I'm thinking you may not even have to install the engine side nitrous system if one really wanted to avoid running nitrous through the engine. Just use a typical ALS tune to light off the afterburner.
A typical ALS tune would be running on a 2 step with around 5%+ rich on the a/f mixture and a certain amount of timing retard. This should give you some burning of the mixture in the exhaust system. Maybe enough to light off the afterburner.
The amount of mixture richness and ignition retard would need to be figured out on an individual basis.

The main advantage to also running some of the nitrous through the engine is to help get the engine on the torque converter if the total combination was using a relatively tight torque converter.

 

Hey Mike - I'm going to try that with mine this year. If it doesn't light off right away how about using the 3 step trick and bumping into the beams with the rev limiter set to a low rpm while on the brake pedal? I'm in the same boat as you, need to get the nitrous out of the motor completely. Give me a call sometime and we can compare notes.

 

At this point im undecided on which way I will go but leaning toward nitrous through the motor.
This is a rear mount turbo setup so I think it would act a bit different being farther from the engine. LIke a motor on nitrous there is always a flame coming out the collector. ON this setup im not sure that flame would reach the turbo. I guess it doesnt need to if I feed it at the collectors. Its just adding volume.

Before we did this setup it was NA with a 100hp kit on gasoline. This was like a holy hell wake up call to the motor and the S-10 would go 12.5s at 104. With the current setup on 13-14 psi on e85 it goes consistent 105 mph but about a second down on ET. Yeh its probably more like 2 sec. out before full boost. Im thinkin with a 50 shot in the motor and a hobbs switch to turn the kit off at a set psi of boost she should be able to get up on boost pretty quick. ONce it builds boost its fast. It just cant quite get there.
There is so many ways to do this better but this a low low buck deal for him. I just have fun and wanna see it work.

DAVe,
Hows it going bud? Im thinkin with a 3 step like your talking you would have enough flame going on in the exhaust to light off the mixture .
Not so sure what notes I might have to compare but im good at bouncing ideas back and forth .

 

you tried M5 VP brand methanol yet ??

 

read up on ideal gas law...
http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/idegas.html

 

How are you applying this to my particular situation?
Do you know the particulars of my situation?
Would you like to know some important specifics about my particular situation?
I wouldn't want you to continue with certain incorrect assumptions in mind.

 

I guess I could put a spark plug in just after the entry point of the nitrous kit.


Whats up with the M5.

 

I've decided to start on a new series of tests involving the afterburner.
The tests will involve shutting off the large primary nitrous system at the same 175 kPa MAP as I'm presently doing, but instead of also shutting down the afterburner at this same point, I'm going to leave it on through the end of staging and into part of the 60 foot. I'm hoping this will create a reserve level of compressor speed for me to tap into during the launch. I want to be able to step up the boost level at some point in the first 60 feet of the run. Right now, the boost ramp up is very closely tied to the rpm ramp up with practically no reserve compressor speed to tap into.

 

No compressor speed on reserve ? You mean it won't spool any faster on its own ?

 

During the launch, The MAP rise is closely tied to the RPM rise. Or, the compressor/turbine speed is already accelerating as fast as it can. In other words, I have the wastegate and BOV clamped down hard and the rpm and map rise relationship cannot be improved upon. If I wanted to massively step up the boost level, say 20 feet out, I couldn't. The wastegate and BOV are already clamped down to give me all that I'm getting.
Once I have the compressor up to speed and the engine is over about 6400 rpm, the wastegate comes into play to control the upper boost level. But, before that point, the wastegate is clamped down hard to get that boost up as quick as possible. The extra exhaust energy that the afterburner would provide would improve on that map to rpm rise relationship. Maybe enough to have the wastegate come into play to actually have to slow down the boost rise rate, giving me some reserve to command a step up in boost level during the 60 foot.

 

Imagine this. If one were to not run a wastegate, they would need to carefully match a turbine wheel and housing large enough so that the turbine wheel and housing would control the compressor speed and boost level relative to the engine rpm. The compressor speed would be closely tied to the engine rpm.
Wastegates have made us lazy when it comes to matching the turbine wheel and housing more carefully to the engine and the expected boost to engine rpm relationship. We just throw a smaller turbine wheel and housing on the thing and dump the excess exhaust energy to control the turbine speed. With this large turbine side that I'm using, I certainly don't have that luxury.

And before anyone asks, a smaller a/r turbine housing is not available.

 

Your Turbine housing is an open scroll or a split scroll?

Tom Vaught

 

It's a split housing.

 

Each cylinder bank feeding each side of the split scroll?

It's amazing to think you are putting 100 percent of the exhaust through that turbo for that length of time before the wastegate comes into play.

 

The short exhaust collectors from each bank 'Y' together right at the T/4 to T/6 adapter of the turbine housing. The 'Y' section is not internally split to completely separate the two banks before the split housing. The T4 to T6 adapter is also split, and incorporates my homemade spool valve, which I'm not presently using. The afterburner is feeding about six inches from the end of only one of the collectors.

The wastegate comes into play just before the 1-2 shift. The boost peaks to a controlled level just before the 1-2 shift and I have to actually control down the boost level during, and slightly after the 1-2 shift to maintain traction. I'm presently playing with some chassis settings to see if I can eventually get away with more boost through the 1-2 shift.

 

I'm thinking that if I can improve the performance of the car during the 60 foot, that should automatically allow me to step up the boost level through 2nd gear. That has seemed to hold true in the past as the power level was increasing as I was getting the tuning with this 91mm squared away. I've now reached a point with the tuneup where she just won't spool any quicker without the use of any nitrous in the 60 foot.
Still, the rise rate is respectable considering the engine size and the turbo, but she could use just a tad bit more help.

 

Kinda off topic but do you have an anti-roll bar on this GN?

 

Yes. I'm using a TRZ Motorsports model.

 

OK. I've decided I'm not going to fool around with this thing. The new plan is to use a relay controlled by the transbrake circuit that will switch between MAP switch and delay box control of the nitrous system. The routine will go like this;

On activation of the transbrake, the relay will switch control of the nitrous system ground circuits to the MAP switch. This switch will control the level of MAP during staging. This staging MAP level will be 5200-5500 rpm and 175 kPa MAP.

On release of the transbrake, the relay will switch the ground circuit control of the nitrous system from the MAP switch to a constant ground. This will allow the nitrous system to reactivate for the launch of the car.

The power side of the nitrous system is controlled by a relay that is controlled by a delay box. On the release of the transbrake, the delay timer will keep power going to the nitrous system until the desired time out. I'm going to start with .6 sec of delay and move the time up from there.

 

This run was with the delay timer set at .600 sec.
I'm sure glad I didn't pick one full second to try.

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