Project REAR WW LINER - GTS & Others
08-12-2011, 07:12 PM
#196
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Jerry,
Update on the left side GTS fender liner. Porsche has stopped/on hold the left liner even though they have over 20 sitting in Germany. I have sent a few back due to the fact that they do not fit the GTS fender very well and leave a gap of approx. 1". It is as if they were made for a 91 S4/GT and not a GTS. If I have sent them back I am sure others have done the same and finially Porsche is looking at it. So no pictures of the Left fender liner - sorry.
Even more need for you to have these ready for the market 8>)
Roger
Update on the left side GTS fender liner. Porsche has stopped/on hold the left liner even though they have over 20 sitting in Germany. I have sent a few back due to the fact that they do not fit the GTS fender very well and leave a gap of approx. 1". It is as if they were made for a 91 S4/GT and not a GTS. If I have sent them back I am sure others have done the same and finially Porsche is looking at it. So no pictures of the Left fender liner - sorry.
Even more need for you to have these ready for the market 8>)
Roger
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
08-12-2011, 07:28 PM
#197
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Thread Starter
That cube-shaped indent on the GTS liners is interesting - wonder why Porsche put it there; its definitely not an accident.
Possible NVH improvement? Or a higher strength area where road debris like gravel or small stones is most likely to contact the liner?
Thinking about it for a few seconds, it may be a combination of both.
With a smooth inner surface, small stones thrown up by the wheels would follow the complete arc of the liner's interior, giving more abrasion, and also making more noise (longer distance over which the scraping sound would occur). Adding that shape would interrupt the parabola and the debris would become airborne before a single bounce off the front half of the liner.
Possible NVH improvement? Or a higher strength area where road debris like gravel or small stones is most likely to contact the liner?
Thinking about it for a few seconds, it may be a combination of both.
With a smooth inner surface, small stones thrown up by the wheels would follow the complete arc of the liner's interior, giving more abrasion, and also making more noise (longer distance over which the scraping sound would occur). Adding that shape would interrupt the parabola and the debris would become airborne before a single bounce off the front half of the liner.
wow, Hilton. You are really thinking way way outside of the box. I can't even get my mind around just about any of what yoiu are theorizing. Keep up the good work anyway.
08-12-2011, 07:33 PM
#198
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Thread Starter
Jerry,
Update on the left side GTS fender liner. Porsche has stopped/on hold the left liner even though they have over 20 sitting in Germany. I have sent a few back due to the fact that they do not fit the GTS fender very well and leave a gap of approx. 1". It is as if they were made for a 91 S4/GT and not a GTS. If I have sent them back I am sure others have done the same and finially Porsche is looking at it. So no pictures of the Left fender liner - sorry.
Even more need for you to have these ready for the market 8>)
Roger
Update on the left side GTS fender liner. Porsche has stopped/on hold the left liner even though they have over 20 sitting in Germany. I have sent a few back due to the fact that they do not fit the GTS fender very well and leave a gap of approx. 1". It is as if they were made for a 91 S4/GT and not a GTS. If I have sent them back I am sure others have done the same and finially Porsche is looking at it. So no pictures of the Left fender liner - sorry.
Even more need for you to have these ready for the market 8>)
Roger
Stand by for further progress. I think these liners are going to come into very good foucus in the very near future.
Jerry Feather
08-12-2011, 07:44 PM
#199
Nordschleife Master
Its the reason Porsche added the liners in the first place, in the 91S4 and later the GTS. They reduce the interior noise by 3dba according to the "evolution" list of model year changes found on Wikipedia.
Thus, if there is no object in the wheel well to avoid where that form impression is, there must be another reason, and its logical to suppose the reason is related to the primary purpose of the liners - i.e. noise reduction. Porsche likely spent a fair bit of money developing the liners, so I wouldn't just discard some elements of their shape that you can't divine any reason for.
Now - to help you get a handle on what I was thinking, try thinking about what happens to a small stone that is thrown up by the tread of the rear wheels, in both your smooth liner, and Porsche's stepped one.
08-12-2011, 07:54 PM
#200
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Thread Starter
Jerry - NVH is "Noise Vibration and Harshness" - an auto industry term.
Its the reason Porsche added the liners in the first place, in the 91S4 and later the GTS. They reduce the interior noise by 3dba according to the "evolution" list of model year changes found on Wikipedia.
Thus, if there is no object in the wheel well to avoid where that form impression is, there must be another reason, and its logical to suppose the reason is related to the primary purpose of the liners - i.e. noise reduction. Porsche likely spent a fair bit of money developing the liners, so I wouldn't just discard some elements of their shape that you can't divine any reason for.
Now - to help you get a handle on what I was thinking, try thinking about what happens to a small stone that is thrown up by the tread of the rear wheels, in both your smooth liner, and Porsche's stepped one.
Its the reason Porsche added the liners in the first place, in the 91S4 and later the GTS. They reduce the interior noise by 3dba according to the "evolution" list of model year changes found on Wikipedia.
Thus, if there is no object in the wheel well to avoid where that form impression is, there must be another reason, and its logical to suppose the reason is related to the primary purpose of the liners - i.e. noise reduction. Porsche likely spent a fair bit of money developing the liners, so I wouldn't just discard some elements of their shape that you can't divine any reason for.
Now - to help you get a handle on what I was thinking, try thinking about what happens to a small stone that is thrown up by the tread of the rear wheels, in both your smooth liner, and Porsche's stepped one.
Jerry Feather
08-13-2011, 10:54 AM
#201
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Thread Starter
As to the cube-like indent in the upper rear corner of the factory liner for the right side as shown in the pictures from Roger, I think my more rounded shape is probably going to simply miss that area of the wheel well entirely without any need to form around whatever might be there. The shape of my liners is basically two 13 inch arcs connected by a 5 inch tangent. That is fairly different than the roughly trapazodial shape of the factory liners; so the upper rear corner where the indent is is probably not even in the "realm" of my liner.
If it turns out when mine are finally fitted to a GTS, that something is in the way, I guess it will be no big deal to put something in the form to accomodate for it. I hate to waste the effort and the plastic, however, in finding out.
Hilton's input is, however, one of the things that makes doing this development on an open forum like this so much fun. His theory is interesting; but I wonder why the indent is only on one side? And I wonder why it doesn't have any sound deadening foam in it?
Jerry Feather
If it turns out when mine are finally fitted to a GTS, that something is in the way, I guess it will be no big deal to put something in the form to accomodate for it. I hate to waste the effort and the plastic, however, in finding out.
Hilton's input is, however, one of the things that makes doing this development on an open forum like this so much fun. His theory is interesting; but I wonder why the indent is only on one side? And I wonder why it doesn't have any sound deadening foam in it?
Jerry Feather
08-13-2011, 10:57 AM
#202
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Thread Starter
P.S. I'm not sure actually how to describe an arc, whether by radius or diameter of the circle, but the 13 inches stated above is radius. JF
08-13-2011, 06:38 PM
#203
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Thread Starter
Last weekend I had completed a little secondary forming devise for forming the hem or whatever on the lower inside edge of the inside half of the liner so that it will sort of clip up and over the flange on the bottom of the frame member in that area, thus I think eliminating the need to put some screw holes in the earlier cars to hold the liner in this location. It was a bit of a chore to do, but not too involved and it came out great. It also works great; and it is adjustable so I can vary to width or depth of the hem as needed for thickness of the material in this area. That is important because I also intend to put a doubler on the car-side of the liner in this location to add some body and to add extra strength especially for those who still want to have holes for the GTS here and for those who might like to drill holes in their frames of the earlier cars to emulate the GTS.
I also got done most of the stand/jig that I designed for doing two things with the liners after they are formed and trimmed. One is to hold down another doubler that goes arount the circumfrence of the inner half of the liner next to the flange which will be glued on with ABS glue. I need to hold that firm til the glue sets, so I made this jig to be able to do that rather than try to do it with a whole bunch of clamps somehow. I'll do it with a simple hold-down strap.
The stand/jig will also then be used to put the two halve of finished liners together and drill the common holes for joining them with connectors. I still have to trim part of the jig and I have to mount the devise on it to hook the clamping devises to. It too is nearly complete.
Today I worked on some of the stand/jig; but I spent most of my time on the form for the outer halves. I have it about 2/3 done including the basic perimeter frame that I have had conmpleted for a while.
Tomorrow I am going to work on the rest of the outer half form and that will be the inside that will define the outer edges of the outer halves. That is going to take some free hand sculpting, but I will develop that pretty much as it goes. This is where the drawing that Gary made for me comes in to play. It is going to be worth its weight in something at this point.
I had to knock off kind of early so I could clean up for dinner. We are having guests for dinner and drinks, so I have to straighten up some of my stuff around here.
See you tomorrow.
Jerry Feather
I also got done most of the stand/jig that I designed for doing two things with the liners after they are formed and trimmed. One is to hold down another doubler that goes arount the circumfrence of the inner half of the liner next to the flange which will be glued on with ABS glue. I need to hold that firm til the glue sets, so I made this jig to be able to do that rather than try to do it with a whole bunch of clamps somehow. I'll do it with a simple hold-down strap.
The stand/jig will also then be used to put the two halve of finished liners together and drill the common holes for joining them with connectors. I still have to trim part of the jig and I have to mount the devise on it to hook the clamping devises to. It too is nearly complete.
Today I worked on some of the stand/jig; but I spent most of my time on the form for the outer halves. I have it about 2/3 done including the basic perimeter frame that I have had conmpleted for a while.
Tomorrow I am going to work on the rest of the outer half form and that will be the inside that will define the outer edges of the outer halves. That is going to take some free hand sculpting, but I will develop that pretty much as it goes. This is where the drawing that Gary made for me comes in to play. It is going to be worth its weight in something at this point.
I had to knock off kind of early so I could clean up for dinner. We are having guests for dinner and drinks, so I have to straighten up some of my stuff around here.
See you tomorrow.
Jerry Feather
08-16-2011, 10:37 AM
#204
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Thread Starter
I have been working on the mounting points for the left liner in my S4. I found that I really need to have the inner half of the liner accruately mounted in the car before I can finalize the design and form for the outer halves. I have the outer form about 2/3 finished, but am now developing the mounting points. I have them pretty well mocked up and need only a little bit of adjustment in the mockups before I can finalize the design. I think I am going to make the final version of them in aluminum.
One thing I am finding at this point is that there is a lot of difference between the S4 and the GTS cars in terms of mounting points that I can use to hang these new liners. I had hoped that all the mounting points in the S4 had carried over to the GTS with the GTS having just the two extrta points up in the top of the wheelwell. Not to be!
Actually the mounting of the liners in the S4 can very nicely be done without any need for additional points up in the top, but the GTS liners are not going to be mounted the same. I now have to figure out a way to develop a mounting connector for the top of the GTS cars, and I have to figure out how to do that without a GTS car available, so far. I don't think I can, so I'm going to have to scout out a GTS to do some fitting with. Any takers?
I did get the stand/jig done at least enough to see how it works to glue on the doubler that goes over the circumfrence of the inner half. It works great. I still have to trim it a tiny bit for the second stage of its use and that is mounting the two halves of the liners to it to drill the common holes for connecting the two halves of the liners in the car.
As to finishing the form for the outer halves, I find that it is kind of tricky to try to get the pattern of the wheel arch/opening lined up in the form so it is in the correct proximity to the inner half of the liners. It is more difficult than I had anticipated, but I think I will get it pretty soon now that one of the liner halves is correctly mounted in the car. Then I have to sculpt the form for the wheel openings, and there are going to be four of them--two for the S4 and others and two for the GTS. I have to make the S4 first of course because that is what I have to work with, and I don't want to do all four and then find out that they are all wrong. When they are done I will then be able to blow a prototype of the outer halves. When I do I'll post some pictures.
Jerry Feather
One thing I am finding at this point is that there is a lot of difference between the S4 and the GTS cars in terms of mounting points that I can use to hang these new liners. I had hoped that all the mounting points in the S4 had carried over to the GTS with the GTS having just the two extrta points up in the top of the wheelwell. Not to be!
Actually the mounting of the liners in the S4 can very nicely be done without any need for additional points up in the top, but the GTS liners are not going to be mounted the same. I now have to figure out a way to develop a mounting connector for the top of the GTS cars, and I have to figure out how to do that without a GTS car available, so far. I don't think I can, so I'm going to have to scout out a GTS to do some fitting with. Any takers?
I did get the stand/jig done at least enough to see how it works to glue on the doubler that goes over the circumfrence of the inner half. It works great. I still have to trim it a tiny bit for the second stage of its use and that is mounting the two halves of the liners to it to drill the common holes for connecting the two halves of the liners in the car.
As to finishing the form for the outer halves, I find that it is kind of tricky to try to get the pattern of the wheel arch/opening lined up in the form so it is in the correct proximity to the inner half of the liners. It is more difficult than I had anticipated, but I think I will get it pretty soon now that one of the liner halves is correctly mounted in the car. Then I have to sculpt the form for the wheel openings, and there are going to be four of them--two for the S4 and others and two for the GTS. I have to make the S4 first of course because that is what I have to work with, and I don't want to do all four and then find out that they are all wrong. When they are done I will then be able to blow a prototype of the outer halves. When I do I'll post some pictures.
Jerry Feather
08-16-2011, 10:45 AM
#205
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Thread Starter
Now, it occurs to me that I don't have much of a good idea how the liners or splash shields might be mounted in the GT cars. I wonder is they are the same as the S4 or as the GTS, or something else in between, perhaps.
Can some of you post some pictures of the inside of the GT wheel wells showing the mounting points for whatever is or should be mounted there? It will be a great help for me to see how much additional design work is going to be needed for mounting these in those cars. Thanks.
Jerry Feather
Can some of you post some pictures of the inside of the GT wheel wells showing the mounting points for whatever is or should be mounted there? It will be a great help for me to see how much additional design work is going to be needed for mounting these in those cars. Thanks.
Jerry Feather
08-16-2011, 11:33 AM
#206
Rennlist Member
Thread Starter
Here is the process that I am using to develop the mounting connectors.
In the S4 there are four points in the front of the WW and four in the rear. The bottom two of each set of four is going to be used directly since the liners are snug against them. The upper two of the front and the rear are more spaced out and do not come very close to the liners, except the bottom of those two in front, but not close enough.
For the back two, they seem to be on the same plane, so I took a fairly substantial piece of ABS plastic scrap in 3/16 inch thickness and trimmed one edge so it would fit up to the inner car body and cover both connecting points. Then I marked and drilled the holes for mounting it to the points. Then I put the inner half of the liner in place and took another piece of flat ABS with a nice clean straight edge and put that up against the one mounted at a 90 degree angle and over flush to the outer side of the flange on the liner circumfrence. Then I marked their proximity and marked the arc of the circumfrence on it. Then I took it to the band saw and cut the arc, but I cut it thin because it will have to mount on the other side of the flange on the liner half.
Then I put it in place to test the fit and checked my marks for proximity to the mounted piece. Then I put ABS glue on it and put it into place on the other side of the flange, the side toward the center of the car and held it in place for the glue to set. After the glue set for a while I took the liner out and then took the glued up connector out and clamped them in place together and let them set overnight.
When they were firmly glues together I started cutting away what will be excess material then put it back into the car and tested it to fit. With a little bit of grinding it came out very nice and has enough surface spread to put two mounting pioints between it and the liner flange.
The front one was similar, but the connector is going to be completerly different.
This process is going to have to be used to make a similar connector for the GTS car upper two mounting points. First screw a flat piece to the two points then cut and glue a verticle piece to it at the flange. Then trim it out and drill it for mounting. Actually I'll use these mock-ups as a basis for redoing these in aluminum.
Jerry Feather
In the S4 there are four points in the front of the WW and four in the rear. The bottom two of each set of four is going to be used directly since the liners are snug against them. The upper two of the front and the rear are more spaced out and do not come very close to the liners, except the bottom of those two in front, but not close enough.
For the back two, they seem to be on the same plane, so I took a fairly substantial piece of ABS plastic scrap in 3/16 inch thickness and trimmed one edge so it would fit up to the inner car body and cover both connecting points. Then I marked and drilled the holes for mounting it to the points. Then I put the inner half of the liner in place and took another piece of flat ABS with a nice clean straight edge and put that up against the one mounted at a 90 degree angle and over flush to the outer side of the flange on the liner circumfrence. Then I marked their proximity and marked the arc of the circumfrence on it. Then I took it to the band saw and cut the arc, but I cut it thin because it will have to mount on the other side of the flange on the liner half.
Then I put it in place to test the fit and checked my marks for proximity to the mounted piece. Then I put ABS glue on it and put it into place on the other side of the flange, the side toward the center of the car and held it in place for the glue to set. After the glue set for a while I took the liner out and then took the glued up connector out and clamped them in place together and let them set overnight.
When they were firmly glues together I started cutting away what will be excess material then put it back into the car and tested it to fit. With a little bit of grinding it came out very nice and has enough surface spread to put two mounting pioints between it and the liner flange.
The front one was similar, but the connector is going to be completerly different.
This process is going to have to be used to make a similar connector for the GTS car upper two mounting points. First screw a flat piece to the two points then cut and glue a verticle piece to it at the flange. Then trim it out and drill it for mounting. Actually I'll use these mock-ups as a basis for redoing these in aluminum.
Jerry Feather
08-16-2011, 11:43 AM
#207
Rennlist Member
Grand Junction..
We're considering to make a Grand Junction - Dallas roundtrip with the GTS if we can figure out a time slot that works for both of us.
How long would you need the GTS for to measure the mounting points ( in other words how long should we plan to stay in or around Grand Junction) As part of the round trip we would like to visit at Glenwood Hot Springs and make a half way stop between Grand Junction and Dallas at a friends mountain cabin in Mosquero NM.
How long would you need the GTS for to measure the mounting points ( in other words how long should we plan to stay in or around Grand Junction) As part of the round trip we would like to visit at Glenwood Hot Springs and make a half way stop between Grand Junction and Dallas at a friends mountain cabin in Mosquero NM.
08-16-2011, 08:58 PM
#209
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Thread Starter
Hi Herman. Great idea. What would be ideal is for you to be here from midday Sat to midday Sun. A next best alternative would be the same from fri to Sat. I would need to be able to block the time off from the office for fri afternoon. With either I think we could get the mounting point for the top of the liners mocked up and cured overnight and then trimmed to fit on Sat morning or Sun Morning. Then I could make the finished components later and would have the matching hole layout cut in the liner for finish later.
What time frame are you thinking of coming this way. I suppose I could be ready to do this within a short time period, because all I will need to do is have an inner liner set ready to fit. It will not matter if I don't have the outer halves ready to finish since they are not going to be critical to fitting the mounting points which all or most all fasten the the inner halves.
Great to hear from you. Hope we can work something out.
Jerry Feather
What time frame are you thinking of coming this way. I suppose I could be ready to do this within a short time period, because all I will need to do is have an inner liner set ready to fit. It will not matter if I don't have the outer halves ready to finish since they are not going to be critical to fitting the mounting points which all or most all fasten the the inner halves.
Great to hear from you. Hope we can work something out.
Jerry Feather
08-17-2011, 12:56 AM
#210
Rennlist Member
How about..
The second weekend in September I could plan to be with the GTS in Grand Junction Friday the 9th in the afternoon (you pick the best time for you) through Sunday the 11th