Kapok6
15+ Year Contributor
- 1,392
- 267
- Aug 10, 2004
-
Fort Worth,
Texas
Attention High Compression E85 users. I need some input and advice here. I'll start off by saying I know that every motor is different even if they are the same or similar on paper.
So, what I am trying to figure out is, how you guys tune your high comp motors on e85...specifically what your timing maps look like.
Up to this point I have been an 8.3-8.5 compression guy with HKS 272's.
Now, I have a Curt Brown block and head (2G) with GSC S2's. Pistons are 10.5:1. DSM76 HTA turbo.
So, I have spent the last few weeks trying to tune out "knock" based on my knock sensor readings. AFRs are high 11's to about 12.0. I have pulled ignition timing WAY back. That seemed to help get most of it gone. I had to pull timing down to 0* at 5500-6500 (guessing that is peak torque area) to get it nearly completely gone. There would still be an occasional blip here or there with 1ct or so and the ecu will pull timing to -1*, and occasionally it will show knock in the middle of a shift as the rpms are dropping. So, shifting from 1-2 or 2-3 as the rpms fall from 8700 to 6300, it will register knock in that area.
So right now, I am at 0* 5500-6500, then ramping up from there to about 7-8* up top around 8500-9000. IMO previous experience, that is NOT a lot of timing at all. And I know a lot of the high HP Honda guys run negative timing on their high efficiency motors, but does this sound right?
I know generally speaking, high comp motors, (or boosted motors in general) like more boost, less timing, but honestly at this point the car is slow as bawlz compared to what it was on my previous hodge podge motor. Best trap I have got it to do in the 1/8 so far is 97.8 which is laughable compared to the 101 I got on my old lower comp motor and less boost with the same turbo.
So with all that rambling done, what kind of ignition timing are you guys running on your high comp e85 motors? I think one of my problems may be going off the stock knock sensor as my understanding is that with E85, you will blow a HG or bend a rod before you actually register real knock...
So, what I am trying to figure out is, how you guys tune your high comp motors on e85...specifically what your timing maps look like.
Up to this point I have been an 8.3-8.5 compression guy with HKS 272's.
Now, I have a Curt Brown block and head (2G) with GSC S2's. Pistons are 10.5:1. DSM76 HTA turbo.
So, I have spent the last few weeks trying to tune out "knock" based on my knock sensor readings. AFRs are high 11's to about 12.0. I have pulled ignition timing WAY back. That seemed to help get most of it gone. I had to pull timing down to 0* at 5500-6500 (guessing that is peak torque area) to get it nearly completely gone. There would still be an occasional blip here or there with 1ct or so and the ecu will pull timing to -1*, and occasionally it will show knock in the middle of a shift as the rpms are dropping. So, shifting from 1-2 or 2-3 as the rpms fall from 8700 to 6300, it will register knock in that area.
So right now, I am at 0* 5500-6500, then ramping up from there to about 7-8* up top around 8500-9000. IMO previous experience, that is NOT a lot of timing at all. And I know a lot of the high HP Honda guys run negative timing on their high efficiency motors, but does this sound right?
I know generally speaking, high comp motors, (or boosted motors in general) like more boost, less timing, but honestly at this point the car is slow as bawlz compared to what it was on my previous hodge podge motor. Best trap I have got it to do in the 1/8 so far is 97.8 which is laughable compared to the 101 I got on my old lower comp motor and less boost with the same turbo.
So with all that rambling done, what kind of ignition timing are you guys running on your high comp e85 motors? I think one of my problems may be going off the stock knock sensor as my understanding is that with E85, you will blow a HG or bend a rod before you actually register real knock...