Prospective 981 GT4 Owners Discussion Forum.
Discussion
PorscheGT4 said:
nope. no adjustment on the Spyder and it weighs more than my old car, but still with a roof you have to get out the car and run round twice to take off, add the longer speeds and the faker steering and it had no appeal over the old One.
My R is also going.
Kind of interesting of all the Pork you've had including 911 you'd sell them all and keep the older spyder . Can see the logic in that you find your driving Nivana and stick with it. My R is also going.
Been looking at them myself
isaldiri said:
Out of topic but a bit of a question i had asked in the RS thread previous and would hope you might be able to shed some light on this.
A friend of mine has told me some people who should know (engineer for a gt3 team) that the 918's e-motor braking is able to help the car brake better than through pure tyre grip and has quoted the sport auto supertest results where the 918 recorded a decently better 200-0kmh braking number over the 991 gt3rs despite being ~150kg heavier and where both cars are running identically sized Cup2s. he was likewise told the hybrid GT3-R porsche ran at the ring a few years ago likewise had a decent braking advantage over the non hybrid RSRs....
Does this sound plausible at all as it's completely at odds with anything i have ever read on braking dynamics or anything I personally was told by reasonably experienced people.....?
Nope!!. A friend of mine has told me some people who should know (engineer for a gt3 team) that the 918's e-motor braking is able to help the car brake better than through pure tyre grip and has quoted the sport auto supertest results where the 918 recorded a decently better 200-0kmh braking number over the 991 gt3rs despite being ~150kg heavier and where both cars are running identically sized Cup2s. he was likewise told the hybrid GT3-R porsche ran at the ring a few years ago likewise had a decent braking advantage over the non hybrid RSRs....
Does this sound plausible at all as it's completely at odds with anything i have ever read on braking dynamics or anything I personally was told by reasonably experienced people.....?
I havent seen the figures for any SportAuto 991 RS test however the 918 didnt do meaningfully better than the 991 GT3 or 991 Turbo S in the Supertests. I didnt look any further after that.
918 had a mean deceleration 0.04G higher than the GT3 and Turbo over the two hot tests. GT3 and Turbo had the same mean (1.23G). GT3 and Turbo S were on the same size rubber, 918 had larger tyres. The GT3 and 918 had MPSC2, Turbo S had Sport Maxx Race.
Given the less than scientific nature of these "tests", I dont see the difference as being significant. The difference in stopping distance between the GT3 and the 918 on the 200km/h test equals a difference in pedal application of 0.12 seconds for example.
I can think of a handful of ways that the measured difference in deceleration would be well within the error bars for such a test.
Even using E-motor braking, the tyres are still required to stop the car. The e motor only replaces the physical brake application. It doesnt change the method of contact with the road so tyres still resist the forward momentum.
Where there could be an advantage is with heat build up in the brakes during repeated braking.
The 918 is heavy and the kinetic energy required to be converted or stored with each stop will be considerable. With conventional braking it would all go to heat, with the e-motor this is not the case.
How much of an advantage this would be would depend on the rotor size, cooling capabilities etc etc.
One should be able to package more efficiently due to the e-motors, using smaller brakes and saving on cooling since the brakes don't need to do as much braking. I haven't noticed this being the case on the 918.
The same benefits would apply for the GT3-R hybrid. It would see reduced brake heat and reduced brake wear. Both would be good in endurance racing. It wouldnt be able to stop any quicker however.
PorscheGT4 said:
I am still saying the GT4 is like these cars +20% people are missing out that quote ;-) it's just not moved the game on much to give it a wow factor, in fact after 2.5 hours in the thing I was quite board.
on a fast track the GT4 grip advantage would muller a Spyder or a Cayman and for some that's enough.
I wasnt making any comment on your comments about the GT4. You are absolutely entitled to any opinions that you have on the car just as all others are. Some choose to share, some don't. Its a forum so that's a large part of what it is all about.on a fast track the GT4 grip advantage would muller a Spyder or a Cayman and for some that's enough.
PorscheGT4 said:
ALso if you are talking weight lets not forget the 350mm CCB on my Spyder only weigh 10 lbs a corner the GT4 are 15 lbs and 13.3 lbs, and the steels are 27lbs/24lbs
So total rotating mass is another 15 lbs off vs GT4, and steels 63lbs lighter on top of the wheel tyre combo.
It all adds up and my car weighs over 100kg less.
I wasn't talking weight. You were. I was specifically replying to your comment about the "massive" weight introduced by the wheels on the GT4. And was doing so by putting it into perspective of the total weight of the car. This whole weight must be accelerated.So total rotating mass is another 15 lbs off vs GT4, and steels 63lbs lighter on top of the wheel tyre combo.
It all adds up and my car weighs over 100kg less.
Your Spyder is under 1240kg wet with no driver? Thats pretty cool if thats the case. Weight sucks. My project porsche has about another 140kg on you there though. Its brilliant as a result. It also has short as heck gears.
PorscheGT4 said:
Brakes are NOT all about the tyre in the first 30/40mph mph or so, as there is NO way you can lock a wheel on a car with that rotating mass at 70mph. I proved this on my R vs my Spyder when we chatted about it last time, the R was way off the stopping distance of my Spyder.
Stopping is all about the tyre. The moment you start decelerating faster than the natural rate of deceleration due to drag its the tyres resisting the forwards momentum that enables this. They do this by slipping on the road surface. There is nothing else in contact with the road to enable the deceleration. Unless you run a drag parachute?This is why rate of deceleration is so low on ice. Your brakes still function perfectly in this situation, however there is very low tyre mu available to resist the forwards momentum so it takes a long time to stop.
Since I have some numbers to hand.
991 GT3, 1443kg, MPSC2
Deceleration rate 200km/h - 0, 11.9 m/s2
991 Turbo S, 1595kg, Sport Maxx Race
Deceleration rate 200km/h - 0, 12.0 m/s2
GT4, 1379kg, MPSC2
Deceleration rate 200km/h - 0, 11.9 m/s2
991 GT3 RS, 1461kg, MPSC2
Deceleration rate 200km/h - 0, 12.0 m/s2
Edit to add in GT3 RS from SportAuto via isaldiri
Edited by fioran0 on Tuesday 11th August 01:33
PorscheGT4 said:
selling it, it will never feel as good as the Spyder and I am happy with that car for my fun car but prob not till Spring 2016.
I will go for another brand for my normal car for a year or so and see what happens. ie some thing with a bit of real poke.
I might put it up for a silly price as it's an early car and see if any fools can be parted with big money :-)
I won't be trying to sell it, but no harm in a daft priced advert.
Good luck to you. I'm sure someone will. Still don't understand the idea of buying a car only to flip it. Feeds the sad world where genuine buyers miss out. I will go for another brand for my normal car for a year or so and see what happens. ie some thing with a bit of real poke.
I might put it up for a silly price as it's an early car and see if any fools can be parted with big money :-)
I won't be trying to sell it, but no harm in a daft priced advert.
I guess not everyones morale compass points north.
fioran0 said:
Nope!!.
I havent seen the figures for any SportAuto 991 RS test however the 918 didnt do meaningfully better than the 991 GT3 or 991 Turbo S in the Supertests. I didnt look any further after that.
918 had a mean deceleration 0.04G higher than the GT3 and Turbo over the two hot tests. GT3 and Turbo had the same mean (1.23G). GT3 and Turbo S were on the same size rubber, 918 had larger tyres. The GT3 and 918 had MPSC2, Turbo S had Sport Maxx Race.
Given the less than scientific nature of these "tests", I dont see the difference as being significant. The difference in stopping distance between the GT3 and the 918 on the 200km/h test equals a difference in pedal application of 0.12 seconds for example.
I can think of a handful of ways that the measured difference in deceleration would be well within the error bars for such a test.
Even using E-motor braking, the tyres are still required to stop the car. The e motor only replaces the physical brake application. It doesnt change the method of contact with the road so tyres still resist the forward momentum.
Where there could be an advantage is with heat build up in the brakes during repeated braking.
The 918 is heavy and the kinetic energy required to be converted or stored with each stop will be considerable. With conventional braking it would all go to heat, with the e-motor this is not the case.
How much of an advantage this would be would depend on the rotor size, cooling capabilities etc etc.
One should be able to package more efficiently due to the e-motors, using smaller brakes and saving on cooling since the brakes don't need to do as much braking. I haven't noticed this being the case on the 918.
The same benefits would apply for the GT3-R hybrid. It would see reduced brake heat and reduced brake wear. Both would be good in endurance racing. It wouldnt be able to stop any quicker however.
Thanks for that, much appreciated for the reply. at least I can reassure myself I wasn't completely crazy as i was thinking something of the same about the e-motor braking being a transfer of kinetic energy to electric rather than heat but no impact on the actual tire friction. I never thought of calculating the actual times concerned as well with the 200-0 braking and only looked at distances so 0.1-0.2s as you say looks well within margin of error.I havent seen the figures for any SportAuto 991 RS test however the 918 didnt do meaningfully better than the 991 GT3 or 991 Turbo S in the Supertests. I didnt look any further after that.
918 had a mean deceleration 0.04G higher than the GT3 and Turbo over the two hot tests. GT3 and Turbo had the same mean (1.23G). GT3 and Turbo S were on the same size rubber, 918 had larger tyres. The GT3 and 918 had MPSC2, Turbo S had Sport Maxx Race.
Given the less than scientific nature of these "tests", I dont see the difference as being significant. The difference in stopping distance between the GT3 and the 918 on the 200km/h test equals a difference in pedal application of 0.12 seconds for example.
I can think of a handful of ways that the measured difference in deceleration would be well within the error bars for such a test.
Even using E-motor braking, the tyres are still required to stop the car. The e motor only replaces the physical brake application. It doesnt change the method of contact with the road so tyres still resist the forward momentum.
Where there could be an advantage is with heat build up in the brakes during repeated braking.
The 918 is heavy and the kinetic energy required to be converted or stored with each stop will be considerable. With conventional braking it would all go to heat, with the e-motor this is not the case.
How much of an advantage this would be would depend on the rotor size, cooling capabilities etc etc.
One should be able to package more efficiently due to the e-motors, using smaller brakes and saving on cooling since the brakes don't need to do as much braking. I haven't noticed this being the case on the 918.
The same benefits would apply for the GT3-R hybrid. It would see reduced brake heat and reduced brake wear. Both would be good in endurance racing. It wouldnt be able to stop any quicker however.
Swiped from rennlist - the supertest 991RS data if you are interested given you mentioned you hadn't seen it yet. Also i think not included there it recorded 1.55g of lateral acceleration vs 1.45g on the gt3.
Thanks, I hadnt seen that.
Its rate of deceleration is right in there with the 991 GT3, the 911 Turbo S and the 918. Which is as expected really.
Thats interesting on the lateral G figures. I always wonder about the SportAuto lateral G results. It regularly looks suspiciously like they grab the peak values but I've never seen anything to clear it up. Peak doesnt mean that much sadly.
Its rate of deceleration is right in there with the 991 GT3, the 911 Turbo S and the 918. Which is as expected really.
Thats interesting on the lateral G figures. I always wonder about the SportAuto lateral G results. It regularly looks suspiciously like they grab the peak values but I've never seen anything to clear it up. Peak doesnt mean that much sadly.
N
I guess not everyones morale compass points north.Yes but you can tell from the way he writes he is really a Porsche works driver some say it is Mark Webber! Others say it is your worst nightmare to meet him in a pub!
Trotmant said:
PorscheGT4 said:
selling it, it will never feel as good as the Spyder and I am happy with that car for my fun car but prob not till Spring 2016.
I will go for another brand for my normal car for a year or so and see what happens. ie some thing with a bit of real poke.
I might put it up for a silly price as it's an early car and see if any fools can be parted with big money :-)
I won't be trying to sell it, but no harm in a daft priced advert.
Good luck to you. I'm sure someone will. Still don't understand the idea of buying a car only to flip it. Feeds the sad world where genuine buyers miss out. I will go for another brand for my normal car for a year or so and see what happens. ie some thing with a bit of real poke.
I might put it up for a silly price as it's an early car and see if any fools can be parted with big money :-)
I won't be trying to sell it, but no harm in a daft priced advert.
I guess not everyones morale compass points north.
Trotmant said:
Good luck to you. I'm sure someone will. Still don't understand the idea of buying a car only to flip it. Feeds the sad world where genuine buyers miss out.
I guess not everyones morale compass points north.
The issue is you cannot try the cars. so a 3.8 Cayman is launched you have to order it 2 years in advance !!!I guess not everyones morale compass points north.
nothing else you can do, I hate buying this way but it was the only way to get one !
Can you NOT SEE THAT ?
PorscheGT4 said:
Trotmant said:
Good luck to you. I'm sure someone will. Still don't understand the idea of buying a car only to flip it. Feeds the sad world where genuine buyers miss out.
I guess not everyones morale compass points north.
The issue is you cannot try the cars. so a 3.8 Cayman is launched you have to order it 2 years in advance !!!I guess not everyones morale compass points north.
nothing else you can do, I hate buying this way but it was the only way to get one !
Can you NOT SEE THAT ?
Genuinely curious to what you might buy if you are underwhelmed with the GT4 - you would be bored silly in lardy R8 V10, Lotus S2/S3 Exiges are flawed in so many ways and you don't like GT3's.......what would you buy instead?
FWIW, ran the GT4 at the Gold Track Silverstone GP event yesterday in wet and dry conditions, with the rear anti roll bar in its stiffest setting, the car felt excellent, very safe and predicatable with plenty of feel in both sets of conditions. Have had a twin external silencer system made up by Mike Edwards Motorsport which I tried for the first time yesterday, makes the car very quiet, should have no noise problems at places like Bedford or Goodwood. This is now my third hard driving track day and the Pilot Cup 2's seem very wear resistant so far ! As ever the only tangible improvement that in my view thus far the car needs is another hundred horsepower !
Scooty100 said:
PorscheGT4 said:
nope. no adjustment on the Spyder and it weighs more than my old car, but still with a roof you have to get out the car and run round twice to take off, add the longer speeds and the faker steering and it had no appeal over the old One.
My R is also going.
Kind of interesting of all the Pork you've had including 911 you'd sell them all and keep the older spyder . Can see the logic in that you find your driving Nivana and stick with it. My R is also going.
Been looking at them myself
My "problem" is that my driving in these cars is 98% road and 2% track. I don't need the GT4's extra power on the road but hydraulic steering would be nice to have every day. It's certainly not coming back.
Lack of roof and the special looks are plus points. Not to mention the savings. Maybe I'll get a 987 Spyder and keep it in addition to the GT4.
The old Spyder seems to be a remarkable combination of light weight, hydraulic steering, decent sounding engine and a relatively comfortable yet tight damping. A perfect storm in some ways.
It never felt harsh on my test drive. I often found myself bracing for the impact of a pothole but it just soaks it up and strolls on. More so than the GT4 in the softer setting. Speed bumps are also not an issue. The only thing I would berate is the noise on long distances trips with the top on.
Would love to test a 981 Spyder to compare but my dealership has yet to get one.
n17ves said:
Putting the ceramics issue aside, I personally I found the GT4 pretty perfect for a road/track car (apart from a few minor things).
Genuinely curious to what you might buy if you are underwhelmed with the GT4 - you would be bored silly in lardy R8 V10, Lotus S2/S3 Exiges are flawed in so many ways and you don't like GT3's.......what would you buy instead?
MP12c for a bit :-)Genuinely curious to what you might buy if you are underwhelmed with the GT4 - you would be bored silly in lardy R8 V10, Lotus S2/S3 Exiges are flawed in so many ways and you don't like GT3's.......what would you buy instead?
I think people forget I have my Spyder to use for blasts for pure fun and nothing beats real steering and roof off motoring.
GT4 now feels under powered with that 245/295 cup 2 set up and just did not give me a WOW moment , how ever good a car it is, I have to have that gut wow feeling.
One will soon find out if it can wow on UK B roads though, then I might keep it, just voicing first thoughts out loud, which some times comes back to bite me a year later !!
25 mph above UK B road limits in 2nd gear could kill it for me though , time will tell.
I am also getting more frustrated with UK roads, half the time it seems pointless to own stuff esp long geared Porkers !! , the MP12C will give me another angle on motoring.
One car I am looking forward to is the 2017 Lotus Exige 400, a new redesign and charge cooler set up with 1100kg and 400bhp.
swimd said:
I still have my GT4 on order (feb delivery) and also have been looking at some of the older stuff, 987 Spyder or R to bridge the gap.
My "problem" is that my driving in these cars is 98% road and 2% track. I don't need the GT4's extra power on the road but hydraulic steering would be nice to have every day. It's certainly not coming back.
Lack of roof and the special looks are plus points. Not to mention the savings. Maybe I'll get a 987 Spyder and keep it in addition to the GT4.
The old Spyder seems to be a remarkable combination of light weight, hydraulic steering, decent sounding engine and a relatively comfortable yet tight damping. A perfect storm in some ways.
It never felt harsh on my test drive. I often found myself bracing for the impact of a pothole but it just soaks it up and strolls on. More so than the GT4 in the softer setting. Speed bumps are also not an issue. The only thing I would berate is the noise on long distances trips with the top on.
Would love to test a 981 Spyder to compare but my dealership has yet to get one.
Spyder is the perfect 2nd fun car, I need to get that into my head and not keep changing cars looking for some thing that is not available., we will NOT see cars like that again sad to say.My "problem" is that my driving in these cars is 98% road and 2% track. I don't need the GT4's extra power on the road but hydraulic steering would be nice to have every day. It's certainly not coming back.
Lack of roof and the special looks are plus points. Not to mention the savings. Maybe I'll get a 987 Spyder and keep it in addition to the GT4.
The old Spyder seems to be a remarkable combination of light weight, hydraulic steering, decent sounding engine and a relatively comfortable yet tight damping. A perfect storm in some ways.
It never felt harsh on my test drive. I often found myself bracing for the impact of a pothole but it just soaks it up and strolls on. More so than the GT4 in the softer setting. Speed bumps are also not an issue. The only thing I would berate is the noise on long distances trips with the top on.
Would love to test a 981 Spyder to compare but my dealership has yet to get one.
In the technical specification it lists "electronically controlled rear differential".
Is this a true electronically controlled diff? Like an E-diff? Similar to the 991GT3 diff?
I had assumed it was just a standard plated/clutch diff as the lock-up values are so low.
Can anyone with actual real (not assumed) information confirm the set-up?
Is this a true electronically controlled diff? Like an E-diff? Similar to the 991GT3 diff?
I had assumed it was just a standard plated/clutch diff as the lock-up values are so low.
Can anyone with actual real (not assumed) information confirm the set-up?
jackwood said:
In the technical specification it lists "electronically controlled rear differential".
Is this a true electronically controlled diff? Like an E-diff? Similar to the 991GT3 diff?
I had assumed it was just a standard plated/clutch diff as the lock-up values are so low.
Can anyone with actual real (not assumed) information confirm the set-up?
I'd like to see where they mention a e-Diff. Is this a true electronically controlled diff? Like an E-diff? Similar to the 991GT3 diff?
I had assumed it was just a standard plated/clutch diff as the lock-up values are so low.
Can anyone with actual real (not assumed) information confirm the set-up?
The GT4 definitely does not have an e-diff, it has the standard "tame" 22%/27% mechanical limited slip differential. The same as in some 987/981s and 991s with PTV package.
I can only assume the "electronically controlled rear differential" refers to the torque vectoring via brakes. It's not a real e-diff as found in the GT3 and future 991.2s.
re spyder
i don't believ you can get to 1250kg with a full tank of gas.
Mine was lightweight with PCCB, no AC and Lithium battery. when you drain the window washer fluid, ditched the top, toolkit and insulation, I got to 1270kg. Take away another 6kg for sound pack plus stereo, you can only get to 1263kg.
1250kg means you need some other non-oem modification like lightweight exhaust and lighter non airbag seats. In fact, I don't know how the factory achieved 1275kg full wet without PCCB and lithium battery.
i don't believ you can get to 1250kg with a full tank of gas.
Mine was lightweight with PCCB, no AC and Lithium battery. when you drain the window washer fluid, ditched the top, toolkit and insulation, I got to 1270kg. Take away another 6kg for sound pack plus stereo, you can only get to 1263kg.
1250kg means you need some other non-oem modification like lightweight exhaust and lighter non airbag seats. In fact, I don't know how the factory achieved 1275kg full wet without PCCB and lithium battery.
PorscheGT4 said:
MP12c for a bit :-)
I am also getting more frustrated with UK roads, half the time it seems pointless to own stuff esp long geared Porkers !! , the MP12C will give me another angle on motoring.
Consistency isn't your strongest point is it? I am also getting more frustrated with UK roads, half the time it seems pointless to own stuff esp long geared Porkers !! , the MP12C will give me another angle on motoring.
Have you actually ever driven a 12c? That car is seriously quick to the point if you're complaining about not being able to use a gt3 properly on the road with the speed limits the Mclaren is going to be utterly impossible. And as far as complaining about gearing you are doing almost 80 at 2nd gear at 8k rpm and certainly in excess of 100 at 8+k rpm in 3rd.
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