A little nitrous scare

[rockSTAR_SS]

As the title says, I'm a nitrous newb. I'm runnin a 55 shot on my ss/sc. I need all you nitrous geeks to give me your opinions on something.

I sprayed my car tonight for the second time since I've had the kit put on (about a month and a half). The first time I ran it on the track, I noticed a little bit of popping and sputtering in the higher RPMs. I didn't think much of it. The car ran great afterwards!

Well, tonight I ran it again. This time, I took more notice to the high rpm sputtering. It's happening around 5-6k rpms. After that, I ran the car with no spray. No sputtering. It pulled nicely and still runs great in normal driving and at idle.

Now, don't get me wrong. The car pulls way harder on the nitrous. It's just this sputtering that has me worried. I don't have a wideband to keep an eye on my AFR, so I can't really tell you what's going on there. I can give my mods list in hopes that we can make sense of all this mess.

performance mods list:
GM Stage 2 tune
2.9" pulley
NGK BKR7e gapped @ .035"
Airbox mod
Magnaflow exhaust
Lightly ported and polished throttle body and m62
ZEX wet kit w/55 shot jets

I'm trying to find some 60's and a modular 2.8" pulley so I won't have to worry about maxing out the 42's anymore. Any help would be greatly appreciated

 

[ACE]

i would lay of the spray till you figure it out. it would suck if you detonated

 

[rockSTAR_SS]

Good advice! I think I'll do just that until I figure it out, like you said.

 

[ACE]

yeah where did you buy the kit ?

 

[rockSTAR_SS]

Got it from a friend of mine. It's a full kit. Standard Zex wet kit, with lots of extras. Bottle heater, purge, pressure gauge, etc. I like it so far.

 

[ACE]

nice kit maybe call zex's customer service and ask them im sure they would be helpful

and let me know the outcome btw ive always though about adding spray to my ride

 

[rockSTAR_SS]

Will do brotha

 

[CBodnar]

performance mods list:
GM Stage 2 tune (fine)
2.9" pulley (fine)
NGK BKR7e gapped @ .035" (fine)
Airbox mod (fine)
Magnaflow exhaust (problem #1)
Lightly ported and polished throttle body and m62 (big problem #2)
ZEX wet kit w/55 shot jets (semi ok)

let's see, your on gm stage 2 tune and i listed everything that is ok for you to be spraying in the dark with out a wideband (well not completely ok, but could be acceptable if you have the balls and get lucky, i did, however ssdan aka damien aka dan did not and he blew up on just a 50shot). the fact that you have a exhaust and semi-slightly ported s/c and tb is where your problem started. your ether having pre-detonation or your afr is really really off which is probably true. if you didn't have an exhaust and semi-ported s/c & tb i would be able to help you easily but the fact you don't i can not help you as easily. If you know how to check your spark plugs after doing a run you could stop and pull each of them out to figure out what is up if your running lean or rich.

1. Your best bet is to get a wideband and stay on gm stage 2 tune
2. ditch the exhaust and go back to stock.
3. then from there you can just mess with your fuel jet to even out the fact that your probably leaning out to get back on the safe side to run high 11's afr.

!If i was you, I would take my advice, i ran gm stage2+2.80+airbox mod+45 wet shot+cx h/e+same spark plugs as you for over a year spraying over 10+ bottles through the car (with out a wideband, spraying in the dark not knowing what my afr was). I then changed my injectors to 60lb injectors and kept the 2.80 and up'd my shot to 75 and added a header + 3dp w/cat on the car and ever since i haven't had as much fun with the car. i wasted a little bit more money and honestly didn't get much power out of the car for the money spent in the car. Leave your car alone the way you will have the most amount of fun the way it will be if you listen to my advice above.

Also your exhaust doesn't help you out at all! All it does is make noise. Don't_Blink aka StreetDreamz, damien aka SSdan, BWSW214, and myself have all tested that out (this is why when all of us run a 75shot it is on stock exhaust). bru and dan both have tested out different downpipes and exhaust on there car and both went back to stock exhaust. All 4 of our cars have had a 50 shot run through it and now dan (damien), bru (bwsw214), and i both run a 75shot through our cars with the stock exhaust.

PROOF: http://videos.streetfire.net/video/Two-2007-Chevy-Cobalt_644357.htm
we took off the catless dp and ark exhaust off his car and then him and i were tied...
http://videos.streetfire.net/video/no-nitrous-2007-Chevy-vs_643889.htm
same day me vs him i am running nitrous with cx h/e mounted but not hooked up- http://videos.streetfire.net/video/Nitrous-Run-2007-Chevy-vs_643890.htm

how much i put down on gm stage 2 tune + 45wet shot- http://videos.streetfire.net/video/Cobalt-SSSC-makes-307whp_645209.htm

I have been running nitrous on my car for close to 2 years. I've got almost all my advice from italianjoe1, the person i believe has the most experience with these cars and some others when it comes to nitrous. I've sprayed in the dark, I switched up setups, I have given out advice to others, I've kept cars together and also advised people not to do something and run the fuel jet richer and they didn't listen and they blew up. I have all my proof and can back it up with video proof if not write up about nights when weird things occurred. PM me if you have any other questions.

another vid i just uploaded for you. dan with a 50wet shot vs me with a 45wet shot him with stock dp gutted and ark exhaust vs me with stock dp/stock header/ stock exhaust. http://videos.streetfire.net/video/Cobalt-wNitrous-vs-Cobalt_698691.htm

-Chris

 

[rockSTAR_SS]

Alright. Let me be a little more specific with my mods list. Perhaps this will make a difference in your suggestions.

I'm running stock header, downpipe, and pipes on the car. I'm used to saying I have a magnaflow exhaust because I bought a magnaflow muffler and tip and had it welded on. So it's not a full magnaflow exhaust. The ONLY reason I have it is because it sounds good to me.

When I say LIGHTLY ported and polished tb/m62, I basically mean we took a flapper wheel and smoothed out the inside of the m62. I basically did the same thing with my TB. We didn't cut any material out, just simply smoothed things out a bit. Do you still think it would cause my afr to be off real bad?

I bought the smallest jets I could buy on zex.com. Those jets are 17(fuel) and 32(nitrous). If I understand right, you're basically saying to try out larger fuel jets until the car runs high 11s in afr with the stage 2 tune?

Let me explain my future plans a little more. I was planning on getting 60's and a 2.8. I already have a tune from OTT Performance for that set-up. I was then going to do some data logging with the car and get the tune tweaked for nitrous by, say, Trifecta. I also have a meth kit, but I'm very skeptical about installing it. As if the nitrous isn't a big enough risk of blowing the engine, the meth would only increase my caution even more. Anyways, that is what I was planning on doing. Do you have any input on that? Do you still think i should stick with what you told me before and run the stage 2 tune with the set-up I have now?

I really appreciate your help. I'm going to stay off the nitrous until I get the issue solved. I definitely don't need a blown engine.

 

[CBodnar]

Alright. Let me be a little more specific with my mods list. Perhaps this will make a difference in your suggestions.

I'm running stock header, downpipe, and pipes on the car. I'm used to saying I have a magnaflow exhaust because I bought a magnaflow muffler and tip and had it welded on. So it's not a full magnaflow exhaust. The ONLY reason I have it is because it sounds good to me.

When I say LIGHTLY ported and polished tb/m62, I basically mean we took a flapper wheel and smoothed out the inside of the m62. I basically did the same thing with my TB. We didn't cut any material out, just simply smoothed things out a bit. Do you still think it would cause my afr to be off real bad?

I bought the smallest jets I could buy on zex.com. Those jets are 17(fuel) and 32(nitrous). If I understand right, you're basically saying to try out larger fuel jets until the car runs high 11s in afr with the stage 2 tune?

Let me explain my future plans a little more. I was planning on getting 60's and a 2.8. I already have a tune from OTT Performance for that set-up. I was then going to do some data logging with the car and get the tune tweaked for nitrous by, say, Trifecta. I also have a meth kit, but I'm very skeptical about installing it. As if the nitrous isn't a big enough risk of blowing the engine, the meth would only increase my caution even more. Anyways, that is what I was planning on doing. Do you have any input on that? Do you still think i should stick with what you told me before and run the stage 2 tune with the set-up I have now?

I really appreciate your help. I'm going to stay off the nitrous until I get the issue solved. I definitely don't need a blown engine.

1. porting the sc & tb will cause your afr to change. even if you only did it a little bit it will affect it a lot!

2. i never liked zex and the reason of jet sizes is a whole other reason for me to hate them some more. there kits don't know what fuel rail pressure our cars are at so guessing like there charts say to put a 17fuel in the car isn't the best idea. our fuel rails flow at about 58 so if you wanted to get technical you should prob have at least a 21jet size to be in your car just to be safe if you didn't touch your sc & tb. that is what i ran when i used to run with the 45shot. the sc & tb would cause you to run leaner so if i were you and not planning on getting a wideband i would run a 21 or 24 fuel jet/ 32nitrous jet.
http://www.zex.com/Catalog/ZEX101-05/PG22.pdf

3. the sc porting and tb porting would cause you to run leaner and could be the reason why your car is breaking up. i would tend to think if you hook up a wideband sensor in your exhaust and gauge somewhere in your car you prob. running lean and since your on the stage2 map's it knew it was breaking up or there was problems so it cut out. just a thought. i've had this happen to me when i was on the highway while it was really cold out and the car was running like an animal and ether the boost would go half way or the car would just shut off while romping on it down the highway. lol. happened to my friend and i. both of us thought we blew up our cars but we didn't. lol

4. if i were you i would stay on gm stage 2 tune + 2.90 pulley + airbox mod + get a wideband!!! if you get the wideband you can pretty much tune yourself out leaner or richer by the fuel jet.


option #1- stay on gm stage 2 tune
GET WIDEBAND!

a. if your running rich you put a smaller fuel jet in and you run leaner.
b. if your running lean you put a bigger size jet in and you run richer. pretty basic.
c. you would want to stay on a 50shot or less because the higher the shot the more chance you have of getting knock since your on the gm stage 2 tune.
d. get someone with hp tuners to hook it up to your car and go do some pulls with it monitoring knock. if your car gets no knock then your good to go and you can monitor your afr yourself with a wideband. to get someone to scan your car and monitor things should cost no money because you do not need to un-lock the car or change anything your keeping gm stage 2 tune all you want them to do is scan the car and watch and monitor for knock. after have them save the file or highway pull and do some more then you can have them send it to your e-mail and then you can send it to my e-mail and i can look over them for you.

option #2- get 60lb injectors and get 2.80 pulley

a. bump up your shot to 75
b. work with me on tuning your car to copy cat my car however a little more on the safe side
1. ether come to me (i live in new jersey) and will tune you.
2. buy hp tuners for yourself and i will work back and forth with you over the phone and exchange tunes through e-mails or i'll fix yours up.
3. i send out my laptop and hp tuners to you and you pay for the shipping to get to you and the credits you have to un-lock to tune your ecu ($100 bucks) and throw me some money on the side also for in convincing myself to help you
c. *enjoy your 300whp+/300+torque machine while spinning them tires like crazy*
d. *save up for a 6 puck clutch so your car can handle the power.* http://www.chevycobaltforum.com/forum/showthread.php?t=496

i kind of already said what i would do but i gave you 2 options. only you can make the decision. i must ask you though, what are you looking to get out of the car? dyno numbers? 1/4 times? auto-x'ing? roll racing? or just highway enjoyment for yourself?