N2O 2G at school Options

[SCCA Stang]

ok, so some of you know that I attend school at UTI in Glendale heights, IL... well anyway, for the past 2 and a half weeks I have been in coarse 3 (street legal power and performance). even though we focus on street legal, we also get into N2O.

the car that my group has been working on is a '97 GST with stock internals, 2 and a half inch mandrel bent exhaust with a stock cat (street legal) a stock turbo with a boost controller and tuned with an SAFC II. also mounted on this car is a Nitrous works wet N2O system.

over the coarse we have base line dyno'd, and tuned individual components to see what accually works and what doesn't.

all of this was on 12 LBS boost and a stock BOV

base line we pulled 154 HP at the wheels and 165 torque.

with a K&N drop in, we accually lost 2 HP and lost 3 torque

with a K&N bolt on replacement filter (takes the place of the stock air box), we picked up the pace quite a bit 167 HP and 172 torque at the wheels.

with the exhaust we didn't do a damn thing to either numbers above the K&N

Now here's the fun part

N2O time: today we were able to use N2O. we set everything up, built the pressure in the tank to 900 PSI and checked the spray patterns in the fogger.
we noticed the the last people to use the car had crushed the jets, so we attained new ones from the instructor.

the jets we pulled out were .024" (fuel) and .052" (N2O)
the jets he gave us wer .024" fuel and .055" N2O

we asked about the change and he said that we didn;t have anymore .052 jets, so we just get a little extra N2O flow.

now on the dyno: 1st pass, all mods combo'd without N2O, 176 hp, 178 torque
2nd pass, all mods combo'd N2O armed (WOT switched)
starting my pull at 2,000 RPM I started to see large quantities of smoke at 3,000, I backed out of the pull, the instructor was sure it was just tire smoke, so he gave me the go to pull again.
this time as I hit 3,000 rpm, the engine backfired, WOT with N2O spraying hard. the increase in manifold pressure exploded the BOV..... DAMN!!!!! first thing I thought was blown up engine because of the explosion, fire and smoke that I saw, not to mention now with an engine that died instantly upon explosion.
turns out that I don't think it is as bad as I originally thought, at least till we tear into it and find out if we destroyed anything internally.

really bad news... turns out that the .052" N2O jets that were in the car were the wrong ones to begin with... it was supposed to be .038"!!!!!!!!!!!!

BTW, looking at the dyno sheet, my power lines were headed straight vertical at 2500 RPM and crashing at the bottom at 3000 RPM (backfire point). at 3000 RPM I had 190 HP showing and it was going up in a hurry... damn that was a big N2O shot.

just though I would share my one and so far only experience with laughing gas.

[treydawgs4g63T]

sounds like fun!

[turbohcar]

Show 'em how to do a 6-bolt swap!

[awd4kicks]

Wow... I'm surprised that the teacher didn't know better. (Maybe he didn't have the time)

I'm not an N2O expert by any means, but I have learned there are set combinations that each Nitrous supplier comes up with to reach particular levels of power with their kits. A 55 jet on the nitrous may equate to some realistic shot such as 100HP or something, but it has to have the right amount of fuel to burn properly and keep it safe. For instance if you say a 38 jet is good for 50HP then you were only giving enough fuel for a little more than half of the nitrous he set you up with.

Also I understand these are mule test cars so it doesn't matter. But if they are going to allow a cat back in the mix as street legal (Which it technically is not in Illinois) then he might as well let you put on a race cat. That stock cat is a rediculous bottle-neck!

BTW - I've found out that you can have a nitrous back-fire without destroying the engine. I don't know if that holds true when the jetting is so nitrous biased though.

Good learning experiences anyway. Definitely sounds like fun and even better that it's not your car!

[natedogg]

The letter of the law says that a catback is legal as long as it doesn't make the exhaust louder than stock, which it almost always does...

[Shaun@AMS]

i heard about that when i went to class yesterday. are you in the morning or afternoon class?

[SCCA Stang]

I am in the morning.... BTW from what I understand, they tested the car somewhat and found that it definately does have a loss of vacuum (15 hg") at idle... so the next test they will do is a CLT and compression check.

[SCCA Stang]

The letter of the law says that a catback is legal as long as it doesn't make the exhaust louder than stock, which it almost always does...

I was talking about emmisions legal, not noise DB level

[natedogg]

I always associated street legal with legal to drive on the street. As in complying to all of Illinois' crazy vehicle laws.

[scrapin_frame]

we dont need to obey no stinkin laws! my exhaust is proof of that!!!!
i can launch a midget from my exhaust like a human cannon

[SCCA Stang]

so the verdict says that the engine damage is most likely piston rings or valve issues or holes blown in pistons...

at idle it only pulls 15"hg vacuum and it runs real rough
just off idle vacuum increases and the engine smooths out... all classic signs of extremely lost compression...

like kicks said... good thing I learned about N2O on a car that I didn't own

[turbohcar]

Show 'em how to do a 6-bolt swap!

[Chicago_DSM]

Dont judge low vacuum as a blown motor....Your saying you did a compression test or no?

My 1g pulls - 15in of vacuum at idle on stock cams and I understand its low, but it still could be a number of things....Large air leak, timing off a tooth, etc...

BTW, I have quite a few dsm buddies that go there....Do you know Ronnie, greenish/blue 1g with a big turbo (not sure if hes telling anyone what it is)...Its super clean, everythings rebuilt...

Then my friend Tony has a black 2g, 16g and FMIC....

I have quite a few other buddies there, I dont wanna list them all....
-Josh

[SCCA Stang]

I didn't diagnose much of any of it... I am reporting based on what the instructor told me is his prognosis of the problem...

I might have seen your friends around, but know them well... I know that low vacuum isn't an end all to be all internal damage indicator... but it is a good symptom of it.