I think I am running around 1 kpa.... No clue?

what pulley and what FMU disc do you have?

3.125 and a 6.1 disc.

Is that at idle? Where did you T into the fuel line? You should be T'd between the fuel filter and fuel regulator. You may be T'd into the fuel return which is a low pressure line.

I think thats what it is. Thanks for the help guys :-)

is 1Kpa = 7psi?

you should get about 11psi from your 3.125 and your FMU is 6:1.

assuming your base fuel pressure is 38 if u dont have an aftermarket FPR.


so....

fuel pressure at boost = peak boost pressure * FMU ratio + 1/2 * (base fuel pressure)

FP = 11* 6 + 38/2
= 85psi.....

how come you have 6:1 with a 3.125? that's kinda low for a small pulley like 3.125.

Yea....a 6:1 Disc is really risking it with a 3.125 imo. Couldnt that starve the engine/cause detination? BOOM.

Actually the conversion factor is 6895 Pa per psi, so 1kPa is pretty close to nothin'. I think either the gauge isn't hooked up right or the pressure transducer is on the fuel return line, like Maxin said.

Thanks Ramius for hooking the gauge rite this time ;-)

Car is idles at 36.25 PSI and I did peak it at 52.20 PSI. Is this a justification to go for 8:1 disc? Still trying to learn this boost stuff :-)

idle seems right....but peak is way too low, make sure the vacuum hose connect to the FMU is not leaking. how's your EGT?


even with a 6:1, you should get at least 80psi of fuel with your pulley. what fuel pump are you using? if it is the aux pump, make sure it is wired correctly.

8:1 is a must for a small pulley like yours. IMO, the kit should come with an 8:1 instead of 6:1. Stillen uses 6:1 for the 3.60 pulley because they dont want to maxxed out the stock injectors. But it's either pushing your luck and pray that the injectors wont lock-up or running super lean all the time.

Now the question is how can I check the peak. Peak should be at maximum boost correct?

EGT maxed out at around 750-800 C. I have the walbaro fuel pump. Kit came with 8:1 but Bosco had 6:1 on it.

-OS

Just went for a test drive again but freakin traffic sucks downtown.

I was able to get to 8psi boost, 76.85psi Peak FP and 700ish C EGT.

Comments?

looking good. did you pull from dead stop or from rolling?

8 * 6 + 36/2 = 66psi <---- that's the fuel pressure that you supposed to get.


It doesnt surprise me that you get more fuel p. because I got way lot more on my 8:1 as well.

I pulled it from dead stop and then also from roll. So am I alrite with 6:1 disc? or you want me to do some more runs ;-)

a dyno run will be nice.....if you are running rich, your are fine.

http://forums.maxima.org/showthread.php?t=249395

I know this is an old post, but just so everyone knows, the stock injectors are 'supposed' to lock up at 110 psi. If you run a 8:1 disk with a 3.125" pulley, your asking for trouble. The math is easy to do. The safe way to go about it, would be getting 370cc injectors and do some tuning on the dyno with the s-afc. I just dont want oss going and blowing his motor up.

Thanks bosco! I am still not sure wth is going on. I guess I need to take the max to get dyno tuned so I know wat a/f i am running.

they didnt give you an AFR from your last dyno?

Now when I think about it.. they should have :-\

that's true and I agree with ya! I have been pushing more than 110 psi to my injectors near the red line and I am very concerned about this. However, 3.125 has to go with 8:1 for people like me (5th gens) that have no acess to larger injectors.

my other suggestion for 5th gen peeps who have no access to larger injector is to get the adjustable FMU and FPR so you can lower your peak fuel pressure a little.

Actually I think you 5th Geners have more options for fuel injectors since many companies make top feed injectors...