Bilstein shock questions for Tiga FFA-77...

[fshort]

Hi all:

In our thrash to get my 38-year frame-up completed before the 50th @ RA, I found that the shocks from the car (back in the day) are missing. I just have (8) Bilstein cores.

So, as I know less than zero about valving, etc, stroke, etc, etc. - I need input from the collective...

I have:

(4) shocks with an over all length of 328 mm & a stroke of 67 mm, all with 10 mm shafts.

(3) shocks with an over all length of 345 mm & a stroke of 98 mm, all with 10 mm shafts. Plus (1) with a bent lower eye (on the body).

I am sending the shocks to be rebuilt and need the valving, and which shocks should go on the front vs the rear.

I didn't run my car back then, so I have only info that I had 2.25" x 7" springs - nothing on the shocks...

I'm assuming:

1) Upgrade the shafts to 14 mm.

2) Have the longer stroke shocks on the rear.

3) Change the valving to? I have one note that the old shocks were 180/60, but that's all...

Due to budget & time, I need to stick w/ Bilsteins.

Thanks for any & all input!

Regards,
James

[rdracr]

From years ago. I just use it as reference. A starting point if nothing else

[alangbaker]

Hi all:

In our thrash to get my 38-year frame-up completed before the 50th @ RA, I found that the shocks from the car (back in the day) are missing. I just have (8) Bilstein cores.

So, as I know less than zero about valving, etc, stroke, etc, etc. - I need input from the collective...

I have:

(4) shocks with an over all length of 328 mm & a stroke of 67 mm, all with 10 mm shafts.

(3) shocks with an over all length of 345 mm & a stroke of 98 mm, all with 10 mm shafts. Plus (1) with a bent lower eye (on the body).

I am sending the shocks to be rebuilt and need the valving, and which shocks should go on the front vs the rear.

I didn't run my car back then, so I have only info that I had 2.25" x 7" springs - nothing on the shocks...

I'm assuming:

1) Upgrade the shafts to 14 mm.

2) Have the longer stroke shocks on the rear.

3) Change the valving to? I have one note that the old shocks were 180/60, but that's all...

Due to budget & time, I need to stick w/ Bilsteins.

Thanks for any & all input!

Regards,
James

The Bilsteins on my RF89 had their valving stamped right on the outside... ...at least the valving they had when they were first made.

If your shocks are like mine, I'm pretty sure that the 180/60 refers to the Newtons of damping (divided by 10) at 0.5m/s shock speed and Bilsteins are essentially linear (again, if they're like mine).

The equations in Newtons and metres/s:

F(r) = 3600*V(r), and
F(c) = 1200*V(c)

become in pounds and inches/s:

F(r) = 0.224809*3600/39.37*V(r) = 20.5lb/(in/s)
F(c) = 224809*1200/39.37 = 6.9lb/(in/s)

If I've done my math right.

[fshort]

Hi rdracr:

Your chart is a lifesaver!

From it, I learned that the (4) 328mm OAL w/ 67mm stroke & 110/30 valving are fronts, and the 345mm OAL w/ 98mm stroke & 180/40 valving are rears.

Hi Alan:
Thank you for the formula & the conversion. I'll figure the shocks' rates & see the if the rebuilder will dyno them or not.


BTW, I'm using Steve Nelson of TSM Enhanced (Tucson, AZ) steve@tsmenhanced.net, for the rebuilds. He said 1-2 days turn time (depending on parts) and $60-85/shock labor plus parts. I'll report back after the shocks come back.

This forum is so valuable! Back in the '80s, I would spend hours on the phone getting info... Thanks to all who share their info!

Regards,
James

[Jayeff]

I think engraving in some way on each shock what corner it is will help some poor schmuck in the future.

[Sports Car International]

Call Archie Hodge !

He has done most of the Bilstein shock rebuilds. At Indy til Tuesday.

(206) 979 -1405


Michial

[fshort]

Hi Jayeff & Michial:

From no records (almost) in the '80's, I've gone to the opposite extreme: serializing all components, logbook entries of maintenance done, a parts list, etc. I became an corporate jet A & P mechanic in 1990, so that might explain it...

I'll call Archie Hodge Tuesday, thanks for the recco!

Regards,
James

[cgscgs]

The Bilstein website used to list the specs for a number of cars, including the Tiga FF. I sent them the shocks from my FFA-81 and they rebuilt them for me. I assume they still have those numbers on a dusty piece of paper somewhere.

[fshort]

Hi cgscgs:

Are you going to the 50th @ RA?

Regards,
James

[Brian Forster]

fshort: I know you're on a crunch now, but are you planning to stick with the Bilsteins? I also have an FFA77 (number 31) and I'm planning to put on a set of Koni's that I have. (After I've gone through them that is...) I'm not a fan of Bilsteins and mine are shot anyway. I've found out some things in this thread, including that I have the original spec on my car. Also, I didn't know that Archie Hodge can rebuild them, in case I go that route.

[fshort]

Hi Brian:

Yes, I'm staying w/ Bilsteins because: I own them & I need to simply driving the car. I know that having adjustable shocks is important...

Regards,
James