Modified Magazine Cover Story: FD Testing Event Virginia International Raceway
09-23-13, 07:18 AM
#451
All out Track Freak!
iTrader: (263)
Join Date: Jul 2001
Location: Charlottesville VA 22901
Posts: 10,672
Received 412 Likes
on
250 Posts
Engine torque loads on the chassis are nothing compared to road loads. A sharp impact at one front tire can put well over 2000 lb-ft into the chassis. Also figure that the chassis engine/trans/diff mounting arrangement has been designed (to some degree) to deal with driveline shocks from highish-rpm clutch-drops or poor shifting/declutching loading which will give a brief instantaneous torque load greater than the smooth application of 450 lb-ft from the engine. IMO, most semi-modern car chassis' ability to "handle" significant increases in power is often underestimated, at least for road course applications (as opposed to 1/4-mile with massive 1st gear launches on super-sticky traction-compounded launch pad).
The only limitation I've found with my 20b turbo FD is the tranny which kept blowing 3rd gear (4 tranny's this season). I've had no nothing else break or grow wrong on the car all season (8-9 track days). I think I fixed it this weekend though cause I was running the car at full power all day and it didn't break where before it would only last 3-4 laps. Liberty built stock gearbox ftw.
thewird
thewird
What specifically did liberty do to the trans to correct the problem?
On my car the shaft bends the case flexes the bearing are worn or it's a combination of all 3 and the gears separate and all hell breaks loose but it's always on the top side of the 3rd gear and BOOM!
09-23-13, 09:03 AM
#452
The whole purpose of this testing originally was to compare the power delivery characteristics of turbo powered cars versus naturally aspirated as it effects track times. I believe that the tremendous increase in power over a very short time and rpm range for turbo powered cars makes it harder to use the power coming out of corners in particular. This should effect track times.
There is also the issue, of course, of the chassis and drivetrain being able to handle the power. thewird seems to have no issues, now, but has blown trannies before. As Fritz and others have noted, the chassis and drivetrain were not designed to handle that kind of power and things will twist and break under the intense stress of that kind of high power. That, however, is not the issue we are trying to address here. Just the power and power delivery's effect on track times.
Gordon
There is also the issue, of course, of the chassis and drivetrain being able to handle the power. thewird seems to have no issues, now, but has blown trannies before. As Fritz and others have noted, the chassis and drivetrain were not designed to handle that kind of power and things will twist and break under the intense stress of that kind of high power. That, however, is not the issue we are trying to address here. Just the power and power delivery's effect on track times.
Gordon
My car has gone from this...
to this...
and currently at this...
Yep 3rd gear is a problem for sure even on my car making max torque of around 350.
What specifically did liberty do to the trans to correct the problem?
On my car the shaft bends the case flexes the bearing are worn or it's a combination of all 3 and the gears separate and all hell breaks loose but it's always on the top side of the 3rd gear and BOOM!
What specifically did liberty do to the trans to correct the problem?
On my car the shaft bends the case flexes the bearing are worn or it's a combination of all 3 and the gears separate and all hell breaks loose but it's always on the top side of the 3rd gear and BOOM!
thewird
09-23-13, 10:16 AM
#453
Insanity is the correct word 
each month there's a new 3 rotor build thread started and 2 or 3 1/2 built 3 rotors in the for sale section.
Just flipped through the MAG and Phils car is SWEEET! Can't wait to read that article.
PS I'm on my way to Richmond to pick up a parts car (stay tuned for some crazy cool parts) stop by sheetz to pick up the mag and while waiting in line the guy in front of me sees me holding the magazine and says "I didn't know that modified was still going" and I'm like "yep and take a look there's an article with my car in it" I felt like a rock star
each month there's a new 3 rotor build thread started and 2 or 3 1/2 built 3 rotors in the for sale section.Just flipped through the MAG and Phils car is SWEEET! Can't wait to read that article.
PS I'm on my way to Richmond to pick up a parts car (stay tuned for some crazy cool parts) stop by sheetz to pick up the mag and while waiting in line the guy in front of me sees me holding the magazine and says "I didn't know that modified was still going" and I'm like "yep and take a look there's an article with my car in it" I felt like a rock star
HAH , in the FD world I thought you already were
also .. I'm secretly rooting for your 350 whp FD . since thats what I'm shooting for .
09-23-13, 01:11 PM
#454
All out Track Freak!
iTrader: (263)
Join Date: Jul 2001
Location: Charlottesville VA 22901
Posts: 10,672
Received 412 Likes
on
250 Posts
My goal is to run a 2.00.xx lap at VIR in the next 12 months which is actually about what I'll have to run to even step on the podium these days there are some FAST effin cars out there.
09-23-13, 01:13 PM
#455
All out Track Freak!
iTrader: (263)
Join Date: Jul 2001
Location: Charlottesville VA 22901
Posts: 10,672
Received 412 Likes
on
250 Posts
Here's the plan
Lets all sign up for the Audi Club event NOV 9nth and 10nth and rent the S or N course Mon the 11nth if possible. If it's not possible so what we'll have a great weekend running with a laid back super cool club 
09-23-13, 01:30 PM
#456
Senior Member
David's 400rwhp result on 2 out of his engine's 3 rotors demonstrates what 3- and 4-rotor engines are really for: to still have decent power when an apex seal or two goes :P
I keed, I keed
09-23-13, 01:52 PM
#457
All out Track Freak!
iTrader: (263)
Join Date: Jul 2001
Location: Charlottesville VA 22901
Posts: 10,672
Received 412 Likes
on
250 Posts
Good point I guess need is relative depending upon your appetite for speed but my old jalopy would surely disintegrate at that speed and I don't want to burn a hole in my trousers.
09-23-13, 05:54 PM
#458
. Hopefully at the next event I can have all 675 WHP working to give you a run for your money. You pesky reliable V8 guys!On the south course I think all times would be about the same as there aren't big opportunities for large HP.
09-23-13, 09:02 PM
#459
No guarantee I can make it but if I can I would love to put fritz behind the wheel of my car and Gordon's to do a fun little comparison. Can't recall if Gordon has a bbk but I will be on stock brakes and figured I could supply stock wheels with some good street able tires for us to both run on for the event?
I'm just interested to see how my emissions compliant stock port 2 rotor with stock intake box/stock IC will stack up against his NA 3 rotor. I hope I can make the event either way and think it is awesome an event like this is taking place.
I'm just interested to see how my emissions compliant stock port 2 rotor with stock intake box/stock IC will stack up against his NA 3 rotor. I hope I can make the event either way and think it is awesome an event like this is taking place.
09-24-13, 12:04 PM
#460
LS what?
iTrader: (3)
Join Date: Aug 2001
Location: Raleigh, NC
Posts: 1,180
Likes: 0
Received 0 Likes
on
0 Posts
Ouch! Sometimes the truth hurts. . Hopefully at the next event I can have all 675 WHP working to give you a run for your money. You pesky reliable V8 guys!
Too funny, this coming from the rotary world's "Stig". I very much want you and Peter to drive my car when it's right so I can see what it is capable of. My theory is you'll be in partial throttle thru the turns and then full throttle on the straights to capture that elusive sub 2 minute time. Thàt of course would be on the full course.
On the south course I think all times would be about the same as there aren't big opportunities for large HP.
. Hopefully at the next event I can have all 675 WHP working to give you a run for your money. You pesky reliable V8 guys!Too funny, this coming from the rotary world's "Stig". I very much want you and Peter to drive my car when it's right so I can see what it is capable of. My theory is you'll be in partial throttle thru the turns and then full throttle on the straights to capture that elusive sub 2 minute time. Thàt of course would be on the full course.
On the south course I think all times would be about the same as there aren't big opportunities for large HP.
What is your brake and suspension setup? Brakes are going to be a huge factor with your car as a ton of heat is going to be generated after those long straights. Do you have cooling ducts installed? Have you added any aero since May? I can't imagine what top speeds will be in that monster!! I don't have any aero and it starts to get hairy for me as I approach 145 to 150.
I guess what I am saying is, I am glad it is in the capable hands of Fritz!!
Robin
09-24-13, 04:39 PM
#461
^BBK (Outlaw) on the front with Blue DOT brake fluid. Can't remember the pads on the front and back, but they are track quality. Yes, the fronts have cooling ducts installed.
No aero added as of yet. I like the clean looks but do know that will hold the car back for sure. I've had the car up to around 140 at VIR with no issues but that's not to say things won't get dicey above that.
It's a balancing act for me between what I like regarding a clean look and making it better for the track. I may need to add aero but I'll do that after we see how it handles at the next event.
And I'm right there with you regarding Fritz, at my grandmother speeds, a Kia would be safe out there
No aero added as of yet. I like the clean looks but do know that will hold the car back for sure. I've had the car up to around 140 at VIR with no issues but that's not to say things won't get dicey above that.
It's a balancing act for me between what I like regarding a clean look and making it better for the track. I may need to add aero but I'll do that after we see how it handles at the next event.
And I'm right there with you regarding Fritz, at my grandmother speeds, a Kia would be safe out there
09-27-13, 08:49 AM
#464
Senior Member
I was hitting 140 on the straight on the south course, lifting WAY early at pit exit due to street pads (PosiQuiet and Duralast Gold :O) and year-old brake fluid degraded by 4 track days.
David's car on all 3 rotors should be seeing ludicrous speeds on the full course
That car should be good for 200mph at the Texas Mile, maximum speed 210+ with enough road
David's car on all 3 rotors should be seeing ludicrous speeds on the full course
That car should be good for 200mph at the Texas Mile, maximum speed 210+ with enough road
09-27-13, 08:52 AM
#465
All out Track Freak!
iTrader: (263)
Join Date: Jul 2001
Location: Charlottesville VA 22901
Posts: 10,672
Received 412 Likes
on
250 Posts
No guarantee I can make it but if I can I would love to put fritz behind the wheel of my car and Gordon's to do a fun little comparison. Can't recall if Gordon has a bbk but I will be on stock brakes and figured I could supply stock wheels with some good street able tires for us to both run on for the event?
I'm just interested to see how my emissions compliant stock port 2 rotor with stock intake box/stock IC will stack up against his NA 3 rotor. I hope I can make the event either way and think it is awesome an event like this is taking place.
I'm just interested to see how my emissions compliant stock port 2 rotor with stock intake box/stock IC will stack up against his NA 3 rotor. I hope I can make the event either way and think it is awesome an event like this is taking place.
I tracked a bone stock R1 with 18k miles on it 4 or 5 times at both summit and VIR and had a blast with it. Ouch! Sometimes the truth hurts. . Hopefully at the next event I can have all 675 WHP working to give you a run for your money. You pesky reliable V8 guys!
Too funny, this coming from the rotary world's "Stig". I very much want you and Peter to drive my car when it's right so I can see what it is capable of. My theory is you'll be in partial throttle thru the turns and then full throttle on the straights to capture that elusive sub 2 minute time. Thàt of course would be on the full course.
On the south course I think all times would be about the same as there aren't big opportunities for large HP.
. Hopefully at the next event I can have all 675 WHP working to give you a run for your money. You pesky reliable V8 guys!Too funny, this coming from the rotary world's "Stig". I very much want you and Peter to drive my car when it's right so I can see what it is capable of. My theory is you'll be in partial throttle thru the turns and then full throttle on the straights to capture that elusive sub 2 minute time. Thàt of course would be on the full course.
On the south course I think all times would be about the same as there aren't big opportunities for large HP.
David,
What is your brake and suspension setup? Brakes are going to be a huge factor with your car as a ton of heat is going to be generated after those long straights. Do you have cooling ducts installed? Have you added any aero since May? I can't imagine what top speeds will be in that monster!! I don't have any aero and it starts to get hairy for me as I approach 145 to 150.
I guess what I am saying is, I am glad it is in the capable hands of Fritz!!
Robin
What is your brake and suspension setup? Brakes are going to be a huge factor with your car as a ton of heat is going to be generated after those long straights. Do you have cooling ducts installed? Have you added any aero since May? I can't imagine what top speeds will be in that monster!! I don't have any aero and it starts to get hairy for me as I approach 145 to 150.
I guess what I am saying is, I am glad it is in the capable hands of Fritz!!
Robin
^BBK (Outlaw) on the front with Blue DOT brake fluid. Can't remember the pads on the front and back, but they are track quality. Yes, the fronts have cooling ducts installed.
No aero added as of yet. I like the clean looks but do know that will hold the car back for sure. I've had the car up to around 140 at VIR with no issues but that's not to say things won't get dicey above that.
It's a balancing act for me between what I like regarding a clean look and making it better for the track. I may need to add aero but I'll do that after we see how it handles at the next event.
And I'm right there with you regarding Fritz, at my grandmother speeds, a Kia would be safe out there
No aero added as of yet. I like the clean looks but do know that will hold the car back for sure. I've had the car up to around 140 at VIR with no issues but that's not to say things won't get dicey above that.
It's a balancing act for me between what I like regarding a clean look and making it better for the track. I may need to add aero but I'll do that after we see how it handles at the next event.
And I'm right there with you regarding Fritz, at my grandmother speeds, a Kia would be safe out there
See vids: 1st one is chasing a highly modded C6 who's likely doing close to 160 on the back. Second is the 2.03 lap with GPS indicated speeds which I love to advertise hehe
09-27-13, 07:41 PM
#467
Fritz what setup are you using to record the second video, and link speed and Gforce data and overlay it like that? Pretty slick, I like it alot.
A mostly stock or even a stock FD is no slouch. With just good pads and tires it's capable of sub 2.16 laps at VIR and I'd love to toss one around I tracked a bone stock R1 with 18k miles on it 4 or 5 times at both summit and VIR and had a blast with it.
Doing a sub 2 minute lap at VIR is stupid, silly, ridiculous FAST and it takes a heck of lot more than just going down both straights and 160 plus although that helps LOL
No doubt the brakes in my car are tested heavily at just 150 once you get above 120 you really start to test braking and each 10 MPH jump higher than the last is like 10 times harder on the brake setup. I'm not a physics or math wiz but you get the idea. Bottomline I wouldn't push or test the braking of any car I'm not intimate with.
140 is certainly not grandma speeds hehe
The only cars going 170 are pro driven cups and that's extremely rare. Typically really REALLY fast cars like a modded C6Zs etc... hit about 160 (on GPS not speedo). On my 2.03 lap pushing pretty hard on good tires I was at 148 back and 143 front and wouldn't push much harder during a TT.
See vids: 1st one is chasing a highly modded C6 who's likely doing close to 160 on the back. Second is the 2.03 lap with GPS indicated speeds which I love to advertise hehe
I tracked a bone stock R1 with 18k miles on it 4 or 5 times at both summit and VIR and had a blast with it. Doing a sub 2 minute lap at VIR is stupid, silly, ridiculous FAST and it takes a heck of lot more than just going down both straights and 160 plus although that helps LOL
No doubt the brakes in my car are tested heavily at just 150 once you get above 120 you really start to test braking and each 10 MPH jump higher than the last is like 10 times harder on the brake setup. I'm not a physics or math wiz but you get the idea. Bottomline I wouldn't push or test the braking of any car I'm not intimate with.
140 is certainly not grandma speeds hehe
The only cars going 170 are pro driven cups and that's extremely rare. Typically really REALLY fast cars like a modded C6Zs etc... hit about 160 (on GPS not speedo). On my 2.03 lap pushing pretty hard on good tires I was at 148 back and 143 front and wouldn't push much harder during a TT.
See vids: 1st one is chasing a highly modded C6 who's likely doing close to 160 on the back. Second is the 2.03 lap with GPS indicated speeds which I love to advertise hehe
09-28-13, 09:38 AM
#469
140 is certainly not grandma speeds hehe
The only cars going 170 are pro driven cups and that's extremely rare. Typically really REALLY fast cars like a modded C6Zs etc... hit about 160 (on GPS not speedo). On my 2.03 lap pushing pretty hard on good tires I was at 148 back and 143 front and wouldn't push much harder during a TT.
The only cars going 170 are pro driven cups and that's extremely rare. Typically really REALLY fast cars like a modded C6Zs etc... hit about 160 (on GPS not speedo). On my 2.03 lap pushing pretty hard on good tires I was at 148 back and 143 front and wouldn't push much harder during a TT.
And even though I could go faster on the straights, you are right that it is only a small part of the overall battle. It's maintaining speeds through the turns that does it as evidenced by my ride with you on the South Course. Holy crap! I had no idea the FD could take that kind of abuse but you see quickly that if you can get better through the turns, you can make up a lot of ground on the higher HP cars.
My point was to equip you with a car that can handle like yours with more HP and see what can be done. For me, I've got to take baby steps and learn how to drive as I've only now done 3 HPDE events. Got another one coming up early next month if the car is ready.
09-28-13, 09:58 AM
#471
All out Track Freak!
iTrader: (263)
Join Date: Jul 2001
Location: Charlottesville VA 22901
Posts: 10,672
Received 412 Likes
on
250 Posts
Well, I don't feel that bad then. It did scare the crap out of me, especially as you go over the blind rise on the back straight. And then the instructor has you holding on braking to you hit close to #1 on the markers - well that did freak me out too. But it was my first track experience which should explain a lot.
And even though I could go faster on the straights, you are right that it is only a small part of the overall battle. It's maintaining speeds through the turns that does it as evidenced by my ride with you on the South Course. Holy crap! I had no idea the FD could take that kind of abuse but you see quickly that if you can get better through the turns, you can make up a lot of ground on the higher HP cars.
My point was to equip you with a car that can handle like yours with more HP and see what can be done. For me, I've got to take baby steps and learn how to drive as I've only now done 3 HPDE events. Got another one coming up early next month if the car is ready.
And even though I could go faster on the straights, you are right that it is only a small part of the overall battle. It's maintaining speeds through the turns that does it as evidenced by my ride with you on the South Course. Holy crap! I had no idea the FD could take that kind of abuse but you see quickly that if you can get better through the turns, you can make up a lot of ground on the higher HP cars.
My point was to equip you with a car that can handle like yours with more HP and see what can be done. For me, I've got to take baby steps and learn how to drive as I've only now done 3 HPDE events. Got another one coming up early next month if the car is ready.
I second that emotion but I'm not one to talk about looks my poor car is the epitome of a track/crack *****.
09-28-13, 11:19 AM
#472
Senior Member
Also, having the rear jacked up like that relative to the front gives a higher rear roll center, pretty much the opposite of what you want to put the power down on corner exit as that effectively gives more rear roll stiffness.
Since the body is already somewhat butchered, I'd go full widebody front and rear with only modest tire stagger and level the car out.
09-28-13, 11:56 AM
#473
All out Track Freak!
iTrader: (263)
Join Date: Jul 2001
Location: Charlottesville VA 22901
Posts: 10,672
Received 412 Likes
on
250 Posts
Need more grip at the rear for corner exits (as opposed to straightline dragstrip usage)? Bias more roll stiffness to the front and get wider FRONT tires. Not that yours aren't already wide, but relative to the rears they almost give your car a Pro Stock/"Pro Street" look... I think the optimal tire setup for putting down massive power will be a bit more "square"...
Also, having the rear jacked up like that relative to the front gives a higher rear roll center, pretty much the opposite of what you want to put the power down on corner exit as that effectively gives more rear roll stiffness.
Since the body is already somewhat butchered, I'd go full widebody front and rear with only modest tire stagger and level the car out.
Also, having the rear jacked up like that relative to the front gives a higher rear roll center, pretty much the opposite of what you want to put the power down on corner exit as that effectively gives more rear roll stiffness.
Since the body is already somewhat butchered, I'd go full widebody front and rear with only modest tire stagger and level the car out.
Front end high = push rear end high = over steer
staggered setup will push every time UNLESS you've done some pretty stupid things, like jack up the back, put in a fat rear bar and small front bar etc......
Balance all the way around is the key to going fast in the fd. Match equal springs and bars to tires/grip, equal camber (maybe slightly more in the front to keep grip in the back underpower etc..... if you have trouble turning after bar and shock adj mess with toe but stick with equal tires all the way around and try to keep it as low and level as possible with just the smallest amount of rake. Bottomline don't mess too much with a 50 50 car.
09-28-13, 11:23 PM
#474
Guys, I agree with you 100% on a square setup but when I went 20b EVERYTHING changed. My car handled like absolute ***. I had to completely rethink my suspension settings, nothing from before worked at all. I added a ton of weight up front and also raised the center of gravity as the engine sits about 1" higher then factory. My rear is also quite damn light with the carbon fiber hatch and gutted everything on the rear pretty much. And you guys are forgetting, I'm trying to plant down 650 rwhp with a super light rear end.
To put it simply every corner is delt with separately and having balanced settings have been completely thrown out the window. I spent all season setting the car up and trying new things and it only started to make sense when I cleared my mind and started fresh. Here is a gist of my current settings...
left front camber: ~3.5 degrees
left rear camber: 2.3 degrees
right front camber: 1.5 degrees
right rear camber: 1.3 degrees
front toe: approaching zero (I'm gonna try toe out next year)
rear toe: 1/4" total
Spring rates 16k front/ 12k rear
Tri-point front sway bar set on 1 setting soft from center
Racing Beat rear sway bar
My tire temperatures and wear patterns are near perfect at the moment. Although, after getting the built transmission and pushing the car faster then its ever been before on fresh tires, their telling me to add even more camber so I'll probably add 1/2 degree all around next year.
Also, the rear is set like that because that is what the scales tell me to do. I've rescaled the car at least 5-6 times this year alone after every single change I made to the car. I have a 1/2" wedge on the front left tire and then I corner balance the rest of the car based on that. My heights are set by the scales, I don't care how the car sits.
I am fairly confident that my current settings are close to ideal as I was finally able to have and hold a slip angle coming out of corners on power. I should note though that the car is setup to turn right more then it is to turn left haha. All our tracks here are right turn biased and I think most tracks are that way anyway so it works amazing.
Fritz, I'd be very interested in seeing what you think about my cars handling, it'll probably confuse you haha. I'm going to be at the 13 hour Enduro on October 26th at VIR supporting the Mazdee's race team running the rotary Miata so if there's lapping around that date, would be convenient for me to bring the car down and have a track meet with you guys
Their 17x14" with 335 Hoosier slicks. Initially, I had gotten 17x12" but after a few events with them, I realized I wasn't using the edges of the tire so I e-mailed Hoosier about it and they told me the ideal rim size for that tire would be 14". Ordered a pair of new lips from CCW and easy rim upgrade . This also allowed me to remove the spacers on the back I had added because the tire was rolling and touching the shocks.
I have a 295 tire on the front vs a 335 rear, I have no need for more front tire. I might just stretch the front a little bit to make full use of the tire and get less tire roll. A wider front tire will slow the car down on the straights so if I don't need it, no sense in putting it on. My front fenders are already 20mm wide.
thewird
To put it simply every corner is delt with separately and having balanced settings have been completely thrown out the window. I spent all season setting the car up and trying new things and it only started to make sense when I cleared my mind and started fresh. Here is a gist of my current settings...
left front camber: ~3.5 degrees
left rear camber: 2.3 degrees
right front camber: 1.5 degrees
right rear camber: 1.3 degrees
front toe: approaching zero (I'm gonna try toe out next year)
rear toe: 1/4" total
Spring rates 16k front/ 12k rear
Tri-point front sway bar set on 1 setting soft from center
Racing Beat rear sway bar
My tire temperatures and wear patterns are near perfect at the moment. Although, after getting the built transmission and pushing the car faster then its ever been before on fresh tires, their telling me to add even more camber so I'll probably add 1/2 degree all around next year.
Also, the rear is set like that because that is what the scales tell me to do. I've rescaled the car at least 5-6 times this year alone after every single change I made to the car. I have a 1/2" wedge on the front left tire and then I corner balance the rest of the car based on that. My heights are set by the scales, I don't care how the car sits.
I am fairly confident that my current settings are close to ideal as I was finally able to have and hold a slip angle coming out of corners on power. I should note though that the car is setup to turn right more then it is to turn left haha. All our tracks here are right turn biased and I think most tracks are that way anyway so it works amazing.
Fritz, I'd be very interested in seeing what you think about my cars handling, it'll probably confuse you haha
. I'm going to be at the 13 hour Enduro on October 26th at VIR supporting the Mazdee's race team running the rotary Miata so if there's lapping around that date, would be convenient for me to bring the car down and have a track meet with you guys . This also allowed me to remove the spacers on the back I had added because the tire was rolling and touching the shocks.Need more grip at the rear for corner exits (as opposed to straightline dragstrip usage)? Bias more roll stiffness to the front and get wider FRONT tires. Not that yours aren't already wide, but relative to the rears they almost give your car a Pro Stock/"Pro Street" look... I think the optimal tire setup for putting down massive power will be a bit more "square"...
Also, having the rear jacked up like that relative to the front gives a higher rear roll center, pretty much the opposite of what you want to put the power down on corner exit as that effectively gives more rear roll stiffness.
Since the body is already somewhat butchered, I'd go full widebody front and rear with only modest tire stagger and level the car out.
Also, having the rear jacked up like that relative to the front gives a higher rear roll center, pretty much the opposite of what you want to put the power down on corner exit as that effectively gives more rear roll stiffness.
Since the body is already somewhat butchered, I'd go full widebody front and rear with only modest tire stagger and level the car out.
thewird
09-29-13, 12:55 AM
#475
Rotary Enthusiast
iTrader: (19)
Join Date: Apr 2002
Location: Colorado Springs, CO
Posts: 1,169
Likes: 0
Received 11 Likes
on
10 Posts
I read the michelin tire engineers remarks in some presentations. they say to install the tire with a stretch. run a 11" wheel with 295's, 10.5 with 285mm or 265mm, 10" 255mm, 9.5" 245mm. look at section width of tire and stretch it a good .5" or so.
Porsche runs wider rear tires because of the weight distribution, they are roughly the same percent size as static weight distribution.
if this is the case, I would think you need wider front tires and less rear tire. much like FWD cars.
Wider tires give better handling, they typically suffer from worse braking and acceleration, as the contact patch becomes more landscape than portrait shape. chemical adhesion to road surface and tire pressure are the only effects one can have on grip with given weight of vehicle outside of aero.
here is an article about wider front wheels being the key to speed.
URGE designs
Porsche runs wider rear tires because of the weight distribution, they are roughly the same percent size as static weight distribution.
if this is the case, I would think you need wider front tires and less rear tire. much like FWD cars.
Wider tires give better handling, they typically suffer from worse braking and acceleration, as the contact patch becomes more landscape than portrait shape. chemical adhesion to road surface and tire pressure are the only effects one can have on grip with given weight of vehicle outside of aero.
here is an article about wider front wheels being the key to speed.
URGE designs