Going RWD...
07-21-2023, 08:02 AM
#1
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Going RWD...
Last night I was considering the dynamic changes that will occur when I remove the AWD system. Benefits are fairly obvious; reduced driveline loss, lower weight, crisper handling. Disadvantages will likely be reduced traction, acceleration stability, perhaps more inclination to oversteer.
The car has been setup for GT2 alignment specs since I got it, along with GT2 sized wheels/tyres. The PSS9s are set within a 1/10th inch of ride height, cannot recall off the top of my head where the valving is set - no fancy GT2 suspension parts, however, Eibach's with poly bushings and Tarrett end links are both front and rear.
By removing some 80ish pounds from the chassis, not entirely sure exactly how much over the front axle, my thinking is it will likely benefit from one click softer on the front shocks. I am also likely going to be ordering a set of Tarrett camber plates:
Front Monoball Camber Plate (pr), 996/997 C4 or TT (tarett.com)
The reason for this is that it would appear you can offset the camber by an additional .6 of a degree, so my thinking is that I would add .5d to the GT2 alignment spec in an effort to give the front end a more planted feeling to offset the reduction of sprung weight.
Is this sound logic?
Cheers,
The car has been setup for GT2 alignment specs since I got it, along with GT2 sized wheels/tyres. The PSS9s are set within a 1/10th inch of ride height, cannot recall off the top of my head where the valving is set - no fancy GT2 suspension parts, however, Eibach's with poly bushings and Tarrett end links are both front and rear.
By removing some 80ish pounds from the chassis, not entirely sure exactly how much over the front axle, my thinking is it will likely benefit from one click softer on the front shocks. I am also likely going to be ordering a set of Tarrett camber plates:
Front Monoball Camber Plate (pr), 996/997 C4 or TT (tarett.com)
The reason for this is that it would appear you can offset the camber by an additional .6 of a degree, so my thinking is that I would add .5d to the GT2 alignment spec in an effort to give the front end a more planted feeling to offset the reduction of sprung weight.
Is this sound logic?
Cheers,
07-21-2023, 09:32 AM
#2
Last night I was considering the dynamic changes that will occur when I remove the AWD system. Benefits are fairly obvious; reduced driveline loss, lower weight, crisper handling. Disadvantages will likely be reduced traction, acceleration stability, perhaps more inclination to oversteer.
The car has been setup for GT2 alignment specs since I got it, along with GT2 sized wheels/tyres. The PSS9s are set within a 1/10th inch of ride height, cannot recall off the top of my head where the valving is set - no fancy GT2 suspension parts, however, Eibach's with poly bushings and Tarrett end links are both front and rear.
By removing some 80ish pounds from the chassis, not entirely sure exactly how much over the front axle, my thinking is it will likely benefit from one click softer on the front shocks. I am also likely going to be ordering a set of Tarrett camber plates:
Front Monoball Camber Plate (pr), 996/997 C4 or TT (tarett.com)
The reason for this is that it would appear you can offset the camber by an additional .6 of a degree, so my thinking is that I would add .5d to the GT2 alignment spec in an effort to give the front end a more planted feeling to offset the reduction of sprung weight.
Is this sound logic?
Cheers,
The car has been setup for GT2 alignment specs since I got it, along with GT2 sized wheels/tyres. The PSS9s are set within a 1/10th inch of ride height, cannot recall off the top of my head where the valving is set - no fancy GT2 suspension parts, however, Eibach's with poly bushings and Tarrett end links are both front and rear.
By removing some 80ish pounds from the chassis, not entirely sure exactly how much over the front axle, my thinking is it will likely benefit from one click softer on the front shocks. I am also likely going to be ordering a set of Tarrett camber plates:
Front Monoball Camber Plate (pr), 996/997 C4 or TT (tarett.com)
The reason for this is that it would appear you can offset the camber by an additional .6 of a degree, so my thinking is that I would add .5d to the GT2 alignment spec in an effort to give the front end a more planted feeling to offset the reduction of sprung weight.
Is this sound logic?
Cheers,
Kirk
07-21-2023, 09:50 AM
#3
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I'm not going to be changing the springs, they are sufficient for my driving style, and, the condition of the roads around here.
Going with a lighter front spring as you are doing will most certainly make the front end more compliant, my hope is that I will achieve the same effect by removing a click of compression dampening out of the front end. The Ohlin's are very highly regarded, could you not achieve the same compliance by dialing out compression?
Going with a lighter front spring as you are doing will most certainly make the front end more compliant, my hope is that I will achieve the same effect by removing a click of compression dampening out of the front end. The Ohlin's are very highly regarded, could you not achieve the same compliance by dialing out compression?
07-21-2023, 10:28 AM
#4
I'm not going to be changing the springs, they are sufficient for my driving style, and, the condition of the roads around here.
Going with a lighter front spring as you are doing will most certainly make the front end more compliant, my hope is that I will achieve the same effect by removing a click of compression dampening out of the front end. The Ohlin's are very highly regarded, could you not achieve the same compliance by dialing out compression?
Going with a lighter front spring as you are doing will most certainly make the front end more compliant, my hope is that I will achieve the same effect by removing a click of compression dampening out of the front end. The Ohlin's are very highly regarded, could you not achieve the same compliance by dialing out compression?
Experts, please chime in!
Thanks,
Kirk
07-21-2023, 10:36 AM
#5
Just fyi, 60 N/mm and 120 N/mm converts to 343 lb/in and 685 lb/in. I believe the Bilstein's come with 260 lb/in front and 515 lb/in rear. A friend with PSS10's changed his rear springs to 672 lb/in and H&R rear bar to full stiff. Much better balance after the change!
07-21-2023, 12:14 PM
#7
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Frank Abe (07-24-2023)
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07-21-2023, 12:38 PM
#8
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I don't get anywhere near that kind of mpg, going rwd certainly isn't going to make it happen. I dunno, I've been sitting on the stub axles to go rwd for awhile now. Honestly I don't think it's all that, it doesn't get in the way on the track and it's nice to have on the street. Even if you do get 30 mpg on the freeway, how much money in fuel is that actually going to save you? Certainly not enough to recoup the costs of doing it, not for years and years...
07-21-2023, 12:41 PM
#9
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07-21-2023, 12:49 PM
#10
Last night I was considering the dynamic changes that will occur when I remove the AWD system. Benefits are fairly obvious; reduced driveline loss, lower weight, crisper handling. Disadvantages will likely be reduced traction, acceleration stability, perhaps more inclination to oversteer.
The car has been setup for GT2 alignment specs since I got it, along with GT2 sized wheels/tyres. The PSS9s are set within a 1/10th inch of ride height, cannot recall off the top of my head where the valving is set - no fancy GT2 suspension parts, however, Eibach's with poly bushings and Tarrett end links are both front and rear.
By removing some 80ish pounds from the chassis, not entirely sure exactly how much over the front axle, my thinking is it will likely benefit from one click softer on the front shocks. I am also likely going to be ordering a set of Tarrett camber plates:
Front Monoball Camber Plate (pr), 996/997 C4 or TT (tarett.com)
The reason for this is that it would appear you can offset the camber by an additional .6 of a degree, so my thinking is that I would add .5d to the GT2 alignment spec in an effort to give the front end a more planted feeling to offset the reduction of sprung weight.
Is this sound logic?
Cheers,
The car has been setup for GT2 alignment specs since I got it, along with GT2 sized wheels/tyres. The PSS9s are set within a 1/10th inch of ride height, cannot recall off the top of my head where the valving is set - no fancy GT2 suspension parts, however, Eibach's with poly bushings and Tarrett end links are both front and rear.
By removing some 80ish pounds from the chassis, not entirely sure exactly how much over the front axle, my thinking is it will likely benefit from one click softer on the front shocks. I am also likely going to be ordering a set of Tarrett camber plates:
Front Monoball Camber Plate (pr), 996/997 C4 or TT (tarett.com)
The reason for this is that it would appear you can offset the camber by an additional .6 of a degree, so my thinking is that I would add .5d to the GT2 alignment spec in an effort to give the front end a more planted feeling to offset the reduction of sprung weight.
Is this sound logic?
Cheers,
Last edited by powdrhound; 07-21-2023 at 01:04 PM.
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LinwoodM (07-23-2023)
07-21-2023, 12:51 PM
#11
I am in the process of going RWD as well and have made similar decisions as you... I am no expert, but went down the path of modifying a C5 Z06 learning a lot along the way. Recently moved to the 996 Turbo (long time dream car). I am doing Wavetrac rear diff, Tarret top mounts front and rear (0.6 degrees extra camber up front), Tarret drop links front and rear, Tarret rear toe arms, and Ohlins Road & Track coilovers. I did go with a slightly lighter spring up front. They normally come with 70N/mm front and 120N/mm rear. I dropped the front to 60N/mm. I did this for two reasons... A little lighter front end and it should give me a little better front grip. I will start with stock sway bars front and rear. Will add the H&R adjustable rear bar to dial in balance if I think it is needed.
Kirk
Kirk
Last edited by powdrhound; 07-21-2023 at 12:55 PM.
07-21-2023, 12:59 PM
#12
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I don't get anywhere near that kind of mpg, going rwd certainly isn't going to make it happen. I dunno, I've been sitting on the stub axles to go rwd for awhile now. Honestly I don't think it's all that, it doesn't get in the way on the track and it's nice to have on the street. Even if you do get 30 mpg on the freeway, how much money in fuel is that actually going to save you? Certainly not enough to recoup the costs of doing it, not for years and years...
With the drag of the AWD leaving, and not a big wing with full downforce applied, I think I may be able to hit it...
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diverzeusy (09-26-2023)
07-21-2023, 01:00 PM
#13
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Cheers,
07-21-2023, 01:04 PM
#14
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Guess that's my issue then, speed limits here are 75mph, I'm usually doing 80-85mph. Plus when I'm heading to the track I'll pulling the tire trailer which doesn't do good things for fuel economy.
John, I may have to call you to talk about swaybars. Pretty sure I've got the stock front bar with H&R rear bar on my car...
John, I may have to call you to talk about swaybars. Pretty sure I've got the stock front bar with H&R rear bar on my car...
07-21-2023, 01:05 PM
#15