I have a 09 C6 with intake, 2" race headers, no cats, X pipe and Corsa exhaust with a tune. Car makes 446whp. I just ordered a Nitrous outlet plate kit. I am going to start with a 100 shot. Is timing retard necessary?

 

With the mods that you have listed above, 446 rwhp is hard to believe...that's almost 500 crank hp depending on whether you have a A6 or a M6

 

 

Dyno run it will data logging, and pull timing as needed to prevent engine knock.

Also, get your Nos and added fuel mixtures correct as well. With nos, the burn it going to be hotter, and added fuel goes a long way for not only the needed extra HP, but extra cooling as well.

Hence with supercharging, your adding more air pressure, but the oxygen to Nitrogen ratio's stay the same. With Nos, more oxygen in the air mix compared to nitrogen ratio, and this cause the hotter/more powerful burn isntead.

So base line, your trying to hold a AFR of 12.5, and depending on how fast the engine temp is spiking, may want to fatten that AFR up a touch isntead.

As for since your going to be running a hotter burn, this means that piston rings are going to see more heat as well, and would gap them in the plus .025" range for the top rings, and plus .030 for the lowers to prevent ring expansion that takes the rings to zero gap from the increased heat, which snaps the top of the pistons off when the rings at Zero gap heat expansion bind on the cylinder walls.

Also, you need to wire in/ tune in a fall safe system if there is a problem with added fuel loss during spray. If you spray without the needed extra fuel, not only do you have the AFR going lean as hell, but producing a ton of over-heat too.

 

im running 100 shot on my hci z and pull 2deg through a lnc box, afr is right around 11:9

but every scenario is diff. it may bog pulling 4 deg, and you may yeild only 80hp on that 100 shot.
if your trying to maximize that , the best way is to keep a VERY close eye on afr and street test it.

for instance, mine was DIALED in on a loaded dyno, but was FAT rich on the street, i played with the jets for almost an entire 10lb bottle getting it in the correct afr and not break up all the way through the pull. took it back and it picked up 130 ft lbs of tq and 98hp
"test & tune"

 

 

11.3-11.9, is pretty fat for an NA car. Ideally, you want to match your AFR on nitrous to your AFR on motor, or slightly fatter. I would definitely look at getting your motor tune leaned out a bit. Running too rich on nitrous is just as bad as running lean.

Start at 5-6 degrees and then you can add some back in. It depends on your total timing. I'd also throw in a bottle of octane booster when you are going to spray. Just added safety.

I recommend a set of BR6EF plugs. Definitely change them out before you spray. They are going to be one of your highest maintenance items now.

 

No intention to hijack here, but how well would meth injection offset the extra heat that this process produces?

 

Inquiring minds have to know....why would there be a difference in HP due to tranny type ??....

 

 

I'd target ~12.5, personally but I'm no tuner.

If you don't have a way to log the car I would definitely pull, at least, 5 degrees to start. Better to veer on the side of safety than to get aggressive with it right away. You can always add timing back, you can't take out timing if the motor blows.

I use a different method to pull my timing but the LNC will work for what you want.

 

Your already throwing in Nos without Dyno logging/tuning to get it right/close from the start, and now you want to add a meth kit in mix as well without out initial dyno tuning as well?????

Hate to say it, but I see your motor blown to pieces day one, blindly winging it from the start.

 

I think you have me confused with the OP. I'm not OP, and I don't have nitrous. My question was simply regarding meths cooling properties in offsetting the added heat that comes with nitrous.

 

Depending on the transmission type, the loss from crank to wheel HP ratio is different. The A6 cars lose a bit more % to the wheels than the M6 cars do.

 

Yea....but the post in question (#2) specified crank HP....I believe.