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Old 10-09-09, 08:35 AM
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Loose at top end

I ran for the first time with et streets and the car was scary towards the end of the track, I had to keep getting out of it. I tried anywhere from 12-16psi. I have read not to mix bias and radials so I have some rx8 spare rims coming and I'll get the m&h skinnies for them. Has anyone else had problems mixing? I don't expect it to drive like street tires, but this was really bad.

What do you do when you launch, I have read about getting the slack out of the drivetrain to help avoid breaking things, I was just trying to hold the clutch at the point where the car would almost start to roll, is this right? I had a couple ok 60's but messing with air at the same time was making it hard to be consistent, they really start grabbing as the pressure goes down.

Thanks
Old 10-09-09, 10:01 AM
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Yes no mixing bias with radials thats your first problem and too low tire pressure 14psi or less will make it float on the top end too. What size are the Rx8 rims 16s ? you dont have alot of tire choices with those.
Old 10-09-09, 10:15 AM
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^Agreed... And another question, what is your suspension setup?
Old 10-09-09, 01:27 PM
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M&H does make some gaint size 16's... dont get them! Either spend the money on some welds or such or use the spares and coker tires. They work perfect, thats what I run so do a **** ton of vettes, supras.

Tire pressure, Hmm , I am still trying to figure the magic number on et streets. Maybe Turbor1 will shed more specific info??????????

Getting the slack out of the driveline is a big factor in not breaking parts. Just use the e brake to stage the car, once both lights are lite put clutch in and you know the rest...
Old 10-09-09, 02:07 PM
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I dont believe there could ever be a magic number. Everyones setup is different. The rpm you launch at, the weight of the car, what kind of power it makes at that rpm, leaving with boost, 2step/antilag etc, different setups will all respond differently since they dont make the same power at any given rpm, the clutch and technique used either slipping or not, not to mention I have yet to find any tire pressue guage that is consistent with others. When Im at the track sometimes I use 3 different guages and all of them are off each other by 2-4psi. Its all trial and error. Get a really good gauge and always use the same one, see what works and see what it says but remember unless its a really expensive one with a scale up to 15psi only, its probably not that accurate. But dont worry about the exact numbers just mark where it works the best so you have a reference point. Im usually in the 11-16psi range but who knows sometimes I think im at 14psi and I use another gauge and it will say 18psi. plus the track and weather plays a big part too. These are things that always change and you will need to adjust accordingly each and every time. You have to do your own homework here no cheating
Old 10-09-09, 03:12 PM
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Originally Posted by turboR1
I dont believe there could ever be a magic number. Everyones setup is different. The rpm you launch at, the weight of the car, what kind of power it makes at that rpm, leaving with boost, 2step/antilag etc, different setups will all respond differently since they dont make the same power at any given rpm, the clutch and technique used either slipping or not, not to mention I have yet to find any tire pressue guage that is consistent with others. When Im at the track sometimes I use 3 different guages and all of them are off each other by 2-4psi. Its all trial and error. Get a really good gauge and always use the same one, see what works and see what it says but remember unless its a really expensive one with a scale up to 15psi only, its probably not that accurate. But dont worry about the exact numbers just mark where it works the best so you have a reference point. Im usually in the 11-16psi range but who knows sometimes I think im at 14psi and I use another gauge and it will say 18psi. plus the track and weather plays a big part too. These are things that always change and you will need to adjust accordingly each and every time. You have to do your own homework here no cheating



I guess I cam across wrong as I am far from a cheater I usually hit the track with 13psi and go down from there. But my car is always scary after the 1/8th mile mark on. Never thought to try more air.. Hmmm.. So if your big brother does your work is that cheating? Who said cheaters never come out first!
Old 10-09-09, 07:46 PM
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Any car will be more stable with more air pressure in the rear tires. You have to find that fine line between hooking and enough tire pressure to be stable at the top end. Like R1 said, it's trial and error and every track will be different. It's always best to start with a little higher pressure and go down from there.
Old 10-09-09, 08:17 PM
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I'm running jic coilovers, not strictly drag car. The rx8 wheels are just like the fd spare but 17" to clear bigger brakes. I would like to get some welds but they get really expensive in that size. I think the m&h tires are 26".

So when you preload are you holding the e brake right up till you drop the clutch? I was getting ok burnouts when the pressure was higher, but when I dropped the pressure I was having a hard time getting it to do a good burnout in second without getting wheel hop.
Old 10-09-09, 08:53 PM
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if you run the bias ply et streets without tubes like most people do, it does get scary on the top end. if you look on the side of the tire it does say tube type. i run the bias ply's without tubes on the stock rims. i used to leave them at 15psi. first time i dropped them to 13 it scared the **** out of me past the 1/8th. you just have to get used to it and keep a loose grip at the top end. i now run 12psi in the tires, i launch with 15psi of boost and the car does consistent low 1.7 60ft times. at the top of third and especially when you shift into 4th it starts to float. you just have to get used to it.
Old 10-10-09, 06:40 PM
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Originally Posted by sk8world
I guess I cam across wrong as I am far from a cheater I usually hit the track with 13psi and go down from there. But my car is always scary after the 1/8th mile mark on. Never thought to try more air.. Hmmm.. So if your big brother does your work is that cheating? Who said cheaters never come out first!
You misinterpreted what I said and obvisouly missed the point. I said no cheating in this area as meaning you just cant ask someone else what worked for them and think thats whats going to work for you. you have to check it yourself and see what works. and i do my own homework when it comes to my car. my brother has his own shitbox to worry about. If you dont know me you shouldnt be making assumptions about me Mike.
Old 10-10-09, 08:53 PM
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Chasing numbers

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Originally Posted by turboR1
You misinterpreted what I said and obvisouly missed the point. I said no cheating in this area as meaning you just cant ask someone else what worked for them and think thats whats going to work for you. you have to check it yourself and see what works. and i do my own homework when it comes to my car. my brother has his own shitbox to worry about. If you dont know me you shouldnt be making assumptions about me Mike.


It was a joke. Chill.... Your car speaks for itself..
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