need nos tuning help on hot air car

[jas85t]

ok got everything put back togther arter top end was redone and ported and polished bought a nos wet shot for my hot air car got it put on installed 41 nos and 31 fuel jet for a 75 shot or so i thought the wet shot is located right under my turbo where it goes into the intake was going to head to track but i thought i would try it out first to see how it did well i floored it and hit the switch and it popped really loud 2 times and started smoking got turned back around and went back to house oil comming out opened my hood to find my maf screens in my air filter maf split in half and blew seals out of turbo and bent rod inside turbo after i toor it down well now that turbo is in shop getting rebuilt and upgraded to a 49 might as well while its in there getting rebuilt anyway my fuel pressure is at 38 with vac. off i was running stock chip when this happened and fuel was some 93 and 109 mixed togther i would say about 100 octane so my guestion is this what went wrong any help would be appreciated would like to fix before turbo gets back if i need to order something thanks

 

[NOSjohnWE4]

nitrous help

jas-
first and foremost, use punctuation. it's hard to dicipher what you're saying. you left out a TON of important information:
1) are the pistons stock cast?
2)did you increase fuel pressure?
3)what spark plugs did you use?
4)did you pull out any timing?
5)what manufacturer was the NOS kit from?
6)was it a "generic" EFI kit or the one from NOS that was built for GN's?
7) lastly, and i know this seems obvious, but did you read ALL the directions? thouroughly? at least twice?
....not that i'm making fun, but i know in my hasteness when trying out a new part, if i get too excited, i forget sh!t and get anxious and then all hell breaks loose. believe me when i say it pays for me to read the destructions (directions) at least 2 times, if not 3 times.
- off hand it sounds like you ran it too lean. But, with everything there could be 1 of 1,000 other explanations. i hope i can help further. my 2 pennys worth.

 

[KEVINS]

Sounds like it may have been a lean backfire. Check the white ceramics on the plugs VERY carefully. If it detonated then it may have cracked the ceramics.

ks

 

[jas85t]

answers to some of your questions,
1) stock pistons
2) FP 38 this is what i normally run and i didnt change it
3) stock chip thought i would run this because my others are hi timing
4) kit is made by nos for all efi they dont make a (special) one for hot air cars
5) 1 deg. cooler plug dont remember brand off the top of my head
6) i do now how to install nos kits i have one on my other vehicle that hasnt given me any trouble even after 120000 miles and still gets a bottle every weekend while tr is toor down
----- i agree it sounds like a lean problem what i need to know is --
1) how much fp
2) jet sizes for tr from one that is running nos on there tr
thanks for your help

 

[NOSjohnWE4]

NOS....we love it

jas-
you went the right route in using plugs that were colder but i think you should raise your fuel pressure at least 3 to 4 psi. i'm almost positive it's a lean condition from fuel starvation but you could also have a bad plug wire, vacuum leak or incorrect timing (hence the 2 degree recommendation). is not 38 the static pressure for a stock car? also i think it's important to pull at LEAST 2 degrees of timing out. you tune a car by reading the plugs...especially when running nitrous. did you take a look at the plugs?
i've installed, at MINIMUM, 10 nitrous kits from various manufacturers. so, just because i've installed some doesn't mean the next one will be right. call NOS if you need recommendations on jet sizes. they will be more than helpful. i know a ton of stuff about cars but the first time i admit i know everything will also be the first time i'm wrong.

 

[SLOW_85]

This was posted by Louie Arnold. Might be of help.
THANKS, Louie!

http://www.turbobuick.com/forums/showthread.php?s=&threadid=12380

 

[alb84]

" What is really scary about NOS to me". Otherwise known as what I did on my summer vacation. With a waste spark system, if the plug does'nt fire on the compression stroke, it will on the exhaust. You would think that would be ok, but its not a perfectly timed event. In other words it blows the turbo off its mounts, and damages everything else in its path. All because the ignition was'nt able to overcome the higher cylinder preassure. Lower the boost, increase the fuel preassure, And get the absolute best plug wires you can find. Use AC Delco plugs. (no titanium tips or split fire anything) The stock chip is great. The fuel should be over 100 octane. Fuel pump must be up to the job, and a guage that you can see while you are makeing a run is a good idea. A boost gauge is a must. Just my humble opinion. Later.....Danny

 

[IRaceAV6]

What is even scarier!!!!...

Folks who have never used NOS on anything giving advice on what to do with the system on somebody elses car.

In the case of a "stock" '84 to '87 car you would have no need to reduce boost from the stock factory setting - the stock setting is around 14lbs max. On the '84/'85 cars you will be lucky to see 12lbs as the stock factory boost setting because they did not come with adjustable wastegates. (My '87 T motor didn't have an adjustable wastegate either... go figure)

Mine is put away for the winter... too much work and too little time for the damn thing. I might take it out for a spin or two on Indian Summer days - (those nice rare unusually warm sunny winter days).

I have to chuckle a bunch when I read some of the commentary in this section of the board. I realize the resistance from the moral outstanding majority who believe "BOOST" is all you'll need... and NOS is a waste. Catch a clue... it does work and it works especially well on these cars.



HUH? Spark firing on the exhaust? That's new information to me. Imagine if it fired on every exhaust cycle without NOS? Wouldn't that suck too? I guess I need some more explanation on the quote below... while your at it please explain the theory of atomic fusion to me too.

With a waste spark system, if the plug does'nt fire on the compression stroke, it will on the exhaust. You would think that would be ok, but its not a perfectly timed event. In other words it blows the turbo off its mounts, and damages everything else in its path.

 

[TurboTR]

re:

Since we have a waste spark system what he says is true of course; our plugs fire once each rev, not once every 2 revs.

>All because the ignition was'nt able to overcome the higher cylinder preassure.

Since the plug fires into compression pressure, not combustion pressure I'm not sure there's really much more pressure in the cyl at plug firing time, if any in fact with or without the juice. Just my opinion though. When the new engine comes in I can shoot before/after cyl pressure traces and show the real world results once and for all...

I do agree that having the nitrous section in the same section as the alcy section probably leads to some unnecessary, frustrating troll-like replies though. The moderators refused to give juice it's own section, last time I asked anyway.

TurboTR

 

[alb84]

I did noy say combustion preassure. I said cylinder preassure, that being how many atmospheres or whatever else you would like to compare it to that the spark has to overcome to jump across a specified distance. You can reliably calculate the energy available in a ignition system by increasing the distance between two electrodes until you no longer get an arc. You can make the same calc by having a set air gap, and increaseing the atmospheres until it (in my terminology)puts the fire out. With a turbo Buick it has been my experience that you encounter max cylinder preassure(during a 1/4 mile run)right after the shift into 3rd gear. If you have a weak plug wire or similar ignition disfunction you will find out about it then. If you are going to run NOS, it would be prudent to start tuneing with higher fuel preassure(get an adjustable regulator)Lower boost(get an adjustable waste gate)and all fresh and new ignition cmponents. Also I would suggest that you have the proper gauges to quantify the changes you make to the boost and fuel. I don't think its wise to go over 50 to 75 HP shot on a t buick. I found that I got aprox. a 100 HP increase from a dry 50 shot on my hot air GN. Just my humble thoughts on the subject. Later.....Danny

 

[TurboTR]

re:

Yeah, cyclinder pressure- like this trace from my own engine at wot and 26 psi boost, right? ;-)

TurboTR

 

[quickt]

Originally posted by jas85t
ok got everything put back togther arter top end was redone and ported and polished bought a nos wet shot for my hot air car got it put on installed 41 nos and 31 fuel jet for a 75

I have not fooled with the Juice on a turbo car but on the N/A cars the Nos jet is always smaller than the fuel jet. You have 41nos and 31 fuel. IMO this should be reversed. Should be 31 NOS and 41 Fuel. On a N/A car I start with a 11-12 spread on the jets and work the fuel jet down to 10 or 9 or lower it just depends on plug readings. I have installed 400 plate shots on Big Blocks with no problems.

Lonnie Diers

 

[NOSjohnWE4]

nitrous

quickt,
you are right! the fuel jet is ALWAYS bigger than the NOS jet so a motor will not lean out with all that NOS pressure. there is a guideline attached, check it out for all who want to know. later...

Nitrous Jetting

 

[alb84]

As I was trying to relate in my earlier posts. I suggested that you use a small dry system. The hot air intake manifold (unless highly modified) is not well suited to accepting raw fuel at its intake. It splits the air in two and runs it along the full length of the bottom before it turns up and back finally to the runners. this leads to pooling , puddleing, and a erratic fuel air ratio. We have a fuel control system in place that with simple upgrades can easily provide the fuel required with optimal distribution points at the intake valves. My intake is modified. my NOS enters from the center of the top of the manifold where there used to be a vertical plate running the full length front to back. Good luck with your system. Start conservative, and you stand a much better chance of not hurting your car. Later....Danny