I have a stock fuel pump with an additional 255 Walbro in-line pump on my Trans Am. I went to the dyno and recorded a 11.1/1 A/F across the board. When I hit the 125 shot (NX wet) with the proper jets I jumped to 13.5/1 across the board It acually dropped near 13.0 in the upper rpm range. I put a larger fuel jet to compensate, butthe A/F stayed the same. I had my tuner adjust the car to 12.6/1 N/A with LS1-Edit, but I am afraid that I am going to be leaner on the NOS. What to do? If I had a fuel pump problem, why would the A/F stay constant and even drop to a lower A/F at the higher rpms? Wouldn't it start getting leaner up top if the fuel delevery was the problem? BTW I have a stroked 382ci LS6 with a mild cam most of the bolt-ons.


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I take it thats a dry kit right what inj. are you running and are they maxing out on the spray? might be the inj. they run fine NA but the xtra strain put on them when using N20 it might not be able to keep up.

 

It's a wet kit. I even jetted up the fuel jet.

 

do you have a fp guage? whats it do when you spray maybe the inline pump can't pull threw the stock pump quick enought.

 

I have not checked the pressure while spraying. I need to find a way to hook up the gauge.