964 track suspension setup (understeer issues)
10-31-2002, 03:20 PM
#16
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Erick, yeah understeer sucks. Till you get it fixed ,you just have to slow
down for the turns more. We have 2 sets of wheels. The originals are long
gone. We have the Hartmans which are bigger but they're much heavier. 7.5
and 9 inch. Then we had some Kinesis custom made 8" and 10" with the 245
and 275 tires.17 inchers. There's less of a difference in size ratio between
the 245/275 than the 205/255. That is to say, the difference between the
205's and 255's is 2.4" of treadwidth. The difference between the 245's and
the 275's is only 1".That puts more grip up front. We had to use a 1/8? very
small spacer to keep the tire from rubbing an oil line in the rear wheel
well. The Carrera Cup adj. sway bars are great. They can be adjusted quickly
and easily. I believe they are 5-way in the front and 3-way in the rear. I
believe, our front is full soft and the rear is in the middle. This gives
great rotation for autocrossing. Keep in mind we have fast autocrosses in
San Diego.3rd and 4th gear stuff. You may have to dial out some oversteer
for an even faster course so that the car is a little more forgiving. Hope
that helps, Cheers! Tim Comeau
down for the turns more. We have 2 sets of wheels. The originals are long
gone. We have the Hartmans which are bigger but they're much heavier. 7.5
and 9 inch. Then we had some Kinesis custom made 8" and 10" with the 245
and 275 tires.17 inchers. There's less of a difference in size ratio between
the 245/275 than the 205/255. That is to say, the difference between the
205's and 255's is 2.4" of treadwidth. The difference between the 245's and
the 275's is only 1".That puts more grip up front. We had to use a 1/8? very
small spacer to keep the tire from rubbing an oil line in the rear wheel
well. The Carrera Cup adj. sway bars are great. They can be adjusted quickly
and easily. I believe they are 5-way in the front and 3-way in the rear. I
believe, our front is full soft and the rear is in the middle. This gives
great rotation for autocrossing. Keep in mind we have fast autocrosses in
San Diego.3rd and 4th gear stuff. You may have to dial out some oversteer
for an even faster course so that the car is a little more forgiving. Hope
that helps, Cheers! Tim Comeau
11-03-2002, 05:17 PM
#17
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Here's what worked for me:
I bought H&R Coilovers bc I didn't want to bother or pay for a custom setup. I bought some adjustable sway bars from the Rennlist classifieds for $200/pr. I bought used 993/996/Boxster take-off wheels and mounted Hoosier 225/255 tires. This set-up offered all of the performance and adjustability I could want at a budget price.
I would have preferred Fikse wheels at $3000 per set ($6000), but I found that you really need 2 sets of track wheels and I got mine for under $2k. That's a savings of $4000!! - just for the wheels... Also - I can always sell the old wheels and buy new ones later.
RSA - there is no one answer here. What you want is flexibility / adjustability. You also want to look for ways to get the most for your $$.
I bought H&R Coilovers bc I didn't want to bother or pay for a custom setup. I bought some adjustable sway bars from the Rennlist classifieds for $200/pr. I bought used 993/996/Boxster take-off wheels and mounted Hoosier 225/255 tires. This set-up offered all of the performance and adjustability I could want at a budget price.
I would have preferred Fikse wheels at $3000 per set ($6000), but I found that you really need 2 sets of track wheels and I got mine for under $2k. That's a savings of $4000!! - just for the wheels... Also - I can always sell the old wheels and buy new ones later.
RSA - there is no one answer here. What you want is flexibility / adjustability. You also want to look for ways to get the most for your $$.
11-03-2002, 08:57 PM
#18
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[quote]<strong>I found that you really need 2 sets of track wheels.</strong><hr></blockquote>
Jack,
Assuming you mount "R" rubber on one set of wheels, what do you use the second set of track wheels for - rain tires or ? Do you trailer your Porsche? Just curious...
Jack,
Assuming you mount "R" rubber on one set of wheels, what do you use the second set of track wheels for - rain tires or ? Do you trailer your Porsche? Just curious...
11-03-2002, 10:34 PM
#19
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[quote]Originally posted by Bill Gregory:
<strong>
what do you use the second set of track wheels for - rain tires or ?</strong><hr></blockquote>
If you are going to have rain tires, then you need three sets of wheels! <g>
The advantage having a second set of wheels is that you don't have to try to determine how much life is in a set of tires before you go to an event. You can have a good set and then a worn set when the worn set is completely gone, you just switch wheels and go. I normally would run a new set of tires on Friday for a short session to get some heat into them and then put them aside until qualifying and the race on Sunday.
<strong>
what do you use the second set of track wheels for - rain tires or ?</strong><hr></blockquote>
If you are going to have rain tires, then you need three sets of wheels! <g>
The advantage having a second set of wheels is that you don't have to try to determine how much life is in a set of tires before you go to an event. You can have a good set and then a worn set when the worn set is completely gone, you just switch wheels and go. I normally would run a new set of tires on Friday for a short session to get some heat into them and then put them aside until qualifying and the race on Sunday.
11-03-2002, 10:42 PM
#20
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Roger,
According to Jack's web site, in 2002, he only did drivers education, which is why I asked (not evident in my post, however). When racing, multiple sets of wheels are good, and you gave an good example why.
According to Jack's web site, in 2002, he only did drivers education, which is why I asked (not evident in my post, however). When racing, multiple sets of wheels are good, and you gave an good example why.
11-04-2002, 07:38 AM
#21
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Erick,
Please define the following:
1) performance street alignment
2) massive understeer
FWIW, I also drive a 93 RSA in DE and Auto-X. My first 2 DEs and all Auto-X's were street tires, Bridgestone RE730s, which did rather well. At most I experienced very mild understeer. My suspension is entirely stock.
Since those DEs, I've moved up to Hoosier tires and had the front camber set at -1.0. The result is oversteer when I want it, and absolutely no understeer.
You didn't mention your driving style. I'm a firm believer in throttle-induced oversteer; maybe that's the difference.
Please define the following:
1) performance street alignment
2) massive understeer
FWIW, I also drive a 93 RSA in DE and Auto-X. My first 2 DEs and all Auto-X's were street tires, Bridgestone RE730s, which did rather well. At most I experienced very mild understeer. My suspension is entirely stock.
Since those DEs, I've moved up to Hoosier tires and had the front camber set at -1.0. The result is oversteer when I want it, and absolutely no understeer.
You didn't mention your driving style. I'm a firm believer in throttle-induced oversteer; maybe that's the difference.
11-04-2002, 08:08 AM
#22
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Bill -
My need for 2 sets of track wheels for DE's was magnified by the fact that I had to support 2 drivers - as my wife was driving, too. In 2001, I did one extra 2-day event, on my own, but we did 19 together. So I drove for 21 and she drove 19. Of those 19, 3 were 3-day events. A 3-day event with 2 drivers is like 6 days.
So - If I had a set of tires with 50-75% tread left, they might not make it through 6 days. So - the second set really came in handy, so that I could use one set until they wore out completely, and then use the 2nd set. Most tracks don't have tire-changing facilities nearby, so just taking the tires would not suffice.
Even with one driver, it just takes one bad spin to flat-spot your tires and then they are shot. Also, with one driver, a set of tires with 25-50% of use left can still be used to their completion, with confidence, at a multi-day event, when you have a second set at the track.
I would be able to manage the tires/wheels better if I had the use of a mounter/balancer at home, but switching tires costs me $100. The tires themselves are so expensive that a $1000 set of wheels pays for itself in a hurry. (especially considering the fact that the wheels don't depreciate too much).
Do I trailer my Porsche? I used to have a trailex trailer, and I toted my street tires plus 2 sets of Hoosiers. I sold the trailex and my tow vehicle to help with a house down-payment, and I bought a small tow-behind trailer. Because I have this thing about 2 sets of track tires, I changed over to Kumhos so that I could leave the street tires at home and mount 1 set of Kumhos on the car for travel to/from the track and I had the 2nd set on the tow-behind trailer.
I'm giving up track events for some time due to a recent major crash, and the new house/new baby syndrome. Moved into the new house in May, and my wife is due with our first born on Friday.
My need for 2 sets of track wheels for DE's was magnified by the fact that I had to support 2 drivers - as my wife was driving, too. In 2001, I did one extra 2-day event, on my own, but we did 19 together. So I drove for 21 and she drove 19. Of those 19, 3 were 3-day events. A 3-day event with 2 drivers is like 6 days.
So - If I had a set of tires with 50-75% tread left, they might not make it through 6 days. So - the second set really came in handy, so that I could use one set until they wore out completely, and then use the 2nd set. Most tracks don't have tire-changing facilities nearby, so just taking the tires would not suffice.
Even with one driver, it just takes one bad spin to flat-spot your tires and then they are shot. Also, with one driver, a set of tires with 25-50% of use left can still be used to their completion, with confidence, at a multi-day event, when you have a second set at the track.
I would be able to manage the tires/wheels better if I had the use of a mounter/balancer at home, but switching tires costs me $100. The tires themselves are so expensive that a $1000 set of wheels pays for itself in a hurry. (especially considering the fact that the wheels don't depreciate too much).
Do I trailer my Porsche? I used to have a trailex trailer, and I toted my street tires plus 2 sets of Hoosiers. I sold the trailex and my tow vehicle to help with a house down-payment, and I bought a small tow-behind trailer. Because I have this thing about 2 sets of track tires, I changed over to Kumhos so that I could leave the street tires at home and mount 1 set of Kumhos on the car for travel to/from the track and I had the 2nd set on the tow-behind trailer.
I'm giving up track events for some time due to a recent major crash, and the new house/new baby syndrome. Moved into the new house in May, and my wife is due with our first born on Friday.
11-04-2002, 09:04 PM
#23
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[quote]<strong>I'm giving up track events for some time due to a recent major crash, and the new house/new baby syndrome. Moved into the new house in May, and my wife is due with our first born on Friday.</strong><hr></blockquote>
Jack,
Sorry you have to give up track for awhile, but more importantly, congratulations to you and your wife on your soon-to-be first born!! Yahoo!!
Jack,
Sorry you have to give up track for awhile, but more importantly, congratulations to you and your wife on your soon-to-be first born!! Yahoo!!
11-13-2002, 09:16 AM
#24
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Bill -
Thanks for the congrats!
Baby Jack arrived on Monday...
<a href="http://www.ranrace.com/jack/family.jpg" target="_blank">http://www.ranrace.com/jack/family.jpg</a>
btw, did my explanation about the multiple sets of wheels make sense?
Thanks for the congrats!
Baby Jack arrived on Monday...
<a href="http://www.ranrace.com/jack/family.jpg" target="_blank">http://www.ranrace.com/jack/family.jpg</a>
btw, did my explanation about the multiple sets of wheels make sense?
11-13-2002, 09:33 AM
#25
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Jack,
Congrats to Mom and Dad, hope baby Jack is doing great!
Understand about the multiple wheel sets. Sure would be nice to have your own mounter/balancer, in addition to....and.....now I understand why 3 car garages are becoming more popular
Bill
Congrats to Mom and Dad, hope baby Jack is doing great!
Understand about the multiple wheel sets. Sure would be nice to have your own mounter/balancer, in addition to....and.....now I understand why 3 car garages are becoming more popular
Bill
04-16-2003, 04:33 PM
#26
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Thread Starter
Update:
Thanks to everyone for their very helpful advice. Re-reading this post tells me how much I've learned since the original post!
With your advice, (coupled with my budget) I've changed the following since last year:
1. Kirk Racing bolt-in roll bar (safety first!).
2. Sparco 5-point harnesses (safety first!).
3. 996 twist wheels 7"x17" front and 9"x17" rear.
4. Michelin Pilot Sport Cups - 225 front and 255 rear.
5. H&R coil overs.
6. Alignment and Corner balance:
Left front camber: -2.4 degrees
Right front camber: -2.4 degrees
Left front caster: 3.8 degrees
Right front caster: 3.7 degrees
Left front toe: -0.01 degrees
Right front toe: 0 degrees
Front cross camber: 0 degrees
Front cross caster: 0.1 degrees
Total toe: -0.02 degrees
Set back: 0.18 degrees
Left rear camber: -2.6 degrees
Right rear camber: -2.6 degrees
Left rear toe: 0.12 degrees
Right rear toe: 0.11 degrees
Rear total toe: 0.23 degrees
Rear thrust angle: 0.01 degrees
If anyone has any comments on these alignment specs, I'd appreciate them. I'm still in the process of learning their meaning (ala Fred Puhn's book), but I'm anxious to try them out on the track.
I can tell everyone already that the H&R coil overs are significantly more "jarring" than the M030/Eibach combination that I was using last year. It has yet to be seen how different they perform on the track, but considering the uncomfortable street ride, IT HAD BETTER BE IMPRESSIVE!!!
Best to all. <img border="0" alt="[burnout]" title="" src="graemlins/burnout.gif" />
Erick
Thanks to everyone for their very helpful advice. Re-reading this post tells me how much I've learned since the original post!
With your advice, (coupled with my budget) I've changed the following since last year:
1. Kirk Racing bolt-in roll bar (safety first!).
2. Sparco 5-point harnesses (safety first!).
3. 996 twist wheels 7"x17" front and 9"x17" rear.
4. Michelin Pilot Sport Cups - 225 front and 255 rear.
5. H&R coil overs.
6. Alignment and Corner balance:
Left front camber: -2.4 degrees
Right front camber: -2.4 degrees
Left front caster: 3.8 degrees
Right front caster: 3.7 degrees
Left front toe: -0.01 degrees
Right front toe: 0 degrees
Front cross camber: 0 degrees
Front cross caster: 0.1 degrees
Total toe: -0.02 degrees
Set back: 0.18 degrees
Left rear camber: -2.6 degrees
Right rear camber: -2.6 degrees
Left rear toe: 0.12 degrees
Right rear toe: 0.11 degrees
Rear total toe: 0.23 degrees
Rear thrust angle: 0.01 degrees
If anyone has any comments on these alignment specs, I'd appreciate them. I'm still in the process of learning their meaning (ala Fred Puhn's book), but I'm anxious to try them out on the track.
I can tell everyone already that the H&R coil overs are significantly more "jarring" than the M030/Eibach combination that I was using last year. It has yet to be seen how different they perform on the track, but considering the uncomfortable street ride, IT HAD BETTER BE IMPRESSIVE!!!
Best to all. <img border="0" alt="[burnout]" title="" src="graemlins/burnout.gif" />
Erick
04-16-2003, 09:37 PM
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Hi Erick, you will be pleased with the result. I used to run H&R coilovers and 225/255 Cups on my now street car and I loved it. Minimal understeer if any.
Now with the race car and the RSR coilovers with adjustable sways , still 225/255 cups it understeers like a pig... The spring rates on the H&R's I think are great compared to the RSR's...presently I'm puzzled with the handling on the coupe...
Now with the race car and the RSR coilovers with adjustable sways , still 225/255 cups it understeers like a pig... The spring rates on the H&R's I think are great compared to the RSR's...presently I'm puzzled with the handling on the coupe...
04-16-2003, 09:41 PM
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"><strong>Now with the race car and the RSR coilovers with adjustable sways.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">What size adjustable sways?
04-16-2003, 11:08 PM
#29
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Bill Gregory:
<strong> </font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"><strong>Now with the race car and the RSR coilovers with adjustable sways.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">What size adjustable sways?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">They are the Racers group 5 way front 3 way back. I first tried middle everywhere, understeered like a pig on medium and slow corners. Hot pressures all around 34. Then took off two pounds of the front, bit better still understeered like a pig. Went softer one hole on the front sway, car felt better but still the undertseer was there.
Next morning i completely forgot I had left in the trunk from the previous night my race jack and a few stuff in the trunk (about 50 pounds of weight) and was faster from the previous evening by 3 seconds! The car felt better and I thought this was because I was fresh from the previous day. Removed all the stuff from the trunk and lap times went up again with understeer galore..
So I guess next event I will stiffen the back to full stiff and we will see.
It is interesting however how the additional weight helped! Do you think lowering the car a bit up front will have the same effect?
<strong> </font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"><strong>Now with the race car and the RSR coilovers with adjustable sways.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">What size adjustable sways?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">They are the Racers group 5 way front 3 way back. I first tried middle everywhere, understeered like a pig on medium and slow corners. Hot pressures all around 34. Then took off two pounds of the front, bit better still understeered like a pig. Went softer one hole on the front sway, car felt better but still the undertseer was there.
Next morning i completely forgot I had left in the trunk from the previous night my race jack and a few stuff in the trunk (about 50 pounds of weight) and was faster from the previous evening by 3 seconds! The car felt better and I thought this was because I was fresh from the previous day. Removed all the stuff from the trunk and lap times went up again with understeer galore..
So I guess next event I will stiffen the back to full stiff and we will see.
It is interesting however how the additional weight helped! Do you think lowering the car a bit up front will have the same effect?
