951 Spec to be Competitive with 997 GT3 RS
06-14-2010, 09:50 PM
#32
Drifting
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the main advantage of the 951 is its the spare shell you have sitting in the yard ..
so Pat last time you where asked what do you think would make your car 3 seconds quicker per lap it wasn't hp .. i thought it was brakes ....
i think a valid question here is when we have seen a gt3 and 951 race and its close where are we seeing the gt3 get the upper hand ..
i was under the impression you can match them on the strait and mid corner speed over the apex .. but they are more stable under brakes and putting power down with a bit of sterring on..
so Pat last time you where asked what do you think would make your car 3 seconds quicker per lap it wasn't hp .. i thought it was brakes ....
i think a valid question here is when we have seen a gt3 and 951 race and its close where are we seeing the gt3 get the upper hand ..
i was under the impression you can match them on the strait and mid corner speed over the apex .. but they are more stable under brakes and putting power down with a bit of sterring on..
06-14-2010, 09:57 PM
#33
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06-14-2010, 10:29 PM
#34
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http://www.youtube.com/watch?v=vExPd7IlCbc this is a good one 2
06-14-2010, 11:59 PM
#35
Rennlist Member
the main advantage of the 951 is its the spare shell you have sitting in the yard ..
so Pat last time you where asked what do you think would make your car 3 seconds quicker per lap it wasn't hp .. i thought it was brakes ....
i think a valid question here is when we have seen a gt3 and 951 race and its close where are we seeing the gt3 get the upper hand ..
i was under the impression you can match them on the strait and mid corner speed over the apex .. but they are more stable under brakes and putting power down with a bit of sterring on..
so Pat last time you where asked what do you think would make your car 3 seconds quicker per lap it wasn't hp .. i thought it was brakes ....
i think a valid question here is when we have seen a gt3 and 951 race and its close where are we seeing the gt3 get the upper hand ..
i was under the impression you can match them on the strait and mid corner speed over the apex .. but they are more stable under brakes and putting power down with a bit of sterring on..
As has been outlined in another thread, there are superior current suspension systems which unless you want to pour a big bunch of $ into, we can't compete with modern tech. Very evident under braking as can be seen in my clip. He is just a lot more settled even taking the fact that he's not pushing 10/10ths.
06-15-2010, 03:31 AM
#36
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always nice and interesting discussions.
I have raced a couple of seasons trying to compete with GT3 RS's, changed everything in the suspension department, (custom A-arms, Kokeln rear axis, Double adjustable shocks, Big red brakes, lowered, widened, 285 tires), lightened the car to 1060 kg, and with my 340 HP engine I could about match the 996 GT3 RS up to the 2004 version. To beat those, I calculated i needed 380+, and to have that as a reliable race engine costs over 20k . And that would be a recurring cost....
In my experience so far the major laws of speed are:
1. In cars that stay close to road-going cars, lap times = $$$ You just have to spend a certain amount of money to get to a certain lap time. And with $$$ I mean overall running cost.
2. Fast 996/997 are driven harder. They have sequential gear boxes, and/or power shift and/or multiple gear bos revisions and/or multiple engine revisions per year. All unaffordable to the amateur racer.
3. To beat law 1 you have to cheat: The car must loose the road car limitations: Two main area's: Body stiffness and weight. Both lead in the extreme to a car that basically looks like a 951, but in reality a a tubular frame with GF /Carbon body panels. I took some steps in that direction, and I could keep up because my power to weight ratio was advantageous (= cheat!). I could brake where they braked, and run a higher corner speed.
4. The one area that I still lost was in traction out of low speed corners. That really is a rear suspension issue. (cf the other thread on suspension). I considered moving to a 996 rear suspension, but yeah.. where does it end.
If I would do the project again, which I won't , I would definitely go with a stiffer/lighter frame as close to a tubular frame as I could afford. It would cost like 15-20k but in the end is the cheapest way to cheat / be competitive.
I have raced a couple of seasons trying to compete with GT3 RS's, changed everything in the suspension department, (custom A-arms, Kokeln rear axis, Double adjustable shocks, Big red brakes, lowered, widened, 285 tires), lightened the car to 1060 kg, and with my 340 HP engine I could about match the 996 GT3 RS up to the 2004 version. To beat those, I calculated i needed 380+, and to have that as a reliable race engine costs over 20k . And that would be a recurring cost....
In my experience so far the major laws of speed are:
1. In cars that stay close to road-going cars, lap times = $$$ You just have to spend a certain amount of money to get to a certain lap time. And with $$$ I mean overall running cost.
2. Fast 996/997 are driven harder. They have sequential gear boxes, and/or power shift and/or multiple gear bos revisions and/or multiple engine revisions per year. All unaffordable to the amateur racer.
3. To beat law 1 you have to cheat: The car must loose the road car limitations: Two main area's: Body stiffness and weight. Both lead in the extreme to a car that basically looks like a 951, but in reality a a tubular frame with GF /Carbon body panels. I took some steps in that direction, and I could keep up because my power to weight ratio was advantageous (= cheat!). I could brake where they braked, and run a higher corner speed.
4. The one area that I still lost was in traction out of low speed corners. That really is a rear suspension issue. (cf the other thread on suspension). I considered moving to a 996 rear suspension, but yeah.. where does it end.
If I would do the project again, which I won't , I would definitely go with a stiffer/lighter frame as close to a tubular frame as I could afford. It would cost like 15-20k but in the end is the cheapest way to cheat / be competitive.
06-15-2010, 03:39 AM
#37
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Patrick sad fact is buddy we both "had" the money for a GT3 but neither of us "have" the money ....if i get there one day I promise you a steer mate..
Hans as i said i believe my rear sub-frame to be better than the KOKLEN I'll show you if you like and you can make one ..
Hans as i said i believe my rear sub-frame to be better than the KOKLEN I'll show you if you like and you can make one ..
06-15-2010, 06:15 AM
#38
Nordschleife Master
always nice and interesting discussions.
I have raced a couple of seasons trying to compete with GT3 RS's, changed everything in the suspension department, (custom A-arms, Kokeln rear axis, Double adjustable shocks, Big red brakes, lowered, widened, 285 tires), lightened the car to 1060 kg, and with my 340 HP engine I could about match the 996 GT3 RS up to the 2004 version. To beat those, I calculated i needed 380+, and to have that as a reliable race engine costs over 20k . And that would be a recurring cost....
In my experience so far the major laws of speed are:
1. In cars that stay close to road-going cars, lap times = $$$ You just have to spend a certain amount of money to get to a certain lap time. And with $$$ I mean overall running cost.
2. Fast 996/997 are driven harder. They have sequential gear boxes, and/or power shift and/or multiple gear bos revisions and/or multiple engine revisions per year. All unaffordable to the amateur racer.
3. To beat law 1 you have to cheat: The car must loose the road car limitations: Two main area's: Body stiffness and weight. Both lead in the extreme to a car that basically looks like a 951, but in reality a a tubular frame with GF /Carbon body panels. I took some steps in that direction, and I could keep up because my power to weight ratio was advantageous (= cheat!). I could brake where they braked, and run a higher corner speed.
4. The one area that I still lost was in traction out of low speed corners. That really is a rear suspension issue. (cf the other thread on suspension). I considered moving to a 996 rear suspension, but yeah.. where does it end.
If I would do the project again, which I won't , I would definitely go with a stiffer/lighter frame as close to a tubular frame as I could afford. It would cost like 15-20k but in the end is the cheapest way to cheat / be competitive.
I have raced a couple of seasons trying to compete with GT3 RS's, changed everything in the suspension department, (custom A-arms, Kokeln rear axis, Double adjustable shocks, Big red brakes, lowered, widened, 285 tires), lightened the car to 1060 kg, and with my 340 HP engine I could about match the 996 GT3 RS up to the 2004 version. To beat those, I calculated i needed 380+, and to have that as a reliable race engine costs over 20k . And that would be a recurring cost....
In my experience so far the major laws of speed are:
1. In cars that stay close to road-going cars, lap times = $$$ You just have to spend a certain amount of money to get to a certain lap time. And with $$$ I mean overall running cost.
2. Fast 996/997 are driven harder. They have sequential gear boxes, and/or power shift and/or multiple gear bos revisions and/or multiple engine revisions per year. All unaffordable to the amateur racer.
3. To beat law 1 you have to cheat: The car must loose the road car limitations: Two main area's: Body stiffness and weight. Both lead in the extreme to a car that basically looks like a 951, but in reality a a tubular frame with GF /Carbon body panels. I took some steps in that direction, and I could keep up because my power to weight ratio was advantageous (= cheat!). I could brake where they braked, and run a higher corner speed.
4. The one area that I still lost was in traction out of low speed corners. That really is a rear suspension issue. (cf the other thread on suspension). I considered moving to a 996 rear suspension, but yeah.. where does it end.
If I would do the project again, which I won't , I would definitely go with a stiffer/lighter frame as close to a tubular frame as I could afford. It would cost like 15-20k but in the end is the cheapest way to cheat / be competitive.
Also, no way you should keep a 944 motor the LSX platform is better in every single way.
06-15-2010, 06:50 AM
#39
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just a little reminder a wider tire does not provide any more contact patch surface area.. the surface area of the patch is a function of tire pressure and car load only ... tire width only effects the shape of the contact patch and the thermal mass of the tire ....
06-15-2010, 07:29 AM
#40
Nordschleife Master
http://performancesimulations.com/fa...on-tires-1.htm
06-15-2010, 07:34 AM
#41
Drifting
Okay - so there are a lot of projects going on out there, all with different objectives. If I set as my objective the creation of 951 which could be competitive for performance with a 997 GT3 RS both on road & track (with the emphasis on track) what specification would be required, bearing in mind I'd be looking for the most cost-effective options. The car must retain a full interior, not be caged & retain its original bodywork. Tim
.
06-15-2010, 09:11 AM
#42
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So many things to react to…!
First, the 50/50 comment (already mentioned but now with more detail) – why is 50/50 better? The answer is that it is only better during the very brief period that the car is cornering without braking or accelerating. In most other situation the 911 has us beat.
Acceleration – you want the most weight over the driving wheels for traction.
Braking – you are shifting weight towards the front wheels under braking – so if you have a rear bias when static you can come closer to getting an even weight distribution under heavy braking. 911s can kick our *** under braking
In reality what the poster originally requested is not possible, unless you will accept a barely disguised race car for a street vehicle.
My ‘educated’ guess is that if you can match the power to weight of the 911 you will have to be 400lbs lighter to make up for the handling advantages of the 911. If you think you can ‘whip up’ a suspension that will match the GT3 you can give it a try. Porsche invested many, many millions in R&D on the GT3…whats your budget?
First, the 50/50 comment (already mentioned but now with more detail) – why is 50/50 better? The answer is that it is only better during the very brief period that the car is cornering without braking or accelerating. In most other situation the 911 has us beat.
Acceleration – you want the most weight over the driving wheels for traction.
Braking – you are shifting weight towards the front wheels under braking – so if you have a rear bias when static you can come closer to getting an even weight distribution under heavy braking. 911s can kick our *** under braking
In reality what the poster originally requested is not possible, unless you will accept a barely disguised race car for a street vehicle.
My ‘educated’ guess is that if you can match the power to weight of the 911 you will have to be 400lbs lighter to make up for the handling advantages of the 911. If you think you can ‘whip up’ a suspension that will match the GT3 you can give it a try. Porsche invested many, many millions in R&D on the GT3…whats your budget?
06-15-2010, 09:34 AM
#43
Rennlist Member
1 Kabillion Rizzos! I shall not accept failure. You're either with me or 'agin me.
Hey it's fun theorizing at the very least.
As far as Fishey descending from the mount to take free aim at all and sundry, well don't mind him, that's his gig. People like Hans, Chris, Van and others have way more experience than most of us so scorn them at your own peril Mr Fishman.
Hey it's fun theorizing at the very least.
As far as Fishey descending from the mount to take free aim at all and sundry, well don't mind him, that's his gig. People like Hans, Chris, Van and others have way more experience than most of us so scorn them at your own peril Mr Fishman.
06-16-2010, 10:13 AM
#44
Nordschleife Master
So many things to react to…!
First, the 50/50 comment (already mentioned but now with more detail) – why is 50/50 better? The answer is that it is only better during the very brief period that the car is cornering without braking or accelerating. In most other situation the 911 has us beat.
Acceleration – you want the most weight over the driving wheels for traction.
Braking – you are shifting weight towards the front wheels under braking – so if you have a rear bias when static you can come closer to getting an even weight distribution under heavy braking. 911s can kick our *** under braking
In reality what the poster originally requested is not possible, unless you will accept a barely disguised race car for a street vehicle.
My ‘educated’ guess is that if you can match the power to weight of the 911 you will have to be 400lbs lighter to make up for the handling advantages of the 911. If you think you can ‘whip up’ a suspension that will match the GT3 you can give it a try. Porsche invested many, many millions in R&D on the GT3…whats your budget?
First, the 50/50 comment (already mentioned but now with more detail) – why is 50/50 better? The answer is that it is only better during the very brief period that the car is cornering without braking or accelerating. In most other situation the 911 has us beat.
Acceleration – you want the most weight over the driving wheels for traction.
Braking – you are shifting weight towards the front wheels under braking – so if you have a rear bias when static you can come closer to getting an even weight distribution under heavy braking. 911s can kick our *** under braking
In reality what the poster originally requested is not possible, unless you will accept a barely disguised race car for a street vehicle.
My ‘educated’ guess is that if you can match the power to weight of the 911 you will have to be 400lbs lighter to make up for the handling advantages of the 911. If you think you can ‘whip up’ a suspension that will match the GT3 you can give it a try. Porsche invested many, many millions in R&D on the GT3…whats your budget?
A few reasons I disagree is that the GT3 RS is a production car it has its limitations put in place.
Anyways, as far as setting up a 944 to compete I would do it something like this very generic
LS3 Head/Cam/Intake/Drysump
Multi Disk Clutch
Aluminum Torque Tube
951 Turbo Gearbox + larger cooler
Gearbox Mount Modified + Braced
Aluminum Shift Rod (Long black thing)
Shifter Linkage Change (Throw modification)
Large brake setup with 13-14" rotors front and rear. 2pc floating rotor setup
kokeln style Rear suspension setup
Fabricated front control arms + extended 19mm spindles
Aftermarket front hubs
kokeln swaybar or other adjustable sway setup.
Penske/Moton/Ohlin Coilover shocks front and rear
Seemwelded and braced Chassis
Aftermarket lighter sound proofing + thinner carpet
Aero changes (lights/Wing/Splitter)
Wheels/Tires
1. Lets just look at the specs of a 911 GT3 RS
SAE Net Horsepower @ RPM 450 @ 7900
SAE Net Torque 317 lb.-ft.
Front Tire 245/35 ZR19
Rear Tire Size 325/30 ZR19
Base Curb Weight 3020 lbs
Height, Overall 50.4 in
Track Width, Front 60.2 in
Track Width, Rear 61.4 in
Drag .33
2. Now lets look at a logical setup on a 944 chassis
LS3 Head/Cam/Intake
SAE Net Horsepower @ RPM 575 @ 6500
SAE Net Torque 522lb.-ft
Front Tire Size (without width added) 275/35/ZR18
Rear Tire Size (without width added) 295/30/ZR18
Base Curb Weight 2625lbs(Tony G) 2998(S2) I am guessing realistic 2800lbs for our Street/Race 944.
Height, Overall 50.20 in Stock / 48.20 in Lowered
Track Width, Front 58.20in +2 in for increased tire/rim width 60.20in
Track Width, Rear 57.10in + 2 in for increased tire/rim width 59.10in
Drag .33 (Added Tire Width and modifications to keep similar downforce as a 911 GT3 RS) .38-.40
So looking at the physical between a GT3RS and a properly setup 944 we know off the start 125hp advantage 944 and 320lbs advantage. The 944 is giving up advantages to the 911 GT3 RS in a few places. The very first and most obvious area is Aero Dynamics. The GT3 has years of racing development passed down from the GT3 Cup and GT3 RSR that allow it to achive better downforce with less drag. The second advantage for the 911 would be rear suspension. The front suspensions between the two cars are very similar in design but the rear are very different. Obviously the 944 rear shock setup is going to be modified significantly most likely with a Kokeln type setup. This suspension however does not allow for any kinematic toe or camber compression change.
I think it would be very hard for the GT3 RS to overcome the weight/power disadvantage. Also, its suspension disadvantage is reduced by having a production style shock vs a full racing coilover.
Thats just my $.02
06-16-2010, 10:25 AM
#45
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Better idea - lets get a current F1 car and stick a Porsche crest on it and paint 944 on the side....
“PAF”
Pointless Argument Fail….
“PAF”
Pointless Argument Fail….
I disagree 100%
A few reasons I disagree is that the GT3 RS is a production car it has its limitations put in place.
Anyways, as far as setting up a 944 to compete I would do it something like this very generic
LS3 Head/Cam/Intake/Drysump
Multi Disk Clutch
Aluminum Torque Tube
951 Turbo Gearbox + larger cooler
Gearbox Mount Modified + Braced
Aluminum Shift Rod (Long black thing)
Shifter Linkage Change (Throw modification)
Large brake setup with 13-14" rotors front and rear. 2pc floating rotor setup
kokeln style Rear suspension setup
Fabricated front control arms + extended 19mm spindles
Aftermarket front hubs
kokeln swaybar or other adjustable sway setup.
Penske/Moton/Ohlin Coilover shocks front and rear
Seemwelded and braced Chassis
Aftermarket lighter sound proofing + thinner carpet
Aero changes (lights/Wing/Splitter)
Wheels/Tires
1. Lets just look at the specs of a 911 GT3 RS
SAE Net Horsepower @ RPM 450 @ 7900
SAE Net Torque 317 lb.-ft.
Front Tire 245/35 ZR19
Rear Tire Size 325/30 ZR19
Base Curb Weight 3020 lbs
Height, Overall 50.4 in
Track Width, Front 60.2 in
Track Width, Rear 61.4 in
Drag .33
2. Now lets look at a logical setup on a 944 chassis
LS3 Head/Cam/Intake
SAE Net Horsepower @ RPM 575 @ 6500
SAE Net Torque 522lb.-ft
Front Tire Size (without width added) 275/35/ZR18
Rear Tire Size (without width added) 295/30/ZR18
Base Curb Weight 2625lbs(Tony G) 2998(S2) I am guessing realistic 2800lbs for our Street/Race 944.
Height, Overall 50.20 in Stock / 48.20 in Lowered
Track Width, Front 58.20in +2 in for increased tire/rim width 60.20in
Track Width, Rear 57.10in + 2 in for increased tire/rim width 59.10in
Drag .33 (Added Tire Width and modifications to keep similar downforce as a 911 GT3 RS) .38-.40
So looking at the physical between a GT3RS and a properly setup 944 we know off the start 125hp advantage 944 and 320lbs advantage. The 944 is giving up advantages to the 911 GT3 RS in a few places. The very first and most obvious area is Aero Dynamics. The GT3 has years of racing development passed down from the GT3 Cup and GT3 RSR that allow it to achive better downforce with less drag. The second advantage for the 911 would be rear suspension. The front suspensions between the two cars are very similar in design but the rear are very different. Obviously the 944 rear shock setup is going to be modified significantly most likely with a Kokeln type setup. This suspension however does not allow for any kinematic toe or camber compression change.
I think it would be very hard for the GT3 RS to overcome the weight/power disadvantage. Also, its suspension disadvantage is reduced by having a production style shock vs a full racing coilover.
Thats just my $.02
A few reasons I disagree is that the GT3 RS is a production car it has its limitations put in place.
Anyways, as far as setting up a 944 to compete I would do it something like this very generic
LS3 Head/Cam/Intake/Drysump
Multi Disk Clutch
Aluminum Torque Tube
951 Turbo Gearbox + larger cooler
Gearbox Mount Modified + Braced
Aluminum Shift Rod (Long black thing)
Shifter Linkage Change (Throw modification)
Large brake setup with 13-14" rotors front and rear. 2pc floating rotor setup
kokeln style Rear suspension setup
Fabricated front control arms + extended 19mm spindles
Aftermarket front hubs
kokeln swaybar or other adjustable sway setup.
Penske/Moton/Ohlin Coilover shocks front and rear
Seemwelded and braced Chassis
Aftermarket lighter sound proofing + thinner carpet
Aero changes (lights/Wing/Splitter)
Wheels/Tires
1. Lets just look at the specs of a 911 GT3 RS
SAE Net Horsepower @ RPM 450 @ 7900
SAE Net Torque 317 lb.-ft.
Front Tire 245/35 ZR19
Rear Tire Size 325/30 ZR19
Base Curb Weight 3020 lbs
Height, Overall 50.4 in
Track Width, Front 60.2 in
Track Width, Rear 61.4 in
Drag .33
2. Now lets look at a logical setup on a 944 chassis
LS3 Head/Cam/Intake
SAE Net Horsepower @ RPM 575 @ 6500
SAE Net Torque 522lb.-ft
Front Tire Size (without width added) 275/35/ZR18
Rear Tire Size (without width added) 295/30/ZR18
Base Curb Weight 2625lbs(Tony G) 2998(S2) I am guessing realistic 2800lbs for our Street/Race 944.
Height, Overall 50.20 in Stock / 48.20 in Lowered
Track Width, Front 58.20in +2 in for increased tire/rim width 60.20in
Track Width, Rear 57.10in + 2 in for increased tire/rim width 59.10in
Drag .33 (Added Tire Width and modifications to keep similar downforce as a 911 GT3 RS) .38-.40
So looking at the physical between a GT3RS and a properly setup 944 we know off the start 125hp advantage 944 and 320lbs advantage. The 944 is giving up advantages to the 911 GT3 RS in a few places. The very first and most obvious area is Aero Dynamics. The GT3 has years of racing development passed down from the GT3 Cup and GT3 RSR that allow it to achive better downforce with less drag. The second advantage for the 911 would be rear suspension. The front suspensions between the two cars are very similar in design but the rear are very different. Obviously the 944 rear shock setup is going to be modified significantly most likely with a Kokeln type setup. This suspension however does not allow for any kinematic toe or camber compression change.
I think it would be very hard for the GT3 RS to overcome the weight/power disadvantage. Also, its suspension disadvantage is reduced by having a production style shock vs a full racing coilover.
Thats just my $.02