CobraRed's HPDE-DD Build Thread

[CobraRed]

If you'll notice, I havent compared a PHB to Watts once. I wansn't even referring to a watts just the stock length PHB on a severely lowered car. Not this PHB vs X, just the fact that the driver's side pokes out a inch more than the passenger's and the rear ride height is inexplicably lower on the passenger side than the driver's side with the stock PHB despite spring perch adjustments (havent been able to attribute it to something yet, but I expect the adjustable PHB to help get to the bottom of it).

The way you're addressing each thing I say is in a way that makes me think you haven't been reading this thread at all.

Feel free to make a thread about the Watts discussion.

 

[Norm Peterson]

It's a lateral link. It's either in compression (chassis forces towards the driver's side) or tension (chassis forces towards the passenger side). It has no static vertical contribution, which would be needed if the link were to affect ride height at all, let alone "significantly." The ONLY contribution that it could make in terms of vertical load would be from bushing torsion. IE the bushing was "fixed" to the chassis at a higher ride height, and after lowering, the bushing now has potential energy stored up in it in the form of torsional energy. Given how soft those OE bushings are, the amount of energy stored will be minimal, with negligible effect on static ride height. To completely eliminate that as a variable, just loosen (not remove!) the two bolts that hold it to the chassis and axle (and nothing else: one variable at a time!), bounce the rear end a couple of times, then re-torque the bolts. Any bushing preload will be removed at that point. No change in static ride height? Didn't think so. Try looking elsewhere, like LCA bushing preload (MUCH more significant) or swaybar preload.

Not entirely true. The static measurements I made shortly after I got my '08 have the chassis side pivot about 1.5" higher than the axle side pivot. Put yourself in the driver seat and the chassis side drops a little (something like 0.3" with OE springing) but still has an uphill inclination from axle to chassis. At somewhere closer to maximum vehicle loading (750 or so lbs IIRC) the PHB finally gets close to being leveled out. I doubt that this is mere coincidence, given the car's basic mission as street transportation. 1.2" vertical with a 40" long PHB is 3%, so the vertical force component could be 40 or 50 lbs per lateral g . . . asymmetrically distributed. I would initially assume this to be at least as important as the difference between PHB and Watts link weights.

This whole point being that there is a slight vertical force involved unless you've either lowered the car and accidentally managed to level the PHB or you've specifically gone to some trouble to make it level (hopefully with just the driver aboard - or perhaps the driver+half a passenger in recognition that there might occasionally also be an instructor or student on board, but that's another topic). Then you either have to spring the car firmly enough or drive it gently enough so that your nicely leveled PHB stays that way.

That's before roll starts to happen, and yes, lateral g's and forces getting way ahead of roll (or even out of step with it) is better approximated during a frantic autocross slalom than during turn-in at China Beach or the Light Bulb at NJMP/Lightning.


Norm

 

[CobraRed]

Got the BMR PHB in, the side to side adjustment is dialed perfect.
The rear ride height is still wonky for no explainable reason.

I adjusted with everything loose, then tightened everything (PHB, LCA bolts, Sway) with it sitting on its own weight and zero to minimal difference. With the perches set at equal height there's like a 1-1.5" difference. Even with the driver's side perch real low and passenger's side middle to middle high there's still a big difference with more ehight on the driver's side.

I have no idea.

I also gave both fronts another turn higher, no rubbing yet just want less of a slammed look.

 

[oldVOR]

You've checked the obvious, right?
Springs are seated correctly in both the top and bottom pockets
Springs are the same free length
Springs are the same rating

You're checking everything on level ground, right?

Just verifying the obvious has been checked. Weirder stuff has happened!

 

[CobraRed]

You've checked the obvious, right?
Springs are seated correctly in both the top and bottom pockets yes, ive probably checked this 10 times now
Springs are the same free length They're in the car now, but pictures I have show them looking the same height
Springs are the same rating Progressive, but I can see the last 5 numbers on each springs product number and they match

You're checking everything on level ground, right? Not super level where it sits, but I've driven it around and parked it on flat ground and it remains. It's big enough disparity that the ground can almost be disregarded

---------

The stated drop for these is 1.4-2.2 rear. The driver's side near adjusted all the way down on the perch is barely if not at all making the 1.4". Def seems off.

I think my next move is a call to KW then perhaps swapping the passenger side to the driver's and see if it causes the reverse effect which would point to something odd with a spring.

yay

 

[jayh007]

You could have one of your suspension parts binding. The front A arms may be the problem. The correct way to check is to disconnect the shock and make sure everything moves freely. Any binding in the front will affect the opposite rear. Also make sure you are on level ground (balls on) side to side use leveling plates if needed. The difference from to back can vary a little. To setup a car correctly with coil overs follow this procedure:
1. Set ride hide
2. Set corner weights, 50 / 50 is perfect but I don’t know what the ideal setup for a mustang. In open wheel rear engine we settle for 60/40.
3. Toe in/out
4. Camber
5. Castor??
6. Repeat 2-5
This procedure is probably one of the most frustrating things you will ever do and if you’re anal forget about IT!

 

[CobraRed]

I called KW.
I noticed today after parking at work it was a lot closer. Driver's side's come down a good .5"+

KW said this still could be normal and he's heard of this a handful of times. One spring taking a lot longer than the other to settle.
Even if/when it levels out, it will be around a 1.4-1.6" drop in the back (which I'm perfectly good with - even prefer) but causes me some head scratching when the advertised is 1.4-2.2" and the driver's side is adjusted nearly all the way down right now which would mean on that spring a max drop of 1.4-1.6 not 2.2".

I'm not complaining at this point, just confused.

Oh well, on to more interesting mustang related mod projects!

 

[CobraRed]

Moving on from the ride height, I have another issue.

This morning a squeak/tick started happening and got worse on my ride home. Over every movement in the rear end a squeak.

After some investigating it's the bolt from the UCA to the diff.

Here's a vid of the squeak, it's not subtle.

https://www.youtube.com/watch?v=qMJ460UfrnE&feature=youtu.be

Since the vid, I've put the car on jackstands, took the nut off the bolt - hit the bolt out half way to ensure it wasn't tight. Then lowered the car on its own wheels/weight and re-torqued this bolt. It still squeaks about 75% as much, I can feel the nut when it squeaks and there's resonance. It's definitely this guy. It even squeaks with the nut off and loose.

Not sure how to make it stop.

 

[2013DIBGT]

Yeah..that would get old quickly!

Did you use any of this during install? If not, may see if you can somehow get a blob of it in there but to get it where it needs to be may require getting at the area between the axle housing and the sleeve which wouldn't be fun.

I've had some squeeks in the past in certain areas but they went away after a while once the newness of the part wore down a bit.

 

[CobraRed]

Yeah..that would get old quickly!

Did you use any of this during install? If not, may see if you can somehow get a blob of it in there but to get it where it needs to be may require getting at the area between the axle housing and the sleeve which wouldn't be fun.

I've had some squeeks in the past in certain areas but they went away after a while once the newness of the part wore down a bit.

I've been using Amsoil synthetic polymeric:

http://i.imgur.com/1VdN0As.jpg

Don't think I put some between the diff housing and the UCA mouth. Didn't know I was supposed to. I think taking that arm off the diff right now would be quite a task of getting it back on there with everything else currently on.

 

[BMR Tech]

What tha?

So are you saying it is the actual nut/bolt - and not the rubber?

I am surprised that, when you torque it to 129ftlbs when everything is loaded on the tires - that it still makes that noise. That is odd....

 

[CobraRed]

What tha?

So are you saying it is the actual nut/bolt - and not the rubber?

I am surprised that, when you torque it to 129ftlbs when everything is loaded on the tires - that it still makes that noise. That is odd....

I havent determined it's the bolt causing it, just that I can feel the resonance on it when it squeaks and not elsewhere. So it's being caused by the rubber bushing scraping against the bolt or something.

129 ftlbs, 180 ft lbs 200 ft lbs with level weight on the tires. No difference.

 

[oldVOR]

You're certain it's in the rubber bushing side? Can't really see it coming from there. I could see the spherical end making noise and transmitting it through the bar and you feeling it at the rubber isolated bolt on the pumpkin.

Have a mechanics stethoscope? Place it on the spherical end to see if the noise is loudest at that location.

My 2 cents worth...

 

[Roadracer350]

Replace rubber bushing with a spherical and your good.

 

[CobraRed]

You're certain it's in the rubber bushing side? Can't really see it coming from there. I could see the spherical end making noise and transmitting it through the bar and you feeling it at the rubber isolated bolt on the pumpkin.

Have a mechanics stethoscope? Place it on the spherical end to see if the noise is loudest at that location.

My 2 cents worth...

Yes. With my hand on the spherical end or hardware I can barely feel the vibration but can feel it in the arm. With my hand on the open end at the diff or the hardware I can literally feel the bolt "moving" when it's loose and vibrating when it's torqued.

Replace rubber bushing with a spherical and your good.

Haha, no thanks. If someone knows of an elastomeric bushing for here I'll throw one in, im even weary of poly.

 

[oldVOR]

Haha, no thanks. If someone knows of an elastomeric bushing for here I'll throw one in, im even weary of poly.

I have a poly bush in the pumpkin end UCA mount, it doesn't knock, bang, squeak or anything of the like with suspension travel. What it does do is transmit one hell of an amount of gear whine into the cabin that peaks around 74mph.

I've checked driveline angle and it's all set correctly. I've been told it's a poorly setup ring/pinion from the factory and can be adjusted by a good rear-end guy to where it doesn't make any noise at all. I haven't found anyone in my area that has a good reputation so, I've left it alone...for now.

 

[Norm Peterson]

Yes. With my hand on the spherical end or hardware I can barely feel the vibration but can feel it in the arm. With my hand on the open end at the diff or the hardware I can literally feel the bolt "moving" when it's loose and vibrating when it's torqued.

That almost sounds like the bond between the rubber and either its inner sleeve or its outer shell has failed and you're getting rotation between the rubber and whichever.

The only other explanation I can picture is if the new UCA is bearing with some pressure against the "sides" of the OE rubber bushing.


Norm

 

[CobraRed]

Everyone's suspicions were correct. I hammered the bolt out of the diff bushing (GL to me putting it back in) and with the UCA free it makes the same noise when moved up an down. While the head doesn't make the vibration (mass?) during the squeak, it's definitely the cause.

Big movements of the bearing up and down don't illicit anything, but move it a tad up or a tad down and a very predominant squeak comes out.

Edit: Working on a solution

 

[CobraRed]

It turns out the open end of the UCA was acting as a tuning fork. Even with it unhooked it was making noise/resonating off the diff end.

I hit up my Amsoil dealer and drove an hour round trip but got a free bottle of HDMP.

Solved the problem for now. Glad I took the arm off either way as it took a bit of working into back and forth in order to get it to stop squeaking.

 

[CobraRed]

Car's a hill climb monster. Fun as shit.