Need Quick Answer: Nitrous Question

[jerrysta]

Thanks Fred, that's exactly the advice I was looking for. The only thing is that I would have to send my CPU out to Ion to have the limiter increased I think.

Other than that, do you think it would still be OK to keep the window's active setting at 3000 rpm's?

The point you raised is why I asked Formula Boy about stopping his spray at 5400. It's not as if the car is done pulling at that RPM. Your point kind of confirms what I thought.

[jerrysta]

Fred, what do you think of this:

3k start

5700 stop

5900 Soft touch limiter

6000 Engine CPU limiter


MN6WS6 Mentioned that having the soft touch limiter that close to the engine limiter may not be a good idea. The reason I ask is that I would like to avoid buying three packs of pills, just to use three modules, so I'm trying to keep all the pills odd. Am I just being a cheapskate?

MN6WS6 mentioned a way to make the resistors but I don't trust myself with that yet.

[Injuneer]

I don't see any problem with setting the window switch to allow the nitrous to come on at 3,000rpm. When I still had my original "bolt-on" engine, with an NOS dry nitrous setup, I sprayed a 125-shot at 2,500rpm and never had a problem. I was running an M6 back then, so "spraying through the shifts" wasn't a problem.... I just lifted off the throttle normally to shift, and the spray stopped until I hit the throttle again. I had an MSD rev limiter set at 5,800 and the factory PCM set up to 6,200 with a HPP+ programmer.

The larger the shot, the higher you want the lower limit.... with a 300-shot, mine is programmed to come on at 5,000rpm (actually a little lower, but as soon as the nitrous hits the converter flashes to 5,000rpm). I have the rev limiter set in the ECU at 7,200rpm (it can be programmed to cut spark or fuel, or both) and the nitrous cuts off at 7,000rpm. I shift the TH400 manually to get it as close as possible to the 7,000rpm cutoff, and spray through the shifts, but the trans is built to take it.

[jerrysta]

Thanks so much. I don't know how I could have done this without the help of everyone here. I got a true education on Nitrous systems.

Hopefully the next post will be to talk about the results of the mod.

[MN6WS6]

The resistor building is nothing to it. A cheap resistor, 2 connectors, and a little soldering. It takes me about a minute to make one. Some folks even take there leftover pills from MSD and change the resistors in them so they look like MSD pills (just without the sticker. I use standard resistors, not the metal film ones (because nobody around here sells those) and coat them in hot glue when I'm done. The resistor is not subject to corrosion because the hot glue seals them shut, so they last a long time. I've had mine in my car for probably 3 years, and they are in a spot under the hood that does not always stay dry. It's easy to do, man, real easy. If you don't feel up to it, any car audio shop can do it, probably get somebody to do it on the side for a buck or even free. 2 simple solder joints, that's it. For the price of an MSD pack, I could probably make 40 or 50 pills.

[jerrysta]

Thanks. My brother is very adept at that kind of thing. I'll ask him to do it if it's that simple.

[Kevin - Blown 95 TA]

I don't see any problem with setting the window switch to allow the nitrous to come on at 3,000rpm. When I still had my original "bolt-on" engine, with an NOS dry nitrous setup, I sprayed a 125-shot at 2,500rpm and never had a problem. I was running an M6 back then, so "spraying through the shifts" wasn't a problem.... I just lifted off the throttle normally to shift, and the spray stopped until I hit the throttle again.

Fred, how did the nitrous stop when you lifted? I'm asuming the revs didn't go down all that much (below 3000), or did they? or did you also have a throttle switch of some type? Just curious how youu did it.

[Injuneer]

Fred, how did the nitrous stop when you lifted? I'm asuming the revs didn't go down all that much (below 3000), or did they? or did you also have a throttle switch of some type? Just curious how youu did it.

The NOS 5176-EO version came with an electronic WOT switch. It spliced into the wiring for the TPS sensor, and worked like any WOT switch, cutting the juice when you lift off the throttle for the shift. Its not a matter of dropping the revs below any value, its all in the WOT switch.

The EO version actually came with a CARB-EO number and sticker and was emissions legal, because it included the electronic WOT switch the prevented operation at part throttle. NOS has since discontinued the "EO" option, but I still have the sticker for it somewhere in my toolbox.

With my current setup, the nice thing about the MoTeC engine management system is the ability to program all these features, like lower RPM limit, WOT requirement, nitrous cutoff rpm and engine rev limiter, along with a whole separate program for the nitrous that is activated when the "arm" switch is turned on. The rev limiter uses a synthetically generated pseudo-random sequence for the cylinder ignition cut-off sequence, and you can even choose the "seed" number for the random sequence generater, and get some really wierd sound effects as the rev limiter kicks in. The guys at the shop that do the tuning actually have a library of seed numbers that they can recommend.

[Formulaboy95]

I cut the nitrous out at 5400 for 2 reasons. The first was to be a little kinder on the tranny since it does have higher mileage. The Second was because I found the car wandering towards the guard rail. The track conditions get worse as the day goes on, and the DR's get greasy. I guess I would have eventually bumped it up higher. Probably going to sell all my NX stuff and put that towards the HPE 383/396 block. (If the tranny doesn't die first)

[jerrysta]

Got ya. I am thinking of having the tranny built this winter along with possibly building a short block. It may be time for a rebuild, especially with my ideas for mods I want done. Since the body is solid, I figure why not.

If the car sits for a while right now, I get a cloud of white smoke for about 3 seconds. There is no odor of oil or anything. It's just a white cloud, goes away right away. It only seems to occure when the car sits for a while.

Someone told me it could be moisture built up in the exhaust due to the extreme humidity, but I am skeptical of that.

[Kevin - Blown 95 TA]

The NOS 5176-EO version came with an electronic WOT switch. It spliced into the wiring for the TPS sensor, and worked like any WOT switch, cutting the juice when you lift off the throttle for the shift. Its not a matter of dropping the revs below any value, its all in the WOT switch.

The EO version actually came with a CARB-EO number and sticker and was emissions legal, because it included the electronic WOT switch the prevented operation at part throttle. NOS has since discontinued the "EO" option, but I still have the sticker for it somewhere in my toolbox.

With my current setup, the nice thing about the MoTeC engine management system is the ability to program all these features, like lower RPM limit, WOT requirement, nitrous cutoff rpm and engine rev limiter, along with a whole separate program for the nitrous that is activated when the "arm" switch is turned on. The rev limiter uses a synthetically generated pseudo-random sequence for the cylinder ignition cut-off sequence, and you can even choose the "seed" number for the random sequence generater, and get some really wierd sound effects as the rev limiter kicks in. The guys at the shop that do the tuning actually have a library of seed numbers that they can recommend.

Thanks for the explanation. I have a switch like that, so I should have guessed that's how it was wired.