Does 5mm really make a difference..?
10-22-2008, 10:00 AM
#1
Racer
Thread Starter
Does 5mm really make a difference..?
Hi everyone!
On my 79' I put 5mm rear spacers when I put on 9" cup2's... (I liked the look.. felt that the rear wheels were always too far inward.. yes it's shallow I know)
Thing is the car seemed to be very "stiff" in the cornering.. so I decided to take the spacers off this last weekend.. and suddenly she seemed to be so much more nimble in the twisties....
Does a 5mm spacer on each rear wheel really affect the suspension geometry THAT much... ? Or it is really all in my head?
Many thanks!
Curt
-------------
79 5sp silver/blk
02 boxster 5sp blk/blk
On my 79' I put 5mm rear spacers when I put on 9" cup2's... (I liked the look.. felt that the rear wheels were always too far inward.. yes it's shallow I know)
Thing is the car seemed to be very "stiff" in the cornering.. so I decided to take the spacers off this last weekend.. and suddenly she seemed to be so much more nimble in the twisties....
Does a 5mm spacer on each rear wheel really affect the suspension geometry THAT much... ? Or it is really all in my head?
Many thanks!
Curt
-------------
79 5sp silver/blk
02 boxster 5sp blk/blk
10-22-2008, 10:49 AM
#2
Rennlist Member
A narrower rear track will loosen the rear end. If what you were referring to as stiff was a tendency for the rear wheels to push the front wheels around then it would be a little more balanced and more nibble.
And yes, small changes can make a big difference. I corner balanced a 944 Turbo that only required a 1/32 ride height adjustment on one corner. The car was 2 seconds a lap faster on a 60 second lap after the adjustment.
And yes, small changes can make a big difference. I corner balanced a 944 Turbo that only required a 1/32 ride height adjustment on one corner. The car was 2 seconds a lap faster on a 60 second lap after the adjustment.
10-22-2008, 09:47 PM
#6
Captain Obvious
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A narrower rear track will loosen the rear end. If what you were referring to as stiff was a tendency for the rear wheels to push the front wheels around then it would be a little more balanced and more nibble.
And yes, small changes can make a big difference. I corner balanced a 944 Turbo that only required a 1/32 ride height adjustment on one corner. The car was 2 seconds a lap faster on a 60 second lap after the adjustment.
And yes, small changes can make a big difference. I corner balanced a 944 Turbo that only required a 1/32 ride height adjustment on one corner. The car was 2 seconds a lap faster on a 60 second lap after the adjustment.
You are sure it wasn't just in the head of the driver? Every single suspension conponent on a car has rubber bushings that flex and move. 1/32 is very little considering how much things move around during hard driving.
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10-22-2008, 10:44 PM
#8
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I think it's in your head. Go get a ruler and see what 10mm looks like. If I am wrong, then so be it, but I hardly think there could be a difference.
Now, if you were talking about the front end like in offset, then I would say no question.
Not sure what a 5mm spacer would do for the looks anyway, its barely noticeable.
Now, if you were talking about the front end like in offset, then I would say no question.
Not sure what a 5mm spacer would do for the looks anyway, its barely noticeable.
10-23-2008, 01:55 AM
#9
Rennlist Member
Imre, the 944 Turbo I am referring to had upgraded springs, swaybars, and adj dampers. I did the suspension setup starting with springs with dampers and swaybars set full soft. I tested and tuned to get the most out of the car before adjusting the next thing. After getting the general ride heights adjusted for the maxium speed I could maintain around a 200ft skid pad, then I cranked in swaybar maintaining the front to rear balance bringing both firmer until the speed the car broke loose around the skid pad got slower. Then I used the damper rebound adjustment to get the best entry and exit speeds. The rear just soft enough the rear would start to rotate on turn-in as I released the brakes. The fronts just firm enough that adding throttle going into the apex would not let the rear tires spin. Once satisfied with all the adjustments the car felt like a 4 legged table with one short leg in transitions. The weight would start to transfer then it would feel like it teetered. The teetering upset the balance breaking the car loose. After doing the 1/32nd adjustment corner balancing the car the teeter was gone and lap times came down 2 seconds. The suspension tuning mechanic that helped me was pretty proud of our methods getting the corner balance so close before actually putting the car on the scales. This difference was not just driving around feeling like it was faster, but at the limit driving ie, maintaining a FOUR wheel drifts from turn-in to exit. Oh, and the 1/32 made a 50lb difference.
10-23-2008, 10:03 AM
#10
Captain Obvious
Super User
Super User
Imre, the 944 Turbo I am referring to had upgraded springs, swaybars, and adj dampers. I did the suspension setup starting with springs with dampers and swaybars set full soft. I tested and tuned to get the most out of the car before adjusting the next thing. After getting the general ride heights adjusted for the maxium speed I could maintain around a 200ft skid pad, then I cranked in swaybar maintaining the front to rear balance bringing both firmer until the speed the car broke loose around the skid pad got slower. Then I used the damper rebound adjustment to get the best entry and exit speeds. The rear just soft enough the rear would start to rotate on turn-in as I released the brakes. The fronts just firm enough that adding throttle going into the apex would not let the rear tires spin. Once satisfied with all the adjustments the car felt like a 4 legged table with one short leg in transitions. The weight would start to transfer then it would feel like it teetered. The teetering upset the balance breaking the car loose. After doing the 1/32nd adjustment corner balancing the car the teeter was gone and lap times came down 2 seconds. The suspension tuning mechanic that helped me was pretty proud of our methods getting the corner balance so close before actually putting the car on the scales. This difference was not just driving around feeling like it was faster, but at the limit driving ie, maintaining a FOUR wheel drifts from turn-in to exit. Oh, and the 1/32 made a 50lb difference.
Wow.... I would have never expected 1/32 on an inch to make that much difference. You did a good job setting up that car.
10-23-2008, 02:25 PM
#11
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Oh My where to start...... the rear track on a 928 is 1530 mm so adding two 5 mm spacers is 10 mm or a total change of 6 tenths of one percent. 5 mm is NOTHING . I vote placebo ....
10-23-2008, 04:11 PM
#13
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Wider track softens the effective spring rate because you have a longer lever working against the spring but again very slight change. The bigger heavier wheels and tires make the shocks job much harder.
10-23-2008, 04:11 PM
#14
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