Wicked69

My car has been running extremely well. It is running a 118mph in the 1/8th but only 6.38 is its best. I have tried everything to build boost and really don't want to change the convertor or mess with the tune. Bare with me here. The reason being is my car weighs 4000lbs and I never dreamed of running 118mph. I don't want to take a chance of losing how well the car runs once it gets 80ft out.

I have tried different 2 step settings on the transbrake, tried footbrakeing to build boost, etc.. The car leaves on about 3 psi and is a dog until about 80ft and then runs like a raped ape.

Here is what I want to do. I have a Nitrous Express Hitman kit that I was going to use on my old big block. It has been drilled already for E85. I run the vic jr. manifold and tall edelbrock elbow. The plate should fit there no problem. I have a 2 step, run factory computer, and have a toggle switch to arm the trans brake first. I do that so I can drive the car in reverse without having to push in the trans brake. With that said, what would I need to do run a 50 shot of nitrous and have it activate off the transbrake but either have it kick off prior to the 1-2 shift or have it activate off the transbrake and then spray from 3500-6,000rpms. This way it would activate in each gear but shut off prior to accidentally hitting the rev limiter. I figured a 50 shot would spool up the turbos quickly and also cool down the intake air temps a little throughout the run.. I am not sure I could do it that way or not. I do run meth/water injection that kicks on at 10lbs of boost. The best thing to do would probably just use the 50 shot to get the car the first 80ft or first 2 secs of the pass.

Anyways, how would I go about wiring this up and what would be your suggestion to use the kit I already have? Next week is the 275 race at our dragstrip and I want to show up and surprise some people. No reason the car couldn't run sub 6 if I could get it to launch.

ZNix

iTrader: (1)

What stall converter do you have? You should be able to build more boost just on the transbrake without the nitrous. The 62's should spool pretty quickly. I wonder if you have some underlying issues.

Nix

tt383lt1

iTrader: (3)

you have some kind of issues. on my twin 72mm setup i get boost at 2700 rpm and i can get over 20 psi on the trans brake alnoe.

what is you boost leval at and when does it build up??? and are you sure yor exhaust is 100% sealed.

ZNix

iTrader: (1)

I agree. Something isn't right.

Nix

tt383lt1

iTrader: (3)

here is a drawing i did in about 5 min sorry its not that good.

but when its armed ( nitrous switch on) and your in the rpm range ( rpm window switch)

right when you release the trans brake button it will stot nitrous as long as your in the rpm range and the nitrous switch is on.

here is the wiring but i would find out why your not building boost on the brake ( thats why you have the trans brake so you can leave on boost)

Wicked69

Thanks for the replies. Everything seems sealed. It stopped building boost when we swapped converters. My old converter had no problem. This one will build boost but it pushes the car and I don't want to hit the transbrake button with the car sliding forward. If I just use the transbrake only it won't build but about 3 lbs.

I was thinking with the footbrake the convertor is still spinning (working) and can build boost. With the transbrake isn't the convertor stopped and therefore with it being tight not allow it to build boost?

Wicked69

So this would be just a regular msd window switch? It would work with the factory pcm? I have a white wire that goes to pin 10 on my computer. That would be the tach wire I would splice into? The same one my 2 step is spliced into? thanks.

ZNix

iTrader: (1)

I have seen turbo Buicks push 20+PSI off the trans brake. I don't understand why you can only build 3. It seems like something isn't right. Usually when you can't build boost you have a leak in the waste gate system. Or the down pipe isn't sealing fully. A stall for a turbo motor, and a N/A engine are usually rated differently. Go step on the brake, spool, and tell me at what RPM the car builds 0-1PSI of boost.

Wicked69

Okay. Maybe I do have a leak in the wastegate system. We made our own flanges out of thinner steal and they are slightly warped. I didn't think it was leaking enough to make a difference because once it does get going it goes straight to 15lbs immediately. It just takes a while to get going. Maybe I just need to get the thick flanges and re weld those on.

ZNix

iTrader: (1)

A leak would probably slow spool pretty significantly. Do the paper trick if you can. Take a piece of paper and place it near the areas where the flanges meet. If the paper moves, there is some air leaking.

Nix

Fbodyjunkie06

iTrader: (10)

I would use it all the way down track.

There are plenty of diagrams out there that show how to wire up a kit so that while on the transbrake it doesn't spray any nitrous. Have the window switch activation set to the same rpm you set your two step to on the transbrake. With the interrupt even with the window switch set to spray at the rpm you launch at it won't spray until you release the transbrake.

Are you even using a two step?

Wicked69

Yes, I am using a 2step. I agree about setting it at the same 2 step rpm. I am saying to do a 50 shot. Does everyone pretty much agree that a 50 is all that will be needed? I have always heard that you don't want to spray nitrous with the rpms below 3k. I think if I set the transbrake and nitrous to spray at 3600 and to shut off at 6k, this way it is likely the nitrous will just shut off while shifting or in the ball park. If I do that then I should be at 5k after the 1-2 shift which will still let the nitrous to be used almost all the way through the 1/8th mile and shut off just prior to fnishing the 1/4 mile.

Wicked69

This is the switch I was looking at. Will this switch do what I need and can it be used with my factory pcm? It looks like it can be turned on and off and I could set it in 100 rpm increments. Just need to make sure it can be used with my pcm.

http://www.jegs.com/i/MSD+Ignition/121/8969/10002/-1

Fbodyjunkie06

iTrader: (10)

Yes that is the correct MSD unit to use with our ignition.

Honestly I would set it up to spray through the shifts if you have a well built transmission.

Are you going to run a dry shot or a wet shot? I think 50-75 will be all you need.

Set the two step at 3500-3600 and the activation point there also and hang on. I have a feeling as soon as the nitrous hits it will hit full boost immediately. You may have traction problems then.

May have to yank a couple extra degrees timing in those rpm cells from 3600-4800 where it is going to really add some power so it doesn't spin. If it does initially.

Wicked69

Okay, cool. Thanks man. If I have traction problems I do have a set of slicks on another set of rims.

Fbodyjunkie06

iTrader: (10)

Just a heads up that 8969 will work on your car, just make sure you select the 1 cylinder mode that is for LS1's and 99-up mustangs that use coil on plug ignition.

Wicked69

Is this a selection that I make on the box or when I order it? I just ordered it so hopefully its a selection you make on the box.

Also, you were right there are a ton of diagrams for transbrake and nitrous. Out of those diagrams which would the one I should reference? All of them look a little different. Here is what I have already:

LS1 2step, transbrake and a toggle switch to arm the transbrake, a Nitrous express plate kit, and the new msd box that I just ordered.

I want the nitrous to kick in when I release the transbrake. I have a micro switch to use for full throttle. I can also use the same toggle switch that arms the transbrake to arm the nitrous or I can use a different switch. I still have an extra toggle switch on my control panel. I don't normally arm my transbrake until after my burnout and after I hit the first prestage bulb.

With this information which diagram would be the best one to use that is out there using one nitrous kit?

Thanks again for all the help. Hopefully, we see 5's this weekend.