What's with this loss of power after you hit 120???
08-17-2007, 04:07 PM
#12
3rd Gear Member
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Join Date: Jul 2007
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Posts: 929
RE: What's with this loss of power after you hit 120???
ORIGINAL: danGT06
Our cars aren't very aerodynamic.. The drag coefficient is pretty high i think its like .36 My manual pulls hard to about 130 in 4th, but it doesn't pull very hard after that. Also the hood starts to flutter around 120 and that makes me nervous. The 335i probably has a lot lower drag coefficent like .28 so he doesn't need as much power to push him through the air at higher speeds.
Our cars aren't very aerodynamic.. The drag coefficient is pretty high i think its like .36 My manual pulls hard to about 130 in 4th, but it doesn't pull very hard after that. Also the hood starts to flutter around 120 and that makes me nervous. The 335i probably has a lot lower drag coefficent like .28 so he doesn't need as much power to push him through the air at higher speeds.
08-17-2007, 04:08 PM
#13
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Thread Starter
Join Date: Jul 2007
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Posts: 929
RE: What's with this loss of power after you hit 120???
ORIGINAL: danGT06
Our cars aren't very aerodynamic.. The drag coefficient is pretty high i think its like .36 My manual pulls hard to about 130 in 4th, but it doesn't pull very hard after that. Also the hood starts to flutter around 120 and that makes me nervous. The 335i probably has a lot lower drag coefficent like .28 so he doesn't need as much power to push him through the air at higher speeds.
Our cars aren't very aerodynamic.. The drag coefficient is pretty high i think its like .36 My manual pulls hard to about 130 in 4th, but it doesn't pull very hard after that. Also the hood starts to flutter around 120 and that makes me nervous. The 335i probably has a lot lower drag coefficent like .28 so he doesn't need as much power to push him through the air at higher speeds.
08-17-2007, 04:25 PM
#16
2nd Gear Member
Join Date: Nov 2006
Location: MD
Posts: 231
RE: What's with this loss of power after you hit 120???
There is no speed limiter on the GT's, only a RPM limiter, we are just drag limited without HP adders.
I have had mine to the rev limiter a couple times bone stock in 4th (auto) which is approx ~153MPH.
This is with 3.31 gears and 235/50/18 tires.
Hell, the only real race I have had is with a WRX STi, and he was pulling up on me till ~125, from there to 140+, I walked away from him.
Edit: and the drag co-efficient posted somewhere above is BS, we are slightly lower than a Viper, look it up.
I have had mine to the rev limiter a couple times bone stock in 4th (auto) which is approx ~153MPH.
This is with 3.31 gears and 235/50/18 tires.
Hell, the only real race I have had is with a WRX STi, and he was pulling up on me till ~125, from there to 140+, I walked away from him.
Edit: and the drag co-efficient posted somewhere above is BS, we are slightly lower than a Viper, look it up.
08-17-2007, 04:40 PM
#17
5th Gear Member
Join Date: Apr 2005
Location: Babylon, NY
Posts: 3,031
RE: What's with this loss of power after you hit 120???
Nope, it's theT/C locking. It locksat about 120 mph with the stock gears. This is that "wall" you're feeling.A good tuner can adjust the lockup point for you but it will eventually lock and you will hit that "wall", just at a different speed.
I had the same issue until JDM adjusted it for me, now she pulls real hard up to 135. (I do have a ProTorque customconverter on order though).
I had the same issue until JDM adjusted it for me, now she pulls real hard up to 135. (I do have a ProTorque customconverter on order though).
08-17-2007, 04:45 PM
#20
2nd Gear Member
Join Date: Jun 2007
Posts: 356
RE: What's with this loss of power after you hit 120???
The sure way to tell is try a run in 4th only, and one in 5th.. alternatively, dyno the car to make sure you're not getting power drop-off in high RPM's, but if the car pulls fine, but just seems to lose legs over a certain speed, then most likely areodynamics. I haven't had mine past 120 yet, but I know in other cars I've had, you really start to hit a wall of resistance above a certain speed. I forget the exact equation and math, but it's basically an exponential, the faster you go, the more power it takes to go just 1 mph faster, since aerodynamic drag is stacking up the faster you go.