Neil B

Hey guys, we had a great time at the Carrabelle, FL Speed Festival 1/2 Mile Airstrip Race. My goal was to shake down the car in preparation for the Texas Mile. It ran well and we did some data logging to see what was happening. Here is a snapshot from a 169 mph pass (VSS speed PID maxes out at 158 mph). IATs at the beginning of the run were 85-90 degrees and progressively went up to 160-170's at the top of 5th gear. I will need to get IATs under control before attempting the 1 mile pull. I'm currently running a Procharger F1R (12 psi) with A&A ram air intercooler and 50/50 water/meth mixture through a single 625ml nozzle. 100 octane race gas in the tank. I will work on getting more airflow through the intercooler and spraying more meth. Any thoughts?

user_name

That's not much meth at all. MOAR meth!

BLOWNBLUEZ06

625mL nozzle= 625mL over what period of time??? Hours?

My nozzles are 15GPH, so I run just under 1000mL per minute or 114 liters/hour straight meth.

Neil B

My understanding is that, at 200psi pump pressure, the 625 will flow about 865ml/min. Snow recommended the use of a single 625 nozzle for my horsepower and boost levels. I'm currently running 50/50 water and meth.

HP_Addict

it was advised to me to run dual nozzles and pure meth. my car is setup to run the 1/4 and I use an alky controls kit. For the mile I would think you would need even more.

You could also add a little nitrous to cool things down. A small shot set to come on in fifth gear.

Neil B

I found another reference that says (for 10-15psi boost) to use 18% of total fuel at peak flywheel horsepower. 850fwhp = 6140 ml/min fuel *18% = 1105 ml/min.

helga203

I have F-1c 24psi boost duel 15 nozzles my iat's don't go higher then 80.

Robert 2000

Some useful info is coming up in this thread

user_name

I don't think there is a hard fast rule, and there are at least 2 schools of thought on this. Some people like to tune without the meth and then add just enough to cool IAT's a bit and/or add a little timing. Others, like me, prefer to use enough to make the power they want and get the IAT's where they want. You then compensate in the tune so that the car will lay over and barely rev without the meth.

If my IAT's were too high, and I wasn't using a ton of meth, it would be a no brainer.

Neil B

So here's what I've been able to deduce through this discussion and research...

Assuming my combo with 850fwhp, 12psi boost, and 406ci:

1) I'm currently running 865ml/min and that is not enough (IAT's get hot)
2) Snow literature says I should be running 1105ml/min
3) Devil's Own nozzle calculator says I should be running 21 gph (1324 ml/min)
4) 100% meth guys here on CF running twin M15's (1892 ml/min), but you can't inject as much 50/50 as you can straight meth. You have to limit H20 volume to approx. 10% of total fuel volume. So, if my primary fuel volume is 6140ml/min and I inject 1200 ml/min of 50/50, that would give me 600/6140 or 9.7% of water to primary fuel volume.

Neil B

I'm trying to tune without meth dependency because I really don't want to alter my fueling tables if IAT's spike (that would be the only way to save the motor in the event of a meth failure). As you can see from the log, I am pulling timing at higher IATs, but I'm choosing to run 50/50 water/meth so my A/F ratio stays in the correct range. If I max out the amount of 50/50 I'm able to inject before combustion quench and the IATs are still too high, then I'll look at going 100% meth and a meth dependent tune.

user_name

Judging by your power and AFR I think you are already meth dependent. Won't it be awfully lean with only 93 octane in the tank when the meth pump fails?

I follow your thinking. You could run more meth. You could also just add c16 to the tank and run less meth.

Neil B

I was running 100 octane fuel. The AFR was as rich as 10.89:1 at 5329rpm. In general, across the 5th gear pull, the AFR averaged approx. 11.2:1 to 11.3:1. I really just want to use the meth/water to cool the IAT's.

robert21122

sucks i couldnt make it sunday but i will be there in october.

Neil B

It was a fun day on Sunday. The first run was a little hairy. Nothing like 850hp, drag radials, and a wet track! The white supercharged C6 did a little agricultural work when he couldn't get it slowed down. You had to really hit the brakes to get it stopped in time.

robert21122

o damn hope all is well for him. yeah my wife had to work sunday it was only a 3.5 hour drive. come october hope to be turboed by then or atleast have my 150 shot and cam swap done.i wanted to run one of thoses 5.slow mustangs on my almost stock car but never got to.