How do you tell if you are running to rich or lean, and know which jets to change?

 

these jets on a return fuel system car would be just right, but since these cars run a returnless system, they have a high pressure line of fuel, there for you will need to back off the fuel more. i need to check what the fuel pressure is before i start backing off the fuel.... your ZEX kit should do it automatically for you though.

 

ahhh okay gotcha...you have a different kind of system...thanks again

 

By the way, how hard was it to tap into the fuel system on the Fit? I scheduled to have it installed, and the people seemed to be worried about how to tap the fuel...

 

if you look at my 1st post about nitrous i explain the whole fuel tap thing.... 1st off do not cut the fuel hose its lined with plastic. remove it being carefull with the plastic clips and then by some high pressure fuel hose from your local auto parts store along with a small brass T as shown in this pic:


do not try using the zex T cause its a little on the big side. buy some good fuel clamps that are not going to puncture or rip into the fuel hose. i got mine from some subaru fuel rails that i have laying around. then you should be set!

 

Okay, so I went to have it dynoed today to make sure the a/f is good, and on the baseline dyno around 5200rpm the car starts going really lean...the guys like, "Thats not even on nitrous, so I am gonna try it one time on the spray and if it does the same thing Im done." By the way I made 103whp and 99.9TQ on my baseline. Anyway so he sprays the nitrous and of course at around 5200rpm the a/f immediately starts to jump so he lets off. I dynoed 141.2whp and 147.7TQ on that run and then he said they were done.

SO my question is, do I need to get a better fuel pump? What could be my problem?

 

thats weird, i say put a bigger fuel jet in the fuel line, the Fit puts out a good 51 psi of fuel pressure so a bigger pump is not needed. what jets are you running? your header might make you go a little lean.

 

thats what I said, but the car ran real lean above 5200rpm without nitrous...so something isnt right, and it has nothing to do with NOS jets

 

its your header man, that thing is messing with the AFR's what was the EGT like?

my car runs rich! even with the nirtous.

 

I dunno, doesnt say on the graph, is there anything I can do? I guess I could get an AFC2 to adjust the fuel at different rpms...

 

yea i think your going way lean because of all that exhaust flow, you got header, test pipe and the big skunk2 exhaust

try doing the coolant bypass mod, it will make the car run slightly more rich.

 

THIS thread is a pleasant surprise. Was searching through and found it. Very interesting! Nothing to add. I just needed to tag it for future reference.