I am in need of some tuning help with a NOS 05177 NOS kit. Engine is a stock 346 2000 LS1. With TEA 5.3L Stage 2 heads 11.0 CR, TR 224/224/112 cam, LS6 intake, ported TB, SLP LT Headers, no cats, cutput, K&N FIPK, NOS 05177 kit coming in through the front of the K&N fiberglass filter, TR55 plugs with TR6s ready to put in.

On the dyno without NO2 I tuned in 414 HP using LS1Edit with a AFR of about 12.8. Then with the max jet in the kit (I think that is a 100 shot) I got about 492 HP. According to the WB in the exhaust (forgot to open the cutout) I was about 15 for AFR. I used the resistor in the path of the IAT to the PCM to trick it that it was about ~10 to 20 degrees cooler hopefully causing the PCM to retard the timing based on the lower temp tables. The logs show timing was about 20-23 on the NOS and about 23-27 off the NOS. Yet my LS1Edit table of IAT-MAP timing only had -1 in the table. No knock at all.

No matter what I did to the power enrichment table on the nitrous I could improve my HP some but not the AFR. On the last run we still did not do much better on AFR and the operator said you could see the fuel coming out the exhuast (no cats).

What else can I do to improve the AFR when on the NO2 and the HP? I will put the plugs in but I do not know if that affects AFR. My guess is it won't. I am thinking SVO #30 injectors as I assume (without having logged for injector duty cycle) the stock 26.5# injectors couldn't keep up. I didn't have any more time or $$$ to try dropping the timing on the dyno plus I was concerned with the AFR. I pulled the plugs and they looked good.

Of course there is the wet kit which I don't want to put in right now. I would rather maximize my investment in the 51077 dry kit first for a while.

What I can't understand is how fuel could be seen coming out of the exhaust yet the AFR was so lean.

Dyno specifics:
NO2 Dyno: tuned nitrous from 488 to 492 by adding fuel until it was seen coming out the exhaust yet AFR started at 3000/12.8, 4500/15.2, 55000/14, 6000/13.8 (window switch is 3000-6000). Max HP is at about 6200.

No NO2 dyno: 414 HP, AFR 12.8 to 13 though out the dyno.

I can scan and post the dyno sheets if that would help.

Thank in advanced for any help cause these Cobra friends of my are slowly creeping up with me on the strip and dyno and I just can't have that.

 

AFR? As in Advanced Flow Research?

 

Actually I got that wrong. It is TEA for the heads. The rest is about air fuel ratio.

 

If you have 26.5 injectors I am guessing max duty cycle. they are only good to around 450???. I am sure if I am wrong someone else will chime in.

 

I agree. But, then why the fuel coming out of the exhaust? Any ideas? I would think that this would mean so much fuel you would not be running lean.

 

For sure drop in the TR6's at 0.040. What was ur gap with the TR55? if you had too wide a gap you could have had misfires which would lead to fuel comming out of the exhaust.