Ride Height Adjustment Problem
Nordschleife Master
Joined: Jul 2003
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From: Minneapolis
The suspension doesn't really care about "ride height" it's the angles of the A-arms that are important.
Thread Starter
Race Director
Joined: Sep 2007
Posts: 12,162
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From: Johnson City, TN
Glen, I don't know. First time I've dealt with shocks and ride height. A shop installed them on Jim's behalf a number of months ago. How do I check? I guess I need to do some research.
OK, I'll dig the WSM references out.
Taking the 15mm radius increase on the rears, I think I'm at/around Jim's previously recorded (above) rear ride height of 200-ish. Now I want to know how to go to 170mm.
On the front, honestly, I didn't bother to measure yet. It just looks so very high-water to me. (I have a couple of reference cars for comparison)
OK, I'll dig the WSM references out.
Taking the 15mm radius increase on the rears, I think I'm at/around Jim's previously recorded (above) rear ride height of 200-ish. Now I want to know how to go to 170mm.
On the front, honestly, I didn't bother to measure yet. It just looks so very high-water to me. (I have a couple of reference cars for comparison)
Rennlist Member
Joined: May 2003
Posts: 8,706
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From: Frankenmuth, Michigan
I don't think they're upside down...
Chuck Z had a similar thread not too long ago where a similar question was asked re collar orientation.
Just found it LINK ...but it appears your have already reviewed it.
Chuck Z had a similar thread not too long ago where a similar question was asked re collar orientation.
Just found it LINK ...but it appears your have already reviewed it.
Team Owner
Joined: May 2004
Posts: 31,138
Likes: 4,147
From: Philly PA
the front collars are on correctly.
so this may just be a spring issue did you cross reference the spring colors you have, VS the car and position they should be in?
The lower perches also look to be in the correct positions, .
If you cant move the front adjusters ,
then heat the collars with a torch and use the spring compressor to relieve the tension as best you can.
Warning, have a fire extinguisher handy so the PB blaster wont catch anything on fire.
dont use too much heat as the shocks are gas filled.
Heating the adjusters will usually free them up
The rear spring collars should be about 5 to 10 threads from the bottom on most Bilstien installs I have done
so this may just be a spring issue did you cross reference the spring colors you have, VS the car and position they should be in?
The lower perches also look to be in the correct positions, .
If you cant move the front adjusters ,
then heat the collars with a torch and use the spring compressor to relieve the tension as best you can.
Warning, have a fire extinguisher handy so the PB blaster wont catch anything on fire.
dont use too much heat as the shocks are gas filled.
Heating the adjusters will usually free them up
The rear spring collars should be about 5 to 10 threads from the bottom on most Bilstien installs I have done
Rennlist Member
Joined: May 2003
Posts: 8,706
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From: Frankenmuth, Michigan
FWIW
This 928 has the M474 option Bilsteins from the factory. Historically, the ride height was much lower than it is now.
Then the factory original Bilsteins were changed out for new Bilsteins. Nothining else was changed.
Could the Bilsteins not be the same?
Chris, could you call Roger and ask him to x-ref p/n's?
This 928 has the M474 option Bilsteins from the factory. Historically, the ride height was much lower than it is now.
Then the factory original Bilsteins were changed out for new Bilsteins. Nothining else was changed.
Could the Bilsteins not be the same?
Chris, could you call Roger and ask him to x-ref p/n's?
Thread Starter
Race Director
Joined: Sep 2007
Posts: 12,162
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From: Johnson City, TN
Thanks for helping me figure this out.
Yes, re: part numbers, will-do.
Can carefully put a little heat on the front collars.
Something interesting is going on here I think. We will get to the bottom of it.
The subject car, BTW, is the gray one in Jim's avatar.
We had the rear end out of it last week and I lost the reference marks during cleaning, so it needs alignment. This ride height check / adjustment has turned into a little more of research project, but that's what I love about these cars.
Yes, re: part numbers, will-do.
Can carefully put a little heat on the front collars.
Something interesting is going on here I think. We will get to the bottom of it.
The subject car, BTW, is the gray one in Jim's avatar.
We had the rear end out of it last week and I lost the reference marks during cleaning, so it needs alignment. This ride height check / adjustment has turned into a little more of research project, but that's what I love about these cars.
Under the Lift
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Joined: Mar 2002
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From: Buckeye, AZ
Bilstein only makes one shock that fits. I have them on my car and have had no problem with getting my ride height down and still having a good amount of thread showing. I'm 172 rear, 165 front. But look at the pic below at the adjustment ring I have - supplied with the shocks when I bought them - actually your rear one looks the same and my front ones are like your front ones.
Also, AFAIK, there is no M474 sport spring. M474 is sport shocks, either Boge Red or Bilstein. The springs are the same as non-M474. The paint marks indicate the tolerance group, as shown in the WSM - somebody please correct me if I have this wrong. There is a Club Sport spring option, but that is a separate option and only on Club Sport models.
Also, AFAIK, there is no M474 sport spring. M474 is sport shocks, either Boge Red or Bilstein. The springs are the same as non-M474. The paint marks indicate the tolerance group, as shown in the WSM - somebody please correct me if I have this wrong. There is a Club Sport spring option, but that is a separate option and only on Club Sport models.
Rennlist Member
Joined: May 2003
Posts: 8,706
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From: Frankenmuth, Michigan
...Also, AFAIK, there is no M474 sport spring. M474 is sport shocks, either Boge Red or Bilstein. The springs are the same as non-M474. The paint makles indicate the tolerance group, as shown in the WSM - somebody please correct me if I have this wrong. There is a Club Sport spring option, but that is a separate option and only on Club Sport models.
There are three different versions of same basic spring. Individual springs were measured and split into three groups based on their thightness. Measurement is done by compressing spring to certain spring type specific selected lenght and measuring how much force it creates.
On production line only same group springs were used at same axle. Those cars which got more options only used two stronger group springs to compensate for heavier options. Springs have one to three paint markings which tell which group they are. WSM has values for each group.
When replacing individual springs same group replacement should be used or if not available both need to be changed. Thats why PET has option of ordering all three possibilities.
On production line only same group springs were used at same axle. Those cars which got more options only used two stronger group springs to compensate for heavier options. Springs have one to three paint markings which tell which group they are. WSM has values for each group.
When replacing individual springs same group replacement should be used or if not available both need to be changed. Thats why PET has option of ordering all three possibilities.
I think Erkka might agree with you...
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Joined: Feb 2003
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From: saratoga, ca
yes, 5:1. go do a check as I did. mark the shock piston at rest. jack the car up and measure the wheel droop. I got 1" of shock travel, and 5" of wheel droop. there you go, 5:1.
I even posted pictures of this with measuring proof.
in the other direction, how do I get to this ride hight, which is 4" lower, with only 1" of shock travel available?
I even posted pictures of this with measuring proof.
in the other direction, how do I get to this ride hight, which is 4" lower, with only 1" of shock travel available?
5 to 1? no way.
On the rear the shock mounts on the pivot pin next to the bearing carrier. Moving the spring u/down the shock will lift/lower the body almost the same amount. There are some subtle differences but it's real close.
On the front the shocks mounts roughly half-way between the hub and pivots at the body. 2:1. In practice these have been good estimates. With 1.5mm threads you'll get 3mm change for each full revolution of the nut.
To the issue: did you assemble the hats right?
On the rear the shock mounts on the pivot pin next to the bearing carrier. Moving the spring u/down the shock will lift/lower the body almost the same amount. There are some subtle differences but it's real close.
On the front the shocks mounts roughly half-way between the hub and pivots at the body. 2:1. In practice these have been good estimates. With 1.5mm threads you'll get 3mm change for each full revolution of the nut.
To the issue: did you assemble the hats right?
Thread Starter
Race Director
Joined: Sep 2007
Posts: 12,162
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From: Johnson City, TN
Parts on this car are as follows:
Front
F4 B46 0966 H004
Rear
419 0974 W008
Current Bilstein application guide for 928:
Front
F4 B46 0966 H1
Rear
F4 B46 0974 H1
Footnote: Something about Porsche dealer having equipment / parts to install
Not sure what all that means.
Does the spring perch simply follow the adjustment of the adjuster nut?
What is the talk about installing / pressing-out spring perches?
Front
F4 B46 0966 H004
Rear
419 0974 W008
Current Bilstein application guide for 928:
Front
F4 B46 0966 H1
Rear
F4 B46 0974 H1
Footnote: Something about Porsche dealer having equipment / parts to install
Not sure what all that means.
Does the spring perch simply follow the adjustment of the adjuster nut?
What is the talk about installing / pressing-out spring perches?
Nordschleife Master
Joined: Jul 2003
Posts: 7,741
Likes: 78
From: Minneapolis
Jack the car up? Whatever do you think you're testing?
I've done what the point is: turn the nut and watch the car lift. One full turn lifts the front about 3mm. The threads are 1.5mm pitch. That's 2:1 like the geometry of the suspension would predict. It's basic Mechanics, after all. It sure as &%$^& ain't going up 7.5mm per turn.
Whoops... Diverging into side argument.
I've done what the point is: turn the nut and watch the car lift. One full turn lifts the front about 3mm. The threads are 1.5mm pitch. That's 2:1 like the geometry of the suspension would predict. It's basic Mechanics, after all. It sure as &%$^& ain't going up 7.5mm per turn.
Whoops... Diverging into side argument.
