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-   -   Why not use water/alc/meth injection? (https://www.subaru-svx.net/forum/showthread.php?t=31253)

svxistentialist 04-03-2006 05:24 PM

Quote:

Originally Posted by svxsubaru1
I know many people that are using water/alc/meth injection systems that are running alot less than 20PSI and have had great results from it.

If you boost the SVX on the stock internals and CR as Phil has done, the additional heat in the charge will tend to cause detonation. When the ECU gets the knock signals, it retards the ignition and adds more fuel to cool things down in the cylinders. As it is not burning the mixture at the best ratio in this mode, you do not get all the power the boost should be able to give.

Phil is probably getting good power because he is keeping the boost low. Using race fuel will also help, less tendency to detonate.

As Mychailo says, the fine water spray mist helps cool the charge, which in turn reduces detonation, and lets the ECU run things without retardation. This gives more power. Water is actually better than methanol, because it requires more energy to evapourate it than methanol does. Thus it absorbs more heat, cools the cylinders better. Methanol on the other hand will improve the Ron rating of the fuel mixture, so is a help to improve the burn rate of the mixture, as well as absorbing heat. For ordinary road use, a mix somewhere between 25% and 50% methanol would be a good compromise, but pure water would be 100% OK at lowish boost levels.

If you are going to very high boost levels, 10-15-20 lbs, the sheer amount of heat you are adding here [which is also a function of the efficiency of your blades, not just based on the pressure you are adding], this heat is not possible to remove by water injection alone, at least not without high pressure pumping of large volumes. This is just not practical.

The sensible route is probably to lower the CR for higher boost. In addition, water injection is probably easier to install on our SVXs for boosts in the 6-10 lbs region, and would not need a huge reservoir. You will probably need both injection and an IC if you go for higher boost levels.


Joe

Phast SVX 04-03-2006 06:54 PM

Quote:

Originally Posted by svxistentialist
If you boost the SVX on the stock internals and CR as Phil has done, the additional heat in the charge will tend to cause detonation. When the ECU gets the knock signals, it retards the ignition and adds more fuel to cool things down in the cylinders. As it is not burning the mixture at the best ratio in this mode, you do not get all the power the boost should be able to give.

Phil is probably getting good power because he is keeping the boost low. Using race fuel will also help, less tendency to detonate.

As Mychailo says, the fine water spray mist helps cool the charge, which in turn reduces detonation, and lets the ECU run things without retardation. This gives more power. Water is actually better than methanol, because it requires more energy to evapourate it than methanol does. Thus it absorbs more heat, cools the cylinders better. Methanol on the other hand will improve the Ron rating of the fuel mixture, so is a help to improve the burn rate of the mixture, as well as absorbing heat. For ordinary road use, a mix somewhere between 25% and 50% methanol would be a good compromise, but pure water would be 100% OK at lowish boost levels.

If you are going to very high boost levels, 10-15-20 lbs, the sheer amount of heat you are adding here [which is also a function of the efficiency of your blades, not just based on the pressure you are adding], this heat is not possible to remove by water injection alone, at least not without high pressure pumping of large volumes. This is just not practical.

The sensible route is probably to lower the CR for higher boost. In addition, water injection is probably easier to install on our SVXs for boosts in the 6-10 lbs region, and would not need a huge reservoir. You will probably need both injection and an IC if you go for higher boost levels.


Joe

+1

I run 3.5-4lbs of boost on pump gas and 6psi on race fuel,just to make sure i am not pulling timing. I ran about 60 miles on 6psi without high octane fuel and experienced no timing retard, but im sure given another variable that would be detrimental such as a hot day, i would most likely make less power with more boost. But, given the way the car is setup now, i really do love taking your same tq curve and then just pulling it up even higher ;) If i do decided to lower the compression, ill be forced to go with a TEC-II or possibly program in an AEM, as the need for bigger injectors would be imperative. So for now, i cant say WI wouldnt hurt, but im enjoying endulging(and not over endulging) in boost, while keeping my car on the road ;)

phil

Phast SVX 04-03-2006 06:58 PM

Quote:

Originally Posted by Drewbaru
I know what the rrfpr is but what is the 2v5?? I may know what it is but am not familiar with this abbreviation.
thanks.


Hey Drewbaru,

Im reffering to the ECUtune stage 2v5 engine management system. you can find info on it here:
http://ecutune.com/svx-stage2.htm

They are also desiging a blower kit, which you can see here:

http://ecutune.com/svx-stage3.htm

~phil

Drewbaru 04-04-2006 03:40 PM

thank you sir..

sicksubie 04-12-2006 01:06 PM

how does this sound? I have access to 94 octane at the pump and whenever I want to have fun I add 1-1 1/2 pints of toluene to a full tank of 93 or 94. The toluene is basically pure concentrated octane boost. Could I theoretically run 6-8 lbs of boost with: a fmic, the 93 or 94 in the tank and adding the toluene to every tank, and a MSD Stacker. The toluene would reduce detonation, but wouldit be enough to allow for the additional boost? I really want to get between 6-8lb without changing the internals.

sicksubie 04-26-2006 07:14 PM

Did you ever consider using the Deltacams with your turbo set-up?


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