urbamworm

Still no update, guess it didn't go so well?

Hope nothing bad happened and all is well.

AKnight55

Craig usually posts regardless of the outcome.

black06c230

Craig said he hit 10s fine but was having a few issues with the new gears.

Quote:
Ran 10zzz but had some issues with gear calibration and hitting the limiter on 1-2 shift. Had 20" vossens on the front too, lol.

Sure he will update shortly.

chawkins2001

Long day fellas, will post tomorrow. I have pics, vid and lots of info on the 28" slicks, gears and stall. We could not get the camber arms in the rear for this event.

chawkins2001

Video run link:

http://s138.photobucket.com/user/cha...04331.mp4.html










I had a fun test and tune day yesterday with multiple issues, some new and some old. Maybe you guys could give me some insight on a couple things.

First off, I ran my old setup of 255-50-16 and donut front runners to compare apples to apples. I smoked the tires and went sideways badly out the whole resulting in a 2.1 60ft and ran 11.9 @ 128mph. On that run I hit 4th right before the traps and that was the first issue of the day. After every single run, the car would get stuck in 4th, cel came on with a gear calc error in 4th is what STAR said. No biggie, we just cleared it and moved on.

I then threw on my 28" slicks and taller front runners, and that is where the second issue cropped up. The front runners would rest on that control arms bolt above the wheel in the wheel well. So we took the fronts off and ran the 20" vossens for4 the rest of the day.

My next run were with 28" slicks and 20" vossens upfront. During this run, the next issue cropped up, my car started hitting the limiter on the 1-2-3 shifts. This problem however is not new as it was doing that in November last year when I ran a 10.8... It does not do that on the first couple of runs, but as the day progresses it starts hitting the limiter and it gets worse and worse. You guys think the car is adapting and it is getting stronger and stronger so that is what causes the issue to all of a sudden crop up. I should have done the sneaky ECU resest to see if that helped and possible started it out in M mode, and shifted it myself, but I left it in S mode all day long. I do have some logs of my runs so I will look at those:

11.09



My last run of the day I ran a 10.98 slamming the limiter again:




Launching with the stall is insane, I stalled the car to 2700rpms, and in dyno mode, I could hold it at the line pretty good. With the stock stall, it would start pushing through the brakes around 1500rpms on my car.

RedBullJnky

Good deal brotha! Can't wait til you get it all dialed in. It's gonna be epic.

Btw your race weight is the same as mine.

320 dreamer

couple observations here craig.
1. the 3.06 gearing is the same as what was in my slk32. i never got out of 4th gear passing the traps. when you say stuck do you mean it wont shift manually or that you felt you should be in 5th gear at the traps?
2. your drag times 60 ft and yesterday were minor difference. 1.65 record and 1.60 at the strip. yet your 1/8 mile is down by 2mph same for your trap speeds. times were close but your down almost 4 mph. something is killing your speeds. is it possible your leaning out at high rpm and causing the ecu to pull timing and losing power?

i would think with the slicks, torque convertor and gearing you could have gotten a 1.5 or maybe 1.4 60 ft yet your almost exactly were you were with 255 hoosiers and none of the current changes. something is up there. with close to 700 ft/lbs of torque and slicks you have more than enough power to launch the car and push the slicks down the 60 ft line

chawkins2001

Well, what is killing the mph is going to a 2" taller tire in the 28's. When I say it gets stuck in 4th, this is what I mean:

Start the run and hit 1-2-3-4 and then cross the traps and start slowing down. When I slow down the car remains in 4th, you cannot manually downshift it nor will it down shift itself, and at that point the cel triggers and comes on. I can clear the code and it goes away until I do another run.

I did not try to run my old tire setup to much, as I have never cut a 2.1 60 ft on drags before, and felt I was farming backwards with those tires.

urbamworm

While you went up to a taller tire using the 28s, you also changed your gearing a good bit that would totally negate that taller tire from the shorter gear. What hurt your trap in my opinion is a combination of things, one bouncing the rev limiter is a loss, then shifting to 4th is another loss and then also on that shift to 4th you are down in the rpms where you are making less hp most likely compared to blazing through the traps at the top of 3rd. So all that combined is what is hurting you.

320 dreamer

then i dont understand why run them. your 60 ft inc with them is negligable yet the speeds are definately down.
if they dont inc the 60 ft times and they kill the trap speed isnt that counterproductive?

chawkins2001

With the 28" tires and 3.06 gear, I cross the traps at the top of 3rd and hit 4th right after the traps. That is the whole reason I went to 28's and 3.06 gear, to cancel each other out and get a better 60ft.

E55Greasemonkey

In that case, you wouldn't need the TCU tune for the lower gears, your transmission doesn't know the difference.

I would also suggest checking your wheel speed MPH with STAR, actual values are in ESP, to see your front/rear speed comparisons with your drag and street setup, anything over 5mph or so will cause problems with the computers.

chawkins2001

One more I found:

Mike@Vossen

Craig..thanks for sharing again and congrats!

RaceHorse

Maybe I should be one of the last guys really putting in my 2 cents with very limited track experience, but as already mentioned the 28" rears gotta be much taller than the lowpro 20's up front no? Is it safe to assume you had fitment problems up front even at the highest suspension setting with the taller tires up front? Also Even with the big rears negating the steeper gears you should have been able to load up the rpm's for a better 60 ft even before hitting the rev limiter. Also its hard to quantify if everything is based on the gears and the tires when you have added the stall too. Do you think that it(the stall) could be also contributing to the limp mode issues? Maybe try the original tire setup to see if you have less problems with limp mode and if your 60 ft and 1/8 times improve from the gears. Then worry about the trap speed and end of the 1/4 shift. Hope you get it sorted out....regardless I'd still be afraid to cross your car on the street.

chawkins2001

Thanks brotha for leaving the feedback My first run I ran with my exact same tire setup I had always run in the past which is Hoosier 255-50-16 outback, and 215-45-18 on the skinny donut rims.

I used the usual protocol of backing into the water box, and imploding the tires for a good 6 seconds. Once baked, I staged, and went off idle and got the following result, lol:

2.1 60 ft and 11.9 at 128mph..... The car got extremely sideways out the hole, so I had to back out of it, and then got right back in the game. My MPH would have been alot better had I hooked better on that run.

This pic was right before that run, you can see I dont have the slicks on yet and usual front runners:



I mean the car felt like I had street tires on which it never has done that to the hoosiers before. So I took those off, and threw on the slicks but had to run the heavy 20's, as my other front runners rubbed the control arm bolt.
I lost 2mph going 2" taller in tire, but actually expected to lose more. I feel like I know my mustangs very well and have quite a few frineds who have run faster than I ever want to go, and the premise is going to a taller tire and steeper gear. The taller tire prevents you from spinning and you actual accelerate slower, but the steeper gear still offsets that by mulituplying the TQ factor. This adds back getting the acceleration back up to par, but in the end, when you go so tall as in a 28" slick, you will loose some mph in favour of getting a better ET.

I will say that the 3.06 gear and stall makes the car extremely violent from slow rolls or from a dead stop. It pulls much harder, so once I can get the bugs out, and some more seat time, it will go faster. I actually think it may need more gear, so once I figure out how to fix the TCU, we may go up to a 3.23 gear.

If of you guys coming up to Timmayefest is welcome to go for a ride to feel what the stall does and how hard the gear winds out.