Leaning out up top!

[Grandnat]

I have been tracing a problem with my car leaning out and need some advice on what to do.

I am only runnning 15 psi of boost on 93 octane.

I have the following
GN1 aluminum heads (FLow ~225 cfm @ .500 at 28" vaccum)
TE-44
212/212 cam
3" THDP
CAS V2
009 (42.5 lb/hr) injectors

I am using a JC93 chip which is a 19 degree chip and I am running 43-44psi static fuel pressure.


When I go WOT the O2s start off fine and start dropping to 750mv at which point my knock detector goes crazy.

I have replaced the old fuel pump with a walbro 340 and a new fuel filter because the fuel pressure wasn't keeping up. This did not solve the problem. (but was no doubt part of it.)



My question is this....... do I just need to run more static fuel pressure??? am I just flowing too much air with the big heads?



I have ran this chip for years and never had this problem until the GN1 heads.


shouldn't 009 injectors be enough at such low boost?

I am going to try 46 psi tonight and see if that helps but I am afraid to run too high and have my BLMs drop alot since right now they are about where I want them.



the MAF readings and LV8 readings peg at 255 and I just ajusted the TPS so all the readings look fine until 3rd gear when the O2s just take a free fall.


any suggestions?

 

[bruce]

Originally posted by Grandnat


I am only runnning 15 psi of boost on 93 octane.

I have the following
GN1 aluminum heads (FLow ~225 cfm @ .500 at 28" vaccum)
TE-44
212/212 cam
3" THDP
009 (42.5 lb/hr) injectors

When I go WOT the O2s start off fine and start dropping to 750mv at which point my knock detector goes crazy.
I have replaced the old fuel pump with a walbro 340 and a new fuel filter because the fuel pressure wasn't keeping up. This did not solve the problem. (but was no doubt part of it.)

am I just flowing too much air with the big heads?

I have ran this chip for years and never had this problem until the GN1 heads.
shouldn't 009 injectors be enough at such low boost?
I am going to try 46 psi tonight and see if that helps but I am afraid to run too high and have my BLMs drop alot since right now they are about where I want them.
the MAF readings and LV8 readings peg at 255 and I just ajusted the TPS so all the readings look fine until 3rd gear when the O2s just take a free fall.
any suggestions?

Without a WB your really only guessing.
BUT, you might ask Jay to add some fuel in the FAPE area of the prom.

55s are about right for a stock to mild engine combo. Without going static, and without high F/Ps, I ran out of fuel with 009s on a friends stock car.

Lots of well intended folks will agrue about how far you can go with 009s but, if you stay within their design limits, you can't go far.

Boost is a measure of PEAK Manifold Pressure.
With the GN1s while your at a lower boost, your flowing alot more air, and with the increase in airflow you need fuel.

 

[TurboJim]

Wait, you had that chip calibrated for stock heads, which flow somewhere around 180cfm @ .500, now you're flowing 40 more CFM per hole? Well theres your problem. You need more fuel added in PE. Where a stock head chip might be somewhere around +35-40% at the top of the PE scale, I'd venture to guess, with some heads and maybe a cam you'd wanna be more in the +45-50% area in the top of the PE trims. I'd contact Jay and tell him you've upgraded much of your combo, and have him program what he thinks is best. Additionally, I think Bruce is right that you could probably use more than 009's.

 

[TrboHead]

I would have to agree with Bruce and Jim. If your heads flow what you say they do on your particular motor it is now pushing 20% more air/fuel and thereby making roughly 20% more power even at 15 lbs of boost especially given a TE-44(sweet spot). That's 100 hp increase if youve gone paste static now. Those 009's should be running static at 500 hp or so. Take a stock ported headed car you could easily tap out those 009's given the right combo. Even if you turn the pressure up you are not proportionately getting more fuel. Put some bigger injectors in it, more timing and turn up the wick man....
What are you waiting far?