Honest expectations from a KA

[cdlong]

Had several in-depth discussions with some of the experienced AutoX/DSP guys at the tour this weekend. The 240 made a decent showing but needs more work (no surprise there). One guy said to be competitive in the class I'd need about 10 lbs/hp, so maybe 250hp at the crank. I know that'll never happen but I'm curious what you think the max reasonable expectation is from a KA. If I can't even come close, I'll just keep the car mostly as is until I get bored and sell it.

For those that don't know the class rules, here's the clif notes
Intake/exhaust are free up to 1" inside the head
Tuning/injectors are free
Pulleys/flywheel are free
Adjustable cam gears are allowed
Cams must be stock
Internals must be stock/stock specs (forged or cast pistons)
rebuild is allowed, .0472" overbore, mill head to .010"

Here's what I'd have to do to get to max power as I can tell:
Custom intake w/ITBs
Header and shorty catless exhaust (have a hotshot already on it)
Use S13 engine to rebuild under update/backdate to get s13 cams, 1mm over bore, deck head .008", JWT cam gears
E85 tune
Flywheel/pulleys (already done)

Side note, I'm not going to trailer the car and I occasionally drive it on the street. If I have to make it undriveable, I'll just stick with I've got.

I don't really see that getting it over 200hp. Thoughts?

[Matt93SE]

Not without upping the compression, good cams, and ECU will you get above 200whp. crank hp, yes. wheel hp, no.

You could get close- 175whp or maybe a bit more, but you won't see over 200.

[cdlong]

Yeah, sorry, everything discussed is at the crank.

I'm not entirely convinced that much is necessary anyway. The guy was refering to his VW R32 which has other limitations aside from power to weight, specifically the height.

[djsilver]

I run mine in DSP and you're correct that it's an underdog in power against the 6 cylinder BMW's. If that's not enough, a fellow won the class in a Merkur XR4ti a couple of years ago. Since the rules changed to allow boost adjustments he can just wire the wastegate closed and go!

Here's BigVinnie's discussion on getting 200 crank horsepower from a KA motor; http://www.s-chassis.com/forums/showthread.php?t=30440 (BV is not necessarily well-regarded on FreshAlloy/Silvia but his advice in this thread is valid)

I've got just about the same setup as your list except that I'm already in an S13. My last dyno results were around 165rwhp/168rwtq. I'm currently running a JWT ecu. Don Nimi has advertised 176rwhp in STS trim on a customer's car a couple of years ago (http://www.pdm-racing.com/contact/fe.../court240.html) but I haven't plopped down the $500 for his tune yet. Maybe it's time! The next power move would be a custom intake manifold but I hate to do anything that hurts the low end on this motor because 2nd gear is already a bit tall when run with the commonly available R-tires.

My next consideration is in the post just before this one; E85?

All that said, the car is still a lot of fun and there's a lot more in it that I could get out if I were a better driver! The car can be competitive in SM and several of our members have already proved that! Just needs more $$$ ;-)

Here's my engine setup;
S13 KA24DE, rebuilt .040 over (ACL oem replacement pistons)
K&N cone air filter
S14 MAF
Injen CAI
S14 intake manifold (no SCV's)
JWT timing gears, with exhaust retarded 5 degrees
ASP aluminum underdrive pulley
Fidanza aluminum flywheel
A/C delete (yes, I tow mine now!)
Hotshot header
Random Hi Flow cat
2.5" MR cat-back exhaust (I've tried a 3" and made no difference)
JWT ecu w/7200rpm rev limit
Apexi AFC (to make S14 MAF work and fine-tune AFR's)
Innovate wideband (for tuning and to keep an eye on things)

Changes under consideration;

PDM ECU or other tuneable setup
Ported stock or custom intake
E85?

Good luck!

[cdlong]

HA! Here's my full setup for comparison (differences are in bold)

S13 KA24DE, rebuilt .040 over (ACL oem replacement pistons) Not yet, but that's the plan
K&N cone air filter yep
S14 MAF yep
Injen CAI mine's AEM
S14 intake manifold (no SCV's) well, yes
JWT timing gears, with exhaust retarded 5 degrees not yet
ASP aluminum underdrive pulley yep
Fidanza aluminum flywheel yep
A/C delete (yes, I tow mine now!) part of the plan, I can tolerate no AC here
Hotshot header yep
Random Hi Flow cat yep
2.5" MR cat-back exhaust (I've tried a 3" and made no difference) BRM, but yeah
JWT ecu w/7200rpm rev limit was going to go Nistune
Apexi AFC (to make S14 MAF work and fine-tune AFR's) nope
Innovate wideband (for tuning and to keep an eye on things) maybe

What's our drivetrain loss? At 17% that's right around 200chp. Any competitive 328s in your region? I need to work on my driving too, I've got a friend that occasionally drives my car when his truck is broken, he always beats me.

[djsilver]

What's our drivetrain loss? At 17% that's right around 200chp. Any competitive 328s in your region? I need to work on my driving too, I've got a friend that occasionally drives my car when his truck is broken, he always beats me.

I've always heard 15-18% on RWD cars.

Not locally, but in 2010 Eric Campbell was at the Dixie national tour in his 330ci and it was discouraging. He would have placed 2nd in CSP if we'd bumped him up a class! The fastest semi-local guy runs a Subie 2.5RS. I'm a second behind him on average and he was mid-pack at the recent Toledo tour. At our local events we score everyone on PAX and I seem to end up in the same place in standings regardless what car I'm driving

[sil8y]

you guys keep power steering? thought about running alt off driveshaft, electric water pump, no ac? anything to get losses down? is its even legal?

[djsilver]

you guys keep power steering? thought about running alt off driveshaft, electric water pump, no ac? anything to get losses down? is its even legal?

In our class (SCCA solo, D street prepared) we can remove the A/C (mainly for weight loss) but no moving the alternator, no removal of power steering and no electric water pump. I expect a 1-piece drive shaft would help by dropping the center support bearing but that's not allowed either.

I have considered a WOT cut-out switch for the alternator but I don't think there's much load on the alternator without lights or A/C.

[cdlong]

Same here. Doug Rowse was over 3 seconds faster in his 330i than the next place E36. he would have placed 3rd in CSP and would have won BSP. Dialing in the suspension(and driving better) will help a lot, but I don't see me shaving off 10 seconds over two 60 second courses.

[Tower240sx]

without more cam or compression there's not much to be gotten from a KA24de,

If you were sneaky enough to get away with SOHC pistons you might could make ~215 chp with the E85 and ITB's etc.

[240sxTTC]

Mine is at ~255hp at the crank (215whp) with stock compression and valves. The weak link for the KA to make pwr is the cams and intake manifold. I have 0.500" lift cams and an aftermarket intake manifold. Another area for improvement is the clutch. I have a 5.5" dual-disc QM clutch, whichs weighs 8.5lbs with the auto flex plate.

[Sleepy_Steve]

... never mind.

[Def]

Stock cams are going to choke it down no matter what you put on either end. The bad thing is that an E36 328 can put down about 210 rwhp with an earlier 325 intake manifold, tune and bolt-ons with stock cams. With M3 cams they're in the 220-230 rwhp range (I know, not SP legal).

Later E46 330's can do a pretty easy 230 rwhp from what I remember, maybe a bit more if they really get into the motor, but they don't like to really rev that much(much over 7k RPM will destroy the motor in short order).

[djsilver]

Stock cams are going to choke it down no matter what you put on either end. The bad thing is that an E36 328 can put down about 210 rwhp with an earlier 325 intake manifold, tune and bolt-ons with stock cams. With M3 cams they're in the 220-230 rwhp range (I know, not SP legal).

Later E46 330's can do a pretty easy 230 rwhp from what I remember, maybe a bit more if they really get into the motor, but they don't like to really rev that much(much over 7k RPM will destroy the motor in short order).

I know Terry over at Vorschlag didn't have a good experience with the 3 liter motor but he seems to be the exception, as the E46 330's seem to be doing well in Autox. They do seem to have harmonics issues at high RPM and the folks roadracing them tend to prefer the 2.8 motors for that reason.

[Def]

He didn't have a good experience with the M54 because he revved it well beyond 7k RPM despite everybody telling him he was going to have catastrophic engine failure. Only took him a few events to prove everybody right, but somehow it wasn't him that was wrong, it was the engine that was a pile... right... He sheared the shaft to the oil pump shaft IIRC.


I think he was revving it to 7600 RPM or maybe a bit higher (stock valvesprings and all). Stock redline is 6500 RPM I think.