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Integrator
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Here are the part number I got from Bilstein

24-020541 rear
24-187824 front


The rears are from a C4 Corvette and the fronts from a Nissan Frontier. The rear shocks should be very close, but the fronts may have too much rebound. Bilstein suggested I give it a try and if needed Bilstein's can be re-valved. Bilstein can do this or some shops that revalve shocks can do this.

You can enter these part numbers into Ebay and find them for very good prices.

To use these as coil overs you need coilover kits from Bilstein or other seller on Ebay. The kit you use needs to be for a 2.5" diameter shock. Most of these kits require machining a groove into the shock body for a circlip that holds the threaded sleeve. You will also need springs. $2.5 ID springs are needed and can be found in any spring rate on Ebay for cheap. Not sure of the spring length needed and will try to get that info from Bilstein.

After checking some prices, you could put together a complete set for $500-$700
You may follow this information ( page 2 of this thread), and save some coin. They are listed on eBay for less than 100 bucks. The only drawback is that they are non-adjustable, whilst GAZ and QA-1 are.
 

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Integrator
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FYI:

What do GAZ shocks offer for your car?

Find out in the GAZ NEW catalogue. Check out the whole range. Shock absorbers and suspension kits listed by car make, year and model.

https://issuu.com/edeuro/docs/gaz-2017-catalogue_full

GAZ GP Adjustable Coilovers are a particularly good deal (PUK sells 4 of these for € 1139! ).

Gaz offers a total rebuild and revalve service to back up their product line. Lngths can be adjusted to customers requirements if the car is to be lowered or raised for competition use.
 

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Integrator
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Integrator
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I read a post recently where an owner swapped springs right to left because of sagging. I have since noticed that the drivers side of my car is lower and I suspect a sagged spring.

I also noticed with aggressive "test" braking (on deserted back roads in semi controlled conditions) the passenger front locks up way before the drivers suggesting a corner balance would really improve performance. On the old 911s I played with the very light front ends were very sensitive to corner balance when the spring rates were increased and the handling and braking improvements were noticeable and fun.

I soon plan to add adjustment to the front end on my S4 so i can get a proper CB, I imagine you will enjoy your set up. I wonder if with the stock long springs if you will be able to get the collar low enough for stock ride height? An issue that seems to be reported in many posts on the subject. Do you have a plan for this or will it not be an issue?
 

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Wingless Wonder
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I read a post recently where an owner swapped springs right to left because of sagging. I have since noticed that the drivers side of my car is lower and I suspect a sagged spring.
Before you go 'nutz' check the ride height the proper way, at the bottom of the front frame member. (Stock height is 170mm)

The body is not a good place to check. The body gap to the tires is not accurate, for example.


++++++++++++

That said, I've swapped springs side-to-side on both my own '88 Esprit and a local guy's S4s. Helped my car, not so much the S4s.
:rolleyes:
 

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Integrator
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Bilstein shocks Summary

Since this thread is so big, here are Cliff notes.
Contributor: LantanaTX

Here are the part number from from Bilstein
24-020541 rear
24-187824 front

The rears are from a C4 Corvette and the fronts from a Nissan Frontier. The rear shocks should be very close, but the fronts may have too much rebound.
You can enter these part numbers into Ebay and find them for very good prices.

To use these as coil overs you need coilover sleeve kits from Allstar Performance or other seller on Ebay. Most of these kits require machining a groove into the shock body for a circlip that holds the threaded sleeve. You will also need springs. 2.5" ID springs are needed for front and 3"ID rear, which can be found in any spring rate on Amazon or Ebay for cheap. Not sure of the spring length needed and will try to get that info from Bilstein.

It is probably easier to get Gaz adjustable height shocks, version GP8-2144 front & GP8-2145 rear (ask for large 3" iD spring perches). Beware: 2.5" coil overs will NOT fit the upper rr mount.

The spring rate/length/damper question is more complex than it might seem because Lotus was always fiddling with it to make performance improvements, meet ride height regulations, and adjust oversteer/understeer characteristics.
Here are a few specific model specs that might help.
Lotus was a pioneer in Big Bar Soft Spring Setup (BBSS) application, google it.
Thus, arbitrary spring rate changes don't work well. Don't adapt S4s rates to G-car, your chassis will develop cracks.

Non-SE 89 including G-cars:
Front: Rate – 22.8 N/mm / 130 Lb/in, Free Length – 369mm, Static Length – 203mm
Rear: Rate – 27.5 N/mm / 157 Lb/in, Free Length – 334mm, Static Length – 205.7mm

SE
Front: Rate – 29.1 N/mm /166 Lb/in, Free Length – 372mm, Static Length – 219mm
Rear: Rate – 27.5 N/mm / 157 Lb/in, Free Length – 347mm, Static Length – 218mm

The front damper platform height for each of these measurements is 59mm. The rear platform height is 115mm.
The extended/compressed length for the front is 12in./10in., and the rear is 16in./12in. If you increase the spring rate, you have to shorten the spring to achieve similar preload (vehicle ride height).

S4/S4s -those had STIFFER/STRONGER Chassis
Front: Rate – 41 N/mm / 234 Lb/in, Free Length - N/A, Static Length – 214mm
Rear: Rate – 45 N/mm / 257 Lb/in, Free Length - N/A, Static Length – 227mm

Ride quality is a function of a fine balance between understeer and oversteer and does not respond well to random changes.
It is all out there:
link https://www.lotustalk.com/forums/f164/lower-cost-bilstein-option-123221/f164/lower-cost-bilstein-option-123221/f164...-codes-113033/
https://www.lotustalk.com/forums/f164/lower-cost-bilstein-option-123221/f164/lower-cost-bilstein-option-123221/f164...ndling-242090/
https://www.lotustalk.com/forums/f164/lower-cost-bilstein-option-123221/f164/lower-cost-bilstein-option-123221/f164...-rates-241434/

For more info see Post #86 and on, 99, 130
in https://www.lotustalk.com/forums/f164/lower-cost-bilstein-option-123221/index2.html

.
 

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Integrator
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Do you think a 3" OEM spring will sit on the bottom mount? I think those perches are designed for a 2.5" or even 2.25" ID springs?
You can solve this minor problem by adding a custom collar, which fits over a flange of the adjuster nut. At the rear only.
 

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Super Moderator
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Since this thread is so big, here are Cliff notes.
Contributor: LantanaTX
[snip]
It is probably easier to get Gaz adjustable height shocks, version GP8-2144 front & GP8-2145 rear (ask for large 3" iD spring perches). Beware: 2.5" coil overs will NOT fit the upper rr mount.[snip]
.
Wait - are the 3" ID spring perches for FRONT and REAR? I thought my 87 Giugiaro Esprit needed 2.5" front perches and 3" rear perches.

Do I need 3" spring perches all around on an 87 Esprit?
 
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