E85 Timing

[K4fxd]

I would not turn down the knock sensors. Your log shows less than 1 degree being pulled and then adding it back. Leaving it alone will slow your 1/4 mile times by .0001 and maybe .001 Mph.

It's not worth the risk in my opinion.

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[Kaiden]

Unfortunately that doesn't necessarily mean there isn't any. I've had false knock from really weird things before. Even motor mounts.

The right test, which requires your tuner, would be to run a super low timing tune and see if the knock is still there. Ethanol should not knock on the stock timing curve, if it does, its false.

Sometimes it can't be fixed easily, but turning down the sensors puts you at risk. I don't like it when tuners do that to street cars.

The best test I did was running the car at WOT at the RPM it would knock when shifting but only staying in one gear and no knock occurred. He didn’t suggest turning them down though I asked personally

 

[LOL WUT]

With E80 in the tank and seeing KR only on the 2-3 shift, I too would suspect false knock.

There are people here that chased false knock forever without ever finding a source. It can be maddening.

 

[AWESOMO 4000]

So im wondering what the normal timing for E85 is? my car is on a E85 tune by Tricky and is seeing 30-32.3 degrees of timing at Wot. Is that normal? Also the fuel is tested at E80

Here is an excellent video by Alex from Lund Racing doing an E85 timing test on a dyno. In short, there was virtually no difference between 29 and 32 degrees. 27 degrees cost a total of 4-6hp, and less stress on the motor. Actual data.

 

[Joshinator99]

Here is an excellent video by Alex from Lund Racing doing an E85 timing test on a dyno. In short, there was virtually no difference between 29 and 32 degrees. 27 degrees cost a total of 4-6hp, and less stress on the motor. Actual data.

Makes total sense. 30-32 degrees is a crazy amount of timing IMO…

 

[AWESOMO 4000]

Makes total sense. 30-32 degrees is a crazy amount of timing IMO…

But E85 is also a huge octane jump from 93. He mentions the production file is capped at 31 degrees. But good data nonetheless rather than making assumptions. This is also a 3yr old video, there's probably been a few revisions and refinements since then.

 

[K4fxd]

Makes total sense. 30-32 degrees is a crazy amount of timing IMO…

For a coyote head it is. The old Chrysler hemis liked 45 degrees.

 

[AWESOMO 4000]

For a coyote head it is. The old Chrysler hemis liked 45 degrees.

I remember reading in Hot Rod Garlits saying how they were disappointed with the performance of the 392 Hemi. He cranked the timing way up and all of a sudden the thing came to life and shocked everyone.

 

[K4fxd]

It was the 426 that would not run worth a damn. He cranked the timing thinking it would blow up. The rest is history.

The top fuel motors are running 50 to 60 degrees of lead.

 

[Joshinator99]

But E85 is also a huge octane jump from 93. He mentions the production file is capped at 31 degrees. But good data nonetheless rather than making assumptions. This is also a 3yr old video, there's probably been a few revisions and refinements since then.

Agreed on the octane for sure. I’m running E50 in my 1059 WHP Camaro SS and am at 23 degrees. My tuner and I went up another degree or two on the dyno and didn’t see any power bump. We didn’t feel more timing just for the sake of more timing and maybe a couple extra HP was worth it. If your burn is efficient, and I’m sure a modern Coyote chamber design is, you don’t need tons of timing like an old Hemi. Need enough to make solid near best power and call it a day. Just my 2 cents of course.

 

[ZXMustang]

@Wengerd Performance can you weigh in on this?

 

[cbrtrx]

On an NA bolt on car you won't see a measeable difference past 30* on E85. I've done this hundreds of times now. A more experienced tuner will properly adjust cam timing and yield better results.

 

[Kaiden]

If it is only on shifts , it could indeed be false knock as clutch chatter/slipping can cause it.

Hey man I’m still chasing this issue I was wondering what your logs looked like when you had knock? Like how much knock were you seeing and for how long? I’m seeing between 0.5-MAX 1.75 degrees of knock. Am getting very concerned it may be real

 

[K4fxd]

Have your tuner reduce the timing where you are getting the knock by 1 to 2 degrees. I like to reduce it to what the ECU is giving. So if it is pulling 1.5 and actual spark is 27 I'll set that cell for 26 or 25.5, If it still knocks it probably is false.

 

[Kaiden]

Have your tuner reduce the timing where you are getting the knock by 1 to 2 degrees. I like to reduce it to what the ECU is giving. So if it is pulling 1.5 and actual spark is 27 I'll set that cell for 26 or 25.5, If it still knocks it probably is false.

I actually loaded up my old Lund tune that calls for 30.5 degrees of timing instead of 32.X by tricky. Noticed the car isn’t seeing positive knock in that tune BUT is still adding less timing after the shift if that makes sense? Car will go from. 30.5* to 28-29* then back up. Like it’s still pulling timing after the shift.

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