For those of you with a Cobb Stage2 (stock turbo and injectors), what's the biggest shot of N2o you've run without a problem?
Right now I'm running a NX Express Import Stage1 Wet Kit with a 50 shot on 93oct pump gas with no problems.
I'm taking it to the track this weekend (will be running 104 unleaded) and would like to run a 75 shot.
Here's where the confusion comes in. The lead tech at our local dealership said my injectors (stock) are at MAX duty cycle running a 50 shot as it is.
An "anonymous" person from one of the top tuning shops in the country said to try a 75 and if the injectors can't handle it, it'll just cutout (nothing to lose by trying). Btw, I'm running a Walbro 255 in there right now, so getting fuel to the injectors will not be a problem.
thanks in advance for those of you that can answer this from experience if there is anyone. ;)

hope you make some cash money on these races to put towards a new bottom end. Nitrous on pump gas makes me go :eek:

Stephen
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Subaru Audio Upgrades, Click the Subaru
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dont use nos

dont use nos
:rolleyes: That helps. Although I'm still a firm believer of only using the nitrous with race fuel.

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Trust dont do NoS and never will.

i'm running a dual stage shot on my bone stock wrx. 150 shot through 1st, 250 the rest of the way. horsepower in a bottle.

Why is everyone so scared of the bottle. Installed correctly with all the saftey equipment it yeilds really nice gains.

I bet you if you called Cobb and asked about running NOS with their reflashes their advice would be very similar to Stephen's. What you are doing is bad ju-ju. Just because your car runs good doesn't mean it will run good 10,000 miles from now.

I don't know how many threads I've read in the past that nitrous is just plain bad for our base engines. They simply are not built for it, period. Myriads of pistons with little holes thru them await all who travel down that path. It'll melt your pistons, and cook your engine. If you have to do it, most people say that a 50 shot is pretty much the best you'll get without any engine issues. Again the stock engines just aren't built for it. As far as for "lettucemanatee", OMG man ... a dual stage 150 shot to a 250 shot? You must be joking right? I don't think the stock engine can even flow that much hp. A 250 shot on top of your baseline 227. You'ld be right around 475hp at the crank and 350-370 hp at the wheels. It's just not possible.

Gotta love the internet... spreading misinformation since 1995. First off, he said he's running a wet kit, therefore the duty cycle of his stock injectors is unaffected by how much spray he uses. It's the pump flow you have to worry about. Second, what's wrong with using it on pump gas? how is injecting a gas from a compressed cylinder, mixed with an appropriate amount of fuel, ANY different from running more boost or porting your heads and installing bigger cams??? Answer: it's not. you're adding airflow either way. As long as it's tuned so that EGTs and AF ratios are in check and there's no knock, the car won't know the difference. Furthermore, on a car with a stock IC, nitrous will add a cooling effect similar to running a bigger IC whereas simply turning up the boost will probably cause heat soak, leading to detonation and potential problems.

I've run 55, 75, and 100 dyno tuned wet shots in the past on 115 leaded/unleaded mix (50/50). If you do insist on continuing to use nitrous oxide I would recommend ponying up money for either an EGT gauge or Wide band meter (tuna, innovate, etc) if you do not currently have those items. You'll then be able to have some form of a warning system. Shoot, a knock link would work well too.

"Spraying" is a blast, I loved it, my stock rods hated it. End result was 1 run that went a tad to lean and bang BOOM pow 2 bent rods and 1 snapped one. Will I spray again? Most likely.

Stephen
www.IAPERFORMANCE.com
Subaru Audio Upgrades, Click the Subaru
http://www.iaperformance.com/images/iasignature.gif (http://www.iaperformance.com)

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*** is N2O? dinitrogen oxide?

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Gotta love the internet... spreading misinformation since 1995. First off, he said he's running a wet kit, therefore the duty cycle of his stock injectors is unaffected by how much spray he uses. It's the pump flow you have to worry about. Second, what's wrong with using it on pump gas? how is injecting a gas from a compressed cylinder, mixed with an appropriate amount of fuel, ANY different from running more boost or porting your heads and installing bigger cams??? Answer: it's not. you're adding airflow either way. As long as it's tuned so that EGTs and AF ratios are in check and there's no knock, the car won't know the difference. Furthermore, on a car with a stock IC, nitrous will add a cooling effect similar to running a bigger IC whereas simply turning up the boost will probably cause heat soak, leading to detonation and potential problems.
Amen :banana:

*** is N2O? dinitrogen oxide?

dinitrogen monoxide is proper nomenclature. However, most blue collar non chemist types find nitrous oxide rolls off the tongue a little easier.

Duncan

Actually, NO2 is nitrogen dioxide. N20 is nitrous oxide (which is what people spray into their engines).

KJYN:

I don't think you are going to get much positive feedback (ie answers based on experience) because for the most part people choose Cobb because it is a safe, somewhat conservative, off the shelf map. I wouldn't be surprised if there weren't any Cobb stage II people that use nitrous. Period. I am not saying there are not some. I am just saying that I would not be surprised if there were not any.

Sorry, I had a little brain fart. I did of course mean, dinitrogen monoxide, or nitrogen oxide. Post changed to reflect reality

:)

Duncan

I was running a 60 shot of Nitrous and 4-5 lbs of boost very nicely on a STOCK 1990 2.2 engine. I also ran up to an 80 shot on the engine alone with no problems.

I finally ran into problems (knock) only when I upped the boost to 8-10 psi with no engine management and no fuel pressure upgrade. It was at this point while running down the track at 8 psi and 60 shot that I blew out a piston.

Now please note, I suffered detonation of the type that breaks your piston, not the pre-ignition type that makes little holes in the piston, ie cotton candy. There is a BIG difference in these types of detonation.

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I am runing a NX wet EFI kit and were I live there is no where to get dyno tuned and I have a crap autometer air fuel ratio gauge it feels like I am runing around a thirty shot I was wondering if you guys can give me the jetting numbers your using for a 50, 60, and 75,

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