Need your opinion. Getting alignment in the AM!
07-06-2010, 08:37 PM
#1
Three Wheelin'
Thread Starter
Need your opinion. Getting alignment in the AM!
So got my car down to RS specs at 125mm front and 218mm rear. Now will have 4-wheel alignment at the Porsche Dealer.
How does this look for a sporty street application (no racing):
FRONT
Toe. 0 0
Camber -1.5 -1.5
Caster 4.24 4.24
REAR
Toe 0.10 0.10
Camber -1.3 -1.3
Thanks for your help
How does this look for a sporty street application (no racing):
FRONT
Toe. 0 0
Camber -1.5 -1.5
Caster 4.24 4.24
REAR
Toe 0.10 0.10
Camber -1.3 -1.3
Thanks for your help
07-06-2010, 09:07 PM
#2
IHI KING!
Rennlist Member
Rennlist Member
Join Date: Aug 2001
Location: Nashua, New Hampshire, USA
Posts: 13,384
Received 222 Likes
on
176 Posts
The negative camber will cause increased tire wear. Are you comfortable with that? I had a similar setup on my coupe because I run several DE's a year. However, I'm finding that it is eating the tires, so I will go close to a stock setting the next time the car is aligned.
07-06-2010, 09:55 PM
#3
Addict
Rennlist Member
Rennlist Member
Rob- How many miles did you run these tires and for how many track days? And when you say that the alignment was eating them, could you possibly expand on that?
A while back, I used to run street tires with -1.5 degress of camber and did, maybe, 8-10 track days/year. After 10K miles, my tires definitely showed uneven wear from the alignment but it was more subtle than what you seemed to have experienced. There were still grooves on the inside edges but the entire tread face was simply more worn on the inside. When removed, you could stand up the tires and see that they were slightly tilted (1.5 degrees from vertical, probably
) but it was actually hard to detect unless you were looking for it.
TT- The alignments specs look fine. I usually have a little toe in at the front (for high-speed stability) and almost no toe at the rear. It might be a little twitchy without any front toe, i.e. follow the road. Caster on my car is set at 4 degrees, so that looks about right, too.
A while back, I used to run street tires with -1.5 degress of camber and did, maybe, 8-10 track days/year. After 10K miles, my tires definitely showed uneven wear from the alignment but it was more subtle than what you seemed to have experienced. There were still grooves on the inside edges but the entire tread face was simply more worn on the inside. When removed, you could stand up the tires and see that they were slightly tilted (1.5 degrees from vertical, probably
) but it was actually hard to detect unless you were looking for it.TT- The alignments specs look fine. I usually have a little toe in at the front (for high-speed stability) and almost no toe at the rear. It might be a little twitchy without any front toe, i.e. follow the road. Caster on my car is set at 4 degrees, so that looks about right, too.
07-06-2010, 10:37 PM
#4
Racer
Join Date: Apr 2008
Location: Silver Spring, MD
Posts: 369
Likes: 0
Received 0 Likes
on
0 Posts
So got my car down to RS specs at 125mm front and 218mm rear. Now will have 4-wheel alignment at the Porsche Dealer.
How does this look for a sporty street application (no racing):
FRONT
Toe. 0 0
Camber -1.5 -1.5
Caster 4.24 4.24
REAR
Toe 0.10 0.10
Camber -1.3 -1.3
Thanks for your help
How does this look for a sporty street application (no racing):
FRONT
Toe. 0 0
Camber -1.5 -1.5
Caster 4.24 4.24
REAR
Toe 0.10 0.10
Camber -1.3 -1.3
Thanks for your help
07-07-2010, 08:19 AM
#5
Rennlist Member
I'd take the RS specs and halve them for a sporty street application except for front toe; run the factory spec of +25 minutes. Ride harshness will be less with these settings, in addition to better tire wear.
07-07-2010, 08:37 AM
#6
IHI KING!
Rennlist Member
Rennlist Member
Join Date: Aug 2001
Location: Nashua, New Hampshire, USA
Posts: 13,384
Received 222 Likes
on
176 Posts
Rob- How many miles did you run these tires and for how many track days? And when you say that the alignment was eating them, could you possibly expand on that?
A while back, I used to run street tires with -1.5 degress of camber and did, maybe, 8-10 track days/year. After 10K miles, my tires definitely showed uneven wear from the alignment but it was more subtle than what you seemed to have experienced. There were still grooves on the inside edges but the entire tread face was simply more worn on the inside. When removed, you could stand up the tires and see that they were slightly tilted (1.5 degrees from vertical, probably ) but it was actually hard to detect unless you were looking for it.
A while back, I used to run street tires with -1.5 degress of camber and did, maybe, 8-10 track days/year. After 10K miles, my tires definitely showed uneven wear from the alignment but it was more subtle than what you seemed to have experienced. There were still grooves on the inside edges but the entire tread face was simply more worn on the inside. When removed, you could stand up the tires and see that they were slightly tilted (1.5 degrees from vertical, probably
) but it was actually hard to detect unless you were looking for it.
07-07-2010, 01:08 PM
#7
Addict
Rennlist Member
Rennlist Member
I know there's a lot of apprehension about negative camber on a street car and just wanted to expand on it. For someone who occasionally tracks their car, I think you definitely need some camber. Hard cornering is brutal on the outer edges and, without camber, can dramatically shorten the life of your tires.
While the uneven wear is hardly ideal, IMHO, it's the lesser of two evils for a car that sees track time.
$0.02
Trending Topics
07-07-2010, 01:35 PM
#8
Rennlist Member
TT- The alignments specs look fine. I usually have a little toe in at the front (for high-speed stability) and almost no toe at the rear. It might be a little twitchy without any front toe, i.e. follow the road. Caster on my car is set at 4 degrees, so that looks about right, too.
How much is a "little toe in" as your comment about car being twitchy as speed is Interesting. I have to look at the alignment specs for F toe #. After loweing the car with HD+ H&R reds anf getting alignment, the car is a little nervous at speed and seems to have gone towards over-steers which is much worst on wet track. IIRC the camber is about -2 F and R
07-07-2010, 02:35 PM
#9
IHI KING!
Rennlist Member
Rennlist Member
Join Date: Aug 2001
Location: Nashua, New Hampshire, USA
Posts: 13,384
Received 222 Likes
on
176 Posts
Thanks, Rob!
I know there's a lot of apprehension about negative camber on a street car and just wanted to expand on it. For someone who occasionally tracks their car, I think you definitely need some camber. Hard cornering is brutal on the outer edges and, without camber, can dramatically shorten the life of your tires.
While the uneven wear is hardly ideal, IMHO, it's the lesser of two evils for a car that sees track time.
$0.02
I know there's a lot of apprehension about negative camber on a street car and just wanted to expand on it. For someone who occasionally tracks their car, I think you definitely need some camber. Hard cornering is brutal on the outer edges and, without camber, can dramatically shorten the life of your tires.
While the uneven wear is hardly ideal, IMHO, it's the lesser of two evils for a car that sees track time.
$0.02
07-07-2010, 08:29 PM
#10
Three Wheelin'
Thread Starter
Well, went to get my car and to my dismay the car pulls hard to the left! WTF? Furthermore, I see the specs are almost identical for both sides. Car was NOT pulling before the evo upright "upgrade".
These are the final numerical values for the alignment:
Camber......... -1.3 -1.2
Caster........... 3.9 3.8
Toe IN .......... .07 .07
Total toe....... 0.14
Steer Ahead...... 0
Camber............. -1.5 -1.5
Toe.................. 0.11 0.11
Total toe........... 0.22
Thrust angle...... 0
Any Ideas as to why my car is pulling left?
These are the final numerical values for the alignment:
Camber......... -1.3 -1.2
Caster........... 3.9 3.8
Toe IN .......... .07 .07
Total toe....... 0.14
Steer Ahead...... 0
Camber............. -1.5 -1.5
Toe.................. 0.11 0.11
Total toe........... 0.22
Thrust angle...... 0
Any Ideas as to why my car is pulling left?
07-07-2010, 08:49 PM
#11
Addict
Rennlist Member
Rennlist Member
How much is a "little toe in" as your comment about car being twitchy at speed is Interesting. I have to look at the alignment specs for F toe #. After loweing the car with (Bilstein) HD+ H&R reds and getting alignment, the car is a little nervous at speed and seems to have gone towards over-steers which is much worst on wet track. IIRC the camber is about -2 F and R
As for increased oversteer, first check tire pressures (should be same front and rear) and then sway bar settings, if they have adjustability. Excessive oversteer could also be caused by relative tire/wheel sizes, spring rates, shock valving, camber differences and, of course, toe specs. But it will definitely compromise corner entry and exit speeds and will need to be dialed out to get the most out of your car.
07-07-2010, 08:56 PM
#12
Three Wheelin'
Thread Starter
Hi Joey. Thanks for your thoughts. Its not that the car has over steer, the car does not track straight on flat surface. It pulls to the left and I have to wrestle the steering wheel to the right to go straight.....
Anybody?
Anybody?
07-07-2010, 09:17 PM
#13
Addict
Rennlist Member
Rennlist Member
Yes, Jaime, I was still responding to Nader's question with the oversteer comments.
Your issue has me stumped. Specs seem good so what else could it be?
Your issue has me stumped. Specs seem good so what else could it be?
07-07-2010, 09:44 PM
#15
Three Wheelin'
Thread Starter
Hi guys. Yes, I checked the pressures (front at 33 lbs, rear 36 lbs). I've been checking the pressures with a digital gauge and have seen equal rise of pressure to 0.5 lbs all around depending on how hot or cool it is in the garage. Just before I took it to Porsche I checked again and all was exactly the same (got there at 5:00pm, so had to leave it for alignment in the am).
I disconnected the front strut tower camber brace, and using same wheels as before the upgrade to evo uprights.
Maybe the Dealer's alignment rack is off??
Oh, here's another possibility...... When I re-adjusted the front JIC/Cross competition struts, I unscrewed the seat for the helper spring so the entire coil assembly was loose, then I retightened the helper spring until the primary spring was snug with its mating surface at the top. did same exact thing to both sides. Unless I was not suppose to do this, there's nothing else I can remember I did differently that may introduce an alignment problem.....
Well, I am running less toe-in than before....... could this cause such a prominent pull??
I disconnected the front strut tower camber brace, and using same wheels as before the upgrade to evo uprights.
Maybe the Dealer's alignment rack is off??
Oh, here's another possibility...... When I re-adjusted the front JIC/Cross competition struts, I unscrewed the seat for the helper spring so the entire coil assembly was loose, then I retightened the helper spring until the primary spring was snug with its mating surface at the top. did same exact thing to both sides. Unless I was not suppose to do this, there's nothing else I can remember I did differently that may introduce an alignment problem.....
Well, I am running less toe-in than before....... could this cause such a prominent pull??