We´re tuning a low milage AP1 with Greddy kit and have a problem we can´t figure out. The car has been driven without a real tune and had pretty much zero power when we started, former widebody showcar... The new owner want more power but were stuck at pretty low numbers.

Set up:

Greddy kit as base
AEM v2
FID1000´s
AEM FPR
2,5" full flow exhaust
Walbro 255

Fuel: E85

The car makes 317whp at 11psi but misfires bad when VTEC engages, really bad at low rpm´s and a lot less at high rpm´s. Set the VTEC at 7000rpm now and it runs fine but more boost brings back the problem.

Any clue? Tried plugs in the dyno but didn`t help. Ignition problems should show at boost and not only at VTEC point huh?

 

New thought. Possible that one ot two cylinders engage the VTEC slower than the others? Any way to test this? Will try new oil and OEM oil filter, might be oil pressure related if it´s the VTEC.

 

its probably blown up..

I see this happen pretty often. Someone drives around untuned or on a 1/2 tune and slowly hurts the motor.. Then you start tuning it, put some power to it and something breaks.

What are the plugs gapped to? knock em down to 20thou and see if it changes. If it changes then you know you have an ignition problem. If it doesnt changes its either in the tune or mechanical.

 

Vtec should be set around 7000 with that kit. Anything over 300 is awesome for a Greddy kit on pump btw.

 

wadzii: Yeah, might very well be the case here untuned for maaany years. The old owner had the turbo kit just to tell people he had a turbo kit. Do you think it would show these numbers with bad ring lands or other engine problems? Thanks for your thoughts.

Will check compression and plugs tomorrow, I know it´s on Iridium 7´s now, Greddy´s plugs when we started.

s2knoob89: That´s good info, it´s actually set at 7000rpm´s now since it gives us less misfires there.

 

you'd be surprised.. a few weeks ago I made 900hp on a blown up supra.. haha. pistons were melted, headgasket blown and still made power!

I doubt its got a cracked ring if it runs ok, but I also doubt that the motor is healthy.

 

Haha, you´re probably right. It´s not running ok unfortunatly, will report back.

You´re a sponsor now? Make a thread with pistons and stuff, we need a real engine sponsor here, not just new turbo kits once a week.

 

Yep, got my sponsor status a couple days ago.. I have a thread for CNC Cylinder heads by RLZ and a thread for building motors. LMK if you need anything. I still have an awesome set of Mahle pistons here for an NA build!

 

I wish they made a stock compression turbo piston. Would be cool to have that option, just like the OEM ones but stronger. Want that for my spare engine.

 

I can get you to about 10.5:1 w/the turbo pistons

Do you guys run a 2 liter or 2.2liter crank?