most likely less reliable.
You bring up a lot of really great points and I really appreciate it. It’s great to have people to bounce these ideas around with.

I will be able to do all the fabricating myself so that will save some money. I’m planning on using an S 2000 stock header and adapting it to a K 24 flange. I think the hybrid racing universal wire kit is only $200. You are correct about the horsepower numbers, I will probably make 215ish whp with Bolt ons.

You are also correct about the oil starvation. My car makes significant downforce and the center of gravity is so low it’s going to pull over to 2Glateral. I’m eventually going to have to get a dry sump system. I’m going to run an Accu sump until I do the full system. I am hoping to get a half a season without a major blow up. And then next winter I could do a full dry sump system.

I would love to do the BMW DCT. Using that transmission in a track car is my next goal. But in my race car there simply isn’t enough space even if the transmission output shaft is connected straight to the differential. The K 24 with the Boxster manual transaxle is within 1 inch of the Current bike engine drive line
 

·
Arouse the DAMPFHAMMER!
Joined
·
8,024 Posts
I will be able to do all the fabricating myself so that will save some money
That's great, so only material prices, I assume around 2500 for the engine incl. overhaul, 600 for ECU, 600-800 for tuning and some peanuts. So 4000 USD for the big contributors and about 2000 USD for small items and maybe tools to fab it. So material- and tuning-wise on the very cheap side 6000 USD.

My car makes significant downforce and the center of gravity is so low it’s going to pull over to 2Glateral. I’m eventually going to have to get a dry sump system. I’m going to run an Accu sump until I do the full system. I am hoping to get a half a season without a major blow up. And then next winter I could do a full dry sump system.
That's a low estimation I guess. With the Elise I get into the area of 1.6 to 1.7 g lateral, with the weight and the huge full slicks alone 2 G should be possible. I assume 2.5-3.0 g what is possible with your chassis. Above 1.7 most baffeld sump systems lead to suck issues, a few are claiming to get up to 2 g. A member here reported about one, unfortunately I forgot the name (something with B) of the member and the company. I am not sure if an Accu sump is really that fast acting to prevent starvation. Is here anyone who has an evidence for that? I understand the principle, I just have some worries if the system is big enough (one should know the OEM oil pump flow) to prevent of an starving oil system on longer high speed corners of 1-2 s duration and fast enough and what is with the air the oil pump is evtl. pumping into the oil system? Not sure if this all can be covered and solved just by an oil pressure storage? I see good utilization of break in first oil up and for oil pressure stabilization on shifts or redline bumping.

I would love to do the BMW DCT. Using that transmission in a track car is my next goal. But in my race car there simply isn’t enough space even if the transmission output shaft is connected straight to the differential. The K 24 with the Boxster manual transaxle is within 1 inch of the Current bike engine drive line
Yeah, see your point. You know there is a DQ500 from an RWD 4WD available, which is much shorter (half of it?) then the DCT of BMW? We use it for our 4WD-1200 hp-Golf 2-Drag car. It is rare as only Audi did use it for the Quattro in the A6 if I am correct.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #13 ·
Do you have a recommendation on an affordable dry sump kit? I love the one that uses the chain and doesn’t require external pumps but it’s $6,500!! The cheapest one from drag cartel is $4,500. I could afford $2,500 or maybe a little more. I may be forced to get a race oil pan for $500 and hope it lives.
 
1 - 14 of 14 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top