RS 3.89 R&P and 6th gear conversion..
#1
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RS 3.89 R&P and 6th gear conversion..
Shout out to Chris Cervelli at CTS for installing a RS 3.89 R&P along with the taller RS 6th into my 7.2 gearbox. While Chris had it apart he also put in a new Guard LSD clutch pack, a new 4.0RS Clutch / LWFW and also had the coolant pipes welded while the engine was out of the car. I should be getting the car back at the end of this week. I'm really looking forward to finally driving it as I found the stock gearing ridiculously tall for the modest hp and the stock clutch with the DMFW utterly uninspiring. In addition to this GT3 gearbox, Chris has build several GT2 gearboxes for me in the past including one that he is about to do a full re-gear on. He's also build several Mezgers for me in the past including a 3.8 and my current 4.0 which is simply a monster. Can't speak highly enough of his work. Cheers!
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Steve Theodore (12-15-2022)
#2
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My gear box is out right now for the same ring and pinion swap! I'm doing the gear box Removal and installation myself, but the ring and pinion install will be by Brian in Athens, Ohio. I'm having a hard time deciding where to stop with the work. My car is autocrossed, so I know the chances are I'll be in there agian soon. I would like to freshen up the clutch, but I don't see it being worth $3k if there's nothing wrong with it. What did you do to stop the cam actuator fasteners from backing out? I'm not completely opposed to the lightweight flywheel, but I really don't want to deal with the cam actuators just now. I also wasn't planning on shift cables until I saw how the stock end links work. Defintiely looking at the neumeric cables now.
#3
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I got this done this past summer by BRM. Motorsport synchros, 3.89 R&P, 4.0 RS clutch & LWFW and billet LSD. Totally transformed my 7.2 GT3 imo. I opt to keep the stock 6th gear and enjoy the extra omph when passing cars on the freeway. RPM is not terribly high cruising at 70mph.
#4
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Thread Starter
My gear box is out right now for the same ring and pinion swap! I'm doing the gear box Removal and installation myself, but the ring and pinion install will be by Brian in Athens, Ohio. I'm having a hard time deciding where to stop with the work. My car is autocrossed, so I know the chances are I'll be in there agian soon. I would like to freshen up the clutch, but I don't see it being worth $3k if there's nothing wrong with it. What did you do to stop the cam actuator fasteners from backing out? I'm not completely opposed to the lightweight flywheel, but I really don't want to deal with the cam actuators just now. I also wasn't planning on shift cables until I saw how the stock end links work. Defintiely looking at the neumeric cables now.
Last edited by powdrhound; 12-13-2022 at 07:11 PM.
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Robocop305 (02-24-2023)
#5
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I got this done this past summer by BRM. Motorsport synchros, 3.89 R&P, 4.0 RS clutch & LWFW and billet LSD. Totally transformed my 7.2 GT3 imo. I opt to keep the stock 6th gear and enjoy the extra omph when passing cars on the freeway. RPM is not terribly high cruising at 70mph.
Last edited by powdrhound; 12-13-2022 at 07:13 PM.
#6
Thanks so much for sharing. To echo what @Auto_Werks 3.6 said, I'm also curious what you're doing to address the cam actuators.
@Auto_Werks 3.6 - seems like Brian at https://www.copanstransmission.com is an excellent resource. Will definitely consider him if I decide to do this to my car. Having an expert locally that only works on transmissions great. Can you explain more on your shift cable end links comment? I go back and forth on the shift console and cables. 1) I don't want them to snap so I think doing them preventatively could be a good idea 2) not sure what is the best direction for cables. Porsche motorsport cup cables is an option, I think. Numeric cables are another option. 3) all GT3 shifters are notchy to some extent, mine has some notchy feeling when the car is off or on, it can be mitigated by moving the shift lever left and right when it's in the actual gear before shifting into the next gear. So it seems as if it's something in the shift console (in the cabin) or the cables. It's not in the transmission, it's been isolated to the console or cables. That makes me want to do cables and a new console at some point.
Also, to add onto your comment on how far to go, when my transmission was out for a fresh RMS 1.5 years ago, my clutch was estimated at still 75% remaining. Part of me wanted to do a 4.0 clutch and LWFW, but given that I had so much clutch life, I didn't.
@Auto_Werks 3.6 - seems like Brian at https://www.copanstransmission.com is an excellent resource. Will definitely consider him if I decide to do this to my car. Having an expert locally that only works on transmissions great. Can you explain more on your shift cable end links comment? I go back and forth on the shift console and cables. 1) I don't want them to snap so I think doing them preventatively could be a good idea 2) not sure what is the best direction for cables. Porsche motorsport cup cables is an option, I think. Numeric cables are another option. 3) all GT3 shifters are notchy to some extent, mine has some notchy feeling when the car is off or on, it can be mitigated by moving the shift lever left and right when it's in the actual gear before shifting into the next gear. So it seems as if it's something in the shift console (in the cabin) or the cables. It's not in the transmission, it's been isolated to the console or cables. That makes me want to do cables and a new console at some point.
Also, to add onto your comment on how far to go, when my transmission was out for a fresh RMS 1.5 years ago, my clutch was estimated at still 75% remaining. Part of me wanted to do a 4.0 clutch and LWFW, but given that I had so much clutch life, I didn't.
#7
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I did this 3.89 r&p on my even lower powered 996 gt3 and the improvement in "fun factor" was immense. Felt like an extra 50 ft-pounds of torque. Had to adjust shift points of course but after a day or two it felt "normal." May not be faster on certain tracks depending on shift points and all that, but man does it feel "snappier." I should have done the taller 6th. Its not outrageously high (3500 rpm at 75 mph for my car on 18's), but sometimes if I'm travelling long distances on the freeway a slightly lower rpm in top gear would be nice. And the combo of the 3.9l engine with this gearbox set up is pretty freaking killer. Excited to hear your feedback when you get it back @powderhound
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DD GT3 RD (12-13-2022)
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#8
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I did this 3.89 r&p on my even lower powered 996 gt3 and the improvement in "fun factor" was immense. Felt like an extra 50 ft-pounds of torque. Had to adjust shift points of course but after a day or two it felt "normal." May not be faster on certain tracks depending on shift points and all that, but man does it feel "snappier." I should have done the taller 6th. It’s not outrageously high (3500 rpm at 75 mph for my car on 18's), but sometimes if I'm travelling long distances on the freeway a slightly lower rpm in top gear would be nice. And the combo of the 3.9l engine with this gearbox set up is pretty freaking killer. Excited to hear your feedback when you get it back @powderhound
Last edited by powdrhound; 12-13-2022 at 08:08 PM.
#9
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Thanks so much for sharing. To echo what @Auto_Werks 3.6 said, I'm also curious what you're doing to address the cam actuators.
@Auto_Werks 3.6 - seems like Brian at https://www.copanstransmission.com is an excellent resource. Will definitely consider him if I decide to do this to my car. Having an expert locally that only works on transmissions great. Can you explain more on your shift cable end links comment? I go back and forth on the shift console and cables. 1) I don't want them to snap so I think doing them preventatively could be a good idea 2) not sure what is the best direction for cables. Porsche motorsport cup cables is an option, I think. Numeric cables are another option. 3) all GT3 shifters are notchy to some extent, mine has some notchy feeling when the car is off or on, it can be mitigated by moving the shift lever left and right when it's in the actual gear before shifting into the next gear. So it seems as if it's something in the shift console (in the cabin) or the cables. It's not in the transmission, it's been isolated to the console or cables. That makes me want to do cables and a new console at some point.
Also, to add onto your comment on how far to go, when my transmission was out for a fresh RMS 1.5 years ago, my clutch was estimated at still 75% remaining. Part of me wanted to do a 4.0 clutch and LWFW, but given that I had so much clutch life, I didn't.
@Auto_Werks 3.6 - seems like Brian at https://www.copanstransmission.com is an excellent resource. Will definitely consider him if I decide to do this to my car. Having an expert locally that only works on transmissions great. Can you explain more on your shift cable end links comment? I go back and forth on the shift console and cables. 1) I don't want them to snap so I think doing them preventatively could be a good idea 2) not sure what is the best direction for cables. Porsche motorsport cup cables is an option, I think. Numeric cables are another option. 3) all GT3 shifters are notchy to some extent, mine has some notchy feeling when the car is off or on, it can be mitigated by moving the shift lever left and right when it's in the actual gear before shifting into the next gear. So it seems as if it's something in the shift console (in the cabin) or the cables. It's not in the transmission, it's been isolated to the console or cables. That makes me want to do cables and a new console at some point.
Also, to add onto your comment on how far to go, when my transmission was out for a fresh RMS 1.5 years ago, my clutch was estimated at still 75% remaining. Part of me wanted to do a 4.0 clutch and LWFW, but given that I had so much clutch life, I didn't.
As far as the LWFW, I'm pretty sure it's much less expensive than putting it back to stock with a new DMFW. I really don't like gearbox NVH, which is my one hang up on the numeric shifter. For me, the behavior of the dual mass isn't so bad, but the sifter is the bane of my ownership (like the flywheel is for the OP of this thread). The harmonic issues on these engines really give me pause, and I'd like to not worry about the cam phasers, but it seems like a $30k oops if they let go. I'd love to just throw a new stock disc in mine to extend the life, but I've never done that on a car where I couldn't resurface the flyhwheel before. My guess is I end up with a new dual mass, and a complete clutch kit.
#10
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Are you guys using a damper in conjunction with the LWFW to counteract the theorized source of the cam actuator bolt issue?
What's a rough cost on the re-gear? It's around ~$9k on the GT4. Assume similar ?
What's a rough cost on the re-gear? It's around ~$9k on the GT4. Assume similar ?
#11
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the ring and pinion cost me $4,000 out the door at the dealer. Copans says it’s going to be about $1,500 to install, but it is an 11 year old gear box with 30k miles on it, so who knows if there will be any extras. I didn’t get the 6th gear, I’m not super worried about a few hundred rpm on the highway.
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jreifler (12-15-2022)
#12
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3.89 R&P was $3100 and the 6th gear was $800, direct from Porsche this past April. Out the door a few Lattes over $4K, probably a bit more now with inflation factored in. Makes sense to do the Guard clutch pack at the same time to replace the weak OEM pack. The Guard clutches are about $1150 if I recall available though a Guard authorized vendor.
Last edited by powdrhound; 12-17-2022 at 12:50 PM.
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#14
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My shifter has been the worst part of the car since I bought it. I wouldn't say it feels broken, just incredily imprecise. The sifter on my G50 aircooled car is 10 fold better. When I physically released the cables from the gearbox it was pretty evident how much wasted motion is built into the stock cable. The end link seems to be very rubbery. It's no wonder it's not precise. I'm not sure about the cup cables, I like the idea of the numeric tower working together with the cables, but I haven't talked to anyone from the company.
As far as the LWFW, I'm pretty sure it's much less expensive than putting it back to stock with a new DMFW. I really don't like gearbox NVH, which is my one hang up on the numeric shifter. For me, the behavior of the dual mass isn't so bad, but the sifter is the bane of my ownership (like the flywheel is for the OP of this thread). The harmonic issues on these engines really give me pause, and I'd like to not worry about the cam phasers, but it seems like a $30k oops if they let go. I'd love to just throw a new stock disc in mine to extend the life, but I've never done that on a car where I couldn't resurface the flyhwheel before. My guess is I end up with a new dual mass, and a complete clutch kit.
As far as the LWFW, I'm pretty sure it's much less expensive than putting it back to stock with a new DMFW. I really don't like gearbox NVH, which is my one hang up on the numeric shifter. For me, the behavior of the dual mass isn't so bad, but the sifter is the bane of my ownership (like the flywheel is for the OP of this thread). The harmonic issues on these engines really give me pause, and I'd like to not worry about the cam phasers, but it seems like a $30k oops if they let go. I'd love to just throw a new stock disc in mine to extend the life, but I've never done that on a car where I couldn't resurface the flyhwheel before. My guess is I end up with a new dual mass, and a complete clutch kit.
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#15
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3.89 R&P was $3100 and the 6th gear was $800, direct from Porsche this past April. Out the door a few Lattes over $4K, probably a bit more now with inflation factored in. Makes sense to do the Guard clutch pack at the same time to replace the weak OEM pack. The Guard clutches are about $900 direct from Matt at Guard.
No thoughts on the damper + LWFW combo ?