Fx 3

[Bill M.]

Re: Fx 3

Bill-----

At least as far as SERVICE goes, there was never any different part available for FX-3 versus base suspension.

Joe:

Here are some codes from my build sheet:

My car has both FE7 (HD susp) and FX3 (Sel. Ride).
Front Control Arms: 09-0 53-4
Rear Control Arm: 8YY
Axle: GM3 3.45 ratio axle

I would expect that your car will have FE1, one front control arm the same, one different, the same rear control arm, and the same code rear axle.

Bill

[Joe L.]

Re: Fx 3

Joe:

Here are some codes from my build sheet:

My car has both FE7 (HD susp) and FX3 (Sel. Ride).
Front Control Arms: 09-0 53-4
Rear Control Arm: 8YY
Axle: GM3 3.45 ratio axle

I would expect that your car will have FE1, one front control arm the same, one different, the same rear control arm, and the same code rear axle.

Bill

Bill----


Where did you find the build sheet? I don't have one for mine, but it may be in the car somewhere.

I wish there was some way of relating the build sheet codes for the control arms to GM part numbers. As I mentioned, there was only 1 set of part numbers for the front control arms ever available in SERVICE for 1988-96 Corvettes.

[Bill M.]

Re: Fx 3

Bill----


Where did you find the build sheet? I don't have one for mine, but it may be in the car somewhere.

I wish there was some way of relating the build sheet codes for the control arms to GM part numbers. As I mentioned, there was only 1 set of part numbers for the front control arms ever available in SERVICE for 1988-96 Corvettes.

Joe:

I found the build sheet in the right front spring tower. I had to pull it through the keyhole in the tower, so it's kinda wrinkled, but I can read it. (I understand build sheets for Bowling Green-assembled cars are available from the NCM.)

I saved a question and answer column from Corvette Quarterly where the 1991 Z07 package was detailed. It includes "Front lower control arms with stiffer bushings." I've heard that SCCA stock class (must use stock bushings) autocrossers seek out wrecked FE7 cars to get the lower control arms because you can't get them in service.

Bill

[Bruce C.]

Re: Fx 3

Though this thread was effectively "settled" about 3 months ago, I thought I'd throw my two pennies into the circle:

Bilstein will rebuild your FX3 shocks. I had mine done about three years ago and they charged me $100 each, if memory serves. (Can produce an invoice, if necessary.) Bill Heindorf (pronounced HENdorff) in sales can help you.

They don't restore the outside appearance so if they were cosmetically challenged going in, that's the way they'll look coming back.

My bushings, upper and lower are black.

And like the others, I cannot tell any difference between the three settings so I leave it on "Perf" to impress guests.

Note to any future purchasers of FX3-equipped cars: Be very careful when removing/replacing the rear actuators as they can break easily. I was VERY lucky and got a good used replacement for $125 but I think the salvage market is pushing that upwards these days.

[Bill M.]

Re: Fx 3

Bill-----


You might also check for any parts tags (actual paper labels, not casting numbers) which might be on the various components. Part numbers would provide useful information. However, I don't actually recall seeing any tags on these parts, but I have not really looked closely.

Joe:

I have my '92 Z07 up in the air to fix a P/S leak. I checked for part no.s on the lower control arms.

Stamped in the pass. side arm:
4Z51
H 2555

Stamped in the driver side arm:
3Z51
H 2747

I don't see any color code, but the plant must have used the Z51 to identify the parts. The front bushing is scalloped (daisy) and the rear is normal round.

Bill

[Joe L.]

Re: Fx 3

Joe:

I have my '92 Z07 up in the air to fix a P/S leak. I checked for part no.s on the lower control arms.

Stamped in the pass. side arm:
4Z51
H 2555

Stamped in the driver side arm:
3Z51
H 2747

I don't see any color code, but the plant must have used the Z51 to identify the parts. The front bushing is scalloped (daisy) and the rear is normal round.

Bill

Bill------

Did you find these stampings on or near a slightly raised pad on the outer underside of the arms? If so, I found some similar stampings on my arms in this location. These are as follows:

H 2377

H 2381

The stampings on mine do not appear to be a derivative of the part numbers, so I don't know just what they refer to. Although the Z07 arms had different part numbers (but unknown and never available in SERVICE part numbers), I expect the similar numbers on yours are not related to the arm part numbers, either.

Whatever the numbers are, I don't think they're relative to the basic casting. Otherwise, they'd be cast-in rather than stamped in. So, they're somehow related to the finished machined arms, either before or after installation of the bushings and/or ball joints.

The "Z51" stamping is interesting on yours. Even though there are no part number stampings or labels on either of our arms as I had hoped there would be, this still tells us that there was a difference between the FE1 and FE7 lower control arms as I thought. I doubt very much that there was any difference in the castings and I know there was no difference in the ball joints. So, there was either a difference in the finish machining of the arms and/or in the installed bushings.

Apparently, there was no difference in the color-coding of the bushings as I was once told (at least, not between the 89-96 FE1 and FE7 bushings). However, I believe the bushings were nonetheless different in some functional way, probably at least durometer.

[Bill M.]

Re: Fx 3

Bill------

Did you find these stampings on or near a slightly raised pad on the outer underside of the arms? If so, I found some similar stampings on my arms in this location. These are as follows:

H 2377

H 2381

The stampings on mine do not appear to be a derivative of the part numbers, so I don't know just what they refer to. Although the Z07 arms had different part numbers (but unknown and never available in SERVICE part numbers), I expect the similar numbers on yours are not related to the arm part numbers, either.

Whatever the numbers are, I don't think they're relative to the basic casting. Otherwise, they'd be cast-in rather than stamped in. So, they're somehow related to the finished machined arms, either before or after installation of the bushings and/or ball joints.

The "Z51" stamping is interesting on yours. Even though there are no part number stampings or labels on either of our arms as I had hoped there would be, this still tells us that there was a difference between the FE1 and FE7 lower control arms as I thought. I doubt very much that there was any difference in the castings and I know there was no difference in the ball joints. So, there was either a difference in the finish machining of the arms and/or in the installed bushings.

I stuck my camera under there and this was the only shot of many that clearly shows the stampings in my RH arm.

Apparently, there was no difference in the color-coding of the bushings as I was once told (at least, not between the 89-96 FE1 and FE7 bushings). However, I believe the bushings were nonetheless different in some functional way, probably at least durometer.

Hib Halverson published the stiffness of the LCA bushings:

FE1: front bushing is 11.0KN/mm, rear is 2.3KN/mm
FE7: Front bushing is 13.5KN/mm, rear is 3.5KN/mm

[Joe L.]

Re: Fx 3

I stuck my camera under there and this was the only shot of many that clearly shows the stampings in my RH arm.





Hib Halverson published the stiffness of the LCA bushings:

FE1: front bushing is 11.0KN/mm, rear is 2.3KN/mm
FE7: Front bushing is 13.5KN/mm, rear is 3.5KN/mm

Bill------


My "H" numbers are stamped on the same pad as yours. Of course, mine does not have the "Z51" (or any other stamping) in same area as yours. It sort of looks to me that the "H" stamping and the "Z51" stamping were done at different times in the arm's manufacturing process.