strut brace
06-24-2009, 11:41 PM
#1
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strut brace
i'm building a strut brace for my coupe quattro, and have a few questions of people me experienced then me.
my basic plan is to make sealed barrings for the strut towers to mount the brace, i just noticed that they both twist slightly because of the springs and figured i would do this properly.
how ever i want to know if a one dimension strut brace will make much difference, or if there is a lot of vertical flex too.
secondly if i was to mount it to the frame what would be the best place, should note that i would like a place that is not detrimental to the body, or looks, is i would preform a mounting point like the engine mounts, where if i change my mind or improve the design it wont matter to the looks.
and thirdly i am planning not to mount directly to the towers, but to the tops of the struts, will it matter?
Thanks
Daniel
my basic plan is to make sealed barrings for the strut towers to mount the brace, i just noticed that they both twist slightly because of the springs and figured i would do this properly.
how ever i want to know if a one dimension strut brace will make much difference, or if there is a lot of vertical flex too.
secondly if i was to mount it to the frame what would be the best place, should note that i would like a place that is not detrimental to the body, or looks, is i would preform a mounting point like the engine mounts, where if i change my mind or improve the design it wont matter to the looks.
and thirdly i am planning not to mount directly to the towers, but to the tops of the struts, will it matter?
Thanks
Daniel
06-25-2009, 06:13 AM
#2
AudiWorld Senior Member
Interesting questions sir, and your concerns are not small...
Have you seen the factory strut-brace on the B4 cars?
You can see one end of it here (my '93 CSq):
https://forums.audiworld.com/picture...ctureid=191248
Some have replaced the cross-tube with a lighter alloy tube, sometimes mounted between sphericals vs. the two clamping bolts per side, but as your question suggests, do you want to isolate it from the possible up-down motion, or brace against it? That would be an interesting discussion.
Others have installed brackets that bolt to the double-wall inner-fender towers.
There's a good article about the brace (photo below, with more pictures) here:
http://www.humanspeakers.com/audi/strut-brace.htm
As for myself, I'm gathering the pieces to weld in the OEM brace in my B3. The reasons why are: all these (good cost/benefit) pieces are available, and I really like the way my B4 steers (different from the B3 somehow), and this is one of the principle physical differences between the two.
See the OEM brace installed (where there was none before) here:
http://www.humanspeakers.com/audi/strut-brace-90.htm
You should also be aware that the tops of the strut damper-shafts (you can see the ends of the damper rod in the centre of the top mounts) move in a couple of (three) ways. Simple up-down as the suspension is re & unloaded, radially under braking and cornering etc., but also the real geometric vertical axis of the damper shaft is going to change it's tilt as the suspension moves up and down; <i>and they do not always move together</i>.
What it may come down to is, where on your to-do list does what you have in mind become the limiting technical deficiency. This is because there are several "feelable" economic maintenance items that are logical stepping stones to build on, on your way towards, and which are necessary to really "connect" to, whatever you may want to incorporate into that strut-brace.
With the above in mind, and with your hood up, and a floor jack, you can see some of this motion in action, by observing the behaviour of your strut-top mounts from fully loaded to unloaded. And that that will lead to many other discussions, I have no doubt.
You can see one end of it here (my '93 CSq):
https://forums.audiworld.com/picture...ctureid=191248
Some have replaced the cross-tube with a lighter alloy tube, sometimes mounted between sphericals vs. the two clamping bolts per side, but as your question suggests, do you want to isolate it from the possible up-down motion, or brace against it? That would be an interesting discussion.
Others have installed brackets that bolt to the double-wall inner-fender towers.
There's a good article about the brace (photo below, with more pictures) here:
http://www.humanspeakers.com/audi/strut-brace.htm
As for myself, I'm gathering the pieces to weld in the OEM brace in my B3. The reasons why are: all these (good cost/benefit) pieces are available, and I really like the way my B4 steers (different from the B3 somehow), and this is one of the principle physical differences between the two.
See the OEM brace installed (where there was none before) here:
http://www.humanspeakers.com/audi/strut-brace-90.htm
You should also be aware that the tops of the strut damper-shafts (you can see the ends of the damper rod in the centre of the top mounts) move in a couple of (three) ways. Simple up-down as the suspension is re & unloaded, radially under braking and cornering etc., but also the real geometric vertical axis of the damper shaft is going to change it's tilt as the suspension moves up and down; <i>and they do not always move together</i>.
What it may come down to is, where on your to-do list does what you have in mind become the limiting technical deficiency. This is because there are several "feelable" economic maintenance items that are logical stepping stones to build on, on your way towards, and which are necessary to really "connect" to, whatever you may want to incorporate into that strut-brace.
With the above in mind, and with your hood up, and a floor jack, you can see some of this motion in action, by observing the behaviour of your strut-top mounts from fully loaded to unloaded. And that that will lead to many other discussions, I have no doubt.
Last edited by Lago Blue; 06-25-2009 at 09:45 AM. Reason: add link and photo
06-25-2009, 11:58 PM
#3
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Have you seen the factory strut-brace on the B4 cars?
You can see one end of it here (my '93 CSq):
https://forums.audiworld.com/picture...ctureid=191248
, do you want to isolate it from the possible up-down motion, or brace against it? That would be an interesting discussion.
You can see one end of it here (my '93 CSq):
https://forums.audiworld.com/picture...ctureid=191248
, do you want to isolate it from the possible up-down motion, or brace against it? That would be an interesting discussion.
if i was left all own long enough with a tig welder and my car i would probably make a tube frame chassis for it.
so i need you to tell me when to stop.
how much vertical movement is there?
on that note how much horizontal movement is there?
would mounting it to the frame really improve anything, or am i just going over board.
on a side not would a4 front springs work for a audi coupe quattro?
just seams like they would be a logical choice for cheap stiff springs.
Thanks alot
all the help is great
06-26-2009, 06:18 AM
#4
AudiWorld Senior Member
Re: Strut-Brace; "how much vertical movement is there?"
Unlike say, an old Mustang (has a couple of OEM braces), where the shock-towers are some distance from the firewall, our B3's towers are cleverly fastened right into the corners of the engine bay, so the firewall is going to help brace them vertically. Their domed shape helps too.
But if you think of the engine bay as like a big card-board box, with the top still able to open, and the bottom some-what missing, you can imagine how it might flex. VW Scirocco's 16v's even had an OEM "bottom of the bay" brace. We have a big cradle.
As to "would mounting it to the frame really improve anything,...?" That is precisely what the factory did. Would they add that weight/expense/complexity for nothing?
Getting back to "how much vertical movement", that is an open ended question. It will be subjective to how much force is applied. Previously, I'd suggested jacking-up one corner of your car. Do it again, but with a door open this time, and then while it is still jacked; try to close the door.
With all that said, and before you look to alternate springs or other major component changes, I would suggest you proceed to pick the low hanging fruit of vertical play/movement as follows:
1. Mount-Savers, and the requisite brand new OEM Sachs/Boge strut-mounts; (for the more cost-concious, will work at all four corners) and/or
2. Pro-Mounts and Mount-Savers; (more expensive, but more rewarding, also works on all four corners, but particularly on the front end). This is the combo I chose (Pro-Mounts and Mount-Savers on the front; and Mount-Savers, and the requisite brand new OEM Sachs/Boge strut-mounts on the rear.
3. Go to "20v.org" (old style) and read about replacing -all- your old rubber suspension bushings, and then do it.
In maintenance terms this is called "returning to base conditions". On a car that has not had these <i>wear items</i> refreshed (your's?), you will be surprised at the transformation in driving satisfaction once the car has it's "as delivered" equipment available and functioning as originally intended. Hasn't Audi won just about every competition ever held with this basic design, so it ain't too bad, really.
The reasons I suggest the above are intertwined. You won't benefit from the world's best strut-brace on a car that has not been serviced properly. The strut-mounts in particular, are the Achilles's heel of these cars and any alternatives to #1 & #2 above; are simply not worth the trouble. These items are going remove more slack and movement than any brace ever will. Learning about and installing these items is going to allow you to time to research (use the search function here, under "search forums" at the top of the page) other possible options; without regret. I would suggest also that you try to attend some Audi Club driving events where you'll meet others who have gone down some of these roads.
To you sir I say "Mr. Yetiking, put down (for now) that torch!
P.S. Stiffer springs on a car that hasn't got 1,2, and 3 above done; is going to "feel" worse. No, A4 springs won't work, but B4's might.
But if you think of the engine bay as like a big card-board box, with the top still able to open, and the bottom some-what missing, you can imagine how it might flex. VW Scirocco's 16v's even had an OEM "bottom of the bay" brace. We have a big cradle.
As to "would mounting it to the frame really improve anything,...?" That is precisely what the factory did. Would they add that weight/expense/complexity for nothing?
Getting back to "how much vertical movement", that is an open ended question. It will be subjective to how much force is applied. Previously, I'd suggested jacking-up one corner of your car. Do it again, but with a door open this time, and then while it is still jacked; try to close the door.
With all that said, and before you look to alternate springs or other major component changes, I would suggest you proceed to pick the low hanging fruit of vertical play/movement as follows:
1. Mount-Savers, and the requisite brand new OEM Sachs/Boge strut-mounts; (for the more cost-concious, will work at all four corners) and/or
2. Pro-Mounts and Mount-Savers; (more expensive, but more rewarding, also works on all four corners, but particularly on the front end). This is the combo I chose (Pro-Mounts and Mount-Savers on the front; and Mount-Savers, and the requisite brand new OEM Sachs/Boge strut-mounts on the rear.
3. Go to "20v.org" (old style) and read about replacing -all- your old rubber suspension bushings, and then do it.
In maintenance terms this is called "returning to base conditions". On a car that has not had these <i>wear items</i> refreshed (your's?), you will be surprised at the transformation in driving satisfaction once the car has it's "as delivered" equipment available and functioning as originally intended. Hasn't Audi won just about every competition ever held with this basic design, so it ain't too bad, really.
The reasons I suggest the above are intertwined. You won't benefit from the world's best strut-brace on a car that has not been serviced properly. The strut-mounts in particular, are the Achilles's heel of these cars and any alternatives to #1 & #2 above; are simply not worth the trouble. These items are going remove more slack and movement than any brace ever will. Learning about and installing these items is going to allow you to time to research (use the search function here, under "search forums" at the top of the page) other possible options; without regret. I would suggest also that you try to attend some Audi Club driving events where you'll meet others who have gone down some of these roads.
To you sir I say "Mr. Yetiking, put down (for now) that torch!
P.S. Stiffer springs on a car that hasn't got 1,2, and 3 above done; is going to "feel" worse. No, A4 springs won't work, but B4's might.
06-27-2009, 07:57 PM
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sorry for my incompetence, but what are Pro-Mounts and Mount-Savers?. what company makes them, and how much are they.
sorry you have to waste your time explaining this to me.
one more question though, really i have no complaints with the stock suspension except that the body roll is un-nerving. is there any systems like BMW self leveling suspension?(i know they're not the first, but i forgot who was)is it possible to get self leveling struts for a coupe?
thanks a lot for the help, 1,2 and 3 will be my next priority.
can't tell you how much help it is
sorry you have to waste your time explaining this to me.
one more question though, really i have no complaints with the stock suspension except that the body roll is un-nerving. is there any systems like BMW self leveling suspension?(i know they're not the first, but i forgot who was)is it possible to get self leveling struts for a coupe?
thanks a lot for the help, 1,2 and 3 will be my next priority.
can't tell you how much help it is
06-29-2009, 07:04 AM
#6
AudiWorld Senior Member
Everything you never even knew you wanted to know about...
Mount-Savers and Pro-Mounts is buried; right here in the archives (see search function remarks above). As this is a non-commercial forum, and that the maker has grown tired of the endless <i>unself-informed</i> inquiries, I'm not gonna answer you directly.
Not knowing about these is not a question of competence at all, but part of an almost guerrilla (or reverse) marketing plan that requires a certain amount of self-education on the consumer's part. In this fashion, I think the maker hopes to both weed-out the less determined, and raise the standard of questions he will entertain.
They are made by a private individual who has written extensively about their development, here on this forum; He makes them for his own use; and discerning individuals.
Hint: there is <i>no longer</i> a website;
In your research, you will find his name (it is not for me to give out), address and you can ask him for prices;
There are a only a couple of decisions you will have to make regarding the configuration of these components for use in your particular situation. The more research you have done, the better understanding you will have, and the better questions you may have to ask.
What they are, are; the necessary and final strut-mount solution.
Whether Mount-Savers and/or Pro-Mounts in your case? This is really the question that only you can answer. In order for that to happen, you need to go back and search and read in the archives.
Not knowing about these is not a question of competence at all, but part of an almost guerrilla (or reverse) marketing plan that requires a certain amount of self-education on the consumer's part. In this fashion, I think the maker hopes to both weed-out the less determined, and raise the standard of questions he will entertain.
They are made by a private individual who has written extensively about their development, here on this forum; He makes them for his own use; and discerning individuals.
Hint: there is <i>no longer</i> a website;
In your research, you will find his name (it is not for me to give out), address and you can ask him for prices;
There are a only a couple of decisions you will have to make regarding the configuration of these components for use in your particular situation. The more research you have done, the better understanding you will have, and the better questions you may have to ask.
What they are, are; the necessary and final strut-mount solution.
Whether Mount-Savers and/or Pro-Mounts in your case? This is really the question that only you can answer. In order for that to happen, you need to go back and search and read in the archives.
Last edited by Lago Blue; 06-29-2009 at 09:01 AM. Reason: I'm fussy
06-29-2009, 09:47 AM
#7
AudiWorld Senior Member
Re: Possibly excessive body roll...
Again, worn/damaged parts that no longer function as delivered in 1989/90/91 may be allowing the car to exhibit more roll than when it was new; or last serviced.
Even the latest in techno-flash gimmickry won't solve body-roll <i>until it is properly (re-?)connected to the car</i>. As the car wants to roll, any clearances must first be taken-up (to zero) before the suspension can <i>resist</i> roll. This includes but may not be limited to the following:
- tire pressures;
- worn/damaged strut-mounts (are they new and protected?);
- anti-roll (A/R) bar end link bushings and support washers (are they lubricated, rust-free and new?) and linkage.
Have you done the jack-test yet?
Search for and find the allowable at-rest clearance allowed under the cupped washer (sits through the hole in the fender-top, nested into the top of the strut-mount) and above the fender.
On an car past needing service, I've seen the support washers for the end-link bushings for the A/R bar rusted and pushed up the linkage, such that the A/R bar would not function, there was so much slack. Inspect, lubricate, return to base condition. Do you think that "20v'org" recommends replacement of all those bushings for nothing?
Your car may not lack for anything but service.
Even the latest in techno-flash gimmickry won't solve body-roll <i>until it is properly (re-?)connected to the car</i>. As the car wants to roll, any clearances must first be taken-up (to zero) before the suspension can <i>resist</i> roll. This includes but may not be limited to the following:
- tire pressures;
- worn/damaged strut-mounts (are they new and protected?);
- anti-roll (A/R) bar end link bushings and support washers (are they lubricated, rust-free and new?) and linkage.
Have you done the jack-test yet?
Search for and find the allowable at-rest clearance allowed under the cupped washer (sits through the hole in the fender-top, nested into the top of the strut-mount) and above the fender.
On an car past needing service, I've seen the support washers for the end-link bushings for the A/R bar rusted and pushed up the linkage, such that the A/R bar would not function, there was so much slack. Inspect, lubricate, return to base condition. Do you think that "20v'org" recommends replacement of all those bushings for nothing?
Your car may not lack for anything but service.
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06-29-2009, 07:07 PM
#8
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i did the jack test, and it moved about a half inch from totally in the air to twice the weight of the car.
i've read as much as i can for now about pro mounts, vap spent some time developing these.
informational i cant find any pictures so his explanations are lost on me.
i assume your using some since you seam the rate them highly. if you have a picture i would love how it differs form the stock/track versions.
i also don't really get the grove thing he was talking about
are track bushings eventually just solid metal mounting bracket?
Thanks
Daniel
i've read as much as i can for now about pro mounts, vap spent some time developing these.
informational i cant find any pictures so his explanations are lost on me.
i assume your using some since you seam the rate them highly. if you have a picture i would love how it differs form the stock/track versions.
i also don't really get the grove thing he was talking about
are track bushings eventually just solid metal mounting bracket?
Thanks
Daniel
06-30-2009, 07:49 AM
#9
AudiWorld Senior Member
Here is a cut-away photograph (034's). This may help when...
trying to comprehend those old photo-less posts as you can see the (otherwise hidden) key three metal rings/bands/braces of the strut-mounts inner construction, and the famous bearing.
As damage to the OEM mounts (on left in photo) is such a common and recurring issue, many have tried to solve it; few permanently. On the right is 034's "Density" version. I've never tried them, but a search here may reveal other's experience.
As damage to the OEM mounts (on left in photo) is such a common and recurring issue, many have tried to solve it; few permanently. On the right is 034's "Density" version. I've never tried them, but a search here may reveal other's experience.
Last edited by Lago Blue; 07-02-2009 at 08:06 AM. Reason: clarity
06-30-2009, 08:32 AM
#10
AudiWorld Senior Member
One of the few photos to be found...
On the top left is the Pro-Mount, top side up. In the mount's top recess, more easily seen in the 034 photo, will sit the required Mount-Saver.
Top centre is the Mount-Saver. It works in both new OEM (Boge/Sachs) strut-mounts and (is required in!) the Pro-Mount. These are available in at least a couple of heights that your mounts will eventually settle into. This photo is actually of a Mount-Saver "I" (plastic), I believe the groove thing you mentioned is Mount-Saver "II" (metal), I have no experience with those.
IIRC, generally, of the two types of Mount-Saver's, relative to one another, the type "I's" are currently made taller, allow less settling, and therefore may raise the car slightly from OEM; and the type "II's" are currently made shorter, allow more settling, and may slightly lower the car from OEM. I wanted to avoid further lowering (car came with lowering springs) so I asked for the street-height ones, but if I was to do it over, I go rally-height like I did for my '93 90CSq.
Top right is the Pro-Mount again, bottom side up. A better view here of the installed spherical centre-bearing. This is the feature which I feel makes the Pro-Mount such a joy to drive when installed on the front-end, vice <i>any</i> strut-mount with an OEM style roller bearing, even with a Mount-Saver in it.
At the bottom of the photo, are nuts for the damper shaft; and sleeves for the I.D. of the spherical bearing, to adapt it to the O.D. of that damper shaft.
Top centre is the Mount-Saver. It works in both new OEM (Boge/Sachs) strut-mounts and (is required in!) the Pro-Mount. These are available in at least a couple of heights that your mounts will eventually settle into. This photo is actually of a Mount-Saver "I" (plastic), I believe the groove thing you mentioned is Mount-Saver "II" (metal), I have no experience with those.
IIRC, generally, of the two types of Mount-Saver's, relative to one another, the type "I's" are currently made taller, allow less settling, and therefore may raise the car slightly from OEM; and the type "II's" are currently made shorter, allow more settling, and may slightly lower the car from OEM. I wanted to avoid further lowering (car came with lowering springs) so I asked for the street-height ones, but if I was to do it over, I go rally-height like I did for my '93 90CSq.
Top right is the Pro-Mount again, bottom side up. A better view here of the installed spherical centre-bearing. This is the feature which I feel makes the Pro-Mount such a joy to drive when installed on the front-end, vice <i>any</i> strut-mount with an OEM style roller bearing, even with a Mount-Saver in it.
At the bottom of the photo, are nuts for the damper shaft; and sleeves for the I.D. of the spherical bearing, to adapt it to the O.D. of that damper shaft.
Last edited by Lago Blue; 07-02-2009 at 06:01 AM. Reason: spelling, clarity