Learn me about nitrous

rslifkin wrote:

Paul_VR6 wrote: Wet shouldn't be a problem on EFI? How many have you tuned with good results? My list is small and the caveat list of making it work well makes it not worth it for the n2o neophyte. In my experience with a small shot on EFI (3bar+ base pressure) it's VERY hard to tune because of the fuel jet size needed to not make it extremely rich. I have had problems with the small orifices clogging even on well filtered setups, which can become disasterous. You can make some older low pressure EFI work well with wet setups, OR run a dedicated low pressure fuel system for the nitrous. Now if we're talking a big shot, it's a different story, but I was under the assumption that we're talking reasonable ranges and not doubling or tripling stock horsepower. Very few EFI systems don't have a fuel pressure regulator. Only the newest ones (which likely aren't in a challenge budget anyway!) have fuel pump control to maintain pressure. Dry shots are the easy button for EFI on a small hit. That being said my favorite part about nitrous is when you are wrong, you can usually tell how wrong by what's left on the track.

Chrysler moved their pressure regulators to the pump module in the 90s. That is a good point about the small jets though. I wasn't thinking about issues with supplying a small enough amount of fuel at 50-ish psi.

If there is a regulator with a vacuum line, you can run dry shots with pressure enrichment. Have done it on late e46s with the regulator under the car. Odd that a "stock" 323 can be quicker than an e46 m3

Resurrecting this post because now I actually have to pull the trigger on a nitrous system.

Anything else I should know? What is the best cheap system for spreadbore?

Bump for website issues

I recommend wet shots with some kind of failsafe.

If you go over 75-100hp, port injection is better to reel in fuel distributon issues.

Dry squirts can be dangerous.

Definitely a wet system is happening.

Mostly I'm worried about how hard they are to install now

Not hard, but ive never done one with a mechanical fuel pump, always had electric pumps. 75 shot got my belair from 14.4@93.5 to 13.9@101.5. Have cast pistons so wasnt willing to go more. Bringing 50-150 jets to the challenge and will step up as necessary

I have a spreadbore plate if you cant find one

I've yet to install the system back onto the challenge car, i expect it to take an hour or so because my bottle brackets are installed and my wiring is mostly there. I'd budget 4-5 hours.

Carb off, longer studs or bolts to take up for the plate, solenoids, nitrous and fuel lines, wiring.

I'm not going crazy, 100 hp shot is all I'm going. From what I've read that's perfectly safe with a stock 305 with colder plugs and some timing pulled

Sounds pretty easy to install too

I'm planning to be at the host hotel 3-4pm Thursday if you want someone with nitrous experience to check your work before you hit the button. Seriously though, bring all your jets. There will be 4-5 hours for drag runs, you can start lower and work up, since you're counting on your car to get you home. If i step up too high i load it up and tow it back.

patgizz wrote: I'm planning to be at the host hotel 3-4pm Thursday if you want someone with nitrous experience to check your work before you hit the button. Seriously though, bring all your jets. There will be 4-5 hours for drag runs, you can start lower and work up, since you're counting on your car to get you home. If i step up too high i load it up and tow it back.

I very much appreciate the offer and I really would love to take you up on it but I live in north idaho, it's 2700 miles one way to the challenge. It might be a litle out of your way Lol

I would greatly appreciate someone looking over my work though

In reply to patgizz:

Hope that offer goes for me!

Antihero wrote:

patgizz wrote: I'm planning to be at the host hotel 3-4pm Thursday if you want someone with nitrous experience to check your work before you hit the button. Seriously though, bring all your jets. There will be 4-5 hours for drag runs, you can start lower and work up, since you're counting on your car to get you home. If i step up too high i load it up and tow it back.

I very much appreciate the offer and I really would love to take you up on it but I live in north idaho, it's 2700 miles one way to the challenge. It might be a litle out of your way Lol I would greatly appreciate someone looking over my work though

Ah i thought you were planning to take the car to the challenge

That offer goes for anyone

In reply to Antihero:

This will be of great interest to you then with the 305: Nitrous 305

In reply to patgizz:

Oh I am planning on bringing it I just didn't want you to have to tow it back 2700 miles back home.

Thank you nessumar, I looked at it and it helps quell the anxiety lol

I ran a 150 shot on a cast piston 302. 600 holley, plugs 2 ranges colder then stock and timing retarded almost 10 degrees. Fair warning it ran terrible if it wasnt being sprayed so plan too change the plugs and timing at the event.

If i was being conservative and worried about driving home id stick at 100 and make sure the mechanical fuel pump is good.