GT4 Final Drive Mod
Discussion
I know of a couple of owners/cars that had it done by RPM Technik.
But then ultimately didn’t keep the car that long after, but they sold on well, and I saw the cars back out on track shortly after.
In a brief chats I had they said they loved it. I didn’t get a go or a pax lap myself.
Not many people seem to have done it though, or if there are more they haven’t been on forums.
But then ultimately didn’t keep the car that long after, but they sold on well, and I saw the cars back out on track shortly after.
In a brief chats I had they said they loved it. I didn’t get a go or a pax lap myself.
Not many people seem to have done it though, or if there are more they haven’t been on forums.
They use short ratio PDK in the race cars... locked out 7th.
So not really comparable?? I’m guessing?
As you said if Porsche Motorsport had done something for the race car that could transfer to the road car... would be brilliant.
Just like they did between 996 and 997 gen road GT3 and Cup cars.
So not really comparable?? I’m guessing?
As you said if Porsche Motorsport had done something for the race car that could transfer to the road car... would be brilliant.
Just like they did between 996 and 997 gen road GT3 and Cup cars.
Edited by TDT on Thursday 25th March 21:52
I looked into it but have decided against it as I won't be tracking my car nearly as much to warrant the cost which is quite expensive. I appreciate there is quite a lot of work that RPM do but at £6.6K fitted, that's a fair chunk of change!
Edited by Andy OH on Friday 26th March 10:06
I would’ve thought the mod would be more applicable to those who didn’t track it as you wouldn’t be able to explore the full rev range as much without risking your license.
Is the alternate solution shifting down into first gear more in that case? I’ve read the opposing views of it causing undue stress on the engine/gearbox vs. it being fine because of the rev matching.
Is the alternate solution shifting down into first gear more in that case? I’ve read the opposing views of it causing undue stress on the engine/gearbox vs. it being fine because of the rev matching.
Implus1 said:
I would’ve thought the mod would be more applicable to those who didn’t track it as you wouldn’t be able to explore the full rev range as much without risking your license.
Is the alternate solution shifting down into first gear more in that case? I’ve read the opposing views of it causing undue stress on the engine/gearbox vs. it being fine because of the rev matching.
First is a usable gear in the GT4, yes.Is the alternate solution shifting down into first gear more in that case? I’ve read the opposing views of it causing undue stress on the engine/gearbox vs. it being fine because of the rev matching.
TB303 said:
Final drive change would be great, but the problem for me would be I’d like 6th gear to stay the same, therefore it’s a no go for me.
Yep. Agree Stock 6th is already short for high speed cruising - so have shorter final drive is only going to make that worse - but you can get longer 6th.Also shorter final drive doesn't address the gap between the gears.
Ideally you need shorter 2-3-4-5 and the longer 6th.
With the 996/997 GT3 you could change final drive and also easily change individual ratios.
GT4 box doesn't allow this... 1+ 2 are on the mainshaft - and that labour for the final drive is as much as would be for full re-gear as you have to take the whole box apart anyway as it is in the main case and not separate like the older GT 911 were.
I haven't totally ruled it out, but so far for me - it has made more sense to add power, to have grunt to rip though the gears quicker and make more sense of the existing ratios. Obviously could might be better with custom ratios, as this is a multiplying effect - but gears never been an issue for me personally, but i have felt like i have run out of acceleration with the stock car at the top of the revs.
Flexibility and extending power delivery right to the top of the rev range gives me more options, makes the car even more exciting- just use a gear lower and drive it right out - living between 4.5k-8K.
Soon I'll be ready for 991.2 GT
MannyLon said:
RPM can do that for you.
Have enquired around and Parr and JZM also offer the mod. Parr can do either a shortened CWP plus a taller 5th and/or 6th gear or mod gears 3-6 only. Waiting to receive their charts on the mods and pricing.
JZM offers 14% lower FD and a taller 6th to get back to stock 6th gearing @ £5.2k + VAT.
RPM are c.£6k + VAT for lower FD + taller 6th.
That’s tempting though TDT’s comments have put me off a bit!
I also agree about power a bit - the final bit of the 3.8’s rev range is slightly lacking so in reality it’s not actually the case that I change from 2nd at 82MPH or whatever it is.
Now imagine if someone offered a steering feel software (or part hardware) upgrade.
I also agree about power a bit - the final bit of the 3.8’s rev range is slightly lacking so in reality it’s not actually the case that I change from 2nd at 82MPH or whatever it is.
Now imagine if someone offered a steering feel software (or part hardware) upgrade.
I would think very carefully about the longer sixth because it feels horrible in use imo. I put a long fifth in my Lotus to compensate for drop in FD and hated it. It is basically like skipping a ratio irrespective of whether you wring it out or not. I ended up putting in a short fifth and living with the revs.
I looked at the rpm charts and the long 6th is overall taller than the stock 6th by some margin like skipping two ratios, horrible.
It looks like the FD change makes sixth about the same as stock 5th so worth driving around on the motorway etc in 5th and seeing if you can live with it.
No idea if JZM 6th ratio is shorter or similar to rpm ?
If I cant live with driving around in 5th on the motorway then I will not do the FD change and buy a PDK. I had a 981 spyder and have GTS 4.0 manual on order, just need to borrow one as i cant recall now.
I looked at the rpm charts and the long 6th is overall taller than the stock 6th by some margin like skipping two ratios, horrible.
It looks like the FD change makes sixth about the same as stock 5th so worth driving around on the motorway etc in 5th and seeing if you can live with it.
No idea if JZM 6th ratio is shorter or similar to rpm ?
If I cant live with driving around in 5th on the motorway then I will not do the FD change and buy a PDK. I had a 981 spyder and have GTS 4.0 manual on order, just need to borrow one as i cant recall now.
Not meaning to put anyone off… just expressing my own view so far, but haven’t driven a car with ‘shorter gears’
It could be great.
But to continue - The point another longer 6th is that it’s literally just a cruising/motorway gear. Almost like the 7-speed, 7th gear. I might have run out later to confirm, but i think 70 is around 3k in 6th?
1-5 would be shortened and used for all other scenario.
Changing 3-4-5 without changing 2 has the effect of bringing 3 closer to 2 and the result is almost like 2x 2nd gears.
I guess it depends on what you’re using the car for.
Ultimately I think it’s really tricky and ideally you’d want to try at car with it before taking the plunge.
It could be great.
But to continue - The point another longer 6th is that it’s literally just a cruising/motorway gear. Almost like the 7-speed, 7th gear. I might have run out later to confirm, but i think 70 is around 3k in 6th?
1-5 would be shortened and used for all other scenario.
Changing 3-4-5 without changing 2 has the effect of bringing 3 closer to 2 and the result is almost like 2x 2nd gears.
I guess it depends on what you’re using the car for.
Ultimately I think it’s really tricky and ideally you’d want to try at car with it before taking the plunge.
All the ‘final drive’ mods for GT4 are actually CW&P changes as far as I know.
You have two options CW&P or custom gears (3-4-5 & optional 6). There is an option to do all gears Deman Motorsports offer this for their 4.5L builds. Totally custom gear set matched to the c480wHP performance. Bonkers. Faster than 991 GT3 RS.
You have two options CW&P or custom gears (3-4-5 & optional 6). There is an option to do all gears Deman Motorsports offer this for their 4.5L builds. Totally custom gear set matched to the c480wHP performance. Bonkers. Faster than 991 GT3 RS.
Edited by TDT on Saturday 27th March 09:13
Thanks for posting that.
On paper it looks great, but why have they made 6th quite that tall? I don't really know if 6th was that bad stock, maybe a little short (especially when you look at the rest of the ratios!), but I guess a little taller wouldn't hurt.
Hopefully someone who's done it will post here or a mag or YT review. Sort of thing Jay Emm would do a good review on if he's reading.
On paper it looks great, but why have they made 6th quite that tall? I don't really know if 6th was that bad stock, maybe a little short (especially when you look at the rest of the ratios!), but I guess a little taller wouldn't hurt.
Hopefully someone who's done it will post here or a mag or YT review. Sort of thing Jay Emm would do a good review on if he's reading.
Like I said above drive around in stock 5th ignoring 6th and see if you can live with it, your effectively dropping an extra ratio inbetween the stock 1 -5. Ideal. Thing is that rpm revised 6th is so tall it would be like dropping two gears if you need to drop out of the cruise from 6th to 5th. Its not nice, been there done that. Go for the stock 6th with FD and you have useable acceleration in 6th. Still geared for massive top speed.
TB303 said:
Thanks for posting that.
On paper it looks great, but why have they made 6th quite that tall? I don't really know if 6th was that bad stock, maybe a little short (especially when you look at the rest of the ratios!), but I guess a little taller wouldn't hurt.
Hopefully someone who's done it will post here or a mag or YT review. Sort of thing Jay Emm would do a good review on if he's reading.
The “closest” review would be of the CSR Cayman RPM did by EVO, albeit this was just one of the mods they did. On paper it looks great, but why have they made 6th quite that tall? I don't really know if 6th was that bad stock, maybe a little short (especially when you look at the rest of the ratios!), but I guess a little taller wouldn't hurt.
Hopefully someone who's done it will post here or a mag or YT review. Sort of thing Jay Emm would do a good review on if he's reading.
https://www.evo.co.uk/porsche/cayman/21772/rpm-tec...
Edited by Implus1 on Saturday 27th March 23:50
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