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robbodleimages

st2 points question

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robbodleimages

i must be dense. let me try this again.

 

i have a mustang 3450lbs(+0.2) on 275 DOT tires(+0.4).

 

where do you add the 0.6 points?

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obzezzed350

To whatever is your unadjusted power to weight....so if you make 400whp at 3450lbs, that would be 8.625. Then add .6 to it for a final number of 9.225. Meaning, you should aim to have you power to weight at 8.1 to meet the limit of 8.7.

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robbodleimages

oh....wow. i am going to need to find some hp or lose some weight.

no more potato chips for me this summer.

 

thanks....btw...good to meet you at road atlanta

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jason

Sawzall.

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Cobra4B

I look at it backwards... I deduct it from the 8.7 meaning you can shoot to be at 8.1 lbs/horse. But if you drop weight that +.2 goes away.

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obzezzed350
I look at it backwards... I deduct it from the 8.7 meaning you can shoot to be at 8.1 lbs/horse. But if you drop weight that +.2 goes away.

 

Correct.

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robbodleimages

thats where i got confused. i thought + points were added to the 8.7

and - points were subtracted. in fact its the opposite.

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Cobra4B
thats where i got confused. i thought + points were added to the 8.7

and - points were subtracted. in fact its the opposite.

Well the other way of looking at it is taking your power to weight then adding the points and getting back to 8.7.

 

I.e. you're at 8.1 then add +.2 and +.4 and that = 8.7 which is the min hp to weight. It all works out the same in the end, but just different ways of thingking about it.

 

Or in your case you're at 8.625 then +6 puts you at 9.225 meaning you cand drop .525 to be at 8.7.

 

Like I said... I like to think about it in terms of the adjusted HP/weight I can be at. In my case if I'm running 275 tires that gives me +.4 so I can be at 8.3 instead of 8.7.

 

Clear as mud

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robbodleimages

i have only a handful of laps at vir. my best lap time was a 2:17 during the top gear

shoot in september. my only time drivng the current car there. admittedly i was not

running hard, but still...a 2:04 sounds well beyond what i will be doing there.

 

impressive

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jrgordonsenior

What's the + .6 for?

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kbrew8991

tire correction of 0.4 added to the weight correction of 0.2

 

I always try and make sure to use the terms Unadjusted hp/weight (or straight-up hp/weight, etc) and Adjusted hp/weight. Helps keep the two distinct numbers from being used interchangeably and helps me make sure the correction factors are going the right way and ending up where things need to be.

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jrgordonsenior
tire correction of 0.4 added to the weight correction of 0.2 .

 

OK, I read his post as adding an additional .6 to the .4 (tires) and .2 (weight)....

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jrgordonsenior
To whatever is your unadjusted power to weight....so if you make 400whp at 3450lbs, that would be 8.625. Then add .6 to it for a final number of 9.225. Meaning, you should aim to have you power to weight at 8.1 to meet the limit of 8.7.

 

Conversely I add to the multiplier for slicks (+.75) and weight (+.3) bringing my multiplier to 9.75. I think that's the way the "worksheet" should be configured. You already know your whp and can pretty much get your minimum weight close so all that's left would be multiplying your WHP by your adjusted multiplier....

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Cobra4B
i have only a handful of laps at vir. my best lap time was a 2:17 during the top gear

shoot in september. my only time drivng the current car there. admittedly i was not

running hard, but still...a 2:04 sounds well beyond what i will be doing there.

 

impressive

Thanks Bob... but FYI I'm a TTA car which equates to PTA != ST2/TTS! The fast guys run < 2:00 in TTS/ST2 trim. Same horsepower as I have, but full aero and non-oem suspension i.e. coil-overs for a Corvette.

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robbodleimages

sick. i dont have any meaningful aero on the mustang at present.

by next season very likely. by that time though i would expect to

return to american iron. that hinges on what tire is required i guess.

 

i am not racing to win anyway.

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Spruill242

I think Aero and brakes have become a big thing in ST2 as well. I've got to get this tub of a Trans Am to stop. Aero can help with that.

 

Rob and I can only go but so far suspension wise because the biggest disadvantage we have is the solid axle rear. We could spend 3200 on a full koni race setup but that doesn't fix the solid axle rear. My thinking has shifted to what I can do to shrink that disadvantage. A Fays 2 watts link and a ford 9 inch with some camber built in is the only thing I can really think of. With a Vette posting a 2 minute flat time in ST2, I've got a lot of shrinking to do haha

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Cobra4B
I think Aero and brakes have become a big thing in ST2 as well. I've got to get this tub of a Trans Am to stop. Aero can help with that.

 

Rob and I can only go but so far suspension wise because the biggest disadvantage we have is the solid axle rear. We could spend 3200 on a full koni race setup but that doesn't fix the solid axle rear. My thinking has shifted to what I can do to shrink that disadvantage. A Fays 2 watts link and a ford 9 inch with some camber built in is the only thing I can really think of. With a Vette posting a 2 minute flat time in ST2, I've got a lot of shrinking to do haha

A properly setup stick axle isn't as big of an issue as many think. You're on the right track with the watts link and some built in camber etc. The Panoz has a 9" rear and it'll haul the mail when the motor stops being stupid.

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Spruill242

A properly setup stick axle isn't as big of an issue as many think. You're on the right track with the watts link and some built in camber etc. The Panoz has a 9" rear and it'll haul the mail when the motor stops being stupid.

 

How is the rear setup in that car? I don't know why I thought they where independent rears. Now I wish I would have taken a look under that car.

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Cobra4B

A properly setup stick axle isn't as big of an issue as many think. You're on the right track with the watts link and some built in camber etc. The Panoz has a 9" rear and it'll haul the mail when the motor stops being stupid.

 

How is the rear setup in that car? I don't know why I thought they where independent rears. Now I wish I would have taken a look under that car.

Ford 9" with 4 tubular trailig arms and a watts link that attaches to the bottom of the rear diff. I can't find any pics of the rear end setup on my photobucket.

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robbodleimages

being fair, that 2:00 is just a stupid lap time for ST2. thats a car

with a lot of developement with a lot of driver in the seat.

 

take a 2:04 car to a shaker unit and then back it up with some actual

test days and that 4 seconds can be found.

 

i dont know specifics, but i would not be surprised to find out that corvette

runs a specific VIR setup and so on.

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drivinhardz06
i dont know specifics, but i would not be surprised to find out that corvette

runs a specific VIR setup and so on.

 

Danny felt there's another couple of seconds with further tweaks and fall air. 1:56's for TTS/ST2 Makes you wonder where the bottom is

 

A TTA corvette isn't going to find 4 seconds on a shaker rig w/ shocks, with no aero and no trans gearing changes, decreasing time will be through tire selection/pts planning and just tons of little details. I've always said there's a 2:01 in TTA, but conditions would have to be perfect and there's probably only 1 combo of tire/pts/weight/shocks that'll work. Also the race differences between that ST2 car and PTA would be huge, a PTA corvette would never have the brakes/tires to run that hard that long.

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robbodleimages

i was strictly talking about st2.

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