I had my car tuned on the dyno, I put down 341rwhp/334rwtq NA with the a/f at 13.3. I just bought a Compucar wet kit, it is adjustable from 50-175. I will probably go no bigger than 100-125. Will my a/f be okay for that. Or do I need to get retuned? Help me out fellas, I'm new to the nitrous game.

 

The jetting on your Compucar wet kit will dictate what the A/F ratio is. If you need to richen/lean it up you can just swap out fuel jets.

Matt

 

Correct,
The air fuel wioll be adjusted by changing fuel jets however if your car has been tuned they probley adjusted timming table also.In this case I would have it looked at to see if your timming needs re adjusted. I like to tune our nitrous cars about 12.5 on NA and 11.8 on nitrous.
Dave

 

Thanks fellas, should I retard the timing some? Where do you guys like to see timing set on say a 100-125 shot? I'm not going to spray all the time(maybe 3 or 4 times this year), mostly NA, but I want to get me a nice 11 second pass and like a couple of tenths to pull it off. I'm going to be running tr6's also.

 

The recommended jet sizing that comes with the nitrous kit assumes a stock motor, therefore you'll probably need to use different jet sizes to get a safe AFR. The best way to dial in the system is on the dyno; I would shoot for 12.0 AFR on nitrous.

 

Yes, if you/they added any timing when doing the tune. If so, pull 1 - 2 degrees for every 50 hp added via the N2O kit. If you want to be able to run full timing NA and only pull it when you spray take a look at the LS1 timing tuner. Here's a link:

http://www.harrisspeedworks.com/shop...age=1&featured

Matt

 

I've got a LT1, do you sell something for them? I don't think that will work on my car.

 

Matt,
To pull timing on the lt1 all you need is a MSD 6 AL with a retard box.Or you can use a digital 6 pluss.
Dave

 

You can also get a Mallory Hyfire 6, (Mallory 685) box, that has a rev-limit, window switch, two different timing retards, and a staging rev limiter as well.

 

Thought you had a LS1. You'll have to go with an aftermarket ignition system to pull your timing.

Matt

 

Thanks fellas, looks like I'll have to sell my Accell 300+ and go for a MSD.

 

get the accell 375+ module that connects with the 300+ ignition box, it is fully programable on the fly.FWIW i didnt have to pull any timing in mine i have 39* with no knock but every car is different.

 

If you can adjust a wet NOS A/F to match the car why do you need to pull timing?? Also why do you run richer when on the juice?? How does the PCM know your on the juice and to use a different set of tables?? Can the stock PCM do this or can the ignition box account for all the timing retard?? I was considering this same approach. I am using the Crane HI-6 box at present time and wonder why there are so many recomendations for the Mallroy or MSD. When I bought the Crane, all of the boxes came with a timing retard for nitrous applications so I didn't really see much of an advantage of one over the other. Sorry for the nub questions.

David

 

I did a quick search and found some of the answers here

Cuz Injuneer said so thats why.

I am still not sure about how to adjust the A/F down when on the juice. Also is the timing retard a yes / no type thing or does the amount or retard need to be increased as RPM's increase?

 

you adjust the A/F on the n20 with the fuel pill.the best way is to put it on a dyno or another wideband O2.Mine doesnt need any retard. but every car is different. and i am only running a 100 shot.