The Mule rides again (sort of) - pics.

Real tech discussion on design, fabrication, testing, development of custom or adapted parts for Pontiac Fieros. Not questions about the power a CAI will give.

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Series8217
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Re: The Mule rides again (sort of) - pics.

Post by Series8217 »

The Dark Side of Will wrote: However, it's really close, and probably would rub on a max effort corner. My finger won't fit. I'll see if I can get a better measurement, but I'd guess a 1/4-5/16" gap before initial contact. Initial contact would be harmless.
Also, as mentioned above, I can raise the spring perch over 1.5" by swapping to 10" springs. I'd probably up the rate to 400 in an effort to further copy-cat Steven, however.
I'm running 475# in the rear
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Re: The Mule rides again (sort of) - pics.

Post by The Dark Side of Will »

Took The Mule's suspension apart today. I surprised myself slightly by getting the spring out without unbolting anything but the top of the strut. I was *amazed* that after being installed close to 15 years, the spring perch still turned freely on the sleeve.

The 6 5/8" metal to metal travel limit checks out.
Full droop ride height: 19 5/8"
Metal to metal contact ride height: 12 1/4"
Bump stop *contact* ride height: 13 11/16"

ETA: "Metal-to-metal" means that the top of the strut body just touches the bottom "bell washer" that installs under the strut top bushing. The bell washer is there the retain the end of the strut approximately where it needs to be if the bushing comes apart. A really hard hit would both deflect and maybe tear the bushing as well as possibly flattening the bell washer, so this isn't he "structural contact" ride height that would do serious damage to the tub or the strut... that's maybe 1/4 - 3/8" more jounce travel that what I measured.

It's weird that the difference between the bump stop and metal-to-metal ride heights is 1 7/16", as the bump stop measures a smidge over 1 3/4". I may have compressed it *slightly* when positioning the suspension and could be off on the ride height a little bit, but I don't think those effects can turn 1 3/4 into 1 7/16.

ETA: I just realized that this discrepancy is there because the top of the bump stop fits into the bell of the bell washer, so the bell washer cuts down on the difference between metal-to-metal and touching the bump stop.

Full droop travel:

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Metal-to-metal contact:

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Gap to the outer fender lip:

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Gap to the rear trim strip:

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Gap to the front trim strip:

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From the four photos above, rubbing on the front trim strip is probably the first contact point, but it can be mitigated by moving the wheel back in the wheel house a bit. An adjustable trailing arm could do this on an '88 and a custom fully adjustable control arm could do it on an early car.

2 7/8" from the tread surface to the rear fascia:

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Can't really get a comparable measurement, but ~2" for the corresponding measurement to the quarter panel:

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Inner lip clearance to everything in front of the axle--nothing is even close to the top of the tire:

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Inner lip clearance to everything behind the axle--I can still get my finger between the top of the tire and the wheel well liner:

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The toe link is danger close to the frame rail:

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I bumped my spring rate up 200 ppi, shortened the springs by 2", lowered the car slightly to a 15 3/8" ride height... and the spring perch barely moved :roll:

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The spring is seated directly against the strut top plate, so it won't be going up any more. If I build a fancier top mount with an axial load spherical bearing and a needle bearing set to let the spring squirm, the perch could come down another 1/2" easily. Shoot, I may have to go to 8" springs.

Also, flipping the strut top plates, or making new ones that put a spherical bearing strut top mount ABOVE the top of the strut tower could lower the metal-to-metal contact ride height by *maybe* as much as 2", but that really just means that the current metal-to-metal height becomes the new bump stop height. Still not bad, though. I haven't run the numbers yet to see if I can get 8" springs that will have enough travel from ~15" static ride height to hit the bump stops a meaningful distance before they coil bind.

If I could get the current metal-to-metal height to be the new bump stop height (unlikely that everything can package in the space available), then a 14 3/4" ride height, which is about what Steven's running, would still have 2.5" of compression travel before even touching the bump stop. With 550# springs, that's 1375 extra pounds on the outside tire in a corner... that's a LOT of cornering g's!

Currently, at 15 3/8", I'm only 1 11/16" off the bump stops.
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Re: The Mule rides again (sort of) - pics.

Post by The Dark Side of Will »

So with the car at ~2900# and 55% rear heavy, it should have ~1595# on the rear tires. Less 200# for unsprung weight is 1400# of sprung weight, which is ~700# per spring. Each spring should have compressed about 1.27". Now I need to look up their coil bind height.
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Re: The Mule rides again (sort of) - pics.

Post by The Dark Side of Will »

QA1 says that the coil bind height is 4.5". That's 5.5" of travel from a 10" spring... That's pretty good.

https://www.facebook.com/QA1Motorsports ... 0558213760

So it takes 3025# to coil bind the spring. The whole car doesn't weigh that much.
More to the point, it has 4.25" of travel left and I'm 1 11/16" off the bump stops, so I don't have to worry about coil bind! :-D
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Re: The Mule rides again (sort of) - pics.

Post by Emc209i »

That your kid in the tree?
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Re: The Mule rides again (sort of) - pics.

Post by The Dark Side of Will »

Emc209i wrote:That your kid in the tree?
I wouldn't be able to play with cars this much if I had one of those. He belongs to a good friend (which is why I'm keeping him from falling out of the tree).
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Re: The Mule rides again (sort of) - pics.

Post by The Dark Side of Will »

The Dark Side of Will wrote: More to the point, it has 4.25" of travel left and I'm 1 11/16" off the bump stops, so I don't have to worry about coil bind! :-D
Also, I can raise the strut top pivot by an inch or so, gain a good bit of travel to the bump stop and still not have to worry about coil bind. Raising it an inch would put me at 2 11/16" off the bump stops at the same ride height. I could easily go down to 2 1/2" off the bump stops or lower... especially if it turns out I'm ok with the current height and the 550# rate.
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Re: The Mule rides again (sort of) - pics.

Post by Series8217 »

Could you flip your top hat to get that extra bump travel and see where things hit first?
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Re: The Mule rides again (sort of) - pics.

Post by The Dark Side of Will »

Series8217 wrote:Could you flip your top hat to get that extra bump travel and see where things hit first?
Yeah. I'll be ordering the for realz wheel adapters and my other 285 tire tomorrow. I'll examine flipping the top plate. I mentioned making a new one first for two EDIT: THREEEEE! reasons:
1. I haven't measured or test fitted, but it looks like the OD of the bushing is larger than the hole in the strut tower... I'd have to grind some things to make that work.
2. When I stretch the taco clamps to move the strut body inboard to provide clearance for 10.5" wheels, that will put the existing top mount at a static angle. I don't know how long the rubber will last like that, and it will introduce some amount of binding/friction into the strut.
3. Who wants an almost 30 year old rubber strut top pivot?

Based on your experience and the clearances I observed, I strongly suspect the tire will start rubbing on the rear half of the wheel house liner where it covers the round panel closing out the trunk. IOW, where my hand is here:
The Dark Side of Will wrote: Inner lip clearance to everything behind the axle--I can still get my finger between the top of the tire and the wheel well liner:

Image
So if all I have to do to "mini-tub" a Fiero enough to run 335's is cut that away... hold my beer while I get the Sawzall!
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Re: The Mule rides again (sort of) - pics.

Post by The Dark Side of Will »

Series8217 wrote:Could you flip your top hat to get that extra bump travel and see where things hit first?
I'll still do this, but the limiting factor is very likely to be the toe link touching the frame rail. I'm not sure what I can do with that... if I unbolt the toe link, then tire clearance checks are basically meaningless because I can't verify my correct toe angle.

I ordered my second 285/30 last Thursday morning and TireRack shipped it the same day and *DELIVERED* it to my dad's house Friday... with standard ground shipping from their Ohio warehouse.

I also ordered the actual wheel adapters I'm going to use. Instead of 1 1/8", I went with 1" thick. That will give me a little less clearance to the strut, but a little more clearance to the fender lip. I did this because these Sumitomo 285's have the narrowest tread width of any of the 285/30-18's that TireRack carries. I wanted a little more clearance to the fender lip for when I trade these 200 treadwear rocks in for something really aggressive. Also, I have plans to lengthen the taco clamps on my Koni struts, which will move the struts inboard at least an inch, which will solve all my potential strut to tire clearance issues with these wheels. They quoted me 7-10 business days + shipping time from Reno, NV.

I ordered from www.motorsport-tech.com
The are the *ONLY* adapter outfit I contacted who came back with a sensible response to my email inquiry. I'll thoroughly inspect what shows up in the box, but so far the apparent subject matter knowledge, responsiveness and general competence are head and shoulders better than *ANY OTHER SHOP* I've spoken with for wheel adapters.
Their price was also the best I've seen at $70/each.
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Re: The Mule rides again (sort of) - pics.

Post by The Dark Side of Will »

In looking at the available options, the only front tire in the same make/model as my rear tires, of an equal or smaller diameter that also works well with the Corvette 17x8.5 front wheels is a 245/40-17. This is slightly smaller than the Vette's 245/45-17 front, but a little wider than ideal for a Fiero with 285's on the back. I guess I'll have to hurry up and fit the Z06 18x10.5 wheels so I can move up to 305/30's or 315/30's to balance the rubber out again.
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Re: The Mule rides again (sort of) - pics.

Post by fieroguru »

That's part of the reason I went with Potenza RE-11. They had a 235/40/17 and 285/30/18. I really wanted something in the 225 range, but I couldn't find the right front/rear combo from any mfg.
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Re: The Mule rides again (sort of) - pics.

Post by The Dark Side of Will »

245 isn't crazy. I'd like 235's, but oh well. I'll just have to dial in the suspension a little more carefully.

Speaking of which, I have to figure out what rate I need to get for the front and get some wide track LCA's built to push the high offset Corvette wheels out to the edges of the fenders.

The base C5 wheel combo is 17x8.5 front and 18x9.5 rear. The C5 Z06 wheel combo is 17x9.5 front and 18x10.5 rear. Since I can fit the 18x9.5's, I should be able to fit the 17x9.5's, but those will be much closer to the knuckle on the ID of the inner lip. I think I can fit the 18x10.5's with strut modifications, but the tires I'd have to run end up pretty tall. I'd definitely have to "mini-tub" the trunk to clear those.

I realized that if I'm really crazy, I can step up to C4 ZR1 wheels at 17x11. 315/35-17's are still available and are shorter than the 315/35-18's I'd run with the 18x10.5 wheels. However, *REAL* C4 ZR1 wheels are $rare$, ek$pen$ive and come on $limited$ $edition$ $Corvette$. I wouldn't mount the aftermarket repros on a stroller.
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Re: The Mule rides again (sort of) - pics.

Post by The Dark Side of Will »

Series8217 wrote:Could you flip your top hat to get that extra bump travel and see where things hit first?
Actually, I can tell you exactly what will hit first: the toe link on the frame rail.

One more reason (as if I needed a lot) to get rid of that damned thing.
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Re: The Mule rides again (sort of) - pics.

Post by The Dark Side of Will »

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Re: The Mule rides again (sort of) - pics.

Post by The Dark Side of Will »

New wheel adapters arrived while I was in London, ordered from here: http://www.motorsport-tech.com/wheel_adapters.html
Made in the USA and CHEAP, too! $70ish each. The other places I looked at were $90-$100+

Image

Now both 285's are mounted:

Image
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Re: The Mule rides again (sort of) - pics.

Post by The Dark Side of Will »

How long before packing bearings ironically becomes a legit hipster skill?

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Packing bearings and installing hub seals in my Street Dreams lowering knuckles:

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Re: The Mule rides again (sort of) - pics.

Post by crzyone »

Are you doing it the old fashioned way or using a bearing packer?
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Re: The Mule rides again (sort of) - pics.

Post by The Dark Side of Will »

Since I've had to pack about 8 bearings in my life, I'm doing it the old fashioned way.

I haven't looked for bearing packers... how cheap do they come?
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Re: The Mule rides again (sort of) - pics.

Post by crzyone »

Really cheap, basically a cone that goes over the bearing with a grease zerk.

http://www.ebay.com/itm/UNIVERSAL-AUTO- ... 1380647632

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Best used for re-packing bearings, forces the dirty grease out and replaces with fresh.
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