View Poll Results: RWD or AWD 993tt
RWD
26
44.07%
AWD
33
55.93%
Voters: 59. You may not vote on this poll
2WD vs AWD poll?
01-27-2009, 03:13 PM
#61
Three Wheelin'
Spartan,
I asked Viper Bob what he thought of 2WD since he seems to be a good source of the parts needed for the conversion.
I hope he does not mind me quoting him directly.
"The 2WD is MUCH better.... Saves weight, and frees up the car to handle better. Car feels more like a go kart without the AWD. I have done lots of these, and none of the customers changed back....
Hope that helps Fred.
Bob"
I asked Viper Bob what he thought of 2WD since he seems to be a good source of the parts needed for the conversion.
I hope he does not mind me quoting him directly.
"The 2WD is MUCH better.... Saves weight, and frees up the car to handle better. Car feels more like a go kart without the AWD. I have done lots of these, and none of the customers changed back....
Hope that helps Fred.
Bob"
Looks like Bob and I share the same opinion on the subject
Are you doing the conversion yourself? It's certainly a DIY
01-27-2009, 06:34 PM
#62
Why do I feel so left out!
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OK,
So now i need to do this....
As it is already torch tyres ( iknow they STILL make 'em
) so now i will wear a set of front to 4 sets of rears..... WOOHOO - sounds like fun to me 
S.
So now i need to do this....
As it is already torch tyres ( iknow they STILL make 'em
) so now i will wear a set of front to 4 sets of rears..... WOOHOO - sounds like fun to me S.
01-27-2009, 09:47 PM
#63
Burning Brakes
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JJay, can't believe this old chestnut is up for discussion again
For road use in typical Northern European conditions ie damp roads much of the time and cambered, bumpy roads, 2WD is managable with stock torque output. As torque nears 600NM it starts getting hairy, 700NM is dangerous and 800NM is bloody frightening.
I ran mine in RWD with 800NM and because of the nature of road surfaces being cambered and lumpy, even with a proper LSD (45/65), trying to manage the torque was not possible. MOD500 tried my car out like this and literally the first time the boost hit in second he nearly went into the hedge.
I spent a while looking into traction control systems to make the 2WD usable but none was available. My 997 GT2 has 680NM and in the dry one can see the TC/SC flickering away in 2nd, 3rd and 4th gear when deploying the torque on the road, this is with 325 section rears and only 680NM !!!
In contrast when the 4WD was reinstalled the car tracked much straighter, I believe on a heavily tuned car the visco is always nearer its critical temperature so there is always some transfer of torque to the front - the car was still scary but so much safer and ultimately much more fun and in straight line acceleration was hardly affected, the AWD is pretty efficient....
An old anecdote but for newer users - A customer of RS Tuning had a beautiful white 993 GT2 race car which I saw being refurbished at their premises, fresh 640hp/830NM Secan engine and because the customer struggled with traction they were installing a 996tt AWD system at massive expense, all the improve track performance....
2WD is a joy in the steering and feel department and with sub 600NM I would probably go for it again, it makes the car feel so light....
I will not comment on what Jean says, I mean driving a 700hp/800+NM 2WD on the track - the guy is insane
I think the consistent dryness of the track surface and extreme (torque sapping) heat probably helps him keep it on the black stuff ?
For road use in typical Northern European conditions ie damp roads much of the time and cambered, bumpy roads, 2WD is managable with stock torque output. As torque nears 600NM it starts getting hairy, 700NM is dangerous and 800NM is bloody frightening.
I ran mine in RWD with 800NM and because of the nature of road surfaces being cambered and lumpy, even with a proper LSD (45/65), trying to manage the torque was not possible. MOD500 tried my car out like this and literally the first time the boost hit in second he nearly went into the hedge.
I spent a while looking into traction control systems to make the 2WD usable but none was available. My 997 GT2 has 680NM and in the dry one can see the TC/SC flickering away in 2nd, 3rd and 4th gear when deploying the torque on the road, this is with 325 section rears and only 680NM !!!
In contrast when the 4WD was reinstalled the car tracked much straighter, I believe on a heavily tuned car the visco is always nearer its critical temperature so there is always some transfer of torque to the front - the car was still scary but so much safer and ultimately much more fun and in straight line acceleration was hardly affected, the AWD is pretty efficient....
An old anecdote but for newer users - A customer of RS Tuning had a beautiful white 993 GT2 race car which I saw being refurbished at their premises, fresh 640hp/830NM Secan engine and because the customer struggled with traction they were installing a 996tt AWD system at massive expense, all the improve track performance....
2WD is a joy in the steering and feel department and with sub 600NM I would probably go for it again, it makes the car feel so light....
I will not comment on what Jean says, I mean driving a 700hp/800+NM 2WD on the track - the guy is insane
I think the consistent dryness of the track surface and extreme (torque sapping) heat probably helps him keep it on the black stuff ?
Except the part of Jean being insane, I think your right on the money.
Most of the RWD are not driving around on 285x30's!
01-27-2009, 10:07 PM
#64
Burning Brakes
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I am interested to know the result of the shootout between Viperbob and JJayB, both are very good drivers and have highly tuned engines, so it would be an interesting comparison.
As to 2WD vs. 4WD, it has been discussed so many times, each has is own experiences, my own is that I would not go back to 4WD, 2WD is much more predictable than (our) 4WD, and therefore safer and faster in my books. Under wet conditions, on slippery surfaces and bad roads, for a DD and some spitrited country drives, 4WD is safer I bet.
As to weight bias, given where the front diff is located, low and in the center, the impact on mass transfer is negligeable. Changing from a BMW to a Porsche requires certainly an adaptation to the driving style, but if you drive a Porsche 911 and change the still weight bias around, you will not know you did...What more mass transfer than a passenger in your car? Heavy, high CG, on one side of the car, etc.. do you change your driving style, or has your car become dangerous to drive?? I doubt.
Keep your car in 4WD mode if you drive on the streets only and in wet conditions mainly, or if you go to the track very occasionally for a DE. If your car ownership is more track oriented, a 2WD setup is truly a great modification...but do it right. I do not agree at all to it being any more dangerous to a 4WD setup, it does require some practice in very highly powered TTs and some carefulness when tires are cold.
As to 2WD vs. 4WD, it has been discussed so many times, each has is own experiences, my own is that I would not go back to 4WD, 2WD is much more predictable than (our) 4WD, and therefore safer and faster in my books. Under wet conditions, on slippery surfaces and bad roads, for a DD and some spitrited country drives, 4WD is safer I bet.
As to weight bias, given where the front diff is located, low and in the center, the impact on mass transfer is negligeable. Changing from a BMW to a Porsche requires certainly an adaptation to the driving style, but if you drive a Porsche 911 and change the still weight bias around, you will not know you did...What more mass transfer than a passenger in your car? Heavy, high CG, on one side of the car, etc.. do you change your driving style, or has your car become dangerous to drive?? I doubt.
Keep your car in 4WD mode if you drive on the streets only and in wet conditions mainly, or if you go to the track very occasionally for a DE. If your car ownership is more track oriented, a 2WD setup is truly a great modification...but do it right. I do not agree at all to it being any more dangerous to a 4WD setup, it does require some practice in very highly powered TTs and some carefulness when tires are cold.
I was waiting for the renouned promoter Don King Mellor to chime in
The result was inconclusive as in many track days getting lined up nose to tail doesn't happen when there are 30 cars in a run group and you run into back markers. What I do remember was running 1:30's with a couple of laps in the 1:29's on Hoosiers. ViperBob was running slicks (Yoko's) and a slightly lighter configuation no VC, bumpers, light weight glass, door pannels almost a GT2!
All I can say is Blackie was running good that day
01-27-2009, 10:48 PM
#65
Instructor
“I have owned,driven and raced RWD 993's and the given the reasonable power levels I think there fine. Double the horsepower and torque and there not so fine.”
Jimmy since when is it the car’s responsibility, especially when modified to be safe? Doesn’t that really depend on the driver’s right foot and his ability to control it? I wish I was there to here Mark Donahue complained about how “unsafe” a 917-30 was because it had too much power. Good drivers can drive the car and the box it came in. The fastest cars are still RWD and the only complaint most drivers have is the still don’t have enough power.
"All the arguments for conversion to RWD are emotional and subjective. The best engineering company in the world decided based upon testing that AWD was better and they wanted to keep customers not kill them so they engineered a superior handling car. Now I'm being told by a bunch of non engineers on the internet that RWD is superior!"
Sorry to repeat this but the system in the 993tt is NOT AWD. That term is reserved for a system with a center differential. The best engineering company in the world need their 400hp short wheelbase car to offer predictable understeer for the rich but somewhat inexperienced drivers that could afford to buy it. Don’t think for a minute that the word liability wasn’t mentioned a time or two. Both the 993 system and real AWD can have a positive effect on vehicle dynamics but it does not improve ‘handling”.
Chris and Jean are both on the point and no one here can question their experience. As for the non-engineers they are stating their observations and experiences just as you are, and this driveline engineer is stating his observations from driving a RWD 993 and from real world manufacturing of the very systems we are discussing. Having work for the leading AWD engineering company in the world. Systems from the Ford RS2000 and Escort Cosworth WRC cars to systems for super cars like the Jaguar 220, McLaren FI,(RWD) and most recently the Veyron. Not only did they design the system but manufactured and validated them as well. I was lucky enough to work with and learn from the best. Maybe if you backed off a bit and with an open mind could do the same with your fellow Rennlist members.
Rick
Jimmy since when is it the car’s responsibility, especially when modified to be safe? Doesn’t that really depend on the driver’s right foot and his ability to control it? I wish I was there to here Mark Donahue complained about how “unsafe” a 917-30 was because it had too much power. Good drivers can drive the car and the box it came in. The fastest cars are still RWD and the only complaint most drivers have is the still don’t have enough power.
"All the arguments for conversion to RWD are emotional and subjective. The best engineering company in the world decided based upon testing that AWD was better and they wanted to keep customers not kill them so they engineered a superior handling car. Now I'm being told by a bunch of non engineers on the internet that RWD is superior!"
Sorry to repeat this but the system in the 993tt is NOT AWD. That term is reserved for a system with a center differential. The best engineering company in the world need their 400hp short wheelbase car to offer predictable understeer for the rich but somewhat inexperienced drivers that could afford to buy it. Don’t think for a minute that the word liability wasn’t mentioned a time or two. Both the 993 system and real AWD can have a positive effect on vehicle dynamics but it does not improve ‘handling”.
Chris and Jean are both on the point and no one here can question their experience. As for the non-engineers they are stating their observations and experiences just as you are, and this driveline engineer is stating his observations from driving a RWD 993 and from real world manufacturing of the very systems we are discussing. Having work for the leading AWD engineering company in the world. Systems from the Ford RS2000 and Escort Cosworth WRC cars to systems for super cars like the Jaguar 220, McLaren FI,(RWD) and most recently the Veyron. Not only did they design the system but manufactured and validated them as well. I was lucky enough to work with and learn from the best. Maybe if you backed off a bit and with an open mind could do the same with your fellow Rennlist members.
Rick
01-28-2009, 12:47 AM
#66
Burning Brakes
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[
Jimmy since when is it the car’s responsibility, especially when modified to be safe? Doesn’t that really depend on the driver’s right foot and his ability to control it? I wish I was there to here Mark Donahue complained about how “unsafe” a 917-30 was because it had too much power. Good drivers can drive the car and the box it came in. The fastest cars are still RWD and the only complaint most drivers have is the still don’t have enough power.
Rick,
There's street cars and race cars, if you want to blur that distinction to make your point Ok. But I don't think the 917 Donahue argument makes your point. BTW,the fastest production CAR is a Buggatti Veyron and it's AWD! Didn't you work on that system?
Sorry to repeat this but the system in the 993tt is NOT AWD. That term is reserved for a system with a center differential.
AWD is shorter acronym what I really meant to say was DYNAMIC FOUR-WHEEL DRIVE WITH VARIABLE POWER DISTRUBUTION ON THE FRONT AND REAR WHEELS. What abbrievation would you suggest?
Maybe if you backed off a bit and with an open mind could do the same with your fellow Rennlist members.
Believe it our not, I'm trying to help the Rennlisters from making a huge mistake that I've witnessed more than once. I think TB993tt experience is the best example of what can happen with street car. Jean on the other had has developed a GT2 one off at great time and expense and made it work for him.
Most of the conversions don't achieve the result that the owner intended and in the porsche world mistakes are expensive. I've taken writers liberty to make my point and apparently you didn't see the humor. I've have had more than one encounter with 993tt in RWD configuation and I want to dispel the idea that by removing the VC your going to go faster. It may not be the case.
Jimmy
Jimmy since when is it the car’s responsibility, especially when modified to be safe? Doesn’t that really depend on the driver’s right foot and his ability to control it? I wish I was there to here Mark Donahue complained about how “unsafe” a 917-30 was because it had too much power. Good drivers can drive the car and the box it came in. The fastest cars are still RWD and the only complaint most drivers have is the still don’t have enough power.
Rick,
There's street cars and race cars, if you want to blur that distinction to make your point Ok. But I don't think the 917 Donahue argument makes your point. BTW,the fastest production CAR is a Buggatti Veyron and it's AWD! Didn't you work on that system?
Sorry to repeat this but the system in the 993tt is NOT AWD. That term is reserved for a system with a center differential.
AWD is shorter acronym what I really meant to say was DYNAMIC FOUR-WHEEL DRIVE WITH VARIABLE POWER DISTRUBUTION ON THE FRONT AND REAR WHEELS. What abbrievation would you suggest?
Maybe if you backed off a bit and with an open mind could do the same with your fellow Rennlist members.
Believe it our not, I'm trying to help the Rennlisters from making a huge mistake that I've witnessed more than once. I think TB993tt experience is the best example of what can happen with street car. Jean on the other had has developed a GT2 one off at great time and expense and made it work for him.
Most of the conversions don't achieve the result that the owner intended and in the porsche world mistakes are expensive. I've taken writers liberty to make my point and apparently you didn't see the humor. I've have had more than one encounter with 993tt in RWD configuation and I want to dispel the idea that by removing the VC your going to go faster. It may not be the case.
Jimmy
01-28-2009, 06:57 AM
#67
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I did run most of the time with '04 GT2 wheels and tyres so 12" rears and 315/30 PS2s , but still hairy scary.... There is no getting away from it, if you stick more than 600NM through just the rears on cambered, lumpy less than perfect grip roads it is dangerous. I am currently enjoying just this scenario with my 997 but it has the TC/SC to sort it out, if you turn this off the thing will leap side ways under full torque on a less than flat road - this becomes tiresome after a while........
But I say again for steering feel and nimbleness the 2WD is a joy and for a stock powered car I would probably do it...
But I say again for steering feel and nimbleness the 2WD is a joy and for a stock powered car I would probably do it...
01-28-2009, 08:16 AM
#68
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Well one thing's for certain:
We won't be seeing any "used 993tt DYNAMIC FOUR-WHEEL DRIVE WITH VARIABLE POWER DISTRUBUTION ON THE FRONT AND REAR WHEELS" parts listed for sale from Jimmy!
Dude, you don't have to protect everyone from the EVIL 2WD conversion. But, on one hand, it's cool that you have this much passion about the car, etc etc.
-Garen
We won't be seeing any "used 993tt DYNAMIC FOUR-WHEEL DRIVE WITH VARIABLE POWER DISTRUBUTION ON THE FRONT AND REAR WHEELS" parts listed for sale from Jimmy!
Dude, you don't have to protect everyone from the EVIL
2WD conversion. But, on one hand, it's cool that you have this much passion about the car, etc etc. -Garen
01-28-2009, 10:51 AM
#69
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+1 -- Jimmy does push his car hard with results from what I understand. And this car looks like a garage queen -- so clean.
Anyhow, I guess my quest for RWD isnt so much for outright acceleration, but more so for that RWD 993 steering and front end feel that is long gone in the AWD 993.
Perhaps if I had JJHP and pushed the car as hard as he does at the big track, I may reconsider.
Anyhow, I guess my quest for RWD isnt so much for outright acceleration, but more so for that RWD 993 steering and front end feel that is long gone in the AWD 993.
Perhaps if I had JJHP and pushed the car as hard as he does at the big track, I may reconsider.
01-28-2009, 07:01 PM
#70
Why do I feel so left out!
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AWD, RWD or DYNAMIC FOUR-WHEEL DRIVE WITH VARIABLE POWER DISTRUBUTION ON THE FRONT AND REAR WHEELS all mean JACK schitt if your SET up and Alignement is no good...
My car has fantastic feel and turn in, is not TOO () hard to drive at the limit and is still predictable on exit and easy to control oversteer....
My car is still AWD and the VC is probably a little bit toasted - yes it does understeer on some corners on the circuit (and i can feel it) but I have learnt to drive around it..... In damp conditions on the circuit I would much rather have it.... than not have it...
Ohh yeah - and i STILL beat GT3's
Each to their own....
Simon
Simon.
My car has fantastic feel and turn in, is not TOO (
) hard to drive at the limit and is still predictable on exit and easy to control oversteer....My car is still AWD and the VC is probably a little bit toasted - yes it does understeer on some corners on the circuit (and i can feel it) but I have learnt to drive around it..... In damp conditions on the circuit I would much rather have it.... than not have it...
Ohh yeah - and i STILL beat GT3's
Each to their own....
Simon
Simon.
01-28-2009, 08:59 PM
#71
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Like most mods, the RWD conversion is a personal taste thing and I suspect there is not "right or wrong", "absolute better or worse". It boils down to how you use each mod.
For, me, I'm in Simon's camp
For, me, I'm in Simon's camp
01-28-2009, 11:21 PM
#73
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01-29-2009, 09:35 AM
#74
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Great debate. I follwed this whole thread with great interest. If you have done the 2wd conversion, is there a ratio you should follow as far as HP vs. how much rubber on the rear? I mean with stock HP and RWD, will you be OK with 285s in the back or is 295 recommended? I assume that if you have closer to 500hp on a RWD car, you need 315s in the back? And if you have 550-650hp you probably need 335 or alike, if you can fit them. Many factors to consider with this reasoning I understand that, but just wanted to check what the consensus is since a 2wd conversion would mean that the stock wheels are not usable anymore since they can only hold 285s on the 10" rim or possible 295s but even that is a stretch..
01-29-2009, 06:09 PM
#75
Why do I feel so left out!
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Viggo,
2WD and 285 or 295 or 315 or 335 will still =
There is no real ratio.... or rational.....
Simon.
2WD and 285 or 295 or 315 or 335 will still =
There is no real ratio.... or rational.....
Simon.