I'll do the test today.

I might do the test this weekend. So, basically plugging the lower reference port lowers the amount of pressure force available to open the valve when the top reference port goes into vacuum, correct? If by plugging this port the car holds boost better it means the spring is weakened since that port is there to help open the valve, yes? It sounds like this solution makes the BPV behave as if a stiffer spring was put in. What did you plug it with?

Yeah, you pretty much nailed it. I trimmed an 1/8" vacuum line nipple and stuffed it in there. There's a thread somewhere - by TRex - Who quoted my writeup about the whole thing from M3F. Something like "Stock BPV Leak? I may have a cost effective semi-solution".

^^^ I haven't looked at your write up but wouldn't a better test be to just do a boost leak test starting downstream of the turbo inlet pipe? If you pressurize the tract from the mouth of the turbo instead of the TIP you would see if the BPV leaks. May be I am not getting it.

I guess I also did this test wrong then. Lol.
I just plugged the hose going fromt he manifold to the BPV and left the reference port open. Of course the BPV would crack open at 12 psi and WGDC would go all the way up. Attached a log.

I also ran a parallel test and ramped up timing to 16 deg and disconnected the meth. Well at least I know I can run 16 deg of timing at red line at 12psi of boost. Lol. May be I'll just work backwards and increase boost while leaving timing at 16 deg. See how high I can bring it before I start seeing KR.

pull the recirc tube off the BPV plug it, then pressure test.

if the BPV leaks you'll know instantly.

My GTX3071 seems to be loving the eth. You have CPE injector seals? Are you sure its not phantom knock?

This is exactly the same as pressure testing downstream of the TIP. I've done this many times and the stocker is solid.

Injector seals are at this point the most probable cause. It just bothers me that it's really an almost linear relationship between an increase in timing and KR readings. I am probably going to get those CPE safe seals and see if it solves the issue.

I don't know but it just seems weird that you can only get 11* of timing with e85 (thats why I think inj seals). I'm hitting about 10-11* with 93. I'm at 18* on my e85 map currently and will be bumping it up to 19, and then 20* here pretty soon.

10-11 deg's is exactly the same where I am with 93 at 20 psi

Trust @dani and @phate.,,.,.they pwn

same end result but my method so sooo much easier than removing the TIP :)

plus you get to test the TIP to turbo connection as well.

so your BPV tested out ok and you don't have any other boost leaks...hum. you still have fairly erratic WGDC and boost at times. Not sure a 10PSI spring would be the cause of that.

IIRC some of the GT3071s have a WGA arm binding issue...you might want to check that yours isn't having trouble.

I would assume you are load tuning correct?

Apparently cld12pk is having issues getting above 2.1 or 2.25 load targets above 5k or so as well and he believes it is a Cobb tuning issue.

you might switch to boost targeting to see if that helps.

I see a minimum of 2.70 load right now on the very top end of the rev range, due to MAF scaling. [3.80+ on the bottom end, hahaha.] I just pulled some logs last night and it was 34° outside, so those numbers may be even higher now.

yeah..not exactly sure what 12pk was referring to but he mentioned it in his GTX thread.

I had the same problem and it just turned out my load cuts /limits were getting triggered even when I was well below them. Raised all of them to 5.0 and problem solved lol.

I believe Dj suggested this could be happening due to a baro ir Iat correction/multiplier being applied to tje calc load value.

Pulled the sparkplugs and did compression test.
It's all kosher. Plugs looked perfect.
Took pics of each piston crown with the boroscope. Not sure if DI gives them a few golden looking blots or if there is something else going on. Any comments?

http://i1211.photobucket.com/albums/...t/IV7L0002.jpg

http://i1211.photobucket.com/albums/...t/IV7L0004.jpg

http://i1211.photobucket.com/albums/...t/IV7L0005.jpg

http://i1211.photobucket.com/albums/...t/IV7L0006.jpg

Yeah, does your colon have that much buildup? Inquiring minds want to know.

I can only shit every three days or so so I would think it has even more buildup than my pistons. I'll take the borocpoce to my anus and send you some pics via PM. May be you can help me become more regular?

Fiber.


Tappin

I never would have expected the injector spray pattern to be so obvious. All that buildup behind the spray is ripe for causing knock, not hard to get a hot spot with that mess.

A quick update:

I've finally stopped being lazy for a few minutes and started to work on really refining my tune: that means I'm seeing how we can regain some of the gas mileage that is lost with the switch. So fueling and part throttle ignition timing are going to be tested in my car and one or two of the other E85 cars I'm tuning.

Best of luck Clint.....I did quite a bit of testing without saying anything while running the 50/50. Leaning out part throttle of course is the only real solution. But to me the few gains isn't worth the wildfire of always running lean at part throttle. I'm kinda slow though LOL.

Phate, I'm down for this. At one point I was targeting 14.9 gas afr under light load so I'm not afraid to lean it out on e85 in the name of science.

Farther than 14.9

agreed 14.9 wastes too much gas... lol

Just seeing 16 17 made me nervous enough to revert all back to previous settings. Not gonna lie I didn't put a shit ton of time into it. I'm sure Clint will come up with some good shit and I may revisit it when I go back to e85.

14.9 on pump gas, fellas.

Just making sure that you shift your closed loop max load tables down a few load rows should help a bit (although Phate most likely already does this in his tunes).

Before I go crazy lean with the car, I'm going to get my EGT gauge hooked back up.

My CL Exit is now set at 1.50 load. Realistically, everything below 2.0 is part throttle for us E85'ers, so we could set it even farther up. My fueling tables are set at 14.68:1 up to 1.38 load @ 4500 rpm. The car hits OL fueling targets quickly enough that it's not a worry.

Going from 1.0 CL Exit to 1.5 CL exit has already netted me some mileage. At 65mph, I am cruising anywhere in the .7-.9 load range. There's no sense in transitioning that low with E85, or even the higher eth content mixes.

For the next few weeks, I'll be testing different timing - I'll be lowering it incrementally in the part throttle range first. If that kills mileage (which I think it might hurt a bit), then I'll start going the other way :)

If I remember correctly I have my CL/OL load transition set at ~1.7 load. I also use TP for CL/OL transition.


Tapadatass

Mine is already set for 1.5 load, and you're right, mileage has gone up as a result. I'll try leaning my car out to 15:1 gas afr, and tweaking some other stuff to see how that impacts it.

Let me know what you have temps wise on current afr/timing or if there's some info you want to verify and/or further test.

I disconnected my meth and am running a 30% mix of ethanol now.

I do not have logs yet, but AFR is unchanged and no KR. It's nice to not have to worry about whether or not my meth is spraying!

Are you getting your eth from Thorton's on Ogden like I am?

Not right now.

I stop at a Family Express on 65 near Remington on my travels.

But that Thornton's will be right across from me if the bank ever gets my loan processed!

+1. ^

So we definitely have some more ignition tables that are yet to be uncovered by Cobb. My car doesn't give a damn that I want to limit ignition timing to 20° less than what it actually runs at part throttle/cruising speeds, hahaha. Oh well, I'll just let it do it's thing.

And yes, my ignition tables are aligned and the Max A/B should be limiting the actual timing, but alas, they are not. I guess my dreams of becoming a hyper miler will be put on hold until Cobb has a new ATR update, lol.

@Cobb Tuning

I too found this out...I was hitting timing of 60 decelerating, and in none of my tables OTS or modified did my timing have a commanded value that high. I did a little experimenting with lowering the timing at lower load values and I felt I lost a little MPG and a little throttle response. We definitely need access to more tables.

Evidently, I am not alone. This is probably why all the big power BT people are on MBC, b/c the currently available load tuning options simply will not cooperate at high RPMs and high loads.

I wish Cobb would fix this as I really, really believe boost targeting to be the inferior method of control.

I mentioned this to @phate, @atvfreek and in another thread, and I believe you will be able to use the load tables effectively if you change the wgdc load error tables to 100ths of a percent (as seen in the wgdc boost error comp tables.)

I'm currently using the following, and although it still needs ironing out, I believe it will help.

BTW, in that table I also think that the axis are screwy around the 0, but haven't had the guts to experiment with that yet.

http://i1206.photobucket.com/albums/...rrortables.png

Here's an excellent tool I found online to determine compatibility of different rubbers to chemicals, including E85 (Ethyl Alcohol) and gasoline.

General Chemical Resistance Guide

If we start seeing O-ring deterioration issues, HNBR looks like a good option. The green O-rings sold at parts stores for A/C systems are all made from HNBR.