power-weight class racing??? More power or less weight?
06-03-2010, 05:59 PM
#16
Rennlist Member
This is only true if max torque is above max hp, otherwise it's a staight hp calc.
Where the power is critical, a flat torque curve and short gears help.
As CJ mentioned, the big gains here are through suspension and handling. A newer chassis pays big dividends here. No offense to the air cooled guys (I race one myself) but the 996 chassis really shines here.
Where the power is critical, a flat torque curve and short gears help.
As CJ mentioned, the big gains here are through suspension and handling. A newer chassis pays big dividends here. No offense to the air cooled guys (I race one myself) but the 996 chassis really shines here.
a flat torque curve means a 45 degree angle rise of hp, which not many cars have. a cup car has a flat torque cuve and its a peaky HP curve. its average HP can be improved by close ratios. the flat HP curve cars, generally with equal or more numerical torque, will have falling torque curve where its being used. I think what you said in your prior post is mostly right. Ive spent a great deal of time studying this, and in the end, the lighter cars with the same HP to weight ratios have a distinct advantage in braking and handling. however, if it is a big discrepancy, then on long tracks, HP to drag comes into play, which will help the numerically higher HP values, even at the same HP to weight ratio.
06-03-2010, 06:10 PM
#17
Rennlist Member
a well balanced "big" viper or vet, will be a well handling car and will put up a good fight with any lighter same hp weight ratio car at most any track. just look at WCGT for example. those 3200 lb vipers, 3100lb vets get around Cal speedway very fast. what is a big factor is driver. If the diver cant toss around a big car well, you will have an advantage in a smaller , lighter car. anderson runs 1:41s at cal speedway at 2900lbs and 500rwhp, is that what time you won your race at? anyway, I always use the example of the 3475lb audi RS6 with 500ish-rwhp and it ran 2:14s at Road America. 
I think the fact that some of these cars that are heavier, are usually wider, and for every inch wider, its like the car is performing lower, or lighter as far as G loading capabilities. these vets and vipers with their bigger tires should be able to carry as many Gs as you around any turn with the proper tires and driven to the limit, especially with proper aero. I dont think, by any stretch, you should have had a 15mph difference around the oval, do you ?
anyway, hope to get out there and see you at cal speedway this season or for sure, next!
mk
anyway, I always use the example of the 3475lb audi RS6 with 500ish-rwhp and it ran 2:14s at Road America. I think the fact that some of these cars that are heavier, are usually wider, and for every inch wider, its like the car is performing lower, or lighter as far as G loading capabilities. these vets and vipers with their bigger tires should be able to carry as many Gs as you around any turn with the proper tires and driven to the limit, especially with proper aero. I dont think, by any stretch, you should have had a 15mph difference around the oval, do you ?
anyway, hope to get out there and see you at cal speedway this season or for sure, next!
mk
As others have said - the higher hp, heavier car is going to win in a race. Maybe not in qualifying, but in a race.
Especially at higher speed tracks, HP/Drag dominates acceleration.
I have a lot of experience racing on the lower weight, lower hp side against some heavy, very high hp cars. I raced a 240 hp, 2500 lb car in NASA ST2 and now race a 350 rwhp, 2500 lb car in ST1.
I raced at Cal Speedway in my ST1 car last year, and while I was on pole for the race I got blitzed at the start by the 3200+ lb, 550+ rwhp vipers and vettes. I was able to work my way back by and ended up winning the race, but they had such a huge advantage on the straights. The Oval turn actually helped a lot because I was able to go flat out and carry 155+ mph all the way around this corner (flat out from the straightaway) whereas the vettes/vipers would approach this corner at 170+ and then slow down to 140. On a track with a pure "straight" without the oval corner in the middle I would have been hosed.
Especially at higher speed tracks, HP/Drag dominates acceleration.
I have a lot of experience racing on the lower weight, lower hp side against some heavy, very high hp cars. I raced a 240 hp, 2500 lb car in NASA ST2 and now race a 350 rwhp, 2500 lb car in ST1.
I raced at Cal Speedway in my ST1 car last year, and while I was on pole for the race I got blitzed at the start by the 3200+ lb, 550+ rwhp vipers and vettes. I was able to work my way back by and ended up winning the race, but they had such a huge advantage on the straights. The Oval turn actually helped a lot because I was able to go flat out and carry 155+ mph all the way around this corner (flat out from the straightaway) whereas the vettes/vipers would approach this corner at 170+ and then slow down to 140. On a track with a pure "straight" without the oval corner in the middle I would have been hosed.
06-03-2010, 06:22 PM
#18
a well balanced "big" viper or vet, will be a well handling car and will put up a good fight with any lighter same hp weight ratio car at most any track. just look at WCGT for example. those 3200 lb vipers, 3100lb vets get around Cal speedway very fast. what is a big factor is driver. If the diver cant toss around a big car well, you will have an advantage in a smaller , lighter car. anderson runs 1:41s at cal speedway at 2900lbs and 500rwhp, is that what time you won your race at? anyway, I always use the example of the 3475lb audi RS6 with 500ish-rwhp and it ran 2:14s at Road America.
I think the fact that some of these cars that are heavier, are usually wider, and for every inch wider, its like the car is performing lower, or lighter as far as G loading capabilities. these vets and vipers with their bigger tires should be able to carry as many Gs as you around any turn with the proper tires and driven to the limit, especially with proper aero. I dont think, by any stretch, you should have had a 15mph difference around the oval, do you ?
anyway, hope to get out there and see you at cal speedway this season or for sure, next!
mk
anyway, I always use the example of the 3475lb audi RS6 with 500ish-rwhp and it ran 2:14s at Road America. I think the fact that some of these cars that are heavier, are usually wider, and for every inch wider, its like the car is performing lower, or lighter as far as G loading capabilities. these vets and vipers with their bigger tires should be able to carry as many Gs as you around any turn with the proper tires and driven to the limit, especially with proper aero. I dont think, by any stretch, you should have had a 15mph difference around the oval, do you ?
anyway, hope to get out there and see you at cal speedway this season or for sure, next!
mk
A lot of it was definitely down to driver. I think they should have been able to carry as much speed around the oval as I could. A big heavy car moves around more also, so that maeks it a little scarier. And when you are going 170+ just keeping your foot down and turning is a bit daunting. Even at 155 it is!
My laps were in the 44's. From the data I could have gotten to a :42, but I hadn't been to CS in a couple of years and you always leave some on the table. It is difficult to compare laps there from event to event because the location of the tire barriers in the chicanes and around the last series of left handers onto the banking makes a big difference in the speed you can carry.
06-03-2010, 06:23 PM
#19
Rennlist Member
So Brian,
Here is the deal. power costs cash. Is always better to run at the top of the group with the most hp to weight. it will get you off the corners best, and down the straight faster. If we assume that you want to be at near the top of the class in HP/weight, then its a matter of cash. GTS3-4 is pretty competitive. the holbert 928 (3000lbs, 320rwhp)would have been very competitive in GTS4, but would probably get beat by a guy like Watts in his e36bmw due to a car that was lighter and running slicks. getting a heavier car to run slicks well, might take more trick suspension and more expensive tires. SO, if money was no object, I would probably run a bmw in GTS4. in GTS 5, I would run andersons car. in GTS3, many more choices because the hp weight ratio is low enough that you can make up for a lot of things with handling and set up, which generally are cheaper than the higher hp classes.
After seeing the full range of cars that run at the tracks we run, all I can say, is it all about trade offs.
kip in the NSX , andersons 928, cup cars, comp coupes, e48 m3s, vets, big vipers, old 911s, beefy mustangs like Darrell's, or LS1 powered Rx7s, Evos, Subies, etc etc. They all can run fast, but at what price. and what is the optimal formula for keeping the costs down, while going fast???
If you are trying to validate that the "Estate" is going to be fun in GTS2-3, then I have to say, yes, it probably will. Will it win? probably not. I think the lighter cars in that class will always have an advantage in braking and handling, so best to find the lighters car you can find and max out the HP/weight in your class.
Here is the deal. power costs cash. Is always better to run at the top of the group with the most hp to weight. it will get you off the corners best, and down the straight faster. If we assume that you want to be at near the top of the class in HP/weight, then its a matter of cash. GTS3-4 is pretty competitive. the holbert 928 (3000lbs, 320rwhp)would have been very competitive in GTS4, but would probably get beat by a guy like Watts in his e36bmw due to a car that was lighter and running slicks. getting a heavier car to run slicks well, might take more trick suspension and more expensive tires. SO, if money was no object, I would probably run a bmw in GTS4. in GTS 5, I would run andersons car. in GTS3, many more choices because the hp weight ratio is low enough that you can make up for a lot of things with handling and set up, which generally are cheaper than the higher hp classes.
After seeing the full range of cars that run at the tracks we run, all I can say, is it all about trade offs.
kip in the NSX , andersons 928, cup cars, comp coupes, e48 m3s, vets, big vipers, old 911s, beefy mustangs like Darrell's, or LS1 powered Rx7s, Evos, Subies, etc etc. They all can run fast, but at what price. and what is the optimal formula for keeping the costs down, while going fast???
If you are trying to validate that the "Estate" is going to be fun in GTS2-3, then I have to say, yes, it probably will. Will it win? probably not. I think the lighter cars in that class will always have an advantage in braking and handling, so best to find the lighters car you can find and max out the HP/weight in your class.
06-03-2010, 07:13 PM
#20
Race Director
Thread Starter
MK
When I researched lap times at Thunderhill on the bypass for GTS2 (the class the estate is right now) they tend to run around 2:08-9.....I have run 2:11.07 over the top....using the standard 2-3 second bypass that puts the estate right around top times for GTS2..& thats with the automatic and open diff + 245 tires all around!!!!!!!!!!!!!!!!!!!!!! Did I mention no aero either? It has ran as fast as 2:09.5 over the top....which could be 2:07 on the bypass which near lap record for GTS2
Basically in GTS2 is Spec E30's and stronger spec 944's and some E36 cars.....so with a few mods ( 5speed conversion is the biggest) a bit of aero the Estate should be competitive with the top local GTS2 cars......
whats nice about the car is there is an easy 100lbs I could take out & only $$$ limited HP from the engine... Right now the car is 2800 dry....with the 5 speed (-50lbs) I could get it to just under 2700...pretty easy.....but I would have to turn down the engine to stay in class....
When I researched lap times at Thunderhill on the bypass for GTS2 (the class the estate is right now) they tend to run around 2:08-9.....I have run 2:11.07 over the top....using the standard 2-3 second bypass that puts the estate right around top times for GTS2..& thats with the automatic and open diff + 245 tires all around!!!!!!!!!!!!!!!!!!!!!! Did I mention no aero either? It has ran as fast as 2:09.5 over the top....which could be 2:07 on the bypass which near lap record for GTS2
Basically in GTS2 is Spec E30's and stronger spec 944's and some E36 cars.....so with a few mods ( 5speed conversion is the biggest) a bit of aero the Estate should be competitive with the top local GTS2 cars......
whats nice about the car is there is an easy 100lbs I could take out & only $$$ limited HP from the engine... Right now the car is 2800 dry....with the 5 speed (-50lbs) I could get it to just under 2700...pretty easy.....but I would have to turn down the engine to stay in class....
06-03-2010, 07:39 PM
#21
Drifting
Power wins in a race because allows you to control the pace (rely less on momentum). Lived it last weekend at the Glen... Stuck behind more powerful and heavier cars... Couldn't get around.
06-03-2010, 07:47 PM
#22
Rennlist Member
06-03-2010, 08:48 PM
#23
Burning Brakes
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I agree. If I can get around in the right place then I can stay there but if I have a power disadvantage I find I loose any position as soon as a long straight comes up. Still fun though. Now my home short track, Power seems to NOT be an issue. Just not long enough striaghts to make up the differance in braking and turning advantages. I love racing there.
06-03-2010, 09:04 PM
#24
Drifting
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You did? GTS was started here on the East Coast by a guy I know personally. I'm not saying you didn't. I'd just be interested in finding out how you had a part in setting a rule for a series that you didn't run in on the East coast.
06-03-2010, 09:13 PM
#25
Drifting
here we go..... Mark seems to ask for that sort of stuff!!!!!
06-03-2010, 09:58 PM
#26
Rennlist Member
wow, 44? that is pretty quick. I think anderson is in that range with his cup car and slightly faster with the 928, which has got up to 170+ down the straights! 
your car might be like those other POC, PRC 911s that run near as fast , with a lot less hp, but in the 2000lb range. there is a lot to be said for a lighter car.
(Masuda, and Boss's 911s, which are GT2 and 3 If I remember correctly)
your car might be like those other POC, PRC 911s that run near as fast , with a lot less hp, but in the 2000lb range. there is a lot to be said for a lighter car.
(Masuda, and Boss's 911s, which are GT2 and 3 If I remember correctly)
A lot of it was definitely down to driver. I think they should have been able to carry as much speed around the oval as I could. A big heavy car moves around more also, so that maeks it a little scarier. And when you are going 170+ just keeping your foot down and turning is a bit daunting. Even at 155 it is!
My laps were in the 44's. From the data I could have gotten to a :42, but I hadn't been to CS in a couple of years and you always leave some on the table. It is difficult to compare laps there from event to event because the location of the tire barriers in the chicanes and around the last series of left handers onto the banking makes a big difference in the speed you can carry.
My laps were in the 44's. From the data I could have gotten to a :42, but I hadn't been to CS in a couple of years and you always leave some on the table. It is difficult to compare laps there from event to event because the location of the tire barriers in the chicanes and around the last series of left handers onto the banking makes a big difference in the speed you can carry.
06-03-2010, 10:03 PM
#27
Rennlist Member
Yes, I did. we had some lengthy discussions about the rules, as I was very excited as to the potential of having a HP to weight based series for our cars.
It didnt reach out west for a few years after that, but I was in close contact with the rule makers and basically helped nix the averaging of the hp with torque for cars with less torque than HP for obvious reasons. (nothing more nothing less) Ask him.
It didnt reach out west for a few years after that, but I was in close contact with the rule makers and basically helped nix the averaging of the hp with torque for cars with less torque than HP for obvious reasons.
(nothing more nothing less) Ask him.
06-03-2010, 10:04 PM
#28
Rennlist Member
I think here, we are talking about same HP /weight ratios, which wouldnt give that kind of advantage. more powerful, but less hp/weight, and you would be running around them at the glen!
06-03-2010, 10:07 PM
#29
Rennlist Member
you may have found the formula! sounds like GTS2 will be an absolute GAS for you ! based on the times, you will be right in there. I have a very hard time beliving, that you can get that car under 2:08, I think the times you saw were due to brand new race rubber!! 
However, I would Love to be proved wrong!
If you run, Ill make an effort to go out there with you for a GTS race!
mk
However, I would Love to be proved wrong! If you run, Ill make an effort to go out there with you for a GTS race!
mk
MK
When I researched lap times at Thunderhill on the bypass for GTS2 (the class the estate is right now) they tend to run around 2:08-9.....I have run 2:11.07 over the top....using the standard 2-3 second bypass that puts the estate right around top times for GTS2..& thats with the automatic and open diff + 245 tires all around!!!!!!!!!!!!!!!!!!!!!! Did I mention no aero either? It has ran as fast as 2:09.5 over the top....which could be 2:07 on the bypass which near lap record for GTS2
Basically in GTS2 is Spec E30's and stronger spec 944's and some E36 cars.....so with a few mods ( 5speed conversion is the biggest) a bit of aero the Estate should be competitive with the top local GTS2 cars......
whats nice about the car is there is an easy 100lbs I could take out & only $$$ limited HP from the engine... Right now the car is 2800 dry....with the 5 speed (-50lbs) I could get it to just under 2700...pretty easy.....but I would have to turn down the engine to stay in class....
When I researched lap times at Thunderhill on the bypass for GTS2 (the class the estate is right now) they tend to run around 2:08-9.....I have run 2:11.07 over the top....using the standard 2-3 second bypass that puts the estate right around top times for GTS2..& thats with the automatic and open diff + 245 tires all around!!!!!!!!!!!!!!!!!!!!!! Did I mention no aero either? It has ran as fast as 2:09.5 over the top....which could be 2:07 on the bypass which near lap record for GTS2
Basically in GTS2 is Spec E30's and stronger spec 944's and some E36 cars.....so with a few mods ( 5speed conversion is the biggest) a bit of aero the Estate should be competitive with the top local GTS2 cars......
whats nice about the car is there is an easy 100lbs I could take out & only $$$ limited HP from the engine... Right now the car is 2800 dry....with the 5 speed (-50lbs) I could get it to just under 2700...pretty easy.....but I would have to turn down the engine to stay in class....
06-04-2010, 01:58 AM
#30
wow, 44? that is pretty quick. I think anderson is in that range with his cup car and slightly faster with the 928, which has got up to 170+ down the straights!
your car might be like those other POC, PRC 911s that run near as fast , with a lot less hp, but in the 2000lb range. there is a lot to be said for a lighter car.
(Masuda, and Boss's 911s, which are GT2 and 3 If I remember correctly)
your car might be like those other POC, PRC 911s that run near as fast , with a lot less hp, but in the 2000lb range. there is a lot to be said for a lighter car.
(Masuda, and Boss's 911s, which are GT2 and 3 If I remember correctly)
http://www.vimeo.com/user1583540/videos
Let's put all this heavy/big hp vs light/low hp in math terms.
F=ma
(T=thrust, D=drag, m=mass, a=acceleration)
T-D=ma
T/m-D/m=a
If we hold T/m (power to weight) constant then the heavier vehicle has a larger acceleration.
Corners and braking are another story and a light car definitely has an advantage there.