Im thinking about putting a 50 or 100 shot on my Nova.I have approx 10.5 to 1 compression. I also have aluminum heads. I know I will need to retard timing 2deg per 50 hp.Question............ Can I use N20 with my compression and still run 92 octane without problems?

I assume this would be a dry shot? I might be mistaken, but a "wet" system is more stable, with greater power potential as well.

From what I understand nitrous likes high compression. Shouldn't have any problems with that shot (50 or 100), it's when you get greedy you start breaking stuff.

I agree that you should be okay. A wet shot would definitely be the way to go. Also use an activation and WOT switch and dont kick it on until after about 2500+ RPM. Just my advice anyways.

__________________
1997 BMW M3 - 3.2litre Inline 6 cylinder

From what I have always heard (don't know if this is correct, I'm still learning about the gas). I was taught (don't know if this is correct so tell me if i'm wrong) that nitrous is like forced induction (just limited amounts); It will raise the compression needing more fuel to reduce detonation, and a retard of the timing is necessary.

From some experience a dry shot is dangerous (I've seen many videos of nitrous backfire... and even saw i once in person, in a ironic way its funny watching a manifold blow off but its also scarry in another way) and a wet shot still dangerous it just adds fuel to reduce the chance of detonation. As for your compression I was always told a lower compression was better because it prevented nitrous backfire and detonation?

I know one thing for sure though, watch the RPMs the system fires at as too low is a very bad thing.

Hybrid STE

I'm assuming here (you know what they say about that) that you're running a carb, I mean, you haven't stated otherwise, so being a nova I'm just assuming... which means the previous posters are correct in saying the dry shots can be dangerous, IF you don't add enough fuel to the mix, nitrous won't add more pressure in the combustion chamber before it's ignited, but it will add more combustion pressure, which is where the added horsepower comes from. You'll be fine on 92, but try the 50 shot and see where your a/f is at, either with an o2 sensor, or reading your spark plugs. if it's going lean, I'd jet it richer. your carb really needs to be fat and happy when juicing it. but you should be ok with 100 shot on a dry sys, but a wet system would be better and safer IMHO....

Dry shots are intended for EFI cars only unless you are running somthing small like a sneaky pete. On dry nitrous systems the fuel enrichment is done by the injectors.

All plate systems,tops shots ect will be a wet system.

Nitrous LOVES mild compression engines. My 355 was right at 10.5 to 1 with aluminum heads and I ran pump 93 up to 125 shot. 150 or above and I ran a race fuel.

I see no reason why you could not get away with 50 to 100 on pump gas. Im not sure how much a difference 92-93 octane is but I think you will be ok.

With nitrous is is ALWAYS safer to error on the safe side. I can run 100 to 125 on 93 pump gas no problems but I have EFI and datalogging to insure I'm at the correct fuel mixtures and timing. What can happen though is overall your fuel mixtures may be OK but certain cylinders may be much leaner or much richer. If 7/8 cylinders are OK but 1/8 is lean it will detonate and could hurt a piston.

I'd take more timing out of it to start with and also start the jetting small. After each run on nitrous your plugs are your clue to what is happening. No black specs on the porcelain your likely in OK shape.

The other thing gong in your favor is most prepackaged kits are jetted on the fuel rich side. That gives you some room as well. The other test you may want to try is running the car on 87 octane. If it runs and doesn't detonate that gives you a feel for the tolerance of the motor. Nitrous mixtures burn MUCH faster than normal and that combined with an engine on the edge of detonation makes for a short day.

Wet shots are still recommended on EFI setups too. The system will only be able to account for the nitrous AFTER it has been fired and has reached the O2 setup. Especially on MAF setups where the nitrous is injected after the mass airflow sensor. Nitrous also doesn't follow the same charactistics as air in that even a manifold air pressure setup wont be able to account for the nitrous. Unless for some reason you absolutely have to run a dry shot, I always recommend a wet shot on any setup.

__________________
1997 BMW M3 - 3.2litre Inline 6 cylinder

Thanks guys took me a while to get back here. Yes its a wet kit(NOS super power shot). Ive never tried to run it on anything other than 92 octane. But I do run the engine around 33 deg total and I kick it up to 36 at the strip with no detontion problems. I suppose I will need to run it at 33 all the time when I install the kit. The reason im thinking of buying a kit is that other than the power gains. I installed a power shot kit on a guys S 10 at work (stock 350). And I really liked the ease of the install and the power was great too. I thought maybe I was pushing the limits of my engine if I installed it on mine. I know it has nearly 500 hp already. Im not running junk in the engine, but im not running mega buck parts either.

Grab yourself a crane or MSD multispark box and get the addition timing retard unit. You can then dial in the amount you want the timing to retard, and have it kick on the same time your WOT and activation switch are on.

__________________
1997 BMW M3 - 3.2litre Inline 6 cylinder

I was not saying dry kits are better, just that you would only find them on EFI cars. Im all for wet kits.

As far as the ignition box... the Mallory 685 box has a window switch,start retard,high rpm retard,2 rev limters,ect ect... Mine has performed quite well and the price is decent too.

I am just clarifying that EFI wont automatically compensate with more fuel on a dry shot of nitrous.

__________________
1997 BMW M3 - 3.2litre Inline 6 cylinder

With that much of a shot you will be fine if you have forged parts and a good fuelpump in good shape. Just remember to back off the timing and read your plugs each time. Once you get it tuned you'll love the stuff. Be safe. Perry.

Im running "claimer" pistons in the engine. I suppose that may be the weak link in my engine. The rings are gapped for street use. If I remember correct I gapped the top ring at a lose .026. At the time I built this engine nitrous hadn't crossed my mind. Im kinda on the fence now about n2o. I don't want to waste my engine due to piston failure.Im thinking with correct ign timing,and no lean conditions I might be ok. But there are no guarantees even with a mega buck engine.Any thoughts on this?