Alky affects on O2??

[tazgn]

I just got back from my first real track time with the alky kit and have a question. I have a FAST DFI and my target A/F was set for around 11.6 at WOT (street program, playing it safe). But with the alky turning on around 13 psi boost and pump set at 7, my A/F is going down to 9.81 (I think the bottom of the range of the O2 sensor). How does the alky affect O2 readings? I'm trying to figure out if my WAY rich condition is due to the alky or due to my FAST setup. My EGT at the finsih line was only 950* so the O2 readings are right.

Thanks,
Derrick

 

[graphitert]

Depending on how much alcohol you are injecting, it can impact the AFR considerably. At a lambda of 1, gasoline registers 14.7 AFR, while ethanol registers 6.40 Now if you're injecting 20% alcohol by volume on a given pull/pass, that's no small impact.

You'll need to do some testing to find out, as close as you can, how much alcohol is being injected. Then do some math to gauge the impact of the alcohol on your reading. For a reference table of lambda values and how they relate to specific AFR for gas and alcohol check here:

http://techedge.com.au/vehicle/wbo2/wblambda.htm

Good luck.

Bob
'01 Dakota R/T - water/alk injected Paxton Novi 2000

 

[blackbuick87]

You need more boost or less alcohol. You are adding fuel (alky mix) but not more air (as compared to running race gas at same boost)
You can turn the pump speed down or get a smaller jet or turn up the boost.
You could also lower your FP slightly