Modified 981 GT4
Discussion
IMI A said:
^^^ Doh sorry thought they were all off the shelf kits 
they sort of are. If hope it's ok to post as this is all what Chris car has and his stages.1st off as the GT4 is fixed at the rear and lacking a set up is the Manthey stage 1 road kit.
This allows a basic track set up.
Chris then wanted to swap out the disks to ST and that's been great as they just don't wear out.
after that he wanted a proper Manthey set up so went for their GT4 full racing 3 way kit with a ring set up geo.
this car does not dive or roll, and it must also save tyre wear as the GT4 is too soft oem and does wear edges badly.
A few CUP race car parts with monballs were added to reduce play and add feel and also allow for caster adjustments.
and last the engine mods to 430 HP / 345 LBF-FT with a new M and M big bore full system and Jens magic on the RR.
I think some BBS Fi-R wheels next and some bbi wing uprights would finish it off very nice :-) lol
So yes pretty much off the shelf parts, put picked well and fitted by experts.
Edited by Porsche911R on Thursday 20th June 14:57
Porsche911R said:
IMI A said:
^^^ Doh sorry thought they were all off the shelf kits
they sort of are. If hope it's ok to post as this is all what Chris car has and his stages.1st off as the GT4 is fixed at the rear and lacking a set up is the Manthey stage 1 road kit.
This allows a basic track set up.
Chris then wanted to swap out the disks to ST and that's been great as they just don't wear out.
after that he wanted a proper Manthey set up so went for their GT4 full racing 3 way kit with a ring set up geo.
this car does not dive or roll, and it must also save tyre wear as the GT4 is too soft oem and does wear edges badly.
A few CUP race car parts with monballs were added to reduce play and add feel and also allow for caster adjustments.
and last the engine mods to 430 HP / 345 LBF-FT with a new M and M big bore full system and Jens magic on the RR.
I think some BBS Fi-R wheels next and some bbi wing uprights would finish it off very nice :-) lol
So yes pretty much off the shelf parts, put picked well and fitted by experts.
Edited by Porsche911R on Thursday 20th June 14:53
Edited by Porsche911R on Thursday 20th June 14:56
For the track driver I think this is a much more compelling approach than the latest iterations of the GT4
LaSource said:
Porsche911R said:
IMI A said:
^^^ Doh sorry thought they were all off the shelf kits
they sort of are. If hope it's ok to post as this is all what Chris car has and his stages.1st off as the GT4 is fixed at the rear and lacking a set up is the Manthey stage 1 road kit.
This allows a basic track set up.
Chris then wanted to swap out the disks to ST and that's been great as they just don't wear out.
after that he wanted a proper Manthey set up so went for their GT4 full racing 3 way kit with a ring set up geo.
this car does not dive or roll, and it must also save tyre wear as the GT4 is too soft oem and does wear edges badly.
A few CUP race car parts with monballs were added to reduce play and add feel and also allow for caster adjustments.
and last the engine mods to 430 HP / 345 LBF-FT with a new M and M big bore full system and Jens magic on the RR.
I think some BBS Fi-R wheels next and some bbi wing uprights would finish it off very nice :-) lol
So yes pretty much off the shelf parts, put picked well and fitted by experts.
For the track driver I think this is a much more compelling approach than the latest iterations of the GT4
So to add my view on Chris' upgrades from the passenger seat.
1st thing to say is that Chris can DRIVE. He knows how to handle the mid-engine layout and really knows this car, having developed it in stages.
But really this car now is a package - and as you improve one part you quickly realise other parts might need optimising, and Chris' car now is truly optimised.
As a package it feels like something like this should have come from the factory. I was saying all day on Tuesday... after the 718 GT4 announcements... Chris has already built it.. his car is a 718 GT4 Prototype, apart from his car has more power, ride and handles better and has more braking.
As Peter and David said - the performance of the whole car is in such balance, you can't pick out one thing over the other... it feels like stock + 20% in every dynamic respect. Which I think is a major compliment. Power delivery is smooth - and the power carries all the way through the rev range. It feels meaty. Sounds meaty too - slightly different that stock now... quieter according to donny sound traps - which is good for getting on Track days. The exhaust is designed for power - not wasting it in sound - but it is loud enough. With proper unfettled purpose.
For me though its the suspension that is stand out sparkling from the passenger seat. Unbelievable body control - no roll, pitch or dive - but can take bumps and low kerbs without upsetting the car at all. It means then that all of that new power can really be deployed with great effect.
I'll post a couple videos later which have some comparisons on track...but remember there is a big driver deficit also.... so be kind!.
This is the route to take for 981 GT4 owners if they want to develop the car.... Package.
1st thing to say is that Chris can DRIVE. He knows how to handle the mid-engine layout and really knows this car, having developed it in stages.
But really this car now is a package - and as you improve one part you quickly realise other parts might need optimising, and Chris' car now is truly optimised.
As a package it feels like something like this should have come from the factory. I was saying all day on Tuesday... after the 718 GT4 announcements... Chris has already built it.. his car is a 718 GT4 Prototype, apart from his car has more power, ride and handles better and has more braking.
As Peter and David said - the performance of the whole car is in such balance, you can't pick out one thing over the other... it feels like stock + 20% in every dynamic respect. Which I think is a major compliment. Power delivery is smooth - and the power carries all the way through the rev range. It feels meaty. Sounds meaty too - slightly different that stock now... quieter according to donny sound traps - which is good for getting on Track days. The exhaust is designed for power - not wasting it in sound - but it is loud enough. With proper unfettled purpose.
For me though its the suspension that is stand out sparkling from the passenger seat. Unbelievable body control - no roll, pitch or dive - but can take bumps and low kerbs without upsetting the car at all. It means then that all of that new power can really be deployed with great effect.
I'll post a couple videos later which have some comparisons on track...but remember there is a big driver deficit also.... so be kind!.
This is the route to take for 981 GT4 owners if they want to develop the car.... Package.
Edited by TDT on Thursday 20th June 16:06
ChrisW. said:
No, this was on the full GP circuit which is in my experience rarely used ... At the end of the day we had driven a 1:48.2 with passenger ... good ??
Nicely done Chris, I checked my data logger after the day and discovered that just plugging it in isn’t enough there is actually an open button as well (who new). So in the end no data, but viewing the GoPro it appears I managed 1:48:6 a couple of times with passengers. I’ll link some YT to the other thread in a bit you can here ED giggling as I mess up McCleans on one of the laps.My 997.1 has similar upgrades to your Gt4 ie bigger brakes 3 ways mono ball suspension and extra bhp and torque. I’ve always thought the standard Gt4 and 997.1 GT3 where similar pace on track and it appears modded once’s are too. Looking forward to Oulton
Jon
P.s can’t do snetterton
Thanks everybody ... this is a "labour of love" so it's great to see so many others sharing the process ... and David, many thanks for making a far more eloquent job than I of modularising the process. Thank-you
I noticed a comment regarding the increased weight of the 718 GT4 ... and since we have a local weigh bridge, I thought I'd weigh mine ... full of fuel ... plus or minus 20Kg's but I was told that it was recently calibrated.
The score on the door ? 1440 kilos without driver, but with 200 grams of boiled sweets in the door pocket !
So, strip out 50 kilos of fuel, less the carbon seats and brakes, plus the roll cage ... does 1390 kilos make sense ?
If I can run to the Manthey BBS F1R wheels they will save 14 kilos so that's 1375 ... of course the unsprung mass element adds a multiplier to the effective weight saving ...
The only other thing that I anticipate at some stage is replacing the ultimately worn out LSD for a Gards ? unit ...
Porsche do talk about the enhanced aero of the 718GT4 ... but it's only an extra 12Kg's (50%) at 200kph.
And now a question ...
If Porsche ever build a GT4 RS ...what engine will it have ?
I noticed a comment regarding the increased weight of the 718 GT4 ... and since we have a local weigh bridge, I thought I'd weigh mine ... full of fuel ... plus or minus 20Kg's but I was told that it was recently calibrated.
The score on the door ? 1440 kilos without driver, but with 200 grams of boiled sweets in the door pocket !
So, strip out 50 kilos of fuel, less the carbon seats and brakes, plus the roll cage ... does 1390 kilos make sense ?
If I can run to the Manthey BBS F1R wheels they will save 14 kilos so that's 1375 ... of course the unsprung mass element adds a multiplier to the effective weight saving ...
The only other thing that I anticipate at some stage is replacing the ultimately worn out LSD for a Gards ? unit ...
Porsche do talk about the enhanced aero of the 718GT4 ... but it's only an extra 12Kg's (50%) at 200kph.
And now a question ...
If Porsche ever build a GT4 RS ...what engine will it have ?
ChrisW. said:
Thanks everybody ... this is a "labour of love" so it's great to see so many others sharing the process ... and David, many thanks for making a far more eloquent job than I of modularising the process. Thank-you
I noticed a comment regarding the increased weight of the 718 GT4 ... and since we have a local weigh bridge, I thought I'd weigh mine ... full of fuel ... plus or minus 20Kg's but I was told that it was recently calibrated.
The score on the door ? 1440 kilos without driver, but with 200 grams of boiled sweets in the door pocket !
So, strip out 50 kilos of fuel, less the carbon seats and brakes, plus the roll cage ... does 1390 kilos make sense ?
If I can run to the Manthey BBS F1R wheels they will save 14 kilos so that's 1375 ... of course the unsprung mass element adds a multiplier to the effective weight saving ...
The only other thing that I anticipate at some stage is replacing the ultimately worn out LSD for a Gards ? unit ...
Porsche do talk about the enhanced aero of the 718GT4 ... but it's only an extra 12Kg's (50%) at 200kph.
And now a question ...
If Porsche ever build a GT4 RS ...what engine will it have ?
Good to see you an the banana Chris. It's sounds like a slippery slope. I think your at a point you get less for your money mods. I noticed a comment regarding the increased weight of the 718 GT4 ... and since we have a local weigh bridge, I thought I'd weigh mine ... full of fuel ... plus or minus 20Kg's but I was told that it was recently calibrated.
The score on the door ? 1440 kilos without driver, but with 200 grams of boiled sweets in the door pocket !
So, strip out 50 kilos of fuel, less the carbon seats and brakes, plus the roll cage ... does 1390 kilos make sense ?
If I can run to the Manthey BBS F1R wheels they will save 14 kilos so that's 1375 ... of course the unsprung mass element adds a multiplier to the effective weight saving ...
The only other thing that I anticipate at some stage is replacing the ultimately worn out LSD for a Gards ? unit ...
Porsche do talk about the enhanced aero of the 718GT4 ... but it's only an extra 12Kg's (50%) at 200kph.
And now a question ...
If Porsche ever build a GT4 RS ...what engine will it have ?
The way I see it is, it needs to go on a mega diet but then that compromises the ability to drive comfortably to the track.
I think your at a point where you could maybe run a better semi slick tyre, upgrade the LSD like you have mentioned (if it needs doing), otherwise I'm not sure anything else will be of benefit whilst keeping the road/track balance.
Like this alot, i too am now thinking its time to mod the gt4, i have in the past been a huge modified car guy but with ford RS cars.
But like quite a few 981 GT4 owners, the new 718 GT4 is not really doing it and for the price difference not much point.
I had a center gravity set up many years ago, but looking at engine bolt on's and a bit more suspension adjustment. Like what you have done engine wise and fancy something the same, plus would be interesting to here more about it please.
I was looking at keeping the standard shocks but adding the uprated control box for better control.
Take it you went over to Germany to get the engine bits fitted ?
But like quite a few 981 GT4 owners, the new 718 GT4 is not really doing it and for the price difference not much point.
I had a center gravity set up many years ago, but looking at engine bolt on's and a bit more suspension adjustment. Like what you have done engine wise and fancy something the same, plus would be interesting to here more about it please.
I was looking at keeping the standard shocks but adding the uprated control box for better control.
Take it you went over to Germany to get the engine bits fitted ?
Yes, Jens is near Dusseldorf and I really like the way he works :
1. Drive the car to hi.
2. Have such and explain what you want to achieve.
3. Give him reasonably free rein to interpret the best solutions and either fly home or go and do something else for a fe days.
4. Go watch the car being finished and discuss your geo requirements with the people doing it.
5. Drive home and start getting to know the car again.
Jens is an extremely well informed project manager / race engineer. He doesn't for the work himself, but he knows who he trusts to do all his race car work ... so he doesn't just talk it, he does it.
Yes there may be other people who can do this closer to home, but who ?
When I was at Oulton there was a UK engine modified GT4 that was experiencing electrical alerts .. not at-all what I wanted .. but possibly a situation that will be recovered ... also to watch.
On which subject, so far so good and will keep everybody posted.
Did I say thatI also love offering passenger rides .... ?
1. Drive the car to hi.
2. Have such and explain what you want to achieve.
3. Give him reasonably free rein to interpret the best solutions and either fly home or go and do something else for a fe days.
4. Go watch the car being finished and discuss your geo requirements with the people doing it.
5. Drive home and start getting to know the car again.
Jens is an extremely well informed project manager / race engineer. He doesn't for the work himself, but he knows who he trusts to do all his race car work ... so he doesn't just talk it, he does it.
Yes there may be other people who can do this closer to home, but who ?
When I was at Oulton there was a UK engine modified GT4 that was experiencing electrical alerts .. not at-all what I wanted .. but possibly a situation that will be recovered ... also to watch.
On which subject, so far so good and will keep everybody posted.
Did I say thatI also love offering passenger rides .... ?
Cunno said:
Nicely done Chris, I checked my data logger after the day and discovered that just plugging it in isn’t enough there is actually an open button as well (who new). So in the end no data, but viewing the GoPro it appears I managed 1:48:6 a couple of times with passengers. I’ll link some YT to the other thread in a bit you can here ED giggling as I mess up McCleans on one of the laps.
My 997.1 has similar upgrades to your Gt4 ie bigger brakes 3 ways mono ball suspension and extra bhp and torque. I’ve always thought the standard Gt4 and 997.1 GT3 where similar pace on track and it appears modded once’s are too. Looking forward to Oulton
Jon
P.s can’t do snetterton
John, many thanks for the feedback !My 997.1 has similar upgrades to your Gt4 ie bigger brakes 3 ways mono ball suspension and extra bhp and torque. I’ve always thought the standard Gt4 and 997.1 GT3 where similar pace on track and it appears modded once’s are too. Looking forward to Oulton
Jon
P.s can’t do snetterton
In fairness I should be faster ... next time I'll ride with you if you'll ride with me ??
Very useful
Passenger ride at some point would be nice, as i am still getting my head round rear wheel drive as been a fwd guy for years and 4wd.
But have done lots of track days over the years.
Do you feel that with the extra grunt the car can over come the long gearing, or maybe thats your next move along with fly wheel ?
But seeing yours and others views on the power gained is great as i have looked for views on engine mods before and its very hard to find
But have done lots of track days over the years.
Do you feel that with the extra grunt the car can over come the long gearing, or maybe thats your next move along with fly wheel ?
But seeing yours and others views on the power gained is great as i have looked for views on engine mods before and its very hard to find
Noise update from Snetterton ... 101dB at 4800 rpm ... this compares to 104dB with the original set-up at Oulton Park, both static.
I then re-tested at 5250rpm just to check the upper ceiling, and it read 105.5dB.
Max revs are 7600 at the red line.
Report from Snetterton ... it did take me a while to get up to speed, thank-you Howard for our 2/3rds tank session ! I was always faster than almost any GT4, I was always faster than a lot of GT3 and RS's ... there were always some GT3RS' that were faster than me ....
That is still the case ... it is very hard to make the rear end of a GT4 perform as well as the multilink system of the GT3RS and they still have a power advantage ...
But the car feels absolutely fantastic ... the biggest difference being that it's now possible to run a higher gear in complicated corners or sections, reducing the potential frenzy of gear changes and leaving the car more balanced, allowing the torque to haul the car through.
So is the gearing now an issue ? The gearing will always be an issue unless it's track variable. As an example, at the end of the Bentley straight I was up into fifth seeing a max of almost 135mph ... but from there dropped to third all the way round and out of the bomb-hole ... where otherwise I would have had to use second ... two gear changes saved and much smoother transitions through the section.
I then re-tested at 5250rpm just to check the upper ceiling, and it read 105.5dB.
Max revs are 7600 at the red line.
Report from Snetterton ... it did take me a while to get up to speed, thank-you Howard for our 2/3rds tank session ! I was always faster than almost any GT4, I was always faster than a lot of GT3 and RS's ... there were always some GT3RS' that were faster than me ....
That is still the case
... it is very hard to make the rear end of a GT4 perform as well as the multilink system of the GT3RS and they still have a power advantage ...But the car feels absolutely fantastic ... the biggest difference being that it's now possible to run a higher gear in complicated corners or sections, reducing the potential frenzy of gear changes and leaving the car more balanced, allowing the torque to haul the car through.
So is the gearing now an issue ? The gearing will always be an issue unless it's track variable. As an example, at the end of the Bentley straight I was up into fifth seeing a max of almost 135mph ... but from there dropped to third all the way round and out of the bomb-hole ... where otherwise I would have had to use second ... two gear changes saved and much smoother transitions through the section.
ChrisW. said:
it is very hard to make the rear end of a GT4 perform as well as the multilink system of the GT3RS
There's a fix for that! https://www.autoquestcars.com/custom-09ras62 said:
There has been much talk of the max 310 lb-ft torque limit on the Cayman box even applied to the new GT4. These mods are about 10% above this limit, any special precautions recomended by the tuners?
The torque limit of the box is strictly limited to 310lb/ft from an EU licencing POV and nothing can be done to side track that..If the gearbox goes pop(especially 3rd) then the Porsche warranty won't cover the replacement AFAIK..I'm looking at tuning my Spyder however in hindsight breaching the gearbox's torque limit holds me back somewhat..This is a very interesting question, particularly considering the tuneability of the turbocharged engines.
They don't rev, but they do torque ...
These are engineering specs, my car was one of the very first I assume with the splined third gear, and driving fast on track has to be smooth otherwise you are off !
But the bottom line is that if trouble comes to me, I'll just replace the box and make any gearing and diff changes that suit me.
It's still much cheaper than racing and you know ? I really don't expect trouble.
They don't rev, but they do torque ...
These are engineering specs, my car was one of the very first I assume with the splined third gear, and driving fast on track has to be smooth otherwise you are off !
But the bottom line is that if trouble comes to me, I'll just replace the box and make any gearing and diff changes that suit me.
It's still much cheaper than racing and you know ? I really don't expect trouble.
TDT said:
There's a fix for that! https://www.autoquestcars.com/custom-09
Now that is naughty, I'll have to take a look (Thanks !)
ChrisW. said:
One of the problems I have is that with a little help `i can drive around geometry issues ... it's not so fast but it feels faster!
So I've replied to this and let's see what comes .. thanks Tyrone !
Center Gravity have worked with this kit, on Tim (Ravon's) car, to excellent effect, i hear. Not sure if he still has the car or the kit?So I've replied to this and let's see what comes .. thanks Tyrone !
Gearbox, quoted limit of 310lbft is nothing to really worry about, and certainly not a turn off for modding... which will compromise your warranty anyway?..
As Chris says - if there is a problem... then can just get it fixed and upgraded anyway. Also we need to understand what the peak torque limitation actually is, and why it is implemented... ultimately its for driver comfort and to save some stress on the engagement of the clutch and transfer of load through the drive train. It's not necessarily the ultimate limit of the gearbox.
The GT3 only has a bit more torque.... 339lbft and really the manual gearbox is largely the same, athough the ratios are different and it spins the other way.
As Chris says - if there is a problem... then can just get it fixed and upgraded anyway. Also we need to understand what the peak torque limitation actually is, and why it is implemented... ultimately its for driver comfort and to save some stress on the engagement of the clutch and transfer of load through the drive train. It's not necessarily the ultimate limit of the gearbox.
The GT3 only has a bit more torque.... 339lbft and really the manual gearbox is largely the same, athough the ratios are different and it spins the other way.
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