Koni cup GS porsche dyno power
08-19-2009, 06:33 PM
#122
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Berate me all you want...but I hate to see folks so misinformed on a forum like this so often. And I am by no means alone in this, judging by the reams of PM's and emails I have received on this thread and others where we have done some fact correction on Mark. One day, bad advice dispensed here may get someone hurt on track, and that bothers me a lot. So bite me if you don't like it! 
Professional Racing and Driving Coach
Professional Racing and Driving Coach
Ummm...errr...uhh...I actually wrote that because I was amazed that someone would post a still frame of some embarrassing moments from a Grand-Am Cup broadcast when they know how much ALL OF US look forward to the race weekend and how much ALL OF US want to cut our own throats when things go wrong, leaving us to think about it 100 times per day until the next event. Especially something like a Pro race that inspires extra morning woodrow during the mornings leading up to the event weekend. I'm probably not even one to talk since i've been known to fly off the handle at stuff easily, but Dave...it was inspired in your defense. I don't follow this forum very much and I don't know the history but the photo got to me. I dunno. Maybe the admin can add a 3rd button at the bottom that says "delete prior thread and Tivo backwards before original send time." (insert Tivo popping sound here)
Every now and again I'm reminded of why people tell me I'm not allowed to make any more forum contributions of any kind.
For you though, you can just hit the “sorry for yelling at you John” button.
Roger?
Last edited by BGB Motorsports; 08-19-2009 at 06:35 PM. Reason: incorrect code for quote inclusion
08-19-2009, 07:03 PM
#123
Rennlist Member
Ummm...errr...uhh...I actually wrote that because I was amazed that someone would post a still frame of some embarrassing moments from a Grand-Am Cup broadcast when they know how much ALL OF US look forward to the race weekend and how much ALL OF US want to cut our own throats when things go wrong, leaving us to think about it 100 times per day until the next event. Especially something like a Pro race that inspires extra morning woodrow during the mornings leading up to the event weekend. I'm probably not even one to talk since i've been known to fly off the handle at stuff easily, but Dave...it was inspired in your defense. I don't follow this forum very much and I don't know the history but the photo got to me. I dunno. Maybe the admin can add a 3rd button at the bottom that says "delete prior thread and Tivo backwards before original send time." (insert Tivo popping sound here)
Every now and again I'm reminded of why people tell me I'm not allowed to make any more forum contributions of any kind.
For you though, you can just hit the “sorry for yelling at you John” button.
Roger?
Every now and again I'm reminded of why people tell me I'm not allowed to make any more forum contributions of any kind.
For you though, you can just hit the “sorry for yelling at you John” button.
Roger?
Also, that picture--which i have even used as an avatar--is anything but embarassing for me. Barber 2005, I had a crappy qualifying, but moved up a lot during my stint...so much so that on the restart after a big accident like 45 minutes into the race, I was in 5th. On the restart, Tom Nastasi was behind me & Mike McDowell was to my left into 1, both in Musttangs in GS, me in the 330i in ST. I knew Nastasi would pass me on power, no problem. McDowell missed an upshift & remained to my left up the hill at 3. Nastasi moved right to pass me on the inside at 4....but he screwed up, hit the apex cuurb, and bounced HARD into me....which pushed me HARD into McDowell.
McDowell and I both went into the grass track left, he went almost to the inside wall. It had rained the night before, so there was lots of water in the grass. I caught it & spun, to the right, coming to a stop mid track, broadside to the entire rest of the field at WOT coming up thet blind hill. The Speed TV video is below. I thought for sure I would get T boned 20 times, but everyone missed me.
McDowell was able to keep going. Nastasi rolled to a stop track right in 5 with a broken ball joint. After the field passed, I got going again, on the radiio to the team. The car was clearly messed up--we didn't know how badly. As I braked into 5, though, the brakes immediately locked...and despite coming off the pedal (not quickly enough, I was distracted by my anger), the fronts remained locked & I slid into the sand.
Brakes freed up while being towed backwards out by the emergency crew. Made it to the pits w/o brakes. 3 broken wheels IIRC, plus apparently an ABS system that got all discombobulated by the broken front wheel, causeing immediate front lockup.
Nevertheless, Tim eventually got in, drove a very good race, and we finished--5 laps down--around where we qualified. And, as you can see below, I got 5 uninterrupted minutes of Speed TV coverage! PRICELESS!
So...I love that photo.
VIDEO HERE
Professional Racing and Driving Coach
08-19-2009, 09:34 PM
#124
Race Director
Yep Bob did speak for us all and was point on. Thaks Bob!
08-19-2009, 11:58 PM
#125
Rennlist Member
Thread Starter
read the message. I was referring to frontal area. do you even know the difference vs the older cars? I would be willing to be that the frontal area now is greater. And for dumb dumbs like VR, he doesnt get the fact that if the Cd goes down, as you say it did, and the frontal area goes up, you get the same drag.
Ship of fools, led by capt. VR Dave .
So, we are talking facts here right. RiIGHT VR? So, what is the new Cd? what is the new frontal area? An answer like 'wrong, wrong", is all VR can provide because he has NO facts. Its all mouth and funny pictures.
mk
Ship of fools, led by capt. VR Dave .
So, we are talking facts here right. RiIGHT VR? So, what is the new Cd? what is the new frontal area? An answer like 'wrong, wrong", is all VR can provide because he has NO facts. Its all mouth and funny pictures.
mk
08-20-2009, 12:39 AM
#126
Rennlist Member
Thread Starter
You are going to find any excuse not to meet the challenge.
High Plains Raceway VR. We rent the track and organize a day , or we meet in a lapping day with the 944s already offered by Don.
I just landed to day in Colorado, Could have done it this weekend as planned!
Set it up beach boy!
High Plains Raceway VR. We rent the track and organize a day , or we meet in a lapping day with the 944s already offered by Don.
I just landed to day in Colorado, Could have done it this weekend as planned!
Set it up beach boy!
So would I, Peter. Viking is working with our Make A Wish contact to make this happen. There is no $ to rent a track, so we have to find another way, preferably with the charity beneficiary as the draw. Still not sure if we'll do it in Colorado or at No Problem Raceway in Louisiana, but it is being worked on.
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Professional Racing and Driving Coach
08-20-2009, 01:44 AM
#127
Burning Brakes
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read the message. I was referring to frontal area. do you even know the difference vs the older cars? I would be willing to be that the frontal area now is greater. And for dumb dumbs like VR, he doesnt get the fact that if the Cd goes down, as you say it did, and the frontal area goes up, you get the same drag.
Ship of fools, led by capt. VR Dave .
Ship of fools, led by capt. VR Dave .
That is not necessarily the case at all. You can have the Cd go down, the frontal area go up, and still have less overall drag. It's about the entire package. There's a REASON why people use wind tunnels and CFD to develop aerodynamic packages rather than just rely on grade 12 equations.
Once again, you are looking at things in an overly simplified manner, and failing to grasp the complexities and nuances present in advanced analysis and development.
And yes, I know the difference between the 08's and 09's, as I manage a Grand Am team who just upgraded our '08 bodywork to '09. I can tell you all sorts of things that go along with that upgrade, including the new axles that are 11mm longer due to the increased width, etc., etc. I also do the data acquisition on the car, so am intimately familiar with the actual data.
The '09 frontal area, is, in fact, larger, but it has, in fact, less drag, due to the venting and improved overall aero. It's good for almost 2 seconds on some tracks. Sure, some of that is due to improved suspension geometry due to the wider track, but a lot of it has to do with the improved aero.
Here's our car in '08 trim right after this year's 24 hrs of Daytona:
And here's the car after our recent upgrades to the '09 spec:
08-20-2009, 09:27 AM
#128
Rennlist Member
Thread Starter
Great shots.
Yes, I was oversimplifying a bit, as we are trying to discuss in general terms. (less than 12th grade level )
yes, if you have more frontal area and less drag, the ratio of the two will determine the overall drag at speed and could be more OR less. Of course, when you change wing settings etc, you change the drag settings, without changing thefrontal area that much. I dont know, you dont know, what your Cd is unless you do go to a wind tunnel. you can approximate the frontal area.
In the end, I would also be willing to bet the newer race cars (not street cars) have MUCH more downforce and drag. F1 cars are EXTREMELY dirty aero shapes, but have a ton of power and the downforce they do make, they try and make as effecient as possible. its all relative. ( I think F1 cars have a Cd of over .45). Remember a jet liner can have .08Cd , 3x that of a car, but its drag figures are MUCH higher due to its size.
The point is, i posted some general frontal area x drag numbers for cars we all know. I thought it was interesting for comparisons. more than likely, the cars we are talking about have near the same Cd and frontal area. if they dont, I would also be willing to bet that the larger HP car has a better aero drag /HP ratio, but even that would be slight.
again, this is a great referece to see the trade offs:
http://www.a2wt.com/APPENDIX.htm
Yes, I was oversimplifying a bit, as we are trying to discuss in general terms. (less than 12th grade level
) yes, if you have more frontal area and less drag, the ratio of the two will determine the overall drag at speed and could be more OR less. Of course, when you change wing settings etc, you change the drag settings, without changing thefrontal area that much. I dont know, you dont know, what your Cd is unless you do go to a wind tunnel. you can approximate the frontal area.
In the end, I would also be willing to bet the newer race cars (not street cars) have MUCH more downforce and drag. F1 cars are EXTREMELY dirty aero shapes, but have a ton of power and the downforce they do make, they try and make as effecient as possible. its all relative. ( I think F1 cars have a Cd of over .45). Remember a jet liner can have .08Cd , 3x that of a car, but its drag figures are MUCH higher due to its size.
The point is, i posted some general frontal area x drag numbers for cars we all know. I thought it was interesting for comparisons. more than likely, the cars we are talking about have near the same Cd and frontal area. if they dont, I would also be willing to bet that the larger HP car has a better aero drag /HP ratio, but even that would be slight.
again, this is a great referece to see the trade offs:
http://www.a2wt.com/APPENDIX.htm
Wow.
That is not necessarily the case at all. You can have the Cd go down, the frontal area go up, and still have less overall drag. It's about the entire package. There's a REASON why people use wind tunnels and CFD to develop aerodynamic packages rather than just rely on grade 12 equations.
Once again, you are looking at things in an overly simplified manner, and failing to grasp the complexities and nuances present in advanced analysis and development.
And yes, I know the difference between the 08's and 09's, as I manage a Grand Am team who just upgraded our '08 bodywork to '09. I can tell you all sorts of things that go along with that upgrade, including the new axles that are 11mm longer due to the increased width, etc., etc. I also do the data acquisition on the car, so am intimately familiar with the actual data.
The '09 frontal area, is, in fact, larger, but it has, in fact, less drag, due to the venting and improved overall aero. It's good for almost 2 seconds on some tracks. Sure, some of that is due to improved suspension geometry due to the wider track, but a lot of it has to do with the improved aero.
Here's our car in '08 trim right after this year's 24 hrs of Daytona:
And here's the car after our recent upgrades to the '09 spec:
That is not necessarily the case at all. You can have the Cd go down, the frontal area go up, and still have less overall drag. It's about the entire package. There's a REASON why people use wind tunnels and CFD to develop aerodynamic packages rather than just rely on grade 12 equations.
Once again, you are looking at things in an overly simplified manner, and failing to grasp the complexities and nuances present in advanced analysis and development.
And yes, I know the difference between the 08's and 09's, as I manage a Grand Am team who just upgraded our '08 bodywork to '09. I can tell you all sorts of things that go along with that upgrade, including the new axles that are 11mm longer due to the increased width, etc., etc. I also do the data acquisition on the car, so am intimately familiar with the actual data.
The '09 frontal area, is, in fact, larger, but it has, in fact, less drag, due to the venting and improved overall aero. It's good for almost 2 seconds on some tracks. Sure, some of that is due to improved suspension geometry due to the wider track, but a lot of it has to do with the improved aero.
Here's our car in '08 trim right after this year's 24 hrs of Daytona:
And here's the car after our recent upgrades to the '09 spec:
08-20-2009, 09:43 AM
#129
Rennlist Member
..
Last edited by Veloce Raptor; 11-10-2009 at 12:26 PM.
08-20-2009, 11:26 AM
#130
Race Director
Thanks for the post. It is really hard for a nobody like me to visually see the difference between the 08 and 09 look. I will have to study these harder I guess. Very interesting stuff..thanks!
Wow.
That is not necessarily the case at all. You can have the Cd go down, the frontal area go up, and still have less overall drag. It's about the entire package. There's a REASON why people use wind tunnels and CFD to develop aerodynamic packages rather than just rely on grade 12 equations.
Once again, you are looking at things in an overly simplified manner, and failing to grasp the complexities and nuances present in advanced analysis and development.
And yes, I know the difference between the 08's and 09's, as I manage a Grand Am team who just upgraded our '08 bodywork to '09. I can tell you all sorts of things that go along with that upgrade, including the new axles that are 11mm longer due to the increased width, etc., etc. I also do the data acquisition on the car, so am intimately familiar with the actual data.
The '09 frontal area, is, in fact, larger, but it has, in fact, less drag, due to the venting and improved overall aero. It's good for almost 2 seconds on some tracks. Sure, some of that is due to improved suspension geometry due to the wider track, but a lot of it has to do with the improved aero.
Here's our car in '08 trim right after this year's 24 hrs of Daytona:
And here's the car after our recent upgrades to the '09 spec:
That is not necessarily the case at all. You can have the Cd go down, the frontal area go up, and still have less overall drag. It's about the entire package. There's a REASON why people use wind tunnels and CFD to develop aerodynamic packages rather than just rely on grade 12 equations.
Once again, you are looking at things in an overly simplified manner, and failing to grasp the complexities and nuances present in advanced analysis and development.
And yes, I know the difference between the 08's and 09's, as I manage a Grand Am team who just upgraded our '08 bodywork to '09. I can tell you all sorts of things that go along with that upgrade, including the new axles that are 11mm longer due to the increased width, etc., etc. I also do the data acquisition on the car, so am intimately familiar with the actual data.
The '09 frontal area, is, in fact, larger, but it has, in fact, less drag, due to the venting and improved overall aero. It's good for almost 2 seconds on some tracks. Sure, some of that is due to improved suspension geometry due to the wider track, but a lot of it has to do with the improved aero.
Here's our car in '08 trim right after this year's 24 hrs of Daytona:
And here's the car after our recent upgrades to the '09 spec:
08-20-2009, 11:34 AM
#131
Rennlist Member
So would I, Peter. Viking is working with our Make A Wish contact to make this happen. There is no $ to rent a track, so we have to find another way, preferably with the charity beneficiary as the draw. Still not sure if we'll do it in Colorado or at No Problem Raceway in Louisiana, but it is being worked on.
Professional Racing and Driving Coach
Professional Racing and Driving Coach
Let me know where to mail my $100 for charity. What about talking to the Stephens Bros @ Hallett. Another possibility is FAASST, talk to Judy she is big on charity http://www.faasst.com/ I know when I have lapped with her it has been very low car counts. She also has dates @ Pueblo, & High Plains.
WE WANT VIDEO.
Peter
08-20-2009, 11:36 AM
#132
Rennlist Member
VR,
Let me know where to mail my $100 for charity. What about talking to the Stephens Bros @ Hallett. Another possibility is FAASST, talk to Judy she is big on charity http://www.faasst.com/ I know when I have lapped with her it has been very low car counts. She also has dates @ Pueblo, & High Plains.
WE WANT VIDEO.
Peter
Let me know where to mail my $100 for charity. What about talking to the Stephens Bros @ Hallett. Another possibility is FAASST, talk to Judy she is big on charity http://www.faasst.com/ I know when I have lapped with her it has been very low car counts. She also has dates @ Pueblo, & High Plains.
WE WANT VIDEO.
Peter
Professional Racing and Driving Coach
08-21-2009, 02:07 AM
#133
Rennlist Member
Thread Starter
Ok VR and others looking for some good aero information. Here is a chart from one of my aero books that I just cant find. Its one of the best charts of lift vs drag for an airfoil very close to what we use on race cars, but I cant find the book. Ive looked everywhere, even at my dads house, and I cant find it. So, I appologize for the quality of the picture. However, it makes the point.
If anyone has questions of what the wing will cost as far as drag, HP (or torque), if you find a data point, like downforce lbs, you can then estimate other forces based on the graph. Another thing it does, is shows that near 20 degrees angle off attack, you start to peak in lift( or downforce as we use the wing) and then lift goes down with any more increase angle of attack, BUT drag continues to go higher at an accelerated rate.
One uniqe thing that drag does for us though, is does provide downforce as well, as the wing, which is levered on the rear of the car, adding to the downforce.
So the graph shows lift (Cl), Drag, (Cd) and Lift and drag ratio (L/D). ( as well as center of pressure, Cp)
You can see that at 14 degrees of wing AOA. (angle of attack) you have a near 10:1 lift to drag ratio. You and see how that changes with more or less AOA. One thing to consider is the deflection of air off the roof line. generally , you need to add 7-10 degrees to the AOA, if the wing is not high in clean air.
If anyone has questions of what the wing will cost as far as drag, HP (or torque), if you find a data point, like downforce lbs, you can then estimate other forces based on the graph. Another thing it does, is shows that near 20 degrees angle off attack, you start to peak in lift( or downforce as we use the wing) and then lift goes down with any more increase angle of attack, BUT drag continues to go higher at an accelerated rate.
One uniqe thing that drag does for us though, is does provide downforce as well, as the wing, which is levered on the rear of the car, adding to the downforce.
So the graph shows lift (Cl), Drag, (Cd) and Lift and drag ratio (L/D). ( as well as center of pressure, Cp)
You can see that at 14 degrees of wing AOA. (angle of attack) you have a near 10:1 lift to drag ratio. You and see how that changes with more or less AOA. One thing to consider is the deflection of air off the roof line. generally , you need to add 7-10 degrees to the AOA, if the wing is not high in clean air.
08-21-2009, 02:55 AM
#134
Rennlist Member
Thread Starter
more aero eye candy
Here is something pretty close to a SPEED GT WC vet.
anyone have any cup car specs on width and hight. we could see the frontal area from that. but the Cd is a wild card. I would bet the vet is cleaner aero wise, just on its shape and length proportions.
I found for a porsche cup car, these numbers:
VEHICLE TYPE: rear-engine, rear-wheel-drive, 1-passenger, 2-door coupe
PRICE AS TESTED: $159,000 (base price*: $159,000)
ENGINE TYPE: DOHC 24-valve flat-6, aluminum block and heads, port fuel injection
Displacement: 220 cu in, 3600cc
Power (SAE net): 400 bhp @ 7300 rpm
Torque (SAE net): 295 lb-ft @ 6500 rpm
TRANSMISSION: 6-speed manual
DIMENSIONS:
Wheelbase: 92.5 in Length: 175.6 in
Width: 71.2 in Height: 48.1 in (3425 sq") REF: 3607 sq" for the VET GT2 ALMS)
so, Thats a 5% difference in aero frontal area. BUT, you still have Cd which we dont know, but we can compare the Vet vs the GT3 and see what they end up with, and because the vet is larger and has a larger wing, it can produce downforce with less angle, reducing its drag component. Being a longer body also helps with the drag component.
All in all, anyone would be pretty silly estimating that the total drag would be less with the porsche, without KNOWING any of the facts. Plus, it also goes back to the HP to drag ratio. Assume the differences are ony in frontal area. all the Vet would need would be 5% more HP and it would win the HP to drag war down a long straight. this we all can agree that the vet does win in that catagory. So, Unless the vet only has 420hp vs the porsches 400hp, the vet will be stronger down any straight where aero comes in to play.
How's that for facts VR?
Do you have any facts JGRANT? Based on looks, the vet will probably have a lower coefficient of drag, dont you think?
only 5% greater frontal area, less raised areas, lower wing than a GT3RSR, longer body, etc.
Anyone have drag coefficient numbers for the base cars of a Vet and a new porsche?
anyone have any cup car specs on width and hight. we could see the frontal area from that. but the Cd is a wild card. I would bet the vet is cleaner aero wise, just on its shape and length proportions.
I found for a porsche cup car, these numbers:
VEHICLE TYPE: rear-engine, rear-wheel-drive, 1-passenger, 2-door coupe
PRICE AS TESTED: $159,000 (base price*: $159,000)
ENGINE TYPE: DOHC 24-valve flat-6, aluminum block and heads, port fuel injection
Displacement: 220 cu in, 3600cc
Power (SAE net): 400 bhp @ 7300 rpm
Torque (SAE net): 295 lb-ft @ 6500 rpm
TRANSMISSION: 6-speed manual
DIMENSIONS:
Wheelbase: 92.5 in Length: 175.6 in
Width: 71.2 in Height: 48.1 in (3425 sq") REF: 3607 sq" for the VET GT2 ALMS)
so, Thats a 5% difference in aero frontal area. BUT, you still have Cd which we dont know, but we can compare the Vet vs the GT3 and see what they end up with, and because the vet is larger and has a larger wing, it can produce downforce with less angle, reducing its drag component. Being a longer body also helps with the drag component.
All in all, anyone would be pretty silly estimating that the total drag would be less with the porsche, without KNOWING any of the facts. Plus, it also goes back to the HP to drag ratio. Assume the differences are ony in frontal area. all the Vet would need would be 5% more HP and it would win the HP to drag war down a long straight. this we all can agree that the vet does win in that catagory. So, Unless the vet only has 420hp vs the porsches 400hp, the vet will be stronger down any straight where aero comes in to play.
How's that for facts VR?
Do you have any facts JGRANT? Based on looks, the vet will probably have a lower coefficient of drag, dont you think?
only 5% greater frontal area, less raised areas, lower wing than a GT3RSR, longer body, etc.
Anyone have drag coefficient numbers for the base cars of a Vet and a new porsche?
Last edited by mark kibort; 08-21-2009 at 03:10 AM.
08-21-2009, 03:03 AM
#135
Burning Brakes
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Just be aware that those numbers are generally valid for that specific airfoil profile at specific speeds.
And it has no Gurney flap, which will also dramatically alter those numbers.
And it has no Gurney flap, which will also dramatically alter those numbers.