OK I did some scans and had a fuel pressure gauge hooked up this morning.

I ran a .073 nitrous and .055 fuel jet

As soon as the nitrous hit (4000 rpm at full throttle) the O2's went to a SOLID .890 to .930 during a 1st and 2nd gear trial.

AF monitoring via OBDII stated it was 12.9 to 13.2 through the run

Fuel pressure sat right around 78PSI and held solid.

I know depending on my O2's is not the best case scenario (I'll tune this more accurately on a dyno with a WBO2 later) it seems as though my setup is "safe" so far.

No knock retard was seen.

Spark Advance went from -40 in first at 3400 rpm to -34 with 4 degrees of retard at 4800 rpm.

Spark Advance stayed at -33/-34 throughout 2nd gear from 4200 rpm to 5500 rpm.

Any feedback for me?

Setup is:
NOS 5176 - jets listed above
Walbro 340 in tank fuel pump (adding the NOS inline tonight for safety)
Mallory 685 - 4000 rpm to 5200 rpm window switch (at track it's 3200 rpm to 5200 rpm as I have ET Streets on the car) - 4 degrees of retard
NOS 20360 58MM TB

Mike

 

The scan software only tells you what A/F ratio the PCM was "targetting" based on temp and rpm. It does not tell you what the A/F actually was. The stock sensors are not very accurate at the A/F ratios you need for nitrous, but I'm sure you've heard that before.

What size injectors are you running? If you are running 24's, that fuel pressure only nets you additional fuel flow equivalent to about 90-100HP. As I recall, my original NOS 5176 kit, with the inline pump and nothing in the line to the vacuum tee (the way the kit was originally sold) would develop 85-90psi, and that was intended to support 125-150HP - albeit set up very rich.

What nitrous solenoid are you using? The two NOS Super Powershots in series that come with the 5176 kit may be limiting flow more than the nitrous jet.... depending on what the rest of your nitrous supply system looks like... size of line, length of line, filter type, high flow bottle valve, etc.

 

Good questions, I should have provided better info:

30lb SVO's

The solenoids are Edelbrock from the LT1 kit that is the duplicate from the 5176. I had my choice of the 2 NOS solenoids or 2 Edelbrocks as I had bought 2 used setups.... The Edelbrocks had a much larger gauge of wire and I judged that to be a sturdier build solenoid (coming from car audio field).

I chose the NOS "blue thingy" for fuel pressure as they had been building theirs longer, I still have the edlbrock one left.

I've emailed Edelbrock but no response as of yet on the size of the solenoids orifice.

OK bottle is polished Edelbrock 10# with NOS high flow bottle valve (Edelbrock valve wouldn't work with blow down tube).

4AN line - NOS high flow rebuldable nitrous filter - 20' from rear to solenoids on the passenger inner fender

4AN to 3AN - 4' from fender to NOS 20360 58MM TB - .073 jet is at the TB inlet.

Let me know!

Mike

 

Things look good but I would still fine tune it with a wide band on a dyno. Always target a little rich on the dyno

 

Mike - looks like the car isn't experiencing any trouble. After a couple WBO2 pulls to make certain and some fine tuning, that car should be moving pretty well.

I have a Q for you - how do you have your Mallory Hyfire tied into the ignition? I couldn't find an official Mallory 96+ single connector style ignition harness and ended up with an MSD piece (#8877). Only problem is the wires arent color-coded the same.

 

I'm using a MSD 8876 connector from my old MSD 6A
Here's the wiring diagram:
MSD to Mallory
Red to Red
White to Green
Orange to Yellow
Black to Black


You should have the MSD 8876 since it's the dual connector. The color codes would be the same for all MSD products though.

Have fun!
Mike

 

My car (96 T/A) has the single-connector style coil, so the 8877 is right for my application. Otherwise the Mallory 29068 harness is the official dual-connector style plug-in.

That diagram helps me out a bunch. After studying the application instructions for both the Hyfire and the MSD harness and assuming that black on the MSD harness was still a ground, I had come up with the same wiring order. But I didn't feel confident enough to do it that way just yet. Thanks for the help and the confirmation!

 

I ran a NOS 5176 on my LT1 TA for a few years. I ran it w/o jets and it turned out to be about a 180hp shot. (verified on dyno)
Only fuel mods I had were the included inline fuel pump and 30lb injectors. I never had a prob and it ran very strong for many years. Good luck and have fun.
brad