TurboTommy

How much timing do think you're running, at full throttle?

blown 944

I havnt read everything, but there must be something wrong. You shouldn't be getting knock at 12 psi.

Sorry you're having issues, but I'd be looking at the tune and fuel quality.

I don't have much time right now so my reply is short.

Thom

For what it's worth I had pretty much the exact same hardware as you Tom back when I tried E85 and I do not remember seeing any knock through my knock counter, with the "standard" Vitesse tune for E85, and even with my exotic semi-solid lifter set up that did cause extra noises ... ... I did not run more than 18psi.

333pg333

"Exotic Semi-solid lifter setup" ???

Tom M'Guinn

Well, I may have spoken too soon. I tried again today with better results. I was able to boost to 21psi with no or minimal knock counts, but with the water/meth injection on. I couldn't eliminate the knock counts with timing and fuel alone at 12psi, but the water/meth did seem to do the trick at low and high boost. I didn't have the guts to turn off the water/meth at high boost, since it seems to knock at low boost if the water/meth isn't on, but its possible the extra e85 at high boost can replace the water/meth. I'll keep at it... Thanks for all the input...

David Floyd

1st tank of E85? Did you have enough gas in the tank to dilute ?

Tom M'Guinn

I ran it down as low as I dared, then put in 5 gallons of e85, then burned that down as low as I dared, then 10 gallons of e85 to start testing/tuning. So if they are pumping E70, my current swill is at least E69.8 or so

URG8RB8

Both Dave W and I are using the same Propel E-85 as Tom. I need to install a knock counter. I don't know if Dave has one or not. I did not install one based on Shawn and Sid's results.

Dave W.

Interesting. Do you have control over the timing map? Or are you using the FQS switch to alter timing? I run my setup lean at WOT, typically around 11.5 to 12.5 AFR with approx 8.8 comp ratio on local E85.

URG8RB8

Dave do you have a knock counter?

Dave W.

Not anymore, I took it out since I never got knock.

URG8RB8

Well, there you go! That makes me feel better!

Tom M'Guinn

Still be worth getting a counter in light of your recent experience. If it turns out you have no knock you can always remove it. Your motors are quite different. Just say'n....

Dave, yes, I have control over the timing map. I admittedly didn't work on the low boost map much so it's possible I could tune it out. My main surprise was just to see e85 knock on the same timing maps that had little/no knock on 100 octane with water/meth -- even when running the e85 pretty rich into the mid 11's AFR.

URG8RB8

I will still get one Tom, you can give me pointers on the connections. Thanks!

refresh951

Been doing a considerable amount of tune testing lately and I found a way to get E85 to knock in conditions you would not normally expect knock. Something to look at is dynamic changes in either AFR or timing during a pull. I can cause knock by RAPIDLY changing afr from say 11.4 to 11.9 under load. In addition to the absolute value, rate of change in afr or timing is also very important. Something to look at if you are getting knock when it is not expected.