Jerry Feather

It occurs to me that the reason I am having some difficulty in communicating my thoughts about the Wheel Well Liner project is the unusual quantity of confusing and conflicting directions involved.

For example, since the new liners are going INSIDE the wheel well, should that mean the both sides of the liner are inside? Then, what is BOTH SIDES? Left and right? Or, inside/outside? If the liner is in the wheel well, which surface is inner and which is outer? Since the surface facing the tire is also exposed to the elements does that make it outside. If the liner is laying on the drive way looking like part of some kind of recepticle which surface is now the inside and which is the outside?

How about inward versus outward? Then there is PARALLEL and RADIAL OR RADIALLY (although I haven't even tried that one yet).

Anyway, until I have something produced that I can take a picture of to show what I am doing, or will have done by then, I guess you will all have to do the best you can with my feeble descriptions. When they are confusing just ask and I will try again.

Jerry Feather, FBA Certified
S4's (6)
KGJT

James Bailey

Given that the sole function and purpose for the rear wheel liners was interior NOISE reduction the provision for some closed cell foam would be nice.

ROG100

Jerry,
No problem and I am following your narrative.
I was thinking out loud and trying to work out if we could still add some closed cell foam or sound deadening material of some kind.
As Jim states the sole purpose of the liners on the later cars was "sound deading" so it would be good to achieve that goal.
If the owner is not interested in sound reduction then there is no reason to have the full liner and the partial liners would be much cheaper or none at all.
Keep up the good work please.
Roger

worf928

Maybe noise reduction was the sole original purpose but the rear liners have at least two other purposes:
- keeps dirt, debris, etc away from the rear side marker lights.
- does the same for the PSD bits and pieces.

ROG100

Dave,
They indeed do that but that can be catered for by the individual vertical liners at a much cheaper price.
Why spend circa $300 do do just that.
My interest is for sound reduction. That could be dealt with by "Brown Bread" or some similar materail.
Roger

worf928

No disagreement from me on the sound reduction. They make a real difference and IMO retro-fitting the liners to pre-90 cars would be a useful upgrade. The sound transmitted through unlined wheel wells is not "good" sound.

Jerry Feather

Now, I am glad we are having this discussion. It tends to turn my creative juices back on about the sound deadening. With the new liners I am working on there will be some options:

First, anyone can have the liners with no insulation and then put in or on their own.

Second, I can provide the inner half of the liners with what I had in mind in the first place, and that is a felt-like material with a foil backing which would be glued on the complete surface of inner half of the liner that is between the liner and the rest of the car that makes up the wheel well--the side oposite the tire. That will be a fairly good noise barrier, I think. The foil would be on the outside of the felt as one would look at the liner free of the car.

Third, after the liner inner half is installed and before the outer half is fastened into place, the void created between the liner and the rest of the wheel well can be stuffed with foam or perhaps glass batting to the extent desired for additional sound deadening. The risk that moisture might be collected in what you put in will be minimized by the thin layer of sealing material I anticipate between the inner and outer halves and the snug fit I am shooting for around the edges of the liner assembly when installed correctly. I suppose some kind of sealing material might be used around there also, but I am not planning on it.

Does anyone have any other ideas for the insulation? I suppose we could use blocks of the stuff Roger is talking about like the original, but that does not appeal to me for some reason.

Great to hear from all of you on this project.

Jerry Feather, FBA Certified
S4's (6)
KGJT

P.S. I have the Blow Oven liner/tub pieces in place and have two of the corner pieces trimmed to fit. I'm going back out and get the other two corners cut and fit then see what I can do about the welding. JF

Jim M.

I'm already on the list for a set of these, so if they come without sound deadening I'll add my own. The sound deadening needs to be on the body side of the liner, not on the tire side. I think body side VS tire side is a clear description of what we need/want. No confusion as to inside/outside. Just my $0.02.

Jerry, can you provide more info on the felt insulation or even better a link. Won't the felt hold moisture? FWIW I have installed dynamat extream on the body of my wheel wells, then sprayed undercoating over that to reduce the noise. I also have the straight liners with the aerosol foam sprayed between the front straight liners and the "B" piller. All in all it makes a big difference.

Jerry Feather

It may very well be that the only purpose of the rear Wheel Well Liners in the GT and GTS cars was to provide something upon which to hang the sound deadening insulation provided. That may also be why they are made of such crappy material--they were not perceived as doing anything else, so why make them out of anything sturdy. After all, how sturdy does something have to be that is only holding foam in place? I can hear it all now!

However, even if that is the only or the main purpose of these and even these that I am trying to develop, they can be seen as something more. They can be seen as something upon which to hang foam or other insulation, as with the originals; or they can be seen as something to hold some other insulation in place; or they can be seen as providing a hidden place within which to stuff all the insulation you might want to to kill as much sound as you can.

Thanks for the instruction on directions. I can go with tire side and body side and will try to use that description in the future.

I don't have a link about the foil backed felt, but if you will send my your mailing address I will try to send you a sample if my trim guy has any in stock.

Yes, I think it, the felt, might hold moisture, but I think it can be installed so that it doesn't get much or any moisture exposure.

Jerry Feather, FBA Certified
S4's (6)
KGJT

MattCarp

Guys, I need a left rear liner for my GTS as well.

I'm late to this thread and haven't read it in depth, but I'm very excited to have an option for this part. My limited initial research is that the Porsche part is very (unnecessarily) expensive and maybe NLA.

However, as a potential customer, I'd want a 1-piece unit with insulation... I'm sure the newly designed replacements will work, but I simply want a solid, sealed piece, that does its job to keep noise down in the cabin. I'm open to another option ahead of Porsche, but I'd want to study the end product to be comfortable with its performance.

Regardless, thanks for your effort here, supporting the 928 community!!

Jerry Feather

Hello Matt: Nice to have you show some interest in this project. However, somertimes it is difficult to decide just how to respond, if at all--and I hate not responding, so here goes.

I think this new wheel well liner that I am working on developing will meet your "needs" but is not going to be what you say you want. I had rejected the one piece liner idea almost at the inception based largely on the method that I have figured out to use to make thise liners and also based in part on the problems the GTS guys and gals seem to have in putting them in and taking them out which seems to be required about every other year, at least for the left one. I suspect that is why you are in need of only the left one now.

These new liners are going to be "two-piece." That's two pieces for each side. There will be an inner "half" and an outer "half" although the inner half will be more like two thirds and the outer half about a half, but with the difference being overlapped where they will be fastened together. If you will not be able to live with that then you need to take good care of what is left of what you have now.

Then, needing only the left one is another problem. I do not expect to be making these available for only one side or the other. That is mainly because of the way they are going to be formed in pairs, but also because they are going to look and be very different from the originals and I doubt that anyone is going to want to have that much difference on each side of their great Porsche 928. I suppose the economics of the situation will come into play, but if so it will just tend to shift the burden to me to eat all the right liners that are unwanted. What that could mean is that the price of the left one alone will have to be just about as much as the pair because the right ones are going to end up as waste.

When you study this thread a little more you will be able to tell, as I have, that the left liner is getting destroyed the most, and too, the left liner that the factory provides is not the proper liner for the GTS cars--it is too narrow as having been made only for the GT and S4 cars. I think that means that nearly all the demand for one liner only will be for the left and not the right. That's why the right liners will simply pile up as so much wasted plastic. That's why I think they will come only as pairs. If there turns out to be a balanced demand for singles for either side, that could easily change.

Finally, I am not sure how you are going to get to study the end product. Perhaps you can bring your GTS over here to Colorado and have a look at the liners when they are ready and maybe even when I am going to need a GTS here to develop the minor pieces that I think will be needed to mount the liners in the GTS cars. Or better yet, bring your GTS over here so I can have it to drive for a few months and use it as a test bed for the liners in the GTS cars. That would be a great help. (I'll use one of my own S4's to test the narrower liners.)

I hope this all helps. Thanks again for showing some interest and letting me know what your needs are. It may not change the direction of this project, but it still helps.

Jerry Feather, FBA Certified
S4's (6)
KGJT

worf928

Jerry, Following up from your last post.... I have read the whole thread, but I don't claim to know how you're going to go about making your molds etc. But, I have to wonder about the overall scheme of doing these liners only in pairs.

You are correct that demand for the left-side liner will be far, far higher than for the right side. The left-side liner needs to be removed every two years to flush the PSD system on all 928s MY '91 and newer. (MY '90 has PSD but doesn't have the full liner.) The right-side liner does not need to be removed for scheduled maintenance - basically only when something behind it needs attention like, for instance, the side marker bulb.

So, every single left-side liner in every single 928 MY 91 or newer, either needs replacement now or will soon, while only a small fraction of the right-side liners will ever need replacement.

For me - personally - I'm happy to buy two complete sets of liners for my '91 and our '94. However, it may be difficult for me to convince other local owners in need of a left-side liner that they should buy both. There are four '91+ cars more-or-less in my care in addition to my own, that either need a left-side liner right now, or will need one in the next few years. So, I can "speak" for 2 to 6 left-side liners and 2 or fewer right-side liners.

On the flip-side, retro-fitting these new nifty long-lasting sound-deadening liners in pairs to the older cars might open up a little more volume for you.

I don't want to discourage you even a tiny bit. However, I would hate to see you embark upon a direction that would be unfortunate. The dynamics of your market are such that the natural demand for left-side liners will be ~5-10 times that for right-side. How this all shakes out depends upon the pricing of course. But - and again I cannot opine on your methods - it seems to me that a process more-tailored to your market's demands might end up better for you in the long run.

Last, I have no concerns about a two-piece replacement except for this: I will not modify a 928 to accommodate a part. No drilling etc. Any replacement liner must use only the holes in the car that were present when it left the factory.

Jerry Feather

Hi Dave:

Your points are all very well made. First, in order to do something other than make these liner in pairs would require that I have at least four different forms and to blow each half of each liner seperately. Then, to accomodate the GTS cars (or the earlier cars, however you look at it) I would need an extra pair of forms or at least the ability to change one pair of the forms to make the outer halves for each. With that, I could have make the Blow Oven somewhat smaller, perhaps 2/3 or 3/4 of the size I have made it since I would be blowing a little less plastic at one time. Then, I would be spending twice as much time blowing one set of liners; and I would have somewhat more waste since I would be using about a sheet and a half or more to make one complete set.

The way my brain works is to develop the creative part of this with the most common sense and let the marketing part of it fall into place when the dust settles. However, you might be right--that could be a big marketing mistake. Developmentally, however, it makes the most sense. In the end, what I said before is probably where it will end up. That is, with the right half of each blow ending up as waste in respect to those who feel they can only afford the left liner. The question is who is going to throw it away--them or me? I think it is going to be them since I will be disinclined to throw them away and trying to keep them until the final user decides that both is better than just the left will be a problem. Then, if I keep the right liner, the other question is how much are they going to pay for the left liner given that the right one is going to be thrown away?

As to you other comment, I too, am not inclined to drill holes in things like my airplanes or my Porsches. That problem I have not addressed yet as to the earlier cars since they don't have very many places that might be used to mount these liners. The GTS and perhaps the GT cars have adequate holes already, nothwithstanding that I am not very thrilled with the holes that they already have. I am going to go ahead with the two-piece concept since that does not require anything different that a one piece liner might require.

I am forging ahead. Let's see how the single versus pair concerns wash out.

Jerry Feather, FBA Certified
S4's (6)
KGJT

Jerry Feather

Hi Dave:

Your points are all very well made. First, in order to do something other than make these liner in pairs would require that I have at least four different forms and to blow each half of each liner seperately. Then, to accomodate the GTS cars (or the earlier cars, however you look at it) I would need an extra pair of forms or at least the ability to change one pair of the forms to make the outer halves for each. With that, I could have make the Blow Oven somewhat smaller, perhaps 2/3 or 3/4 of the size I have made it since I would be blowing a little less plastic at one time. Then, I would be spending twice as much time blowing one set of liners; and I would have somewhat more waste since I would be using about a sheet and a half or more to make one complete set.

The way my brain works is to develop the creative part of this with the most common sense and let the marketing part of it fall into place when the dust settles. However, you might be right--that could be a big marketing mistake. Developmentally, however, it makes the most sense. In the end, what I said before is probably where it will end up. That is, with the right half of each blow ending up as waste in respect to those who feel they can only afford the left liner. The question is who is going to throw it away--them or me? I think it is going to be them since I will be disinclined to throw them away and trying to keep them until the final user decides that both is better than just the left will be a problem. Then, if I keep the right liner, the other question is how much are they going to pay for the left liner given that the right one is going to be thrown away?

As to you other comment, I too, am not inclined to drill holes in things like my airplanes or my Porsches. That problem I have not addressed yet as to the earlier cars since they don't have very many places that might be used to mount these liners. The GTS and perhaps the GT cars have adequate holes already, nothwithstanding that I am not very thrilled with the holes that they already have. I am going to go ahead with the two-piece concept since that does not require anything different that a one piece liner might require.

I am forging ahead. Let's see how the single versus pair concerns wash out.

Jerry Feather, FBA Certified
S4's (6)
KGJT

MattCarp

I appreciate your comments and the reply. I do have a better visualization of the two piece design.

Although I occasionally get to Colorado, my study will be based on hearing the reports of the early adopters.....on Rennlist!

Cheers!