New to E85. Getting a baseline...

[CVD]

This is regarding my 4G61 turbo Colt. Stock turbo, enough fuel mods for E85. On to the problem:

I just went from a 1G MAS and 450's on gasoline to a HKS VPC/GCC with 550cc injectors on E85. I feel as if I'm running ridiculously rich though, and have been leaning it out a little at a time. I'm just afraid I'll go too lean.

To start I went +30% across the board. Now I'm maybe at like +25%? Thing is though, I used to hit 70% duty cycle with the 450's on gasoline, in a 1st or 2nd gear pull on a cold night. Now I'm hitting 90-100 duty cycle on the 550's in any gear. So that's like a 40% jump in duty cycle PLUS 20% larger injectors. Am I doing my math right here? The VPC has a 550 chip so it should "zero" with the injectors.
I'm also getting a shit-ton of knock until the car reaches operating temp. Is this rich knock? Is it common with E85?

Is it safe to just lean it out until I see knock then add like +2% across the board? I'm only running 20psi (fading to 16psi at redline) so I'm afraid it's going to be really lean before I see any knock.

I'm getting no knock now, and it pulls strong at WOT. Just stumbles once in a while during cruise and I'm seeing crazy duty cycles at WOT and sometimes while cruising (like 40% under mild acceleration). Also the top end feels a little doggy. Boost from the 11b falls off pretty quick, but duty cycles seem to keep climbing to redline.

As for a real dyno tune, I'm going to tweak it a bit at MAP's dyno day, then slap the 16G on there and get a real tune a week or two later. I just want to drive and enjoy it until then.

[scheides]

The car must be extremely rich if you are hitting those IDC's, or you have a limitation in your fuel system somewhere. You have a walbro pump in the tank I assume? I'm not aware of any weird fuel line issues but sometimes after switching to E85 the fuel filter can become clogged. The best thing I can recommend is a wideband, the next would be to just watch your o2 feedback/fuel trims and see how far off it is...you're logging this thing, right?

[CVD]

I have a logger, but I'm only logging RPM, knock, and duty cycle, as those are the only values that mean anything to me. I have a walbro 255hp and a AFPR set to 43psi. This is my first half a tank on E85 so I don't see having fuel filter issues already.
I hear you on the wideband but it's not going to happen just yet. I just want to get it running within 5% of where it needs to be by dyno day.

[FattyBoomBatty]

As far as the IDC going up with rpm, I looked at mine in a graph, and they do the same thing, with a little bump where the turbo spools up.

[scheides]

Well then the o2 feedback and fuel trims are your friend then, log them at cruise and see how they look.

[jrohner]

I'm also getting a shit-ton of knock until the car reaches operating temp. Is this rich knock? Is it common with E85?

Is it safe to just lean it out until I see knock then add like +2% across the board?

I'm getting no knock now, and it pulls strong at WOT. Just stumbles once in a while during cruise and I'm seeing crazy duty cycles at WOT and sometimes while cruising (like 40% under mild acceleration). Also the top end feels a little doggy. Boost from the 11b falls off pretty quick, but duty cycles seem to keep climbing to redline.


My talon always did that too, I always thought it was due to the lifters.

No that's not safe at all. You can't tune E85 (fuel or timing) with knock, well you "can" but you'll tear stuff up or at least end up running way off from where you should be with no indication of it.

On E85 I never really register knock on my 2G no matter what I do with the fuel or timing. The 2 1G's I've changed to E85 would show knock once in a while, but neither had a wideband, and 1 of them had some issue as it was about impossible to not show knock like crazy when it was on gas (I could pull 10` timing and it would still show knock). 1G's have an overly sensitive and finicky knock sensing system IMO.


Take your injectors size and divide it by 1.4; to tune, pretend that number is your real injector size. If you have a chip for 550's, 750's are what would be ideal for tuning E85 on it. A chip actually designed (for gas) for the injectors you're running is actually more of a burden than a help for E85.

[Swifty1638]

^it's actually 2g's that have a more sensative knock sensor, not 1g's. Hence why most on a EMS run a 2g sensor on their 1g's, like me. I will be swapping to a new 1g though, for further dyno testing with Shane though next spring.

[CVD]

OK scheides, will do. Although the O2 is dead, and it's going to have to stay that way for a couple weeks until I change the turbo.

jrohner - It's not lifter tick in my car, before the switch I had no knock ever (unless I ran shitty gas).
I do have 780cc injectors ready to go in, I just need the rubber donuts so I can install them.

[FattyBoomBatty]

I bought an injector o-ring for a caddy DTS I think, it was exactly the right one. Really cheap.

[jrohner]

^it's actually 2g's that have a more sensative knock sensor, not 1g's. Hence why most on a EMS run a 2g sensor on their 1g's, like me. I will be swapping to a new 1g though, for further dyno testing with Shane though next spring.

It's 1G's that have most of the phantom knock issues. The 2G knock sensor is better.