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300+WHP can be done with OEM bottom end. If the knock isn't bearings, rebuild might not be needed. However, if it's a hobby car, then definitely go for power, just get the limits for the Aisin first. A manual with no rebuild has been known to produce 300WHP. Study your piston CR options and the max boost before re-boring. Big boost and high CR will blow cylinder walls without a Cylinder Support System. K03 - K04 hybrids or a JCW should be OK, just don't exceed 22PSI with any more than 9.5:1 CR. I run 9.0:1 CR and 30PSI with CSS --- manual xmission.
Think about port / relieve on the head too. And maybe some hi-temp valves and springs --- "while it's off". Letting these engines breathe is a good way to add power, and if you have the power bug, it will be inevitable someday.
Thanks for alot of useful info!
For now I think my goal is about 270-280hp with good reliability. But who knows about the future, so forged pistons might be a good idea ”while in there”.
If I can have an engine with 300hp potential, Im even more pleased. Will rods be a weak link at these numbers?
I will start checking compression, plugs and oil next week. Depending on the results, an engine teardown might be the next step.
For now I think my goal is about 270-280hp with good reliability. But who knows about the future, so forged pistons might be a good idea ”while in there”.
If I can have an engine with 300hp potential, Im even more pleased. Will rods be a weak link at these numbers?
I will start checking compression, plugs and oil next week. Depending on the results, an engine teardown might be the next step.
OEM rods are definitely a weak link, at any numbers. Should be OK as a DD, but for any track use or big HP numbers, consider upgrading them.
Any time an engine is torn down for just a bearing replacement, I would never re-use the original pistons or rings. They have already been "seated" and when disturbed, are not likely to regain their original seal --- oil burning and compression loss. It takes more than a good honing to make an old cylinder truly round again. However, when replacing either rods or pistons, ensure they're compatible by doing a "trial fit" --- assemble one set and manually rotate the crank a couple revs while watching for rod / piston wall contact. Some aftermarket suppliers aren't compatible with each other and / or OEM. That's the main reason I chose CP / Carrillo for rods and pistons --- they are (or were) part of the same organization, and known to work OK with each other.
OEM rods are definitely a weak link, at any numbers. Should be OK as a DD, but for any track use or big HP numbers, consider upgrading them.
Any time an engine is torn down for just a bearing replacement, I would never re-use the original pistons or rings. They have already been "seated" and when disturbed, are not likely to regain their original seal --- oil burning and compression loss. It takes more than a good honing to make an old cylinder truly round again. However, when replacing either rods or pistons, ensure they're compatible by doing a "trial fit" --- assemble one set and manually rotate the crank a couple revs while watching for rod / piston wall contact. Some aftermarket suppliers aren't compatible with each other and / or OEM. That's the main reason I chose CP / Carrillo for rods and pistons --- they are (or were) part of the same organization, and known to work OK with each other.
Finally Ive had some time to take a look at my R56. Good news! The sound was a bad tensioner at the water pump. The knockimg sound was created by the tensioner slapping between the pump and crank pulley. Happy days!
So now its time for some updated plans!
I will continue to run the stock bottom end. Im not all that pleased with the stock turbo at these numbers. Its not maintaining the 21psi boost att higher rpm and feels like the limiting factor(and is). The stock turbo should be pumping mostly heat at max boost overrevving?
Is it resonable thinking that a slightly bigger JCW turbo with a ”mild” tune could give better top end power, lower air temps and less backpressure? Being somewhat more healthy for the engine? Maybe keeping it around 20psi?
Finally Ive had some time to take a look at my R56. Good news! The sound was a bad tensioner at the water pump. The knockimg sound was created by the tensioner slapping between the pump and crank pulley. Happy days!
So now its time for some updated plans!
I will continue to run the stock bottom end. Im not all that pleased with the stock turbo at these numbers. Its not maintaining the 21psi boost att higher rpm and feels like the limiting factor(and is). The stock turbo should be pumping mostly heat at max boost overrevving?
Is it resonable thinking that a slightly bigger JCW turbo with a ”mild” tune could give better top end power, lower air temps and less backpressure? Being somewhat more healthy for the engine? Maybe keeping it around 20psi?
My last turbo, a big GTX2860, was losing boost after peaking. Turns out it wasn't big enough for the rest of the engine. However, even with the loss of boost at higher RPM's, there was no loss of HP on a dyno chart, only torque loss. Switching to a bigger turbo and tubular exhaust manifold bought me another 130 HP.
As for air temps and backpressure, I can't say how turbos affect these characteristics. My approach was to improve engine "breathing" --- ported head, 3" exhaust, minimum airflow restrictions for both pre and post turbo hoses, and a good FMIC. And of course, a good tune --- probably the most important part of any performance package.
Before you invest in another turbo, study up on turbo A/R. This spec determines where in the RPM range the power will be noticeable. Remember that bigger turbos will cause boost lag, which also affects where power is noticed. Always trade-offs!
4405/330whp - 13.348lb/hp
3098/230whp - 13.469lb/hp
I put that there because it explains why we were literally dead even at any speed to any speed, was a fun little dance, and I'm sure he was scratching his head about the little green mini that could especially since it's so quiet:-)
I wouldn't classify it as a fast car by today's standards, but it's fast enough to shoot from corner to corner and be entertaining while doing so.
Last edited by Claviger; Apr 19, 2021 at 10:29 AM.
General question. Of all the people who have tunes how many are achieving more than 350bhp and 300 torque, and did you use a tuner in the US, preferable on the East Coast?
General question. Of all the people who have tunes how many are achieving more than 350bhp and 300 torque, and did you use a tuner in the US, preferable on the East Coast?
If your build is capable of that kind of power, talk with Lou at https://prototype-r.com he's based in FL and can do remote tuning --- no need to mail the ECU. My build was started 10 years ago, and just finished last year. Manic tuned it about half-way thru and got me about 330WHP and 400 ft-lbs torque. After more mods, final dyno was 520WHP and 420 ft-lbs. Manic isn't in business any more, but I'm told he's selectively tuning big engines in Europe, where he's based. My 2nd choice would be Lou, if I did it again. Mod list in signature.
