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@changster123 does your car have the cup 4.0:1 final drive? If not, personally, I would do that before an engine build. Shorter gearing really brings the mezger to life, especially in the 996 gen where it didn’t have the meaty mid range of the 7.2.
The part has been sitting here for a long time and it's finally getting installed in a couple weeks along with a refreshed LSD! Finally... hah.
We used the Mahle Motorsport 4.05L kit (they call it a 4.1) which consists of 106mm pistons and liners using the 76.4mm crank. The large bore requires slight machining of the case. We went this route as I wanted a race proven Mahle product (Mahle is the OEM supplier for Porsche). This kit is uber trick with the latest technology employed throughout including ribbing of the sleeves for increased surface area. Attention to detail is evident throughout will all pistons weighing within 1g of each other which is pretty astounding. Here is the GT3 kit.
We used the version of the above kit for a turbocharged application on my build which has the pistons and wrist pins beefed up slightly for the increased stresses. The engine is plenty rev happy as it accelerates at near 16000rpm / sec and decelerates at half that rate. We use a 5.5" carbon RSR clutch which weighs under 13 lbs for the whole clutch / flywheel assembly so that probably has a lot to do with it. An OEM 4.0RS LWFW assembly is right at 30 lbs by comparison.
I just noticed this kit has a CR of 13:1. Is that ok for 93 US / 98 Ron? No detonation issues with a good tune without compromising ignition timing?
I just priced out adding the 3:89 RP and the tall turbo 6th to my 3.6 pumpkin. Likely $10-$12K all in. Parts alone for RP and 6th gear is $6.7K, the balance is labor. Wish I'd picked up the RP 3 years ago. I'm on the fence.
The car is already fitted with the Guards LSD (same as Turbo Cup Diff run at Pikes Peak) and the 4.0 clutch and flywheel kit with fork and bearings. Side Muffler delete, with SW bypass pipes and rear GT3 dual out muffler, SW Tune, pinned coolant lines, 996 Cup shift cables, and Brembo Steel Conversion with rebuilt PCCB calipers w steel brake lines. Recaro ProfiXL Seats, CMG Roll bar in Orange. As an aside, I also picked up the smaller diameter factory RS steering wheel from .2 RS.
Motor is stock other than the SW Tune.
I'm thinking the 3:89 with taller 6th completes the car. Canyon blasting along with some road tripping, Hot Rod style. Should I just pull the trigger already on the Box work? I know what Scott Arizona will say
Yes you should. I wouldn't bother with a taller 6th though. I don't really understand why people do that to be frank. My current R&P is a 3.75 which is close enough to a 3.89, running a 25" rear tire (=shorter effective gearing) which is an inch smaller than the normal 26" tall tire that most 997's run. I find 6th way too tall as is. Runinnig your engine at under 3500rpm I think is bad. The load is too high. Load is what stresses your engine. It is much happer at least I think at 3800ish even when cruising on the freeway.
I just found a used cup trans. Ill probably be into it for $10k when all said in done but it seamed a better way for me. Its a gamble and im gonna to assemble myself but i like a challange. Just inventoried it last night since it was dissassembled and its all there. Cant wait to get on the track with the correct gearing.
I just priced out adding the 3:89 RP and the tall turbo 6th to my 3.6 pumpkin. Likely $10-$12K all in. Parts alone for RP and 6th gear is $6.7K, the balance is labor. Wish I'd picked up the RP 3 years ago. I'm on the fence.
The car is already fitted with the Guards LSD (same as Turbo Cup Diff run at Pikes Peak) and the 4.0 clutch and flywheel kit with fork and bearings. Side Muffler delete, with SW bypass pipes and rear GT3 dual out muffler, SW Tune, pinned coolant lines, 996 Cup shift cables, and Brembo Steel Conversion with rebuilt PCCB calipers w steel brake lines. Recaro ProfiXL Seats, CMG Roll bar in Orange. As an aside, I also picked up the smaller diameter factory RS steering wheel from .2 RS.
Motor is stock other than the SW Tune.
I'm thinking the 3:89 with taller 6th completes the car. Canyon blasting along with some road tripping, Hot Rod style. Should I just pull the trigger already on the Box work? I know what Scott Arizona will say
Yes, best single upgrade for these cars hands down--how they should have come from the factory. P.S. the 997.1 and 997.2 RS steering wheels are the same size. You need to go to a newer 991.2 GT wheel to go a bit smaller.
Only you can answer whether changing 6th is worth it depending on how much highway driving you're doing. I wouldn't bother with the 997.2 RS 6th, it's barely any higher. I personally did the 993 6th and it puts 6th back where it was pre RS R&P.
Thanks for the feedback guys, and wow that Trans in pieces looks daunting. Good luck getting that set up.
I meant the 991.2 steering wheel BTW, thanks for the catch. It'd def smaller than the .1 RS wheel and it came with the air bag so plug n play.
I hadn't heard about the 993 6th gear as an alternative. I do a fair amount of freeway driving, so I am considering a taller 6th gear. The current 7.1 RS 6th is fine, so maybe the 993 will be right. I'll look into it. Vocan, are you glad you did 6th now that you are living with it? How close to 5th is it?
Originally Posted by Vocan
Yes, best single upgrade for these cars hands down--how they should have come from the factory. P.S. the 997.1 and 997.2 RS steering wheels are the same size. You need to go to a newer 991.2 GT wheel to go a bit smaller.
Only you can answer whether changing 6th is worth it depending on how much highway driving you're doing. I wouldn't bother with the 997.2 RS 6th, it's barely any higher. I personally did the 993 6th and it puts 6th back where it was pre RS R&P.
Re the new 6th, just depends on your use case and the roads where you drive. I do a fair amount of freeway driving with 75mph speed limits (which means everyone is going 80 plus). At those speeds I wish I had just a slightly taller 6th to keep the rpms' down just a smidge. Again, not a huge deal, but would be nice on longer drives so the cabin is a bit more subdued during those times. Its not like you need 6th on most tracks or canyon drives anyway.
Thanks Scott and Happy New Year. Glad to see the garage is loaded with the best toys. The 6-3 is perfect.
So did you leave your 6th as it was? I just checked on the 993 version and there are two 6th gears to choose from. One with 31 teeth and one with 32. Is the 32 taller? If you had it to do over, how would you do it?
Thanks for the feedback guys, and wow that Trans in pieces looks daunting. Good luck getting that set up.
I meant the 991.2 steering wheel BTW, thanks for the catch. It'd def smaller than the .1 RS wheel and it came with the air bag so plug n play.
I hadn't heard about the 993 6th gear as an alternative. I do a fair amount of freeway driving, so I am considering a taller 6th gear. The current 7.1 RS 6th is fine, so maybe the 993 will be right. I'll look into it. Vocan, are you glad you did 6th now that you are living with it? How close to 5th is it?
Yes, definitely glad that I did 6th in my car and it's a fairly noticeable drop from 5th to 6th since 5th is now higher (with the RS R&P) and the new 6th is back where 6th was pre R&P. So more noticeable now definitely than the 5th to 6th drop with your current setup.
On the 993 6th, I believe only one of them is currently available new from Porsche (or was when I did it a year ago): .821 993 6th, 950 302 906 01
There's a recent thread on the 997 GT forums about the R&P that goes into detail on the 6th gear options as well:
If you're on the fence and do highway driving, I'd probably just do it personally. Better to spend the couple grand while the box is already open than feel regret about not doing it after the car is back together.
I did the 997.2 RS 6th when I installed my 3.89 and was a bit disappointed when I shifted into 6th for the first time, just not much of a drop. I have justified it to myself as it is now a full factory 997.2 RS transmission... That said I have grown to enjoy cruising at 3,500-4k rpm (75-90mph) in 6th, plenty of passing power at those rpm. My exhaust is on the milder side.
So I did a little research and it appears the Turbo/GT2 6th gear has 33 teeth, and the 993 6th (01) part number has 32 teeth making the Turbo/GT 2 gear 1 tooth taller than 993. I'm assuming more teeth make the gear taller thus lower RPM's. Does this make sense?
Love the most valued input guys. Rennlist is the best.
Originally Posted by Vocan
Yes, definitely glad that I did 6th in my car and it's a fairly noticeable drop from 5th to 6th since 5th is now higher (with the RS R&P) and the new 6th is back where 6th was pre R&P. So more noticeable now definitely than the 5th to 6th drop with your current setup.
On the 993 6th, I believe only one of them is currently available new from Porsche (or was when I did it a year ago): .821 993 6th, 950 302 906 01
There's a recent thread on the 997 GT forums about the R&P that goes into detail on the 6th gear options as well:
If you're on the fence and do highway driving, I'd probably just do it personally. Better to spend the couple grand while the box is already open than feel regret about not doing it after the car is back together.
So I did a little research and it appears the Turbo/GT2 6th gear has 33 teeth, and the 993 6th (01) part number has 32 teeth making the Turbo/GT 2 gear 1 tooth taller than 993. I'm assuming more teeth make the gear taller thus lower RPM's. Does this make sense?
Love the most valued input guys. Rennlist is the best.
Which Turbo/GT2 6th gear are you referring to? I know the 997 turbo 6th gear isn't compatible.
You can certainly get taller gears than the 993 6th if you wanted even more of a drop. I went with it because it most closely approximated the cruising RPM the engine was designed for from the factory.
