Alcohol injection and O2's

bigz

Senior Member
Joined
Sep 7, 2001
I have a question about adding alcohol as I'm increasing boost. I just installed the power plate and was out trying to up the boost on the car. I'm at about 21 lbs right now and my O2s are in the 810-815 range at WOT. As I was increasing boost I did not add more fuel just increased the pump speed on the SMC kit to 7. I got no knock during the runs. My O2's never dropped below 800 even as I was slowly adding boost and alcohol pump speed. I'm thinking of jumping to a 100 octane chip to add a little timing from my current 93. If I can keep upping the pump speed on the alky kit and keeping my O2's in the safe range do I need to worry about adding fuel pressure.


Thanks
 
As long as your O2s, for whatever they are worth, or in what yo call a safe zone, and you have no knock, there is no reason to add fuel pressure.
 
Alchy likes higher timing. What alchy are you running? (isophropyl, denatured?) Sounds like denatured to me, as that is a pretty good pump speed.

I would suggest that you post your set-up with the new chip in the alchy section. Great place to share information.

Every car is different. With my current set-up, running denatured, I start seeing knock below .830. With alum heads, I need to activate at 12 psi. and that's just to run 16 psi. Since I have increased air flow, this is the equivilent of iron heads turning on at 16, and going to 21. (approx).

With the stock heads, I could activate at 18psi, and run to 25 psi. Only the denatured would allow me to do that without transitional knock. All the above was done at 20* timing.

With the higher timing in the new chip, you may need to activate the alchy a couple psi earlier, as you will run a bit hotter. You may find .810 to be too 'thin' at that time, since you will be creating much more heat and power.

Pump gas will only take you so far, so there would be a limit to the benefits of jamming more gas in there. I'd just max out on the alchy, and call it quits. Then again, God hates a coward....:)
 
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