Dual vs. Single nozzle SMC

[scottyb]

I picked up a dual nozzle kit used. I haven't really been able to tune it yet, but my feeling so far is that I have overkill for my car. Sometimes it feels like if bogs/surges, but I don't want to turn down the pump speed any more because I don't think it will atomize well. Based on the spray I saw before the install, I don't think it sprays well under the "4" setting, so I keep it at 5 or more all the time.

I'm thinking about blocking one of the nozzles and turning up the pump a bit so the spray is "better", but less volume. My O2's seem to always be greater than 825.

Thoughts?

 

[salvageV6]

Tue with KR as being the guide.

Increase the turn on point until you get some transitional KR.

I like a high pump speed as well for atomization.

I'd keep the raising the boost up until KR starts then back down about 2psi for safety.

Not sure about the fueling issues with the Thrasher chips.

 

[WSLN 6]

Get an adjustable fuel pressure regulator. My car is way rich with the alky on if my fuel pressure is over 40psi vac off. No knock, 21psi.............

 

[OneLethal87GN]

I just installed the single nozzle kit in my car and get around 820-850s under WOT. This is with no knock, the pump turned to full speed, and 18 psi. I have an old Kenne-Bell Hot Flash chip in which I believe has around 30 degrees of timing. I had thought of putting my MM street chip back in, but it doesn't have lock-up and I may forget to flip the switch during a race. It only has about 20 degrees of timing. I know I could turn up the boost with the lower timing but those cheap Advance Auto clamps come off under 18 psi sometimes. Guess I'll have to wait until I get some good clamps. I wonder if the dual nozzle will allow me to up the boost on the race chip by adding more alky. Any thoughts?

 

[Steve Wood]

Why worry about atomization if the car is not detonating at a given setting?

Flooding the engine with alky on position 10 because you like atomization does not compute if the car runs on position 6 with no detonation. It may be that the velocity of air travelling thru the up pipe covers up the better mist of the higher pressure. After all, lots have used NOS nozzles that give terrible patterns and still run 25# of boost. Steve Yaklin, for one.

Theory is great but performance is what counts.

 

[salvageV6]

He uses methanol too.

Different ballgame.

 

[Steve Wood]

he was using methanol and methanol/water...same game..ask him....he will repeat what I said because I have had his lecture many a time.

 

[Steve Wood]

And, explain to us how spraying methanol is different from spraying ethanol or denatured.

 

[salvageV6]

One word fuel.

Who said anything about flooding the engine?

 

[Steve Wood]

He is spraying methanol or methanol/water just like we do except he uses a home made system using nos jets.

While there are minor differences between the various alcohols with regard to heat content, latent heat of vaporization, etc., the differences are not material when it comes to using alcohol injection.


With regard to flooding, if you spray more alcohol than is required for detonation, then you are basically flooding the engine...it may run but the combustion chamber is overly saturated with vapor that it cannot consume and the engine makes less power than it should. Same as running excessively rich A/Fs as you found on the dyno. When you pump more alky than required, you simply compound the problem.

That is the reason that some reduce the gasoline as the alky comes on...if you use enuf alky to actually get some benefit from the fueling, then you may need to reduce wot fueling from the injectors in order to maintain power. After all, it is not boost level alone that determines hp. You can crank the boost up and kill the horsepower by being off on the A/F too far.

 

[OneLethal87GN]

I've ran as much as 18 psi with no knock with my KB Hot Flash chip. It's getting warmer now and I'm getting as much as 7 degrees of knock with the same boost. How much more boost could I run with a chip that has 10 degrees less timing? I have a street chip from MM but it doesn't have l/u and I may forget to hit the button if a race suddenly came up. also, how much more boost could I run if I switched to the dual nozzle set-up...approximately?

 

[Steve Wood]

I have forgotten how much timing the hotflash had...was it 24 degrees or was it bumped up. KB's chips where not very sophisticated...but not many were in those days...

With a chip with around 21 degs...lots of us seem to run 23-24. Some go more, some go less. Some get buy with even more timing and make the range. So much difference in combos and locals gases, it is hard to have a single answer.

 

[OneLethal87GN]

I had heard the hot flash had about 30 degrees. My MM chip has 20. The clamps I have now aren't the greatest so I'd rather keep my high timing with low boost chip. I think the H.F. chip calls for 21 psi, but I turned it down some.

 

[Steve Wood]

I think you are right. I just noted you had posted that above and it rings a bell. At one time KB wrote that the stock ignition quit at 21# of boost....He was soon proven wrong. Some run a lot of timing with alky with no problem...and even more boost, but I think those that do both probably run something like four Aquamist nozzles and go for the good mist.

As I said above, best performance should be with the minimum amount of alky required to suppress detonation.

In the end, ignore everyone's theory and tune for what gives you the best performance.