SMC owners...what's in your bottle?
- Thread starter Trevor
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I started out with 100% pure denatured and switched to a 50/50 blend (H20/alky). Seems to be the answer as I now have the 02's where I want em and under 1 deg of kr. BUT, as with everything else on these cars what works for me may not for you. BTW, pump speed is set on MAX with alky coming on at 12-13lbs boost.
Turbo__Tim
One heck of a Tim!
- Joined
- May 25, 2001
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- 640
Trevor, denatured is the easiet to tune with. This mix (actually about 10% water) is very forgiiving for lack of atomization, and activation point(s). If it works for you, use it.
When switching to a more 'watery' mix, try more timing, or switching to 2 smaller nozzles.
Everyones combination is different, so it's not suprising that different mixes are needed to achive the desired results.
Atomization is key. You need small nozzles to get this. Unfortunately most people have single stage systems, so 1 small nozzle while getting good atomization, often will not deliver enough water to accomplist cooling. This small nozzle will work to say, 18-19 psi, but will run out of cooling power at higher psi.
Some of the best systems I have heard of use 2 small nozzles for the first stage (activation point of 5-8 psi) and a second stage activating at 15 psi, using about 2 thirds of the combined nozzle size of the first stage. Full pump speed is preferred, and a 50-50 mix is easily achieved. Past research has shown the 50-50 mix works best, if you have the proper set-up. Regulation of the volume of delivery should be done by raising, or lowering the size of the nozzles, or the number of nozzles. Pump speed should always be as high as possible.
As Steve Hill has said - atomization is key!
When switching to a more 'watery' mix, try more timing, or switching to 2 smaller nozzles.
Everyones combination is different, so it's not suprising that different mixes are needed to achive the desired results.
Atomization is key. You need small nozzles to get this. Unfortunately most people have single stage systems, so 1 small nozzle while getting good atomization, often will not deliver enough water to accomplist cooling. This small nozzle will work to say, 18-19 psi, but will run out of cooling power at higher psi.
Some of the best systems I have heard of use 2 small nozzles for the first stage (activation point of 5-8 psi) and a second stage activating at 15 psi, using about 2 thirds of the combined nozzle size of the first stage. Full pump speed is preferred, and a 50-50 mix is easily achieved. Past research has shown the 50-50 mix works best, if you have the proper set-up. Regulation of the volume of delivery should be done by raising, or lowering the size of the nozzles, or the number of nozzles. Pump speed should always be as high as possible.
As Steve Hill has said - atomization is key!
Yeah I found out atomization is the key when I tried a single 15GPH @ 60% pump speed over my normal 10GPH @ max. Slowed the car down big time. 
I don't know...I just moved down to AZ and switched from 93 down to 92. I've got MASSIVE timing advance from the piggyback fuel computer I'm running. I used to run 12.7psi without alchy and 16.4-17.0psi with 100% denatured and 93 octane. While cruising around in the 99F heat today I got audible knock at 15.7psi today doing just a quick 2nd gear punch with the alchy/water mix spraying. Not good! The alcohol is like 6 months old (car was injured). I should probably swap that out and cut down to like a 10% mix to keep it easy to tune.
I don't know...I just moved down to AZ and switched from 93 down to 92. I've got MASSIVE timing advance from the piggyback fuel computer I'm running. I used to run 12.7psi without alchy and 16.4-17.0psi with 100% denatured and 93 octane. While cruising around in the 99F heat today I got audible knock at 15.7psi today doing just a quick 2nd gear punch with the alchy/water mix spraying. Not good! The alcohol is like 6 months old (car was injured). I should probably swap that out and cut down to like a 10% mix to keep it easy to tune.
