Ok well guys, Im stumped as to what to do. I've been to the dyno about 4 times now. The first time I had a problem with a coolant leak and the head gasket was going to blow so, I went home, changed out the headgasket, got some ITR pistons in there while I was at it. Go back for a retune, it revs out fine but just throwing out too much ignition timing, after playing with the distributor we realized the motor itself was off timing by a tooth i'd say. So i took it home redid the cam timing, got everything perfect, wait about a week and go for another retune. This time around we run into some more issues, the car is leaning out up top, no matter how much fuel you add, it still leans out. So the tuner asked me to change out the fuel regulator, so I take it home. Order the new adj. regulator and gauge and hope this fixes everything. Go back for the last time today, same issue, so we think its the walbro 255 fuel pump and swap it out for another one, same thing. What do you think may be the problem, my tuner and I are completely stumped.
The setup consists of :
B18c1
ITR 81mm Pistons
Gsr head,
SK2 Valves
Omni Valve Springs/Retainers
ITR Cams- Stock cam gears
Cast Iron manifold t3/t04e turbo
RC 650cc
Tial bov
Ebay wastegate
Innovate LC-1 Wideband
Crome chipped ecu by phearable.net
Heres a dyno sheet.
Any suggestions would be gladly appreciated. Thanks in advance.

 

I have been out of this for several years but your post intrigued me. How do you know you are leaning out? The reason I ask, is that any exhaust hairline crack or weak gasket can appear to be a lean condition by indication but is not true. Is the engine falling off at boost? Are you getting detonation? Can you hear the engine struggling or is this an indication you are seeing with your wide band?

Here are a few things I have had trouble with when I had a boosted ITR:

1. Exhaust leaks will drive you crazy for tuning. Make sure it is absolutely tight. You must know the wideband reading is correct so you can tune properly.

2. I had trouble with MAP sensors also. Make certain there are not air leaks at its manifold gasket and you may also have a defective one that cuts out at higher boost levels. If you have a buddy with the same unit, try swapping out.

3. Ignition system problems will also drive you nuts. My plugs were good for about 4-5k and were shot. The boost would blow out the spark and it would fall on its face. I also ran an aftermarket ignition system that helped with high boost to the detriment of the plugs.

4. You may also be losing an injector and the only way to tell is to have them bench checked. I would try this as a last resort. 650cc should be plenty unless you are pushing massive amounts of boost.

I would also start with a good inspection of the engine compartment and just check for the obvious discrepancy that may be staring right at you. Defective crank case ventilation system. Cracked vacuum lines on your adjustable fuel pressure regulator etc. your "fix" may be something cheap and easy.

I hope this helps and good luck

 

Thanks alot for your post, im gonna look into every suggestion you've made and i'll be back.

 

are you pulling the plugs to see if its really leaning out or just going off the wideband? where do you have the wideband located in the exhaust? Are you detonating or just showing lean on wideband? What are you considering lean? A walbro 255 with 650's should be plenty of fuel for 300whp. you are tuning it and not just running it on the phearable chip correct? Sorry but i have to ask that cause many peopel do it and then ask why its leanign or really rich