~3 gal e85 tune knock

[Speed3eak]

Attached are two recent 3rd gear logs taken with a ~3 gal e85 mix. I'm still getting quite a bit of part throttle knock when I shift below 2500 rpm, which you can't see here. What you can see is that I get ~.7 KR at WOT even with a 3/9 mix of e85.

When I say 'quite a bit' of part throttle knock, I mean I've pegged the KR sensor (8*) in 4th gear just cruising around 2k rpm. I've heard that the ECU does this to find the knock threshold for CL/part throttle, but I've never noticed it while cruising in CL on the highway at 2.5k+ rpm, and I've done a LOT of highway driving.

I'm also targeting AFRs of 17:1 in cruise loads so that may have something to do with it, but nobody else targeting those AFRs is seeing the same kind of knock. Any boost at all below 2.5k rpm and I usually see over 1*.

I'm only targeting ~10.5* at redline, and the tune has been modified as per Bucker's sticky, and bnoon's closed loop MPG tooning tables, so it is pretty generic in any case. It's a self-tune, obviously.

I have a few tunes with timing increases, going up to 12* @ RL, which I think I'm going to try out at some point later today when I get a chance. I'll post those logs up as well.

I haven't modified my tune for e85, I'm just trying to use it as a knock suppressant right now. Obviously it isn't working.

Mods that matter are JBR 3.5" WP intake - CNT 3" Catted DP - CS TMIC - Stock Plugs. I had one step colder plugs in there, but car didn't respond well, so I went back to stock.

I think the g/s reads high because my intake is so massive - vdyno has me around ~270 whp and ~315 wtq, even though I occasionally see 300+ g/s.

This particular tune shoots for AFRs of 11.8, but I'd like to move to 12-12.2 @ 16.5 psi and 12* at redline once I get this knock figured out.

Suggestions and thoughts are welcome, if anybody sees power on the table without increasing boost or timing, let me know.

[himurax13]

Did you alter the scalar for the JBR intake?

[smoogs12]

Took a quick look at the logs and it seems like you are running a bit lean (relative to your targets).

you should try scaling the injectors and setting the specific gravity to see if your afr come back down to 11.8 for the whole log. I think that 30% e is kind of a lot to not scale for.

[Speed3eak]

Well, it isn't exactly 1/3% e85. That was a rough estimation. It's probably closer to ~2.5 gallons, and I just started putting it in - so that figure is closer to e20 by my calculations, than e33.

I didn't alter the scalar for the JBR intake - just multiplied the MAF table by the % increase in surface area and fine tuned from there.

I'm hesitant to mess with the specific gravity of the table, because there's only one e85 gas station within probably a hundred miles of here, that I've found so far, so I won't always be able to fill up with it. So this tune is designed to be fine on regular old 93. Which it is, mostly.

I used the e85 to see if my knock was real knock, or if it was more indicative of injector seal issues. And to be honest, I can't tell. I don't know what engine noise disguised as knock looks like.

I guess toyota diesel seals are only like $2 and I need to clean my IM anyway. I just have been lazy and don't want to take the IM off.

Thank you for the feedback.

[smoogs12]

I'm on my phone so I can't really get a great look at your logs, but all the kr values were less than 1 right? That's not typically something to get to excited about. I cant say that it's not injector seals, because I have not seen many logs from cars with that as a known issue.

On the flip side, I would find it unusual that they would already be failing at your power level and (can I assume) low miles.

Also as far as the injector scalar/sg and not using them because you only have one source of e85, well, that's the beauty of them. We no longer have to rescale the fuel using an altered maf table every time we want to switch blends. You just change those 2 numbers.

Hopefully someone else will chime in on the seal thing.
@rfinkle2

Tapa

[Mortose]

so, my issue wasn't quite as bad as yours, but i used to get some pretty decent PT KR. i replaced them with the sure halo's, and now i only get like .3 to 1 pt kr. so that is a POSSIBILITY. just sharing to help OP make a decision.

[phate]

Will look at logs when I get to a PC. You shouldn't be anywhere close to the knock threshold of 93 with that timing lol. I would look for loose stuff in the engine bay.

[silvapain]

Have you modified your VVT table at all? Too much intake valve advance at spoolup can cause KR.

Your datalogs all show KR <1 degree. I wouldn't be too worried about that.

[Speed3eak]

Thanks - I've reduced VVT some in the cruising/low load areas. I unplugged the EGR briefly, but I started getting more low throttle knock - 2-3*, so I plugged it back in. Still need to re-check p0401/p0403 in ATR.

What I was worried about, was the PT knock that I see when I'm accelerating. I've seen 8* below 2.5k rpms, still in vacuum, while accelerating. I don't think I've ever seen 8* PT knock while cruising. I would try and get it to show up in a log, but I don't want to force my engine to knock like that if it really is knock.

I don't know, maybe it's nothing. Or maybe my car will explode into flames, trap me inside, and melt my skin to the seat before they can get me out.

I'm gonna go back and look at my VVT table, because I just realized that I do see knock at part throttle when I start to spool. It seems that, in my case at least, changing VVT too much in either direction does increase knock. I remember it being a problem before.

Thanks again everybody, I appreciate the help.