GT500 + Drag Radials + Sticky Track=#%#%

[GT500wantabe]

I'm afraid it's going to take lower gearing than a 3.73 to launch this car. I think with enough gear the clutch programming problem might go away. A low gear is a lot easier on the clutch with less slippage at launch.

Too bad these cars aren't available with an automatic tranny. With a loose converter everything else stock the GT500 would run 1.5 60' times and well into the 10s in cool air. Someone ran 126 mph I believe. That converts to a mid 10!

 

[Lethalchem]

I'm afraid it's going to take lower gearing than a 3.73 to launch this car. I think with enough gear the clutch programming problem might go away. A low gear is a lot easier on the clutch with less slippage at launch.

Too bad these cars aren't available with an automatic tranny. With a loose converter everything else stock the GT500 would run 1.5 60' times and well into the 10s in cool air. Someone ran 126 mph I believe. That converts to a mid 10!

I forget his name, but the gt500 owner on here with the nitrous bottle in his trunk as an avitar is running 1.5x's 60' times regularly at I think 10.2x 140mph. He's using 3.73's. (EDIT: Dustin88lx)

 

[GT500wantabe]

I forget his name, but the gt500 owner on here with the nitrous bottle in his trunk as an avitar is running 1.5x's 60' times regularly at I think 10.2x 140mph. He's using 3.73's. (EDIT: Dustin88lx)

I based my estimate for a mid 10 on what my Camaro ran when I had it. 10.79 @ 122.64 mph, 1.44 60'. I was probably conservative with saying a 1.5 for the GT500 with an automatic and converter. Maybe 1.4s 60' times would be possible. It would take a very loose converter that most would consider unstreetable.

 

[BOD89LX]

Back from testing with LC in mod 6 I have no bog and can't leave any higher then 2800 rpm without spinning the tires, now with everything off LC, TC, AT I can leave at 3500 rpm and if clutch slips to much boost goes to 0 and car bogs clutch protection may be opening the bypass valve as boost drops to 0 then comes back up, now if I roll as slow as the car can about 700 rpm hit boost goes up right away and will spin the tires when boost hits 10 and the rpms come up much faster then when it bogs and it seems like it only does it if the clutch pedal is still depressed and you feed it more throttle to try to keep the rpms up to keep it from bogging . Keep in mind with street tires you will never have this problem and I will see what I can do at the track next weekend.

 

[dgdoc]

Back from testing with LC in mod 6 I have no bog and can't leave any higher then 2800 rpm without spinning the tires, now with everything off LC, TC, AT I can leave at 3500 rpm and if clutch slips to much boost goes to 0 and car bogs clutch protection may be opening the bypass valve as boost drops to 0 then comes back up, now if I roll as slow as the car can about 700 rpm hit boost goes up right away and will spin the tires when boost hits 10 and the rpms come up much faster then when it bogs and it seems like it only does it if the clutch pedal is still depressed and you feed it more throttle to try to keep the rpms up to keep it from bogging . Keep in mind with street tires you will never have this problem and I will see what I can do at the track next weekend.

Good feedback.

Sounds like there is indeed a fine line between clutch slip and throttle application. With the street tires, they spin very easily, and that's not what anyone wants.

Also, you are correct that there is some form of Clutch Protection:
Clutch Protection (Page 12 of GT500 Supplement)
"Your vehicle is equipped with an electronic powertrain feature to reduce clutch damage. When excessive clutch slip is detected at a high power level, the powertrain control module will limit torque to reduce damage to the clutch. Full power is restored as soon as the clutch is fully engaged. This feature is calibrated in a way that it does not interfere with normal driving and does not impede maximum acceleration capability"

Anyway, still intrigued that MotorTrend managed to run 11.6 @125 with the stock tires.
http://www.motortrend.com/roadtests/coupes/1205_2013_ford_shelby_gt500_first_test/viewall.html
Given enough seat time, believe good drivers will be able to beat that time.

When the C6Z06 came out, the magazines ran 11.7@125, (which was the spec from Chevy). Over time (5 years), racers managed to knock 0.7 off of this time on street tires, and a full second on drag radials.

Did you have a chance to try the technique of hitting the throttle harder/quicker, getting the engine into it's power curve, then letting the clutch lock-up, to see if this changed things?

 

[BOD89LX]

Update.
After 2 more trips to the track I have been able to get a few good runs with street tires and drag radials and learned that this car needs gears at stock power levels to get a real good ET I was able to run 11.60@125 and back it up with a 11.68@125 with drag radials but I made 14 runs that day and most were in the 11.8-12.1 range @ 119-122 so only 2 good runs and they were with all traction aids off and a small amount of wheel spin to prevent the car from bogging. On street tires best I could run was a 11.86@123 and car would run 11.9-12.0 all day with the launch control @ 117-121 depending on inlet temps at time of run. So I think with some 4.10's these cars might be able to dip in the low 11's with drag radials and cool air but it will take a freak of a car with Evan Smith driving to get on in the 10's bone stock on DR's.

:burnout::beer:

 

[thePill]

Ensure you completely disable Advance Trac. The launch control and Advance Trac is more like a "I Win" button. With everything off, the engine will have NO restrictions but will take more effort on your part.

80 degrees on the way back is outstanding!!!

 

[dgdoc]

Update.
After 2 more trips to the track I have been able to get a few good runs with street tires and drag radials and learned that this car needs gears at stock power levels to get a real good ET I was able to run 11.60@125 and back it up with a 11.68@125 with drag radials but I made 14 runs that day and most were in the 11.8-12.1 range @ 119-122 so only 2 good runs and they were with all traction aids off and a small amount of wheel spin to prevent the car from bogging. On street tires best I could run was a 11.86@123 and car would run 11.9-12.0 all day with the launch control @ 117-121 depending on inlet temps at time of run. So I think with some 4.10's these cars might be able to dip in the low 11's with drag radials and cool air but it will take a freak of a car with Evan Smith driving to get on in the 10's bone stock on DR's.

:burnout::beer:

Nice work and appreciate the feedback.
Glad to see things improving.

What was your best 60'?

Can you provide some info on launch RPM, with and without launch control, which launch control mode did you use, etc.

Also, were you able to get around the clutch protection system kicking in?

Thanks.

 

[tuffluvcapo]

Before you launch, hold the clutch just at the point of engagement, as if you're sitting on a hill and don't want to use your brakes. When you dump the clutch, there won't be any slack. Worked for me.

 

[BOD89LX]

Nice work and appreciate the feedback.
Glad to see things improving.

What was your best 60'?

Can you provide some info on launch RPM, with and without launch control, which launch control mode did you use, etc.

Also, were you able to get around the clutch protection system kicking in?

Thanks.

Best 60' was 1.895 and 1.903 otherwise it ranged from 1.998-2.260. The 2 best passes were with everything shut off and leaving at 2000 rpm and getting the clutch out fast enough to spin the tires a little which took 7 or 8 tries and on those passes no bog from the clutch protection but on others it would bog or spin bad enough to have get almost all the way out of the gas to get it to hook again. I also tried launch mode 6 with the drag radials and left @ 3000 and it would spin some but the advance track must be pulling power as it was a few tenths and mph slower all of which happens in the first 1/8 mile.

 

[BOD89LX]

Before you launch, hold the clutch just at the point of engagement, as if you're sitting on a hill and don't want to use your brakes. When you dump the clutch, there won't be any slack. Worked for me.

Thanks for the tip I will try that next weekend at the track.
:beer:

 

[tuffluvcapo]

Thanks for the tip I will try that next weekend at the track.
:beer:

Make sure to post results and let me know how it worked.

 

[Turbosnake281]

wind that b*tch up some more

drive the car not the computer

 

[NHRACobra]

Good feedback.

Sounds like there is indeed a fine line between clutch slip and throttle application. With the street tires, they spin very easily, and that's not what anyone wants.

Also, you are correct that there is some form of Clutch Protection:
Clutch Protection (Page 12 of GT500 Supplement)
"Your vehicle is equipped with an electronic powertrain feature to reduce clutch damage. When excessive clutch slip is detected at a high power level, the powertrain control module will limit torque to reduce damage to the clutch. Full power is restored as soon as the clutch is fully engaged. This feature is calibrated in a way that it does not interfere with normal driving and does not impede maximum acceleration capability"

Sounds like the only way to correct this is with a tune, removing torque management.
I'd contact Lund, Livenous, and others who tune these cars. They WILL know.

 

[dgdoc]

Sounds like the only way to correct this is with a tune, removing torque management.
I'd contact Lund, Livenous, and others who tune these cars. They WILL know.

It's not Torque Management. It's a Clutch Protection system designed to limit "abuse" and premature wear on the clutch surfaces.

The question is (despite Ford's documented representation that it "does not impede maximum acceleration capability"), is does it or doesn't it?

If and when we see 60' times in the 1.6x (with Drag Radials), we'll know whether or not the Clutch Protection is "impeding".

And, keep in mind that there will have to be some trial and error testing with various driving techniques, before any solid conclusions can be reached.

 

[Lethalchem]

People are already running 1.5x 60' times

 

[dgdoc]

Best 60' was 1.895 and 1.903 otherwise it ranged from 1.998-2.260. The 2 best passes were with everything shut off and leaving at 2000 rpm and getting the clutch out fast enough to spin the tires a little which took 7 or 8 tries and on those passes no bog from the clutch protection but on others it would bog or spin bad enough to have get almost all the way out of the gas to get it to hook again. I also tried launch mode 6 with the drag radials and left @ 3000 and it would spin some but the advance track must be pulling power as it was a few tenths and mph slower all of which happens in the first 1/8 mile.

Thanks.

Interesting that you got your best times with (only) 2000 RPM launches.

The high release point and strong grab of the clutch sounds like it is going to take some getting used to.

Knowing where the release point is and letting the clutch up quickly to this point, slowing the release, then speeding up again as you squeeze the throttle is what needs to happen. So, kind of a Fast/Slow/Fast motion on the clutch. Not easy, but will probably result in the best 60' times.

The question is if this can be done in such a way to not invoke the clutch protection system.

BTW - Can you post up a couple of your best timeslips. I'd like to see some of the splits, specifically the 330-1320 times.

Thanks again for getting out there and plowing the path. We're all learning and very valuable to share these experiences.

 

[dgdoc]

People are already running 1.5x 60' times

Really? Bone stock?

Please provide a link to a post where this has occured.

Thanks.

 

[BLK93GT]

My friend's 2010 has this EXACT same issue, everything turned off with slicks and 3.73 it bogs. 11.5@132 with a 1.8x 60ft I think. It acts like the throttle is closing, it did it real bad the other day when I drove it and I ran a 12.0@125. We are stumped. The car has a TVS, tune, etc. It seems like it is the Advancetrac somehow.

 

[ericrizner]

I know this post is really really old. So I'm figuring this has been resolved somehow. Just spent my first time at the track last weekend with Drag Radials. It hooked like crazy, but acted just like I see in this thread. What is the secret?