I was browsing through the tech section over at MaximaDriver.com when I came across an article that's probably not new, but it was new to me. It was Thomas Chen's wrie up on NOS (NOS Explained) It seemed to have quite a bit of useful info.

Anyway, when I got down to the Fuel Pressure portion of this article, I noticed that when running a 60shot using the .034 NOS jet and the .042 bypass jet, fuel pressure should be around 67psi.....I'm generally in the 57psi area. Now according to my EGT and A/F gauges, I'm not running lean. EGT temps are around 13-1400F just after a 1/4mi run and that's with 2 step colder plugs.

I haven't had any trouble thus far, and I've gone through...what....10 refills. So my question is, should I change my bypass jet to a .040 and try and raise the FP or should I go with what I have and run with it?

 

Have you read your spark plugs?

 

Cal is right check your plugs if all looks ok, go with it. The bypass jet required to get a given fuel pressure is at best a guess as well. It all depends on a whole lot of variables. I have seen guys use from a .085 to a .038 to achieve the same fuel pressure.

 

I'll do that, thanks.....

Anthony B

 

Yep, every car responds differently, so what fuel pressure works for one, may not be the same for another...

 

Like mine which has no fuel bypass jet and I run 80 psi. I also run a 100 shot and at 80 psi I run really rich.

 

Like others said, check your plugs for detonation. Also, what shot are you running? Where is your EGT probe at? Check around, but I think that 1300-1400 is pretty hot (lean). I may be wrong on this. I've been told back and forth on this so many times, I don't know which way is up. What is your N/A EGT readings @WOT, say at the end of the 1/4?