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Discussion Starter · #1 ·
I'm wondering what people are using for shocks in the Manta A's.

I've read all I can on the forum, and while the KYB's seem to be available for the front there doesn't seem to be anything available for the rear.
I tried finding a set of the Rancho RS99168's that Rally Bob suggested in a thread from the way-back machine, but it appears that those too have been discontinued.

Koni is apparently making their Yellow's for both front and back, but they seem to be backordered (or no longer made) everywhere.

Does anyone have any tips?
 

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Look to buy from distributors in England and Europe for the Koni Yellow's. I have not found any one in the US who sells them, but found several in Europe who do, and who will ship.

I used to use shocks from the rear of early 80's Ford Thunderbirds. I see KYB 343162 and KYB Gas-Adjust KG5556 listed for years like 82 and 84 T-birds.

Here is a dimension chart from KYB. The above are about 2" shorter than the Rancho shocks. You can start with the dimensions of your present shock and verify this fit of the T-bird shock. I'll be out in the garage later and will try to verify myself; I ought to have some old rear shocks lying about.
 

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I did not find and stock shocks yet. So taek one of yours out and check the extended and compressed length for the KYB 343162 in the KYB dimensions table in the link above. I am 99.99% sure the top pin and bottom eye mounts are right.
 

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Discussion Starter · #4 ·
I will do that!

I have to put an engine back in a volvo so I can get my garage space back. But then I'll take out a shock or two and take some measurements!
 

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Discussion Starter · #5 ·
I did not find and stock shocks yet. So taek one of yours out and check the extended and compressed length for the KYB 343162 in the KYB dimensions table in the link above. I am 99.99% sure the top pin and bottom eye mounts are right.
If you're that sure maybe I should just go for gold!?
 

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If you're that sure maybe I should just go for gold!?
Well, I am pretty darned sure on the top pin and bottom eye.... just not on the length. It has been 30+ years since I was using those. If you can return them then you would only be out the shipping. But it only takes a few minutes to pull one out to check the lengths. (It'll be a while before I get to a stock shock, when I scrap out a rust-bucket shell or 2.)
 

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Discussion Starter · #8 ·

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Discussion Starter · #9 ·
Well, I am pretty darned sure on the top pin and bottom eye.... just not on the length. It has been 30+ years since I was using those. If you can return them then you would only be out the shipping. But it only takes a few minutes to pull one out to check the lengths. (It'll be a while before I get to a stock shock, when I scrap out a rust-bucket shell or 2.)
Yea for sure. I just haven't had a minute to work on this car in the garage.

I did find this the other day that might work as a stop gap.

KYB Shocks Opel Manta A

I need to get a baseline of what the car is like to drive to know which way I want to go. But the poly bushings seem to be the only available option for stopping deflection of the suspension.
 

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I’m tinkering with a new low buck shock setup, but haven’t been able to test them yet. The lower bushings will need the properly sized steel sleeves inserted, that is a given.

426355
 
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Discussion Starter · #11 ·
I’m tinkering with a new low buck shock setup, but haven’t been able to test them yet. The lower bushings will need the properly sized steel sleeves inserted, that is a given.

View attachment 426355
I'm more than happy to help test them for you 🤣.
Apparently the person who started KW suspension used to race these in Germany and has all the info to make a really nice setup, similar to what they do for the early Golf's. I've been trying to get in touch with them about this, but with the shutdown they aren't really responding.
 

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I'm more than happy to help test them for you 🤣.
Apparently the person who started KW suspension used to race these in Germany and has all the info to make a really nice setup, similar to what they do for the early Golf's. I've been trying to get in touch with them about this, but with the shutdown they aren't really responding.
It kind of defeats the purpose if Ican’t test them firsthand. Not to mention they are going to be used with my particular set of springs and driving style.

KW makes some very nice stuff. But it is priced accordingly! A friend of mine runs their suspension in his Subaru, it was $6000 for 4 struts.
 
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Discussion Starter · #13 ·
It kind of defeats the purpose if Ican’t test them firsthand. Not to mention they are going to be used with my particular set of springs and driving style.

KW makes some very nice stuff. But it is priced accordingly! A friend of mine runs their suspension in his Subaru, it was $6000 for 4 struts.
Yea it's definitely pricey. But I'm interested to see what they do as far as valving and spring rates.
 

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Yea it's definitely pricey. But I'm interested to see what they do as far as valving and spring rates.
It depends on the usage. European hillclimbs, for example, run spring rates off the charts. But their roads are super smooth.

Dampening rates are directly related to spring rates and vehicle mass, so it’s nearly impossible to make a direct comparison.

You would want spring rates that are suitable for bumpy tarmac rallies in Europe.

Example: stock Manta spring rates are 135 lbs front, 118-180 rear (progressive).

A gravel rally car might run 250-275 front, 150-175 rear.

For tarmac rally, maybe 450-550 front, and 200-225 rear.

I used to run 715 front, 180 lb rear for banked 1/4 mile asphalt circle track.

They run crazy rates like 1400 lbs up front, 400 rear for hillclimbs!

For high-po street cars I like 375 front, 180 rear generally. A bit higher rate in the bank for autocrossing. I used to run 220 lbs. I’ve run as high as 500 front, 200 rear in street cars. If you retain as much travel as possible and choose the dampening correctly, they are quite liveable. Super-low short-travel suspensions ride like sh!t in my opinion.
 

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Discussion Starter · #15 ·
It depends on the usage. European hillclimbs, for example, run spring rates off the charts. But their roads are super smooth.

Dampening rates are directly related to spring rates and vehicle mass, so it’s nearly impossible to make a direct comparison.

You would want spring rates that are suitable for bumpy tarmac rallies in Europe.

Example: stock Manta spring rates are 135 lbs front, 118-180 rear (progressive).

A gravel rally car might run 250-275 front, 150-175 rear.

For tarmac rally, maybe 450-550 front, and 200-225 rear.

I used to run 715 front, 180 lb rear for banked 1/4 mile asphalt circle track.

They run crazy rates like 1400 lbs up front, 400 rear for hillclimbs!

For high-po street cars I like 375 front, 180 rear generally. A bit higher rate in the bank for autocrossing. I used to run 220 lbs. I’ve run as high as 500 front, 200 rear in street cars. If you retain as much travel as possible and choose the dampening correctly, they are quite liveable. Super-low short-travel suspensions ride like sh!t in my opinion.
Yea I was reading a lot of what you had posted about spring rates and custom springs before. I do want the car to sit lower than it currently does, and I want the ride to be "firm but pliable." By that I mean I want it to handle well, and be stable over bumpy tarmac. I don't want a super short travel suspension (as much as I do love the 90s DTM cars) but I don't want it to roll too much either.

Would 400/200 be too out of whack?
 

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Would 400/200 be too out of whack?
That’s still tolerable, as long at the travel is there. It’s really easy to get into the front bump stops if you’re not careful. Also make sure the shocks don’t have too much compression dampening.

Here’s a video from 2009 I made of my friend’s hillclimb car. The front end was literally from my street car, my daily driver. 380 lb springs. It had a 25 mm Euro front sway bar. Rare these days unfortunately.

The rear used 180 lb springs with a modified 3/4” Addco sway bar.

The car is run in the Pennsylvania Hillclimb series, and has run the Mt Washington Hillclimb 3 times. It’s compliant but much stiffer than stock. Very well balanced.
 
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Discussion Starter · #18 ·
That’s still tolerable, as long at the travel is there. It’s really easy to get into the front bump stops if you’re not careful. Also make sure the shocks don’t have too much compression dampening
How do you mean it’s easy to get to the front bumpstops?

how much compression dampening would be too much?
 

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How do you mean it’s easy to get to the front bumpstops?

how much compression dampening would be too much?
It’s easy to bottom out the front suspension if you lower it, is all I’m saying.

The stiffer the spring, the less compression dampening you need. The spring controls the body motions in compression. But the high frequency spring rates tend to need a ton more rebound to avoid excess jounce.
 

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Discussion Starter · #20 ·
It’s easy to bottom out the front suspension if you lower it, is all I’m saying.

The stiffer the spring, the less compression dampening you need. The spring controls the body motions in compression. But the high frequency spring rates tend to need a ton more rebound to avoid excess jounce.
Ah gotcha! All I really know about setting up suspension is how much I really don't know!

So what rebound would you be looking for in a 400/200 setup? Theoretically of course
 
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