Author Topic: How Opentracker Racing Product idea fixed JeffTepper's suspension (Read 2744 times)

cmayna · « **on:** June, 10, 2009, 10:49:32 AM »

Recently Jeff had done the Arning (Shelby) drop on his car which lowered the front end by 1/2" resulting the tire rubbing against the fender lip as well as increasing ground to header interference. Before he started spending lots of money experimenting with different coil springs, he decided to consult with suspension guru John Dinkel of Opentracker Racing Products.

John had recently developed a simple yet effective modification that moves the front spring perch outboard by 1". When you move the perch closer to the ball joint, you get a better motion ratio that makes the car ride better and it happens to also raises the front of the car approximately 1/2" which was Jeff's current concern (tire/fender clearance and header clearance).

John knew that we were working on Jeff's car at my work this past Saturday so he sent us one of his prototype templates on Friday overnight (Thanks John!!) to arrive while we were there. Unfortunately we ran out of time on Sat after playing around so long with the caster and camber alignment project, so Jeff and I came back on Sunday to start the perch relocation project.

Moving the perch requires drilling new holes in the upper control arm 1" outward. The template that John loaned us, fastens to the current perch holes in the arm. The template has two additional 1/8" holes located where you will be drilling the new holes. Here's some photos:

Here’s a photo supplied by John of another arm with a relocated perch:

Jeff's car specs: '67 Mustang with Eibach progressive coil springs (free height 12-3/4"), 1" poly upper coil spring spacers, Opentracker Roller Spring Perches, stock style upper and lower control arms and KYB GR-2 shocks.

Though John mention that you can move the current perch outward keeping the perch, coil and shock assembly together, he learned that Jeff had some of ORP’s original perches which John wanted back for destruction testing which put a wrench into the plans. Since Shag had new ORP perches, we simply removed them from Shag (sorry Buddy) so we could finish the project and off we went removing the shocks, shock tower caps springs and perches.

Once the coil spring and spring perch has been safely removed from the upper control arm, the template was attached to the existing perch mounting holes. Using a 1/8" drill bit, we drilled the two pilot holes in the upper control arm; removed the template and gradually opened up the pilot holes in a couple of steps ending with 3/8" holes. John warned us that depending of the mfg of the upper arm, we might not be able to have the perch’s bolts enter from the top due to possibly not having enough room for a socket underneath. Since Shag's new perches had no splined perch bolts we easily ran the bolts up from the bottom securing at top with a nylon locknut. If one wanted, they could remove the original splined bolts from the perch’s shaft and then run them up from the bottom.

Once we reassembled everything, we dropped the car back down and chose to recheck both camber and caster which did infact become altered during our perch project. After tweaking the caster and camber again, Jeff took the car for a quick spin to settle the front end.

Results: He gained 9/16” in height up front. Goal was 1/2”. Very happy

For those who consider doing this keep in mind the importance of safety when working on coil springs.

Here's a before and after shot, keep in mind we are only talking 1/2"

Before:

After:

Summary:
Since so many have or will be doing the Shelby drop which might affect the height, I felt it was pretty important to publish this project in order to give people another idea on how to obtain some of the height back without going out and spending lots of $$ on new springs. For those with stock or the reproduction rubber bushing perches, you will probably encounter a situation while trying to attach the bottom of the shock to the perch since the perch is very stiff and will not want to easily rotate. It might be a good time to
Buy some new roller ones.

Looking for a way to increase height was never Johns intention. This is a typical bi-product of another idea.

Thanks to Jeff and John for all their input and help.

Craig

Fast68back · « **Reply #1 on:** June, 10, 2009, 10:57:29 AM »

Nice write up Craig. Would make a decent tech article.

joesgt281 · « **Reply #2 on:** June, 10, 2009, 12:11:13 PM »

Quote from: Fast68back on June, 10, 2009, 10:57:29 AM

Nice write up Craig. Would make a decent tech article.

+1

Starfury · « **Reply #3 on:** June, 10, 2009, 12:16:58 PM »

Interesting. Looks like it could interfere with wider 17" rims that go over the upper ball joint, though. Something to keep in mind.

Fast68back · « **Reply #4 on:** June, 10, 2009, 01:10:50 PM »

Quote from: Starfury on June, 10, 2009, 12:16:58 PM

Interesting. Looks like it could interfere with wider 17" rims that go over the upper ball joint, though. Something to keep in mind.

That would depend on the BS of the rim, if the BS is right should not be an issue.

cmayna · « **Reply #5 on:** June, 10, 2009, 01:51:28 PM »

JeffTepper's wheels are 235x17 in front and 245 in back.

monkeystash · « **Reply #6 on:** June, 10, 2009, 03:07:21 PM »

Great write-up Craig, thanks. You learn something new everyday!

Starfury · « **Reply #7 on:** June, 11, 2009, 09:25:44 PM »

Quote from: Fast68back on June, 10, 2009, 01:10:50 PM

That would depend on the BS of the rim, if the BS is right should not be an issue.

Partially. A 17x9 rim should go over the upper ball joint, which could run it right into the perch.

Fast68back · « **Reply #8 on:** June, 12, 2009, 10:18:14 AM »

I t would still depend on the BS, anything with more than 4.5-5 of BS would hit the ball joint. Not may people are running a 9" wheel in the front, especially a 65-68.

Starfury · « **Reply #9 on:** June, 12, 2009, 05:46:22 PM »

No, but to run one, you'd need 5.5" BS. That's half the fun of 17" rims on classic Mustangs; you can actually run 9" wide without running into any problems.

daveSanborn · « **Reply #10 on:** June, 15, 2009, 04:02:02 PM »

Quote

you can actually run 9" wide without running into any problems.

I understand exactly what you are saying, but who would ever want to run a 9" wide wheel on the front? On the rear? Definitely Yes! But the front?

Starfury · « **Reply #11 on:** June, 15, 2009, 05:39:40 PM »

Me :D Some of us like to turn our cars:P I probably wouldn't do it for the street, but it'd be great for a track toy.

daveSanborn · « **Reply #12 on:** June, 16, 2009, 04:27:13 PM »

Okay... so there's at least one person out there.

Opentracker · « **Reply #13 on:** June, 19, 2009, 07:17:30 AM »

Quote from: Starfury on June, 11, 2009, 09:25:44 PM

Partially. A 17x9 rim should go over the upper ball joint, which could run it right into the perch.

If you put too much backspacing on the front, the wheel/tire will hit the tie rod end before it hits the perch. That's what we found while this was being tested on different cars with different wheels.

Starfury · « **Reply #14 on:** June, 19, 2009, 08:51:50 AM »

Ah. I stand corrected:)

Opentracker · « **Reply #15 on:** June, 19, 2009, 09:16:10 AM »

Quote from: Starfury on June, 19, 2009, 08:51:50 AM

Ah. I stand corrected:)

Well, I think of it as shared information not a correction. I am sorry if I sounded like a smart-a$$ .

Though my dad did always say ... "it's better to me a smart-a$$ than a dumb-a$$. :danc

Starfury · « **Reply #16 on:** June, 19, 2009, 05:25:35 PM »

Not at all, just glad to have the proper information:)

Mustang Mike · « **Reply #17 on:** June, 19, 2009, 08:51:07 PM »

I'm running 9" up front :bash. Did you get double time for working Sunday?

67 evil eleanor · « **Reply #18 on:** July, 28, 2009, 10:46:28 AM »

Nice write-up. Does this increase the spring rate? Also for additional height, are the thicker spring insulators dangerous? I need to raise the front of the 65 about 3/4".

MarkStang · « **Reply #19 on:** December, 13, 2009, 10:09:17 AM »

This is great information. I lost almost 2 inches from my drop and new suspension. I think it would be nice to gain back a little and have this added plus to boot. Nice write up John.

cmayna · « **Reply #20 on:** December, 15, 2009, 11:59:15 AM »

I still have the templates and would loan them out as long as you pay the postage and return them when done. If interested, PM me.

Craig

Fast68back · « **Reply #21 on:** December, 15, 2009, 12:58:09 PM »

Quote from: cmayna on December, 15, 2009, 11:59:15 AM

I still have the templates and would loan them out as long as you pay the postage and return them when done. If interested, PM me.

Craig

Is the same true for the trunk panels?

cmayna · « **Reply #22 on:** December, 15, 2009, 02:10:58 PM »

Fast68back · « **Reply #23 on:** December, 15, 2009, 02:30:18 PM »

Quote from: cmayna on December, 15, 2009, 02:10:58 PM

huh?

Didnt you make custom trunk panels for shag? I really want to finish out my trunk, but the daunting task of making templates keeps me from actually doing it....