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      07-15-2017, 09:51 PM   #1
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NASA Time Trial

I have been doing a lot of HPDE with my car and decided to take the next step and do NASA time trials. After reading the rules several times I decided the M2 would be a great TT4 competitor. The power to weight needs to be 12/1 with some small modifiers. I dynoed the car and decided I needed 50lbs of ballast to be a legit TT4. Have my new Hoosiers mounted on my TR 18 wheels, transponder wired, ballast bolted, decals ordered and signed up for Barber in a couple of weeks. I think the car should be a real contender (and probably a top finisher with a better driver! ) based on all the TT results from BMP, NCM, RA and Sebring. I will keep you posted with results....unless I get stomped.
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      07-16-2017, 02:55 PM   #2
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What size tires?
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      07-16-2017, 06:42 PM   #3
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What size tires?
The rules allow sizes up to 275 without penalty , so I am running 275/35/18 R7 square.
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      07-16-2017, 08:56 PM   #4
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Sweet. I'm running 265 square set up on star specs. I've run hoho's on other cars and have been thinking about trying them again. Did you need spacers for the 275's?
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      07-16-2017, 08:57 PM   #5
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Are you on stock suspension? If so I'll be curious as to how much body roll you'll have with that much grip!
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      07-16-2017, 10:00 PM   #6
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Quote:
Originally Posted by MRufo View Post
Sweet. I'm running 265 square set up on star specs. I've run hoho's on other cars and have been thinking about trying them again. Did you need spacers for the 275's?
I have 12mm on front...none on the rear
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      07-16-2017, 10:02 PM   #7
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Quote:
Originally Posted by MRufo View Post
Are you on stock suspension? If so I'll be curious as to how much body roll you'll have with that much grip!
Tossed the stock suspension after my first track day....using the MP coilovers set about two clicks firmer than recommended set up.
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      07-17-2017, 01:49 AM   #8
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Quote:
Originally Posted by Twt View Post
Tossed the stock suspension after my first track day....using the MP coilovers set about two clicks firmer than recommended set up.
Nice. That's where I have mine set too. We should start an M Perf coilovers tuning thread for the US tracks
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      07-18-2017, 10:52 AM   #9
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Are you sure the M2 fits in TT4? I think it's over on p/w especially with Hoosiers unless the driver weighs like 300 lbs. What average hp did your car put down on the dyno? Most stock M2's dyno around 330 whp on a dynojet which is what NASA TT uses. In order to be at 12:1 the car needs to weigh 3,960. If you run DOT tires between 255 and 275 you get .3 back which means you still need to be at about 3730.

My M2 with 18x10 wheels and 275 NT01's with me in it (150 lbs) weighed in at 3540. I don't think you're going to get to 3730 and make it for TT4 unless you have a really low reading dyno and a lot of ballast.

I think realistically it's a TT3 car with some good prep. Around here TX region it's up against some fast prepped E46 M3's that weigh around 3,200 lbs with driver.

Last edited by CosmosMpower; 07-18-2017 at 11:09 AM..
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      07-18-2017, 08:51 PM   #10
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Quote:
Originally Posted by CosmosMpower View Post
Are you sure the M2 fits in TT4? I think it's over on p/w especially with Hoosiers unless the driver weighs like 300 lbs. What average hp did your car put down on the dyno? Most stock M2's dyno around 330 whp on a dynojet which is what NASA TT uses. In order to be at 12:1 the car needs to weigh 3,960. If you run DOT tires between 255 and 275 you get .3 back which means you still need to be at about 3730.

My M2 with 18x10 wheels and 275 NT01's with me in it (150 lbs) weighed in at 3540. I don't think you're going to get to 3730 and make it for TT4 unless you have a really low reading dyno and a lot of ballast.

I think realistically it's a TT3 car with some good prep. Around here TX region it's up against some fast prepped E46 M3's that weigh around 3,200 lbs with driver.
On a NASA approved dyno my "average whp " is 326...for this class they use a four section average so the super boost number is balanced out. As for weight, my DCT car weighs 3505 dry weight according to BMW, add a 200lb driver, 50lb balllast, and fluids and you get:
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      07-20-2017, 10:43 AM   #11
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Man you better be careful with your weights. Did you weigh your car with the competition setup with you in it at 3,775? That seems awfully heavy. Mine was only 3,540 but I'm 6MT and I weigh 50 lbs less than you. I did also have lighter wheels than stock but wider tires.

At 3,775 and 326 whp then factoring in +.3 for tires and -.3 for DCT gearbox you are right at 12.080. At 3750 you'd be underweight, not a lot of wiggle room especially if you are factoring in a full tank of gas at 3775. You can easily use a 1/4 to a 1/3 tank of gas in a TT session. You have about 25 pounds of wiggle room, gas is about 6 lbs a gallon so that's 4 gallons you can burn which is about 1/4 to 1/3 a tank.

Last edited by CosmosMpower; 07-20-2017 at 10:49 AM..
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      07-20-2017, 06:11 PM   #12
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Quote:
Originally Posted by CosmosMpower View Post
Man you better be careful with your weights. Did you weigh your car with the competition setup with you in it at 3,775? That seems awfully heavy. Mine was only 3,540 but I'm 6MT and I weigh 50 lbs less than you. I did also have lighter wheels than stock but wider tires.

At 3,775 and 326 whp then factoring in +.3 for tires and -.3 for DCT gearbox you are right at 12.080. At 3750 you'd be underweight, not a lot of wiggle room especially if you are factoring in a full tank of gas at 3775. You can easily use a 1/4 to a 1/3 tank of gas in a TT session. You have about 25 pounds of wiggle room, gas is about 6 lbs a gallon so that's 4 gallons you can burn which is about 1/4 to 1/3 a tank.
I weighed the car with 1/2 tank...in full track set up. I think the heavier DCT, driver , ballast , TR wheels and 275 tires gets me spot on. Even with this set up I know I will be slower than some of the stripped down full aero S2000 and M3s...if I had to go into TT3 it would be ugly.
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      07-23-2017, 10:04 AM   #13
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I am first on the list for the CL/ CS which should fall right into the TT3 class.
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      07-31-2017, 07:40 AM   #14
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Barber

Well the big girl can run. The car was a solid second place against e46 cars that weighed 700lbs less. This was the only TT car that I saw drive to the track, race, and drive home. Unless you want to trail a full race, purpose built TT car the M2 is a great option....race on Sunday, drive to work on Monday!
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      07-31-2017, 10:59 AM   #15
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Weight on scales for impound and final dyno number?
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      07-31-2017, 09:31 PM   #16
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Quote:
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Weight on scales for impound and final dyno number?
Scale was 3745, but they have a +/- of 10...no dyno at regional event.
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