Got my 12 sec pass

9

96grimreaper

New member
Finally grabbed my 12 sec pass.


91 LMS 3 bar tune, 255/45 Nitto Motivo tires at 28psi. Still lots of spin, so the Nittos may not be a good track tire.  Had another run of 13.01@109 with a 1.90 60 ft. I think the car has more in it with more traction but we'll see what happens next season with more mods.

No, I didn't fall asleep at the tree, was worried more about launch rpm's.  :glare:
 
Congrats on your new times. What was the DA? Where was this ? I can't seem to trap anything past 105 mph ...

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Solid run...welcome to the 12 second club.

I was getting extra spin on my summer tires in the colder weather until I dropped the tire pressure to 22 in the fronts.

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southtxSHO said:
Congrats on your new times. What was the DA? Where was this ? I can't seem to trap anything past 105 mph ...

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Thank you.  :alkashi:
Wichita, KS
DA was around 1700

SHOnUup said:
Solid run...welcome to the 12 second club.

I was getting extra spin on my summer tires in the colder weather until I dropped the tire pressure to 22 in the fronts.

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Thanks. :icon_horns2:

I should've played with the pressure a little more to see if I could find a sweet spot.  I had another 12.99 @108 run, 1.88 60 ft and the tires screaming through 1st gear with major torque steer with the shift into 2nd. Which leads me to believe traction was killing my times. Would've loved to see a 12.6/12.7 but I'm not gonna complain. Today was the last race of the year at the track, so we'll see what happens in the spring.
 
Spinning will get you a higher mph, the 12.9@ 106.9 is exactly what I ran with minimal spin. If I air down to 23psi my car reverts to fwd I guess because the tires are now a different size from the rears. I have not seen anyone else have this happen though... These cars in fwd are ridiculous


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f8tlSHO said:
Spinning will get you a higher mph, the 12.9@ 106.9 is exactly what I ran with minimal spin. If I air down to 23psi my car reverts to fwd I guess because the tires are now a different size from the rears. I have not seen anyone else have this happen though... These cars in fwd are ridiculous


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I would invest in some new tires all around before you end up needing a new PTU unit,the AWD is set to default for a reason,just trying to help ya.  Z
 
The tires themselves shouldn't have anything to do with this. The ptu is always in use, driveshaft is always spinning, the rear diff is electronically engaged by the computer. You are in fwd until Awd is needed the way I understand it.


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f8tlSHO said:
The tires themselves shouldn't have anything to do with this. The ptu is always in use, driveshaft is always spinning, the rear diff is electronically engaged by the computer. You are in fwd until Awd is needed the way I understand it.


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I think you mentioned above that your the only one that has these issues correct?? Isnt your statement alone telling you there's something wrong with the car.  Z
 
f8tlSHO said:
The tires themselves shouldn't have anything to do with this. The ptu is always in use, driveshaft is always spinning, the rear diff is electronically engaged by the computer. You are in fwd until Awd is needed the way I understand it.


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That's what I thought too.

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Tires WILL make a difference.  The AWD is momentarily engaged at launch (due to the high tq being applied).  But how the tires react is important.  They have to have just the right give at the set pressure for the surface conditions.  They need to not be too sticky either so they release quickly to get that forward motion going.  Under the same conditions, the Continental DWS can beat the times that the Michelin Super Sport gets on the track, due to the DWS' slightly softer compound.

So yes, you can optimize the performance (sweet spot) for any tire, but that doesn't mean it is the best performing tire in that category.
 
SHOdded said:
Tires WILL make a difference.  The AWD is momentarily engaged at launch (due to the high tq being applied).  But how the tires react is important.  They have to have just the right give at the set pressure for the surface conditions.  They need to not be too sticky either so they release quickly to get that forward motion going.  Under the same conditions, the Continental DWS can beat the times that the Michelin Super Sport gets on the track, due to the DWS' slightly softer compound.

So yes, you can optimize the performance (sweet spot) for any tire, but that doesn't mean it is the best performing tire in that category.
Click to expand...
I am not arguing tire compounds... My issue is related to the computer realizing the pressure in the front tires is at 23psi and the rears are at 40psi. Then it is fwd only, there is no rear power whatsoever.. It bakes the front tires through 3rd gear... I never aired down all of the tires, just the fronts. So maybe it just sees a huge difference in pressure from the front tires to the back and shuts Awd down.. Maybe if I lower all the tires it wouldn't do it.. Maybe I should test this theory.


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f8tlSHO said:
SHOdded said:
Tires WILL make a difference.  The AWD is momentarily engaged at launch (due to the high tq being applied).  But how the tires react is important.  They have to have just the right give at the set pressure for the surface conditions.  They need to not be too sticky either so they release quickly to get that forward motion going.  Under the same conditions, the Continental DWS can beat the times that the Michelin Super Sport gets on the track, due to the DWS' slightly softer compound.

So yes, you can optimize the performance (sweet spot) for any tire, but that doesn't mean it is the best performing tire in that category.
Click to expand...
I am not arguing tire compounds... My issue is related to the computer realizing the pressure in the front tires is at 23psi and the rears are at 40psi. Then it is fwd only, there is no rear power whatsoever.. It bakes the front tires through 3rd gear... I never aired down all of the tires, just the fronts. So maybe it just sees a huge difference in pressure from the front tires to the back and shuts Awd down.. Maybe if I lower all the tires it wouldn't do it.. Maybe I should test this theory.


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I found this directly from the owners manuel,hope this helps any.  Z    Do not use a spare tire of a different size other than the tire provided. If
the mini-spare tire is installed, the AWD system may disable automatically
and enter front-wheel drive only mode to protect driveline components.
This condition may be indicated by an AWD Off message in the information
display. If there is an AWD Off message in the information display from
using the spare tire, this indicator should turn off after reinstalling the
repaired or replaced normal road tire and cycling the ignition off and on.
It is recommended to reinstall the repaired or replaced road tire as soon as
possible. Major dissimilar tire sizes between the front and rear axles could
cause the AWD system to stop functioning and default to front-wheel drive
or damage the AWD system.  BTW could also be a faulty tpms .  Z
 
ZSHO said:
f8tlSHO said:
SHOdded said:
Tires WILL make a difference.  The AWD is momentarily engaged at launch (due to the high tq being applied).  But how the tires react is important.  They have to have just the right give at the set pressure for the surface conditions.  They need to not be too sticky either so they release quickly to get that forward motion going.  Under the same conditions, the Continental DWS can beat the times that the Michelin Super Sport gets on the track, due to the DWS' slightly softer compound.

So yes, you can optimize the performance (sweet spot) for any tire, but that doesn't mean it is the best performing tire in that category.
Click to expand...
I am not arguing tire compounds... My issue is related to the computer realizing the pressure in the front tires is at 23psi and the rears are at 40psi. Then it is fwd only, there is no rear power whatsoever.. It bakes the front tires through 3rd gear... I never aired down all of the tires, just the fronts. So maybe it just sees a huge difference in pressure from the front tires to the back and shuts Awd down.. Maybe if I lower all the tires it wouldn't do it.. Maybe I should test this theory.


Sent from my iPhone
Click to expand...
I found this directly from the owners manuel,hope this helps any.  Z    Do not use a spare tire of a different size other than the tire provided. If
the mini-spare tire is installed, the AWD system may disable automatically
and enter front-wheel drive only mode to protect driveline components.
This condition may be indicated by an AWD Off message in the information
display. If there is an AWD Off message in the information display from
using the spare tire, this indicator should turn off after reinstalling the
repaired or replaced normal road tire and cycling the ignition off and on.
It is recommended to reinstall the repaired or replaced road tire as soon as
possible. Major dissimilar tire sizes between the front and rear axles could
cause the AWD system to stop functioning and default to front-wheel drive
or damage the AWD system.  BTW could also be a faulty tpms .  Z
Click to expand...

This is how I figured this out.. My rim had a crack and leaked down to 18psi... It was fwd then, and then I put the spare on with no tpms.. As soon as I put new rim and tire at proper pressure back on the car it was back to normal. I don't think it's a problem, I think it's designed this way


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I always move both front & rear down together, with the front usually 2-3 psi lower. Never a big difference in either.

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