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Discussion Starter · #1 · (Edited)

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Discussion Starter · #3 ·
20170226_222251.jpg

First run of the day = 13.71 @102.67 (Too much air in the slicks, 15 psi)
Second run = [email protected] (1.80 60')
Third run, 1st round of brackets (win) = [email protected] (1.79 60')
Fourth run, 2nd round of brackets (win) = [email protected] (1.79 60')
Fifth and finally run (Semi Finals, lost) = [email protected]

As always only the spare was removed.

Mods -

Mountune Intake
Cobb Catted Down Pipe
AEM WMI (not used)
SCT X4 Tunes by Torrie (E40)
M&H 26x8.5x17 Slicks

If not mentioned it's still OEM issue.
 

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AWESOME TIMES MAN! I WANT SLICKS!

Im getting the FRPP tune with TONS of Tq down low, have race motor mount, sway bar, FRPP intake and Short shifter. thinking with slicks like those i can gte to 13.5's. what wheel did you mount them too? can we see pics of what they look like on the car ?

also "Pure" slicks or "cheater' slicks?
 

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Discussion Starter · #6 ·
AWESOME TIMES MAN! I WANT SLICKS!

Im getting the FRPP tune with TONS of Tq down low, have race motor mount, sway bar, FRPP intake and Short shifter. thinking with slicks like those i can gte to 13.5's. what wheel did you mount them too? can we see pics of what they look like on the car ?

also "Pure" slicks or "cheater' slicks?
Pure slicks -

IMG_20160710_145515558.jpg

Any 17x8 5x108 wheel will work. You actually want a 17x9 wheel -


I will be upgrading to a 17x9 wheel soon = more contact patch


one more question: ive never ran slicks...i heard guys talking about using tubes in them ... is this what you did?
Never have used tubes in slicks.
 

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Discussion Starter · #8 ·
Man that looks sweet. any trouble with the stock clutch or suspension holding up? or took it like a champ?
No clutch or suspension issues.

That said, I am looking to improve on the stock suspension tendency to lift the front end and squat in the rear at launch. That dynamic works great with RWD, but not so much for FWD or AWD for that matter.

Best 60' is 1.76 which isn't bad on the stock suspension and stock torque levels.

Lowering the suspension somewhat and going an inch wider on the wheels I hope to get down in the 1.6's and then the tweaking will start.
 

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View attachment 211793

First run of the day = 13.71 @102.67 (Too much air in the slicks, 15 psi)
Second run = [email protected] (1.80 60')
Third run, 1st round of brackets (win) = [email protected] (1.79 60')
Fourth run, 2nd round of brackets (win) = [email protected] (1.79 60')
Fifth and finally run (Semi Finals, lost) = [email protected]

As always only the spare was removed.

Mods -

Mountune Intake
Cobb Catted Down Pipe
AEM WMI (not used)
SCT X4 Tunes by Torrie (E40)
M&H 26x8.5x17 Slicks

If not mentioned it's still OEM issue.
Curious that 2.1/13.71 that says "PB"... what does that mean?
 

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Discussion Starter · #10 ·
Personal Best
 

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Wider tire fallacy

You actually want a 17x9 wheel -

I will be upgrading to a 17x9 wheel soon = more contact patch

Never have used tubes in slicks.
Dude, you are doing some cool sheit here, for sure. I would just like to point out, before you buy wider wheels: a wider wheel *will* not give you a bigger contact patch ~ all else being equal (car weight, tire pressure). It will only change the shape of the contact patch. It will make the contact patch more transverse than longitudinal.

Think about it.

The area of tire-to-road contact won't increase on a tire size change alone, you must adjust the tire pressure (and you don't need wider tires to do it). This is an *enormous* misunderstanding in all motorsports... Wider wheels can/will give a more transverse contact patch and this is quite helpful in turning handling - but for straight line/ drag racing it won't 'help.' Watch a NHRA drag wheel's shape shift in slow-motion (it's really cool). It actually transforms from a wide(transverse) contact at standstill to more narrow(longitudinal). They would *never* design for the narrowing if wider was better, just think about it. It seems counterintuitive, but a wider wheel isn't 'better' in this case.

 

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Discussion Starter · #12 · (Edited)
Well sort of...

A wider wheel in my case will work better as it will extend the contact patch.

My slicks are 8.5 wide and my wheel is 17 x 8 wide.

Looking at the wear pattern on each slick tells me I can use a wider wheel.

Besides it's worth a shot and here's why.

Roughly 1 tenth in 60' is 2-3 tenths at the end of the strip.

Run #1 = [email protected] (2.20)
Run #2 = [email protected] (1.80)

4 tenths = 5 tenths Difference? 3 psi in the slicks (15 psi vs 12 psi) Same launch RPM, same track, same shift points, same lane too.

Every tenth I can pick up in my short game requires less power to make it further down track.

Over in the Honda community this has proven to be true and it's inexpensive enough to try.

 

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Well sort of...

A wider will in my case will work better as it will extend the contact patch.

My slicks are 8.5 wide and my wheel is 17 x 8 wide.
Unfortunately, it won't. I don't make the rules, physics does... I just do what I can to exploit them.
I encourage you to give this some thought, maybe even draw it out. With all else being equal (tire pressure, car weight) the only thing that can change is the contact patch's shape.
Here's an example (numbers are for illustrative purposes only):
If you have a narrower tire with a 3000# car at 15psi tire pressure you will have 12 square inch contact patch area - in a longitudinal shape.
If you have a wider tire with a 3000# car at 15psi tire pressure you will still have a 12 square inch contact patch area - but now in a transverse shape.
Changing wheel/tire width only changes contact patch shape - not area.

It's just physics, you cannot change the size of the area by changing your tires' shape, you can only change the shape of the area. If you want to adjust the size of area (larger or smaller) you adjust the tire pressure.
 

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No clutch or suspension issues.

That said, I am looking to improve on the stock suspension tendency to lift the front end and squat in the rear at launch. That dynamic works great with RWD, but not so much for FWD or AWD for that matter.

Best 60' is 1.76 which isn't bad on the stock suspension and stock torque levels.

Lowering the suspension somewhat and going an inch wider on the wheels I hope to get down in the 1.6's and then the tweaking will start.
A cheap fix for the suspension is drag bags or even pee-wee footballs. Anything to pump up in those springs and keep them from compressing too much. It made a surprising difference for me when I had my Cobalt.
 

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Unfortunately, it won't. I don't make the rules, physics does... I just do what I can to exploit them.
I encourage you to give this some thought, maybe even draw it out. With all else being equal (tire pressure, car weight) the only thing that can change is the contact patch's shape.
Here's an example (numbers are for illustrative purposes only):
If you have a narrower tire with a 3000# car at 15psi tire pressure you will have 12 square inch contact patch area - in a longitudinal shape.
If you have a wider tire with a 3000# car at 15psi tire pressure you will still have a 12 square inch contact patch area - but now in a transverse shape.
Changing wheel/tire width only changes contact patch shape - not area.

It's just physics, you cannot change the size of the area by changing your tires' shape, you can only change the shape of the area. If you want to adjust the size of area (larger or smaller) you adjust the tire pressure.
You're ignoring the issue of a tire under load and the application of lower pressure to slightly deform a tire for drag racing. I see where you're coming from as it relates to ultimate grip in road racing or auto cross, but wider tires properly sized to an adequately wide wheel sure as sh!t helps with traction.
 

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Discussion Starter · #16 ·
A cheap fix for the suspension is drag bags or even pee-wee footballs. Anything to pump up in those springs and keep them from compressing too much. It made a surprising difference for me when I had my Cobalt.
I've seen that trick used before, it's in consideration.
 
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