Need Quick Answer: Nitrous Question

[jerrysta]

I started installing my nitrous system yesterday and all went pretty well. I am just wondering where you guys tapped into the fuel line and how?!

I am running a wet system.

Please get me an answer quick as this is holding up the install.

Thanks guys!!!

[MN6WS6]

Schrader valve on the back, drivers side of the engine. That is also where you should put your fuel pressure safety switch. First you have to purge off the fuel pressure, then remove the needle with a valve core remover tool available at any parts store. Then, you'll need a 4 AN female connector to screw onto the schrader valve, and the corresponding convertors, tees, and whatever else you need to hook up the fuel pressure safety switch and to run the line to the fuel solenoid.

Don't forget you have to change the plugs out to standard ones gapped at .035, the WOT switch, and you need to get a rev limiter that cuts spark (like an MSD box) and not fuel (like the factory computer does) and a window switch for safety reasons. Do not cheapen out and fail to buy these things because without them your first time on the bottle could be your last.

[jerrysta]

I'm just at the point where I am ready to install the electrical stuff. I have the bottle installed and the line has been run to the engine bay.

I thought someone on here had a pic of some type of plumbing adapter that they used as kind of a y connector from the shrader valve. I'm an idiot when it comes to eyeballing sizes and I was hoping someone would know the size of the adapter, too.

Also, I have an arming switch and was wondering where the best place was to run the electrical lines into the interior?

I am also wanting use the rubber sleeve connecting my Vortech elbow to the throttle body as the entry point where the N20 would spray. I saw in another post that you have yours running through a rubber boot. Has that stayed secure for you over the years or do you have to adjust it all the time.

[Injuneer]

The best way yo attach ANYTHING to the Schrader valve is an NOS Part # 17535 -4AN 90deg Swivel Fitting. It's shown on the valve in this picture:



Attach a -4AN hose with a -4AN female on one end, and a 1/8"NPT male on the other (you can get these on e-Bay, or for high $$ from NOS, etc.). Run the hose to a brass "tee" fitting. This is available at most hardware and auto stores. It has a 1/8"NPT female connection on three sides.

Now you will have 2 connections available. Put your fuel pressure safety switch in one 1/8"NPT hole. Put a 1/8"NPT male to -4AN (or whatever size your kit's fuel hose is) male adapter in the other 1/8"NPT hole. Then attach the kit fuel hose to that.

When working on the Schrader valve.... DO NOT apply any serious torque to the Schrader valve. It will snap right off - its only swedged on the line. That's the advantage of the swivel fitting. It allows you to aim the connection any way you want, its not pointed straight up at the cowl, and it is easy to tighten in the correct position.

[jerrysta]

Okay. Thanks a ton Fred. That really cleared it up for me.

The one thing I am still in the dark about is how to hook up the MSD6AL box.

I have a friend who can help but I am trying to do what I can by myself. I'm 28 but am very much "learning" on this car.

Thanks for all the help so far.

[Injuneer]

Did you get the MSD "harness" specifically for your year car? Makes life very simple. All you have to do after you plug in the harness is run a wire from the MSD box to ground, and another (with fuse) to the red "+" box near the battery.

[jerrysta]

I was not aware there was a harness. Should Summit have known about it? If it makes things easier than I will get it.

So I go fuel line Schrader-to the 90 degree NOS fitting-to the 4AN hose-to the tee fitting. One connection to the fuel pressure safety switch-one connection going out from there--

I think I've got it. No spraying until all of the safety stuff is in....I'm nervous enough as it is.

[Injuneer]

MSD has an LT1 specific harness.... not likely that the Summit guys would know about it. They have two different part #'s, one for the dual-connector coils (93-95) and one for the single-connector coils (96/97).

Let me see if a quick search at MSD shows up the part #'s.

Dual-connector is PN 8876
Single-connector is PN 8877

http://www.msdignition.com/install_access_3.htm

[jerrysta]

Is there an easier way to adjust the fuel pressure safety switch? I do not have a fuel pressure gauge.

If not would a local garage have this gauge? I'm very nervous about someone else setting that switch......might not have a choice though.

[jerrysta]

What pressure should the fuel pressure safety switch be set at?

[Injuneer]

I generally set the FPSS by hooking it up to my air compressor piping, using the air compressor air pressure regulator to set the air pressure at my desired cutoff pressure, then tweek the screw on the top of the FPSS so the contacts just closed (verify with a circuit tester across the FPSS terminals) at the air pressure setting.

If you are running a wet nitrous system, and you are using a stock fuel system, You should see at least 41psi in the fuel system at WOT. I would try the FPSS at say 38psi. That may be too close, and the initial shock of opening the fuel solenoid might instantaneously drop the rail pressure to 38psi and trip the switch. That will cause the nitrous system to stutter on and off.

It would be helpful if you know your actual fuel pressure at WOT, then set the FPSS about 5psi lower than that. With that apporach, the system shuts down when you are running about 6% shy of the required fuel. Your tune should be rich enough to prevent that 6% shortage from causing damage.

[jerrysta]

Did you use MSD's supplied 6000 RPM rev limiter or did you buy a different module?

Almost done, I'm getting excited! Especially since the car has been getting progressivley faster anyway, with practice.

[MN6WS6]

You can't run a 6000 pill on a stock ECM tune. The ECM cuts fuel at 5900 in first and 5700 in all other gears I believe. On stock tune, I had my car cut the nitrous off at 5300 with the MSD at 5500. That's a 200 buffer before the ECM cuts fuel, which is plenty. Now, I have a Hypertech with the fuel off at 6500, MSD at 6300, and nitrous at 6000 or 6100 (can't remember).

[jerrysta]

I don't have a stock tune, but I'm not sure what the rev limiter is set at.


My tune was done by MADZ28 a few months ago. I'll try to check his site to see if he lists the normal tuning parameters.

So, did you buy the extra MSD plug in modules when you got the box? It comes with 3k, 6k, 7k and 8k plug ins.

[jerrysta]

The tune set the limiter at 6k.

What rpm would you recommend then?

5700 or so? 5800?