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  • orphancars

    July 28, 2009 2:24 p.m. orphancars New Reader

    So I have a bit of an oddball car/project looming.........

    I have a 77 Puma GTE. Imported from Brazil, it's fiberglass bodied but has aircooled VW mechanicals underneath.

    I got the car just to hoon around in as-is. For some reason, that only lasted about a year or so and one day I found myself in the garage with the car up in the air and the engine out of the car! I think the reasoning was I was going to do a little rewiring in the engine compartment. Why I thought to myself that I needed to pull the engine to route about 8 wires is a little hard to explain after-the-fact....

    ...anyways.

    Once the motor was liberated and I saw how a VW swing axle rear responds to camber changes (answer: not really well), I decided to convert the car from swing axle over to IRS. Well, as long as we're doing the axle conversion, and 944 trailing arms can be used as part of the conversion (to get rear disk brakes, too!), I can also convert over to Porsche wheels. I have the 944 trailing arms and am in possession of a set of polished Fuchs wheels. Wheels are 16 x 6, 36mm offset and as of now, are not clearing the calipers by maybe 1/2" or so.

    Doing a little research on teh intarwebs shows that some Porsches had wheel spacers from the factory. I've always believed/led to believe that spacers are bad evil things that should be avoided. But -- if they're good for Porsches from the factory????

    I'm confused, hence, I'll ask a question of the collective -- any of you out there running spacers on cars that are driven in autox/HPDE events? We're not talking HUGE! spacers that would be needed, just something 1" or less. We're going for function, not hooptie-ness here

    thx!

    -jeff d

  • The Brown Stig

    July 28, 2009 2:38 p.m. The Brown Stig SuperDork

    I would much rather see you use a "hub adapter" than a "spacer". A hub adapter will bolt to the car and the wheel will bolt to the hub adapter.

  • 914Driver

    July 28, 2009 2:41 p.m. 914Driver SuperDork

    I can't put my finger on any car coming from the factory with wheel spacers, but if you say so.

    Have you started all this labor yet? IIRC from Formula Vee racing way too many brain cells ago, a chain was run from near the wheel bearing end of the axle up toward anything frame like. This limited the amount of movement (drop) allowed to each axle.

    Dan

  • walterj

    July 28, 2009 2:44 p.m. walterj Dork

    I have used 15mm H&R spacers on an E36 that did 40k track miles with slicks (huge side loading) and my E30 race car runs 12mm spacers too. Never had a problem except they do tend to use up lot of wheel bearings if you use the kerbs a lot because of the additional cantilever load. Since you are widening the track you will feel the extra effort to move the wheel, tramline, etc.

  • erohslc

    July 28, 2009 3:42 p.m. erohslc Reader

    With the spacers, what are you planning to do about studs/lugnuts? Nothing inherently wrong with properly fitted spacers, as they will be loaded mainly in compression from tightening. Friction from the wheel/spacer mating face transfers torsional shear loads through to the spacer/hub mating face. The studs take all the rest of the forces. A spacer failure (unlikely!) is not a critically loaded Single Point Of Failure, as the studs remain to reatin the (now loose and wobbly) wheel. They will increase unsprung weight a little bit, and perhaps cause some bearing/alignment/geometry issues as stated above. Wheel adaptors OTOH, must cope with a far greater range and magnitude of forces, as they transfer all the forces from one set of studs through the body to another set of studs. They are thus critically stressed SPOF items (ie, a failure means immediate shedding of a wheel). That said, you will likely be fitting larger/stickier rubber, so some sort of stud upgrade is not a bad idea anyway, no matter what route you take.

    Carter

  • TJ

    July 28, 2009 3:58 p.m. TJ HalfDork

    Austin (and Morris) Mini Cooper S's had spacers on the rear wheels, but they were built into the drums. Factory spacers.

  • Toyman01

    July 28, 2009 4:54 p.m. Toyman01 HalfDork

    I used adapters on my 57 Chevy to let me run 3rd gen Camaro wheels. They were 2.25 inches thick. I pulled the wheels every oil change to check the condition of the spacers and torque the lug nuts. Never found anything wrong, but they made me nervous and it was just a cruising machine, no hard driving. They also made the car want to pull on uneven roads.

  • Jensenman

    July 28, 2009 5:04 p.m. Jensenman SuperDork

    The Brown Stig wrote:

    I would much rather see you use a "hub adapter" than a "spacer". A hub adapter will bolt to the car and the wheel will bolt to the hub adapter.

    Same here. I have a bud who autocrosses a 300ZX (and I mean HARD driving!) with hub adapters on the front. They are real good quality, billet with steel taper inserts in the nut seats etc and he's never had a problem

  • xci_ed6

    July 28, 2009 5:06 p.m. xci_ed6 Reader

    I ran 1.25" 2-piece spacers to go from 4x114.3 to 5x114.3 on my old 240sx, I had no problems with them. You will want hubcentric spacers to minimize the chance of vibrations, IIRC the H&R spacers are hubcentric.

  • wbjones

    July 28, 2009 5:34 p.m. wbjones New Reader

    I ran 12mm front and 4mm rear on my LS Integra for a-x and track days for 2 yrs w/ no apparent problems...

  • erohslc

    July 28, 2009 5:41 p.m. erohslc Reader

    In reply to Jensenman: Aluminum, right? Lessee, that's the metal which has no 'safe' fatigue load, ie, will always fail eventually under cyclic loading? How often does he get them crack checked?

    Just sayin ...

    (I have a set of aluminum wheel adaptors myself)

    Carter

  • Jensenman

    July 28, 2009 5:46 p.m. Jensenman SuperDork

    Dunno about the cyclic loading. He's run them for 2 or 3 years with no problems. I do remember they were NOT cheap.

  • fiat22turbo

    July 28, 2009 7:05 p.m. fiat22turbo SuperDork

    The early 944's used spacers from the factory as they were reusing 924 narrow body parts. After 87 or so they used wheels with different offsets or different suspension pieces to achieve their desired solution.

    You might look at later 944's to see if you can mix/match parts to get your offset. Otherwise using spacers that have built in studs are typically better since they are similar to the factory hubs.

    There was a website for someone doing custom vanagon IRS rear brakes and the proprietor is very knowledgeable about the VW/Porsche trailing arm solutions. I'll find it and pass it along....

  • orphancars

    July 28, 2009 7:48 p.m. orphancars New Reader

    Wowsers.............I step away for work, dinner, and a lap around the neighborhood and lookee!!!

    Time to start responding -- thanks in advance for all of y'all chiming in!!

    -jeff d

  • orphancars

    July 28, 2009 7:50 p.m. orphancars New Reader

    The Brown Stig wrote:

    I would much rather see you use a "hub adapter" than a "spacer". A hub adapter will bolt to the car and the wheel will bolt to the hub adapter.

    .......maybe spacer is a little generous in the description department.........hubcentric adapter?

    I get what you're saying -- and the Porsche parts I have found (as well as the H&R adapters) are machined to center off the hub....so it is indeed better than a piece of plate with some holes drilled in it....

  • orphancars

    July 28, 2009 7:58 p.m. orphancars New Reader

    914Driver wrote:

    Have you started all this labor yet? IIRC from Formula Vee racing way too many brain cells ago, a chain was run from near the wheel bearing end of the axle up toward anything frame like. This limited the amount of movement (drop) allowed to each axle.

    Dan

    Dan -- yeah, I'm familiar with camber limiting devices....not what I'd consider the right solution to the problem. The swing axle suspension has a terrible camber curve. Also, I'd like to lower the car an inch or so. Doing that without also doing something to reset the camber (might be able to lower the torsion bars, worst case I'd have to raise the engine and transaxle -- and I don't have the room to go "up") will result in early bearing failure -- the axle bearings at the ends of the swing axle tubes get lubed from oil that essentially "drips" from the transaxle. Lowering = negative camber = early wheel bearing failure.

    All in all, doing the IRS swap results in better handling and isn't all that hard to do....

    thx!

  • orphancars

    July 28, 2009 8:02 p.m. orphancars New Reader

    erohslc wrote:

    With the spacers, what are you planning to do about studs/lugnuts? Nothing inherently wrong with properly fitted spacers, as they will be loaded mainly in compression from tightening. Friction from the wheel/spacer mating face transfers torsional shear loads through to the spacer/hub mating face. The studs take all the rest of the forces. A spacer failure (unlikely!) is not a critically loaded Single Point Of Failure, as the studs remain to reatin the (now loose and wobbly) wheel. They will increase unsprung weight a little bit, and perhaps cause some bearing/alignment/geometry issues as stated above. Wheel adaptors OTOH, must cope with a far greater range and magnitude of forces, as they transfer all the forces from one set of studs through the body to another set of studs. They are thus critically stressed SPOF items (ie, a failure means immediate shedding of a wheel). That said, you will likely be fitting larger/stickier rubber, so some sort of stud upgrade is not a bad idea anyway, no matter what route you take.

    Carter

    Carter,

    THAT was what I was looking for!!!! Appreciate the mechanical explanation.

    One question that this brings up -- two identical cars, one with a wheel and a spacer, the other with just a wheel. The wheel and wheel/spacer combo have the same resulting offset -- does one of these impart a higher load to the suspension? OR do they do the same exact job?

    thx!

    -jeff d

  • orphancars

    July 28, 2009 8:07 p.m. orphancars New Reader

    fiat22turbo wrote:

    The early 944's used spacers from the factory as they were reusing 924 narrow body parts. After 87 or so they used wheels with different offsets or different suspension pieces to achieve their desired solution.

    You might look at later 944's to see if you can mix/match parts to get your offset. Otherwise using spacers that have built in studs are typically better since they are similar to the factory hubs.

    There was a website for someone doing custom vanagon IRS rear brakes and the proprietor is very knowledgeable about the VW/Porsche trailing arm solutions. I'll find it and pass it along....

    Thanks f22t for the explanation on the existence of spacers!!

    Thanks in advance for the link!! Am continually amazed at the cottage industry that surrounds the Porsche/VW communities. There are folks making all sorts of parts out there!

    I am considering the spacers if I stay with the Fuchs wheels. More of a possibility is using a set of ROHs that I found locally. Only thing holding me back from the ROHs right now is math -- have to get out to the shop and use the wheelrite to see if they'll fit.

    thx!

    -jeff d

    -jeff d

  • P71

    July 28, 2009 9:07 p.m. P71 SuperDork

    If you go to Porsche's website and play with their "car configurator" you will see that 5MM spacers are a factory option on certain wheels/cars.

 
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