NOS & Spooling

[tom j]

This is on TA motor, 88mm turbo,and xfi. What timing are you guys running while the spray is on.

 

[Pablo]

I ran 18 degrees during the n2o activation but I think that was probably conservative. The n2o was on at 2800 rpm wot and off at 15 psi or so. Even with only 18 degrees the hit was enough to cut a 1.6 off the footbrake. I'll be trying more timing with the new combo.

I think that since it's off well before full boost it would probably be ok to run closer to full boost timing. Considering that in my case I was running near 30 psi, I don't see that there would be too much difference between the n2o hit at less than 15 psi and full boost timing wise.

Either way, you will love the spool on N2o, it's amazing.

 

[Alky V6]

The size of the shot will be important when deciding how much, if any retard is necessary. A short 50 shot may not require any retard. As the shot size goes up, retard becomes more important. A general rule of thumb is 2 degrees retard for every 50hp of shot. I go with more than that to start out with and work the timing back in little by little, studying the datalogs and the plugs. It's safer to run more retard than too little.
The amount of retard is a good tuning tool also. If you're running a large shot and the hit is too agressive, backing off the timing will tame it down for you.

One more thing. I always run a bunch of retard when working with a new shot size. Only after I'm sure the mixture of the shot is safe do I start bringing the timing back in. This procedure has saved my beehind a few times. I'm up to a 310hp shot and debating on whether to throw another 50 at her.

 

[tom j]

I'm running a 100hp shot and shutting it of at 12lb of boost. Should I start below 20deg im thinking I run 26deg at 26psi and an 100 shot at 12lb. Would it be safe to run the same timing 26deg. I know of guys running as high as 36deg down low in the boost say up to 14psi and then really reduce it above then.

 

[Pablo]

I forgot to add that I run a 125 shot. 18 Deg of timing. Your point about running higher timing at low boost is a good one and why I rationalized that I could probably get away with more timing on my combo.

 

[Alky V6]

I'm running a 100hp shot and shutting it of at 12lb of boost. Should I start below 20deg im thinking I run 26deg at 26psi and an 100 shot at 12lb. Would it be safe to run the same timing 26deg. I know of guys running as high as 36deg down low in the boost say up to 14psi and then really reduce it above then.

This is how I look at it. A Buick V6 n/a is going to need 34 to 36 degrees of timing at WOT by say 2400 rpm. A turbo engine at zero boost WOT is really no different than a n/a engine at WOT. So, at zero boost WOT, if we use our 2 degrees of retard for every 50hp shot rule, you will be running 30 to 32 degrees of timing at the start of the hit. If you're checking the mixture, add in another 4 to 6 degrees of retard until you think the mixture is safe.
As boost rises, the timing will be backed off as usual. Just maintain the same level of extra timing retard that your using at the start of the hit throughout the nitrous hit. After the end of the hit, bring the timing back to the normal timing curve.
If you want to be extra safe, make your own nitrous/retard rule. Instead of 2 per 50, maybe 2.5 or 3 per 50. If you're checking mixture, throw in 10 degrees of extra timing retard. The rulebook is not set in stone. When dealing with nitrous, it is always better to be safe than sorry.

The 60 foot is going to be the tell all as to what timing to run. Start off with a very safe amount of retard and bring the timing back in a little at a time. 60 foots and/or time to boost target should decrease. When you see the amount of gain starting to lessen, I would stop there. On the retard, I would still stick to the minimum rule of 2 degrees of retard per 50 shot.

If you start off with a whole bunch of timing retard and find that the time to boost target is acceptable, heck, leave it alone. Mission successful! And, accomplished very safely.

The real mission here should be to use the most amount of nitrous timing retard that will satify your 'time to boost target' goal.

I have found that with nitrous injection, the mixture is far more important than how much ignition timing you can get away with. Don't get carried away thinking that you have to run a lot of ignition advance with nitrous. It could bite you big time.

 

[8AV8]

I'm up to a 310hp shot and debating on whether to throw another 50 at her.

dayum! that's pretty cool.

 

[kingots2004]

im up to a 310hp shot and debating on whether to throw another 50 at her.

shoot throw another 190 at her to get a nice round number lol

 

[Buickforlife]

I'm up to a 310hp shot and debating on whether to throw another 50 at her.

Wow, that is a lot of nitrous. Reminds me of a 10.5 mustang running ~600hp in nitrous.

 

[Alky V6]

shoot throw another 190 at her to get a nice round number lol

I figure I can throw as much as 80 more at her if I have to, but that would be the limit.

 

[kingots2004]

I figure I can throw as much as 80 more at her if I have to, but that would be the limit.