My VF stage2 M3 Dyno'd!
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The reinforcement that is added to the cabrio isn't in the rear sub frame.Originally Posted by M32911S
I totally agree with you on this Larry. The cabrio does have some additonal reinforcement, and it is up to Ravi if he would like to or not. But with 450whp that is much more than enough to cause additional stress, and the subframe reinforcement is good insurance call it if you will for preventing major problems down the road.
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The E46 ///M's all have the same rear subframe, they're identical. BMW convertibles tend to have more chassis reinforcements to compensate for...not having a ...you guessed it...a roof. It's there to keep eliminate excessive body roll, that is it.Originally Posted by M32911S
I totally agree with you on this Larry. The cabrio does have some additonal reinforcement, and it is up to Ravi if he would like to or not. But with 450whp that is much more than enough to cause additional stress, and the subframe reinforcement is good insurance call it if you will for preventing major problems down the road.
It's not the subframe that fails, the problem is the chassis and body components that the subframe bolts into will fail before the subframe itself will.
This problem is ultimately caused by torsional load from the engine, through the transmission, to the differential, which is bolted to the subframe. The differential will move the subframe until the bushing(s) will not give anymore and then it will move the car.
This is all caused primarily because of the amount of play that the stock rubber bushings have, more movement = more play in the subframe and with the subframe jarring around like that, over time it causes impact and stress fractures in sheet metal where the subframe mounts.
The reason why SMG will fail less frequently than a 6speed is obvious, .4 seconds per shift. The bushings barely have a chance to expand compared to a 6speed, so when the torsional load is put back through the driveline, the impact is substantially less. Thus making SMG cars less prone to having this failure
Solution: Urethane subframe bushings, which minimize the play in your subframe simply because they're substantially stiffer than rubber bushings. Which will also make your car feel snappier and more responsive to your gas pedal.
Ultimately the subframe reinforcements don't really solve the issue of the subframe having too much play and only bandaid the issue.
Here's the install instructions for the chassis reinforcement. (it's a complete pain in the ***)
http://www.turnermotorsport.com/imag...nforcement.pdf
Mitchel knows BMW's.
Oh yeah, and I have some rear shock mount enforcers that should work for you in case you don't already have aftermarket rear shock mounts or a rear strut brace
Quote:
It's not the subframe that fails, the problem is the chassis and body components that the subframe bolts into will fail before the subframe itself will.
This problem is ultimately caused by torsional load from the engine, through the transmission, to the differential, which is bolted to the subframe. The differential will move the subframe until the bushing(s) will not give anymore and then it will move the car.
This is all caused primarily because of the amount of play that the stock rubber bushings have, more movement = more play in the subframe and with the subframe jarring around like that, over time it causes impact and stress fractures in sheet metal where the subframe mounts.
The reason why SMG will fail less frequently than a 6speed is obvious, .4 seconds per shift. The bushings barely have a chance to expand compared to a 6speed, so when the torsional load is put back through the driveline, the impact is substantially less. Thus making SMG cars less prone to having this failure
Solution: Urethane subframe bushings, which minimize the play in your subframe simply because they're substantially stiffer than rubber bushings. Which will also make your car feel snappier and more responsive to your gas pedal.
Ultimately the subframe reinforcements don't really solve the issue of the subframe having too much play and only bandaid the issue.
Here's the install instructions for the chassis reinforcement. (it's a complete pain in the ***)
http://www.turnermotorsport.com/imag...nforcement.pdf
Mitchel knows BMW's.
Mitchel, I don't want to prolong this thread, but remember I was Dinan's test bed for his mods. The urethane bushings made the most God awful noise that I ended up going back to stock after about 4 weeks. I'd recommend the mono *****, either Turner's or Dinan's instead of the bushings. I would still recommend beefing up the sub frame as a preventative measure, especially if the differential ratio is changed to something like my 3.91.Originally Posted by mitchelrl
The E46 ///M's all have the same rear subframe, they're identical. BMW convertibles tend to have more chassis reinforcements to compensate for...not having a ...you guessed it...a roof. It's there to keep eliminate excessive body roll, that is it.It's not the subframe that fails, the problem is the chassis and body components that the subframe bolts into will fail before the subframe itself will.
This problem is ultimately caused by torsional load from the engine, through the transmission, to the differential, which is bolted to the subframe. The differential will move the subframe until the bushing(s) will not give anymore and then it will move the car.
This is all caused primarily because of the amount of play that the stock rubber bushings have, more movement = more play in the subframe and with the subframe jarring around like that, over time it causes impact and stress fractures in sheet metal where the subframe mounts.
The reason why SMG will fail less frequently than a 6speed is obvious, .4 seconds per shift. The bushings barely have a chance to expand compared to a 6speed, so when the torsional load is put back through the driveline, the impact is substantially less. Thus making SMG cars less prone to having this failure
Solution: Urethane subframe bushings, which minimize the play in your subframe simply because they're substantially stiffer than rubber bushings. Which will also make your car feel snappier and more responsive to your gas pedal.
Ultimately the subframe reinforcements don't really solve the issue of the subframe having too much play and only bandaid the issue.
Here's the install instructions for the chassis reinforcement. (it's a complete pain in the ***)
http://www.turnermotorsport.com/imag...nforcement.pdf
Mitchel knows BMW's.
You might want to check an owners manual on the shift times of an SMG. They are accomplished in hundredths of a second not tenths. Even a worn out Hydramatic transmission is faster than .4
Steve Dinan also knows BMW's
The Monoball bushings you're referring to are Rear Trailing Arm Bushings. I'm referring to Rear Subframe Bushings.
I don't know the exact times of SMG shifting, but if it's substantially shorter than what I listed it, oh it only gives me more validation =)
I don't know the exact times of SMG shifting, but if it's substantially shorter than what I listed it, oh it only gives me more validation =)
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You might want to check an owners manual on the shift times of an SMG. They are accomplished in hundredths of a second not tenths. Even a worn out Hydramatic transmission is faster than .4
Steve Dinan also knows BMW's
Also, there's nothing to be done to the subframe really, it stands the test of time, the chassis doesn't.Originally Posted by HUMMM 3
Mitchel, I don't want to prolong this thread, but remember I was Dinan's test bed for his mods. The urethane bushings made the most God awful noise that I ended up going back to stock after about 4 weeks. I'd recommend the mono *****, either Turner's or Dinan's instead of the bushings. I would still recommend beefing up the sub frame as a preventative measure, especially if the differential ratio is changed to something like my 3.91.You might want to check an owners manual on the shift times of an SMG. They are accomplished in hundredths of a second not tenths. Even a worn out Hydramatic transmission is faster than .4
Steve Dinan also knows BMW's
The only thing I'd weld into the subframe are reinforcement plates for the swaybar's, other than that, it's solid.
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The only thing I'd weld into the subframe are reinforcement plates for the swaybar's, other than that, it's solid.
OK, your validated. I'll stand by and watch for the results. I don't know Jack, so Ravi will have to look to you for his engineering solutions. This is the end of the thread as far as I'm concerned.Originally Posted by mitchelrl
Also, there's nothing to be done to the subframe really, it stands the test of time, the chassis doesn't.The only thing I'd weld into the subframe are reinforcement plates for the swaybar's, other than that, it's solid.
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Originally Posted by Jeffxxx
How much did the install run you?
I did about 95% of the install myself!
I had carbcoonn install the fuel pressure regulator and wire up my maf and water pump! Also add coolant to the system!
Ravi