Power - they are overtaking us
Discussion
gt5594 said:
I requested that the factory make us a special GTR lightweight body back in 2013, and Ted very kindly produced one, he said the first one made, although I think he's produced another one since. The factory were very helpful indeed at the time, but then they always are..
It's still completely manufactured in fibreglass, with all the appropriate structural strengthening where it needs to be. The body is not the easiest thing to weigh accurately, but would estimate the saving to be about 25kg - which is very significant to me.
Given the big weight saving, the body finish and fit is excellent, certainly just as good looking and well made as our other body
Personally I just don't like the look of carbon fibre weave, but everyone is different...
Mentioning this to remind folks to just "ask the factory", they've been perfecting stuff over many years and seem to have looked at most things before, not caught them out yet.
Interesting.It's still completely manufactured in fibreglass, with all the appropriate structural strengthening where it needs to be. The body is not the easiest thing to weigh accurately, but would estimate the saving to be about 25kg - which is very significant to me.
Given the big weight saving, the body finish and fit is excellent, certainly just as good looking and well made as our other body
Personally I just don't like the look of carbon fibre weave, but everyone is different...
Mentioning this to remind folks to just "ask the factory", they've been perfecting stuff over many years and seem to have looked at most things before, not caught them out yet.
Are you mounting the rear wing? Will the rear clip be strong enough at that point (you can get stress cracks in the gel coat).
Curious as to why you asked the Factory for a light weight body too?
Paul
corvettedave said:
Olivera said:
6:45 round the ring? I highly doubt it. To my knowledge there is no documented proof (youtube et al) of an Ultima GTR lapping the ring in even 7:45, or even 7:45 BTG (bridge to gantry) which is even slower.
that doesn't mean its not possible thoPaul you are spot on. Yes we have mounted a rear wing, but moved the wing mountings very slightly outwards in order to feed the loads generated directly downwards through the boxed reinforcement in the body. The factory obviously know what they are doing because their lightweight body appears to have the same materials and re-inforcement in all the important areas through which loads are being transferred. This particular car is not for the road.
The new chassis you guys are mentioning, when was it first available? I am seriously considering purchasing a 2012 GTR 720. It has the AS 700++ LS7 engine. I was not aware until reading this thread that there was a chassis revision. This one was completed in 2012, but it was started in 2011.
Cheers,
Andrew.
Cheers,
Andrew.
28Ace82 said:
The new chassis you guys are mentioning, when was it first available? I am seriously considering purchasing a 2012 GTR 720. It has the AS 700++ LS7 engine. I was not aware until reading this thread that there was a chassis revision. This one was completed in 2012, but it was started in 2011.
Cheers,
Andrew.
2013, that car will not have the chassis revision.Cheers,
Andrew.
I doubt you would notice it unless you drive 9/10ths all the time on track.
Thanks for the info and the link guys.
The new chassis does sound very good but the car has never seen a track in its life so far, I will probably take it to a few but certainly wont be pushing 9/10, maybe 5/10 if I am lucky!
I've posted some questions about the car on a new thread, any more words of wisdom would be very much appreciated!
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Regards,
Andrew.
The new chassis does sound very good but the car has never seen a track in its life so far, I will probably take it to a few but certainly wont be pushing 9/10, maybe 5/10 if I am lucky!
I've posted some questions about the car on a new thread, any more words of wisdom would be very much appreciated!
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Regards,
Andrew.
I don't have a sense that the Ultima has a weight problem at all. It's power-to-weight ratio is (or can be with reasonable engine choice) excellent and the F/R weight balance is not bad. If I could make a couple of changes in the interest of performance I'd suggest:
Lightweight wheels (and overall reduction in unsprung weight). This would be a significant fix as every pound of unsprung weight is said to yield the equivalent of 5-7 pounds of sprung weight. Light wheels, aluminum struts, perhaps C/C disks. And the mass/inertia in heavier wheels really affects their rate of change in rotational speeds.
Faster shifting transmission. With the G50 transmission, the car has the same problem as most mid-era Porsche's which is that it's a very long run from the gear shift to the box, too long to be very exacting and negatively impacting gear change speeds. I'd like to see what an electronically actuated shift-by-wire system would do. There are a few (well, at least one) companies that make them for the Porsche transmission that uses a basic fore/aft shifter (w/reverse switch) and a solenoid control box that bolts to the transmission housing. Picking up a tenth or more on each shift would be equivalent to a lot of weight and horsepower.
Better engine breathing. This one is speculative but the surface area of the intake behind the center of the cockpit with that long run to the air box and a sharp turn in to the manifold seems limiting and not necessarily well-tuned when my LS7 is in full gulp mode. I don't know how to test this (a simple vacuum gauge would seem like a start) nor do I know if it could be addressed while enabling a choice of engines, but it seems worth a look.
Oh and I wish that the factory would use a rack that would take one universal joint out of the steering shaft. I know that it's designed for LH or RH drive, but if they used two racks with the shaft input aligned with the steering rack on either side, it would take a small amount of 'slop' out of the system. Having raced go-karts pretty seriously in my youth, it needs to feel like that.
Overall a key difference, both good and bad, is that the Ultima is a pure mid-engine sports car with no electronic aids or AWD. For me, and likely many owners, it provides a fabulous feel and an incredibly exciting driving experience. It's as close to kart-racing as possible and for me, that's the purest racing I've ever experienced. But very modern cars not only make good power but make use of electronics for traction, stability, shifting, throttle mapping, braking, energy caching and a myriad of other things. No amount of conventional power is going to make up for these others techniques which is why I'd guess that 'tuning' the car (as noted above and many other subtle techniques) will enable more speed and excitement than just a better power/weight ratio.
That's all.
V
Lightweight wheels (and overall reduction in unsprung weight). This would be a significant fix as every pound of unsprung weight is said to yield the equivalent of 5-7 pounds of sprung weight. Light wheels, aluminum struts, perhaps C/C disks. And the mass/inertia in heavier wheels really affects their rate of change in rotational speeds.
Faster shifting transmission. With the G50 transmission, the car has the same problem as most mid-era Porsche's which is that it's a very long run from the gear shift to the box, too long to be very exacting and negatively impacting gear change speeds. I'd like to see what an electronically actuated shift-by-wire system would do. There are a few (well, at least one) companies that make them for the Porsche transmission that uses a basic fore/aft shifter (w/reverse switch) and a solenoid control box that bolts to the transmission housing. Picking up a tenth or more on each shift would be equivalent to a lot of weight and horsepower.
Better engine breathing. This one is speculative but the surface area of the intake behind the center of the cockpit with that long run to the air box and a sharp turn in to the manifold seems limiting and not necessarily well-tuned when my LS7 is in full gulp mode. I don't know how to test this (a simple vacuum gauge would seem like a start) nor do I know if it could be addressed while enabling a choice of engines, but it seems worth a look.
Oh and I wish that the factory would use a rack that would take one universal joint out of the steering shaft. I know that it's designed for LH or RH drive, but if they used two racks with the shaft input aligned with the steering rack on either side, it would take a small amount of 'slop' out of the system. Having raced go-karts pretty seriously in my youth, it needs to feel like that.
Overall a key difference, both good and bad, is that the Ultima is a pure mid-engine sports car with no electronic aids or AWD. For me, and likely many owners, it provides a fabulous feel and an incredibly exciting driving experience. It's as close to kart-racing as possible and for me, that's the purest racing I've ever experienced. But very modern cars not only make good power but make use of electronics for traction, stability, shifting, throttle mapping, braking, energy caching and a myriad of other things. No amount of conventional power is going to make up for these others techniques which is why I'd guess that 'tuning' the car (as noted above and many other subtle techniques) will enable more speed and excitement than just a better power/weight ratio.
That's all.
V
Edited by Verde on Saturday 18th April 03:35
Edited by Verde on Saturday 18th April 04:43
Don't you think the F / R weight balance has something to do with the dynamics of the body shape ???
A car can have a 50/50 distribution, but once it is moving at a high velocity this all changes.
Maybe for slow cornering a 50/50 is great, but who does that ?
I think the design (shape) of the Ultima is a big part of it's success and not so much it's distribution F to B.
Can the factory weigh in or one of our racers.
A car can have a 50/50 distribution, but once it is moving at a high velocity this all changes.
Maybe for slow cornering a 50/50 is great, but who does that ?
I think the design (shape) of the Ultima is a big part of it's success and not so much it's distribution F to B.
Can the factory weigh in or one of our racers.
I believe that these folks make the device I was referencing. I didn't check for fitment for a G50 as I was long ago looking to fit it to my 997S but thought it would be out of place in a pure street car.
http://bit.ly/1zvYC7L
And the disks would save a lot of weight, but they (CC disks) go for at least $10 or so (Porsche approx prices) just for the disks. Perhaps the replacement costs for C6/C7 Corvette Z06/ZR1 C/C disks will be more 'reasonable'. But I suspect there is weight to be found in replacing the wheels that will cost a lot less than new disks.
But for me, all of this pales compared to getting that little bit of slop out of the steering linkage. Hate it.
V
http://bit.ly/1zvYC7L
And the disks would save a lot of weight, but they (CC disks) go for at least $10 or so (Porsche approx prices) just for the disks. Perhaps the replacement costs for C6/C7 Corvette Z06/ZR1 C/C disks will be more 'reasonable'. But I suspect there is weight to be found in replacing the wheels that will cost a lot less than new disks.
But for me, all of this pales compared to getting that little bit of slop out of the steering linkage. Hate it.
V
deadscoob said:
A fast shifting gearbox is the only bit of technology I'd like in a car.
Do you have any links to the mechanisms you mention above?
Carbon disks would work well I reckon, lots of unsprung savings there
Do you have any links to the mechanisms you mention above?
Carbon disks would work well I reckon, lots of unsprung savings there
If you are looking for carbon disks have a look at the corvette Z06 brakes. They are pretty big and can handle a corvette for a good few track days. Some guys are also switching to iron rotors as they provide better overall braking and feel so you might be able to pick up a complete set cheap.
Alternatively didn't someone fit some big brakes off an Audi? The carbon versions might be a cheaper option than the Porsche ones.
I think you would loose more weight by fitting lighter wheels than brakes though.....
Alternatively didn't someone fit some big brakes off an Audi? The carbon versions might be a cheaper option than the Porsche ones.
I think you would loose more weight by fitting lighter wheels than brakes though.....
We discussed SQS shifters a while ago and I got a price of 3750 euros + tax + freight from www.cartronics-motors.com speaking to Thomas Kirchofer. They will only fit certain Porsche gearbox and definitely not the G50's which I have. From what I understand you still need to operate the clutch to change gear but perhaps Paul (V8Yes) can comment on how it operates.
Hi Rodger I'm not the best at explaining stuff on computers but ye you still use the clutch what day you going to stoneleigh your more than welcome to have a climb round car for a look and get photos etc and I will do my best to answer questions . Gear change is really easy just bear in mind you can't short shift gears though . Only had one issue with the unit But modified it now to eliminate this happening again the solinoide piston stuck due to car been stood over winter the piston gets a spray of wd 40 now n no issues anymore
Gassing Station | Ultima | Top of Page | What's New | My Stuff