Can't believe no one is using Nitrous & Tuning it w/HP Tuners

[Dragman]

I had another post but no one answered!

I am starting to run my bolt on car with NOS. Since I have it tuned nice in SD I have a few questions. I am running pump gas with cooler plug with reduced gap. I am close w/NOS tune. Just wondering what do guys do differently with tune w/wet kit NOS beside reduced timing? Are u just changing NOS jet pills for AFR or are u changing VE table. I am leaving command the same as N/A tune! Now what I am wondering how are u reading histogram with NOS. Like what are u shooting for 0 or maybe a rich # in WOT area of the histogram.

I think I am explaining this right.
Thanks!

[Dragman]

[redhardsupra]

why would you adjust VE for a nitrous tune? nitrous affects oxidation and temperatures, not the breathing characteristics.

[Bluecat]

I don't normally make any fueling changes on a nitrous tune, just timing. If its a wet kit and the AFR while spraying is not what you want, adjust it with the fuel jet. It would be counter productive to change the N/A tune.

Consequently, even on a dry shot I have seldom had to jack with the fuel compared to running N/A. The way the nitrous over excites the MAF, it usally just works out right. Say your commanding 13:1 on motor and getting it. On a dry shot even though your still commanding 13, it usaully ends up 1 to 1.5 points richer while spraying, if not more.

[Dragman]

I don't normally make any fueling changes on a nitrous tune, just timing. If its a wet kit and the AFR while spraying is not what you want, adjust it with the fuel jet. It would be counter productive to change the N/A tune.

That what I was looking for as I have been told several ways to do this. In the back of my mind (way back in the corner) I thought I should be changing fuel jet but was not for sure. Is there a rule of thumb for changing AFR for a certain fuel jet #?. Like .1 AFR = 1 fuel jet size or something along this line.
Thanks for info! wayne

[Dragman]

By the way it is a wet kit about 100 HP jets.

[Bluecat]

You can make educated moves like that. If you wanted to add 10% more fuel because the car was lean, then you would just make a similar percentage jump on the jet size. To do it half way right you need to go off of effective area. Say your running a .038 fuel jet:

3.14*(.038/2)^2 = .00113

Add 10%:

.00113 * 1.10 = .00125

Convert back:

Sqrt(.00125/3.14) * 2 = .0398

So a .040 would a rough move to add 10%

But it never works that way. Usually you are withing the confines of what jets you have, usually provided in a kit. So if your lean for example, I'd run the 100hp Nitrous jet with the 125hp fuel jet.

As a matter of fact I had a car on my dyno tonight that was pegging the wide band rich while spraying. Ended up with the 150HP nitrous and the 125hp fuel to get the car back around 11:1 AFR and it picked up 25rwhp.