Which bypass jet ?

[ssms5411]

I finally got the my kit hooked up. It is a 5175 dry kit with a .047 jet and a.042 bypass jet. It is showing below 10:1 on my wideband when I hit the nitrous. The fuel pressure was at 80 psi using nitrous. I have it tuned for around 12:5 to 12:8 N/A. I have a walbro intank,36lb injectors, VS cam, built engine with forged pistons, headers , 3" exhaust, etc. I was running a powerdyne supercharger before this with about 10-12 psi and had to sell it. My question is can I put a bigger bypass jet in to get the fuel pressure down and lean the car out with just changing bypass jets? I want to do it this way so I don't have to mess with retuning my car since it is setup for N/A perfectly. Also do the bypass jets use just the regular nitrous jets? I bought a bypass vacuum tee that you can change the bypass jets out. I was thinking of using a .053 or .059 to see if it leans it out. Any suggestions? Thanks Steve

[Nachius]

Re: Which bypass jet ?

Yes the bypass uses regular bypass jegs and increasing the size of the bypass should cause less fuel, thus leaning it out. I know this works in reverse to richen up your mixture.

BUT It's my suggestion to just use 2 different tunes save your N/A tune, and get a 2nd nitrous tune.

IF you are set on only leaning it out with the jets, then I would make SMALL jumps in jet size and monitor each run until you find the correct jet, you could break lots of things if you lean it out too much jumping from a .042 to a .053/.059!

[ssms5411]

Re: Which bypass jet ?

Thanks for the response, I'll start off with a .047 then and go from there. I don't want to load a new tune every time I want to use the nitrous thats why I want to try to tune it using the bypass jets.

[xcdarrel17]

Re: Which bypass jet ?

If you have a good tune N/A then your timing is probably advanced, which wouldn't be good to use with nitrous at all. I highly suggest a tune for each set-up if you want to get the most out of running N/A and nitrous.

Or be on the safe side and get a good nitrous tune and let your N/A performace suffer, rather than the other way around.

[ssms5411]

Re: Which bypass jet ?

I did some more runs today with different bypass jets. The .063 jet worked the best in the bypass. My A/F was 11.5 with 22 deg of timing, zero KR and bottle pressure was around 1100psi. In the nozzel was the .047 jet. My bottle was alomst empty so I'll get that filled tomorrow and take it on some more runs. Looking at my scans my injectors were only at 56%, which is good. When the nitrous hit, it was just about the same as when I had the supercharger on there running 10 psi. In all, I think I like the nitrous better than the supercharger.

[97rs4life]

Re: Which bypass jet ?

good to hear you are figuring it all out. What injectors are you running? They must be bigger with all the work you have done to the thing. I have stockers and NA I am at like 85% when I go WOT. .047 jet, that is like 100 shot isn't it?

[ssms5411]

Re: Which bypass jet ?

I have 36lb injectors, I thought the .047 jet was 85hp. Thats what it said in the instructions, but who knows. I think the .053 jet is a 100hp. I'm going to get the bottle filled tomorrow and make some runs and if all goes well I hit the dyno on Tuesday. Maybe I'll throw in a .053 jet if all is going well.

[Shodown]

Re: Which bypass jet ?

I have 36lb injectors, I thought the .047 jet was 85hp. Thats what it said in the instructions, but who knows. I think the .053 jet is a 100hp. I'm going to get the bottle filled tomorrow and make some runs and if all goes well I hit the dyno on Tuesday. Maybe I'll throw in a .053 jet if all is going well.

I would check that again. The instructions I have say .047 is 100 shot. Might want to check that cuz I dont want you to do any damage.

[ssms5411]

Re: Which bypass jet ?

Your right, I just looked at the instructions and it says a .045 jet is 85hp, so the .047 is the 100hp.

[1DangerousV6]

Re: Which bypass jet ?

if that all works out good try a .055 :D

____________________
12 SECOND NITROUS POWERED 98 A4 V6 CAMARO
www.MySickCamaro.50megs.com
WILL BE IN CAMARO WORLD MAGAZINE THIS FALL

[AZ3.8Camaro]

Re: Which bypass jet ?

if that all works out good try a .055 :D

I thought the .055 was the 100 shot.
Hmm.....
No wonder the car was fast on the street! Should have took it to the track on those jets.