I have been trying to get my car to run with 0 knock for a while on both pump gas and e85 without success. I have tried different A/F ratios and even when timing is pulled a lot I get a blip or two. I have attached a couple of logs on E85 at 24PSI and 28PSI. The car behaves the same between 13.4 and 24PSI and knocks a little more with additional boost. On pump gas I get knock even during spool up.
I have indentations in my pistons (see picture) from when my timing belt skipped and I was wandering if they are creating hot spots that can explain the knock?
relevant info:
new NGK wires (my old set of magnecores was fine as well)
new NGK BPR7ES plugs gapped to .026 (i have tried different plug/gaps with no effect)
new battery
original knock sensor (could it be too sensitive due to age?)
3G lifters
base fuel pressure is set to 43.5 on Aeromotive FPR
FP3052 turbo
PTE 1000cc injectors
rewired Walbro 255 fuel pump
i have seafoamed the engine a couple of times to get rid of carbon build up (after the picture of the pistons was taken)
I have been trying to get my car to run with 0 knock for a while on both pump gas and e85 without success. I have tried different A/F ratios and even when timing is pulled a lot I get a blip or two. I have attached a couple of logs on E85 at 24PSI and 28PSI. The car behaves the same between 13.4 and 24PSI and knocks a little more with additional boost. On pump gas I get knock even during spool up.
I have indentations in my pistons (see picture) from when my timing belt skipped and I was wandering if they are creating hot spots that can explain the knock?
relevant info:
new NGK wires (my old set of magnecores was fine as well)
new NGK BPR7ES plugs gapped to .026 (i have tried different plug/gaps with no effect)
new battery
original knock sensor (could it be too sensitive due to age?)
3G lifters
base fuel pressure is set to 43.5 on Aeromotive FPR
FP3052 turbo
PTE 1000cc injectors
rewired Walbro 255 fuel pump
i have seafoamed the engine a couple of times to get rid of carbon build up (after the picture of the pistons was taken)
Those "indentations" as you say are the factory valve reliefs. That is normal.
I would check for boost leaks, and maybe a bad knock sensor..what not. Personally its hard to get no knock when your running more boost. Like that.
running around 11.0 a/fs with lower timing does it supress the knock? You gotta try to see when the knock starts going away.
I'd definitely look into a bad knock sensor. I have run as lean as 16.xx:1 on e85 by accident and never registered any knock. I normally run around 11.8:1 at 25+psi on my 16g, so you know it's blowing a ton of hot air. At 13psi on a 50trim you should not have any charge temp issues at all, so that's why I'm thinking knock sensor.
Reach back there and feel around for any goo seeping out of it. Leaking goo = bad.
____________________________
Matthew : PTE5027e + Keydiver + e85 = Permagrin
My friend and I recently dyno'd my car. The first time at the dyno we made 672. Car ran great on the dyno. Took it out 2 weeks later to do a little street pull and the CEL came on at 7k. We went about changing the tune since we believed it might be a little lean because of the temperature changes from the dyno day. Nothing. None of us believed it was truly real knock since it's an E85 car. Went back a month later to get back on the rollers and try to work through it. The first pull netted 536...down 136 hp !! Next pull we tried retuning with no success. Pulled the plugs, all looked good. Comp. tested it just out of curiosity. Everything checked out. Just for kicks we bypassed the knock sensor and did a slow pull up to where the problem was occuring. Bingo ! Went with a 31 psi pull and jumped to 631. Next roll was at 36 psi and it jumped to 681. We went with one last pass at 37 psi and saw 708/544. Damn happy about that. Moral of this long winded story...my knock sensor was not my friend in this case.
Those "indentations" as you say are the factory valve reliefs. That is normal.
I would check for boost leaks, and maybe a bad knock sensor..what not. Personally its hard to get no knock when your running more boost. Like that.
running around 11.0 a/fs with lower timing does it supress the knock? You gotta try to see when the knock starts going away.
Actually those "indentations" as I call them are not factory relieve valves. If you notice they are uneven between pistons and they are only on the intake side. Pistons that come with relieve valves have them on the exhaust side as well.
It is not hard to get 0 knock with E85 at these boost levels especially with the amount of timing I have pulled and with a turbo that is still in its efficiency range. Did you look at the logs at all? Boost leak is out of the question since A) I have pressure tested the system and B) My A/F ratio is where it needs to be.
Another thing you might want to consider when giving advice is that 11:1 afr is pretty rich for E85.
Different A/F ratios didn't help with knock but pulling timing did.
Actually those "indentations" as I call them are not factory relieve valves. If you notice they are uneven between pistons and they are only on the intake side. Pistons that come with relieve valves have them on the exhaust side as well.
It is not hard to get 0 knock with E85 at these boost levels especially with the amount of timing I have pulled and with a turbo that is still in its efficiency range. Did you look at the logs at all? Boost leak is out of the question since A) I have pressure tested the system and B) My A/F ratio is where it needs to be.
Another thing you might want to consider when giving advice is that 11:1 afr is pretty rich for E85.
Different A/F ratios didn't help with knock but pulling timing did.
I will try a different knock sensor first.
Woops looked past the e85 part. Im use to running 30+psi on straight 93 pump gas with no meth etc with 13 degrees of timing, which with aem ems 1.5-2.0 volts is not uncommon on pump at that boost with a built motor.
The picture dosent really give a good visual depth for seeing anything out of the ordinary, but regardless I doubt it would cause a problem for knock.
To start your pistons do look pretty carbon'd up. That could be causeing hot spots. After looking at your logs, I would say check your knock sensor. Make sure all the goo didnt come out, if it hasent i would still replace it and go from there.
But If it were me, and I was running e85 I would turn the knock sensor off. Your running low boost and we all know what e85 is capeable of. You could still lean it out and add 10 degrees of timing on that 24 psi log and I wouldnt even bat an eye at it. I would just pull and plug and take a look at them. Its how I tune evey honda I have ever tuned, set the car where things should be good and check a plug. If your feeling brave get more aggressive with the tune and just keep checking plugs. Just my opinion.
To start your pistons do look pretty carbon'd up. That could be causeing hot spots. After looking at your logs, I would say check your knock sensor. Make sure all the goo didnt come out, if it hasent i would still replace it and go from there.
But If it were me, and I was running e85 I would turn the knock sensor off. Your running low boost and we all know what e85 is capeable of. You could still lean it out and add 10 degrees of timing on that 24 psi log and I wouldnt even bat an eye at it. I would just pull and plug and take a look at them. Its how I tune evey honda I have ever tuned, set the car where things should be good and check a plug. If your feeling brave get more aggressive with the tune and just keep checking plugs. Just my opinion.
The carbon build up from the pistons is gone, I have seafoamed the car twice last year and when I changed my HG they were clean. I will seafoam it again and throw in new plugs just in case. The new knock sensor just arrived at my door today so I will be swapping that after Christmas.
BTW wouldn't running E85 get rid of the carbon build up?
DSMtuners is not affiliated with Diamond Star Motors. The Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, Mitsubishi Galant VR-4, and associated logos are trademarks of Diamond Star Motors, Mitsubishi Motors, and Chrysler Corporation.
