Bandimere 4/20

Bandimere's first test and tune of the season is 4/20.. normally a day I would avoid due to huge crowds on opening day.

But this year the gates open at 8:30am. I'm there! Who else?

http://www.bandimere.com/events/day_detail.php?dayID=352&dTargetDate=04/01/2011

Alright it's official - I'm going! Got a compression test today and all is well with my motor (been eating oil, but it's not the rings).

Who else is in.. I'm thinking of heading over around 9:30am for a few hours.

Wish I could make it but working that day and been really lazy with the car. Went to the gas station to switch back to e85 finally and they had the pumps out of order. Put about 5 gallons of gas in so have to burn through that and the lingering fact I haven't done my 60k plug change yet is keeping me off the throttle much. I need to get my ass in gear, just seems things keep coming up.

Dave

Gotta set some goals. I want some new personal bests! I've got brand new street summer tires and still running 18's, so hopefully I won't have to re-learn my launches. Would love to borrow somebody's 17" stockers some time.

Best e.t. on current setup is 12.492 (1.88 60', 111.86mph trap). I want 12.39s.

Best trap on current setup is 112.30 (2.02 60', 12.87 e.t.). I want 113mph

Best 60' on current setup is 1.829s (12.52 e.t., 110.3mph). I want 1.81s

So 12.39 @ 113mph is the goal. Not the fastest Suby at all, but still the fastest 4th gen LGT running stock block and stock location turbo/TMIC.

If I go, I'll probably be towing the car home.

Just take the tires up to 44psi like I do. No, I'll probably never get better than a 1.80 60' but lots of wheel spin really reduces the toll on the rest of the drivetrain. I still usually get better than a 2.0 anyhow.

And also, they've got a tow truck right there on the strip for ya!

245's don't spin, even at 44psi. They grip and things snap. 450 ftlbs is going to snap something soon. My clutch slips and my headgasket is on it's way out. Something WILL break if I take it to the track.

If I hadn't just spent all my money opening the new shop, I might go.

Gotta set some goals. I want some new personal bests! I've got brand new street summer tires and still running 18's, so hopefully I won't have to re-learn my launches. Would love to borrow somebody's 17" stockers some time.

 

Best e.t. on current setup is 12.492 (1.88 60', 111.86mph trap). I want 12.39s.

Best trap on current setup is 112.30 (2.02 60', 12.87 e.t.). I want 113mph

Best 60' on current setup is 1.829s (12.52 e.t., 110.3mph). I want 1.81s

 

So 12.39 @ 113mph is the goal. Not the fastest Suby at all, but still the fastest 4th gen LGT running stock block and stock location turbo/TMIC.

Okay I got results. Despite the great 45-50F track conditions, I only hit 1 of my 3 goals today. I left very frustrated after 5 runs. I encountered the same problem I did last time I went drag racing... the car hits a wall at 109-110mph and loses power. Big time. I kept forgetting to log but I did get one good log and it is very interesting. I think the problem might be too much timing around 5800-6000rpms and/or possible TMIC heatsoak. 2nd and 3rd gear don't complain but 4th gear just chokes up. I get to 5800rpms in 4th at around 11.5-11.6 seconds at around 110mph and just stay there the whole last second... briefly hitting 112mph and 5900rpms kind of coasting the last 50-100'. Real bummer.

Think it would be hitting 113's all day if I could get ever get across the finish without limping. And my good run would have been a 12.3x for sure, maybe 12.2x. Should coulda woulda. Oh well. Pretty obvious though... only gained 22mph on the back half! Last time I went drag racing in October in similar conditions I was gaining 25mph in the back half (and I was hitting that "wall" then too, actually).

http://beeez.com/lgt/1243at111.jpg

Anyhow, I got a new best 60' and new best e.t. but my traps sucked. And I was very inconsistent. This was my last day at the dragstrip. I'm done. At least for this year.

Best run was my second run... 12.43 @ 111.1mph on a 1.780 60', but I lost power..

So, instead, let's talk about my 1/8 mile e.t. and trap... 7.98 @ 89.1mph rocks! Sub 8-seconds. Cool. Not bad for track elevation of 5860' and for having 3 degrees of timing pulled FLKC from my first run.

1st run: 13.07 @ 112.03 mph - This was my first run with my new tires and I wasn't sure how my launch was going to be. Ran 38f/42r like I usually do. Apparently I was the first AWD car to run today because they had sprayed down the ENTIRE staging area with water. (Usually you can just go around to keep the tires dry). Well, I had to go through it. I got a bad 2.09 60' thanks to a pretty impressive AWD smokey burnout that left me spinning instead of moving. I've never seen so much smoke in my rear view mirror and think I smoked 'em well into 2nd gear. I check my LV prior to this run and all FLKC was zero, as usual. About 100' before the finish, I felt the car lose power and a little popping/rumbling in the exhaust. I pulled a LV after the run and saw -3.03 in a single cell (2.6-3.2g/rev by 5400-6200rpms). I was very frustrated and I've seen this before, but only at the dragstrip around 110mph. I was tempted to clear the ecu because I really didn't want to race with 3 degrees less timing in my peak powerband, but figured I'd better let it go so I don't blow the motor the next time I hit 110mph.

Those are excellent results. I wouldn't expect heat soak while traveling at over 100 mph with the throttle wide open.

I hope you sort it out.

Alright I think it has to do with timing... I plotted timing vs. time and also timing vs. gear and I am running 8 degrees more timing in 4th gear than in 2nd or 3rd gears. WTF. My timing from single 3rd gear pulls is pretty but timing in each geat at the dragstrip is very ugly. I think my problem lies herein. This is friggin' nutty. You can see the chaos that hits in 4th gear around 5900rpms!

http://beeez.com/lgt/timinghell.jpg

Alright, looking over the log from the run at the dragstrip, there were 4 knock sum increments in the first 2 seconds and then again 2 more knock sum increments on the 2nd-3rd shift. Knock sum did not increment again until I "hit the wall".

For each knock sum, DA decremented timing by 2 degrees, and that is why my 2nd and 3rd gears at the dragstrip had such low timing compared to my usual tuned isolated street/dyno runs. The car probably would have performed a lot better in 2nd-3rd if the timing were a lot closer to where it is supposed to be.

To compound the problem, the data from this run followed at least 2-3 runs where FLKC in a single cell (5400-6200rpms by 2.6-3.2g/rev) had been decremented to around -3 or -4 from hitting the wall in 4th gear on prior runs. The combination of problems means in 3rd gear at the dragstrip I'm running almost 10 degrees less timing than I should be(!)

By the time 4th gear came around, the time delay from the DA decrements had expired and timing was restored to normal. Timing is finally following the "normal" line, then dips several degrees due to the FLKC, from prior runs, leaves that cell, shoots up several degrees... then chaos, knock sum, popping exhaust, and loss of power.

So, I need to address 2 different problems so that the timing in 3rd and 4th gears are about the same. First, to make 4th gear happy it is clear I need to run at least 2-3 degrees less timing in the problem area. Second, to get 2nd and 3rd to run normal timing, I'll probably need to make a dragstrip-specific map to lessen the effect of knock sum on timing. That is, some combination of decreasing the DA decrement, increase the subsequent increment, and increasing the rate of the subsequent increment. Basically, removing a good degree of protection... a little dangerous.

Uploaded dragstrip log here.

I will look closer at the log in a bit, but I do have some things to hopefully help.

FWIW I don't really do a lot of 3rd gear tuning anymore. I try to make shifts and WOT in all gears work the best, not necessarily the prettiest 3rd gear log, although they do tend to look pretty good.

I honestly believe it is heat-soak. Our TMIC opening are not big enough, and at some speed (like 111 mph) the airflow seems to change and skip the TMIC. I am not an aerodynamicist, but I know a bit about it, and it seems logical, and the evidence seems to support it.

When I had my 68HTA and custom TMIC, I could do good 3rd gear runs all day long, but in 4th gear about the same speed as you I would get into knock. I could reduce timing all day long, but I still kept getting it. I was eventually down about 4 degrees from my clean 3rd gear runs, but I was still getting knock. This happened even when it was 0F outside.

With my FMIC I have done 5th gear logs up to, well let's just say I was very close to the limiter, and it was still pulling hard. and I had no knock.

So IMO your biggest problem is solved, knock at high speeds due to heat-soak. I see no other explanation for it, it went away for me with my FMIC.

Your problems of shift-knock (or drive-train induced perceived knock) I think are easily solved with a tune, you could have it track specific, but I don't think it need to be, just E85 specific.

How much knock can you get at medium loads on E85? I really don't think it is that bad, so lowering the amount of timing that FBKC pulls (I assume it is FBKC that is causing the lowered timing there) seems like a reasonable answer to me. Also changing the delay the ECU uses to phase out FBKC (I am sure I am wording that wrong) can be drastically reduced as well.

If in doubt build some det cans.

Also, FWIW I have slightly lower timing in the "landing zones" after a high rpm shift.

I get some knock when launching, but 2-3-4 gear shifts are 70% of the time knock free for me.

Thanks LBGT. I do have soft-landing zones in my map for shift recovery for both richer fueling and lower timing. I've plotted rolling 1st gear runs though and unfortunately 1st gear wants to skip through some of those cells so my landing zone is a little left of where I'd like it. But I don't think it's knock anyhow but instead all the commotion an all-out 0-65mph (1st-2nd gear) run makes.

I really thought it was heatsoak, especially the first time it happened.. since track conditions were high 80's. But these last 2 times it has happened also it hasn't been much warmer than 50F. I'm torn on whether it is heatsoak or timing, but I think my plot of timing vs. rpms in various gears suggests timing is the likely culprit. But you've (LBGT) been down this road before, and I can't ignore the evidence of your experience. Plus, even when I've done runs after the 1st run (which induces -3 or -4 FLKC) in that cell, subsequent runs also have the same issue. Then again, it might be simply that a sudden snap of increased timing from leaving that very negative cell induces the power loss and FBKC.

I'll go in and lessen the effects of FBKC. I should be doing better in 2nd and 3rd first of all. I suppose to get 4th gear figured out and get a real answer I ought to do some pulls from 50-120mph hard in 3rd-4th and see if I can clear up the issue by finessing timing. But I really don't have the kinds of roads required for doing that kind of testing, unfortunately, so I don't think that will happen.

Then go for a drive to where you can get to those speeds. I think you will find the same thing. Even if you don't start out as hard, and have the residual heat in the system, I think the same problem will suffice.

Like I said before, I had the same problem in the (real) winter we have here.

I think turbulence in the hood-scoop (from too much incoming air) creates a boundary layer (or something like that) and then causes air to flow over it, rather then in. Or maybe the engine bay starts to get too pressurized at that speed and stagnates the pressure differential causing no TMIC air flow.

Unless there is a better explanation I think it is the TMIC system limiting things.

Legend, do you use RomRaider? If so, paste your base and DA timing tables into this utility, and post a screenshot of your total timing...

http://www.romraider.com/forum/viewtopic.php?f=32&t=4439

I find it hard to believe that heatsoak would be a problem on a dragstrip run like this. While I can fully believe that air flow into the hood scoop is affected by speeds above 100 (air flow is probably actually skipping over the scoop opening at that speed), I can't believe that heatsoak would be able to set in within 12 seconds of starting boost - it just doesn't seem plausible. I agree with Legend that timing seems like a bigger concern.

For the old SRRT Legacy car, did they put a FMIC on that thing, or did they continue to run a TMIC?

Legend - any chance your issues at the higher rpm are due to more oil getting burned, thus changing your octane enough that it has to pull timing?