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Affordable performance rear shocks for 240s

Poik

Poik

Backwards Turbo
300+ Club
Joined
Feb 20, 2005
Location
Mountain View, CA
So I have my car set up with 500# springs in front and 250# springs in the rear, the front is matched great, but the rear overwhelms the Bilstein HDs back there without a problem. It's bouncy and uncomfortable over dips, even though it rides pretty good over small bumps. 250# in the rear is 375# wheel rate FWIW.

So I have been trying to find some shocks to put back there that are valved to match the springs, and are affordable and off the shelf. If I wanted my car to be down for 2 months I would just send my rear shocks to get rebuilt/revalved at Bilstein for $130 plus shipping, but I won't do that.

Dave Barton has a very good write up on the Bilstein HDs vs R-Sport shocks on his website with valving specs and dyno graphs etc http://personal.linkline.com/dbarton/SpecSheet.html#bilsteins

I tried to find out what the valving is for the S10 and Suburban Bilstein HD shocks are that people are using, but I came up with nothing. So I went through Bilstein's catalog and found one shock that should work really well for our cars:

Part Number Travel Description Valving Reservoir Ext. Length. Col. Length Shaft Dia. Finish
F4-B46-0930-H5 5.36 Class 11 Rear 345/135 N 16.22 10.86 14mm Plated

So it's 16.22" fully extended, which is about 1.25" shorter than stock so it will be great for lowered cars. Compressed height is about 0.5" less than stock, so we aren't sacrificing any travel. It's valved 345/135 which should be transformational for the rear of the car. Also instead of rubber bushings at each end they come with 1/2" heim joints.

The best part is that these shocks are affordable. They sell online for $105-110. I ordered a set last week from www.ajusa.com for $199 shipped with a phone order discount thing. That's only a little bit more than regular 240 HDs, and is cheaper than Koni Yellows and should outperform them. Unless you get a pair of blown HDs to rebuild for less than $50, this is going to be a cheaper option than revalving your existing shocks. The only downside I can see to these shocks is that they are meant for an off-road racing application, so they do not come with dust boots. I don't think that's a huge deal, and without the dust boot on there you should actually be able to mount the shock inverted like it's supposed to be and lose a tiny bit of unsprung weight.

Just thought some of you on here would be interested in a good affordable shock option for the rear of your cars. These will probably also work on a lowered 740, the extended length is about 2" shorter than stock. When I get the shocks I'll let you guys know what has to be done to fit them, as I'll probably have to make some spacers for the heims.
 
I'm going to be running a 11.225" compressed & 16.425" extended shock with a threaded body as a coilover setup in the rear of my 960 w/ 350lb springs. They're made by Ridetech. Similar setup to yours but it keeps closer to the stock shock lengths. At the ride height I want, the shocks will be around 14" under curb weight.
 
RS1 said:
Try the Koni rear shocks Ben Kaplan offers. Four position rebound adjustment. http://www.kaplhenke.com/index.php?option=com_content&task=view&id=78&Itemid=32 See under "Koni Race Shocks price per pair".
Click to expand...
I'm going to try the Bilsteins I posted about in the first post. $334 vs. $200, and the Bilsteins honestly should outperform the 30 series Konis in every way but adjustability. If it was a race car I'd buy the double adjustable shocks that Ben sells, but the point of this thread was to let people know about an affordable high performance shock.
 
Poik said:
I'm going to try the Bilsteins I posted about in the first post. $334 vs. $200, and the Bilsteins honestly should outperform the 30 series Konis in every way but adjustability. If it was a race car I'd buy the double adjustable shocks that Ben sells, but the point of this thread was to let people know about an affordable high performance shock.
Click to expand...

I doubt it would really out perform it, they are both steel bodied monotubes. The koni is adjustable, the bilstein isn't

I don't see any reason the Bilsteins dampening performance would be inheriantly better then Konis
 
blkaplan said:
I doubt it would really out perform it, they are both steel bodied monotubes. The koni is adjustable, the bilstein isn't

I don't see any reason the Bilsteins dampening performance would be inheriantly better then Konis
Click to expand...

Nobody said the Bilsteins were inherently better performing vis-a-vis the Konis.
False argument..

But right now, without searching tell us what the valving inside the Koni makes for damping force! How many N at what velocity?

And tell us those numbers for the normal Koni's sold as replacement shock AND tell us the damping force in Konis sold at GM truck fronts or whatever Poiken is thinking about.

You can't.

A mere slip of a young boy Myles aka mylesofsmiles in SanFrancisco was well into some hare-brained scheme to use some Saab so called 900 inserts in the front of his 240 and I suggested before he got too deep to call the 1-800 number andask the folks there what the damping numbers were for those...
Turns out they were significantly lighter valved than the silly-soft normal 240 "HD" people use---which at least has 210mm travel...indeed the Saab 900 inserts were valved approximately half as stiff as the most popular rwd car thru the ages was valved for use on loose surfaces in a car 700-800lbs lighter.

From those figures, NUMBERS---he saw it would be plain silly to waste effort using the Saab Bilsteins...

The pistons are virtually identical inside which I'm sure you must know since as an expert in suspension I'm sure you have rebuilt and revalved many scores of Konis and many dozens of Bilsteins.

So the difference lies in how they choose the shim stack---and for the end user what information they have ready access to when they are at the point where they're trying themselves to fine tune to taste...

Put clearly the choice is ready information on precisely what you have-or are contemplating buying versus trust somebody who may have extremely limited experience and no real info on the properties of what is supposedly "the answer".:oops:

I know which way I would choose.:grrr:
 
blkaplan said:
I doubt it would really out perform it, they are both steel bodied monotubes. The koni is adjustable, the bilstein isn't

I don't see any reason the Bilsteins dampening performance would be inheriantly better then Konis
Click to expand...

Sorry, I guess it's been awhile since I looked at the Koni catalog because I thought those were twin tube.
 
John V said:
Nobody said the Bilsteins were inherently better performing vis-a-vis the Konis.
False argument..

But right now, without searching tell us what the valving inside the Koni makes for damping force! How many N at what velocity?

And tell us those numbers for the normal Koni's sold as replacement shock AND tell us the damping force in Konis sold at GM truck fronts or whatever Poiken is thinking about.

You can't.

A mere slip of a young boy Myles aka mylesofsmiles in SanFrancisco was well into some hare-brained scheme to use some Saab so called 900 inserts in the front of his 240 and I suggested before he got too deep to call the 1-800 number andask the folks there what the damping numbers were for those...
Turns out they were significantly lighter valved than the silly-soft normal 240 "HD" people use---which at least has 210mm travel...indeed the Saab 900 inserts were valved approximately half as stiff as the most popular rwd car thru the ages was valved for use on loose surfaces in a car 700-800lbs lighter.

From those figures, NUMBERS---he saw it would be plain silly to waste effort using the Saab Bilsteins...

The pistons are virtually identical inside which I'm sure you must know since as an expert in suspension I'm sure you have rebuilt and revalved many scores of Konis and many dozens of Bilsteins.

So the difference lies in how they choose the shim stack---and for the end user what information they have ready access to when they are at the point where they're trying themselves to fine tune to taste...

Put clearly the choice is ready information on precisely what you have-or are contemplating buying versus trust somebody who may have extremely limited experience and no real info on the properties of what is supposedly "the answer".:oops:

I know which way I would choose.:grrr:
Click to expand...

I just said that in seven words.
 
blkaplan said:
I doubt it would really out perform it, they are both steel bodied monotubes. The koni is adjustable, the bilstein isn't

I don't see any reason the Bilsteins dampening performance would be inheriantly better then Konis
Click to expand...

the bilstien stuff has digressive valving, unless you specificaly order it with linear valving

the koni stuff is all liniar (unless they have changed stuff recently)

so probably not much diiference for the same valving specs, except the bilstiens will dampen better over short hard hits.
 
John V said:
1-800 number andask the folks there what the damping numbers were for those...
Click to expand...
What number was that? I like Bilstein stuff, but their customer service is absolutely terrible. Every time I call, nobody picks up the phone. If I leave a message, I never get a call back.
towerymt said:
Any figures to share from the Koni?
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fidel said:
the bilstien stuff has digressive valving, unless you specificaly order it with linear valving

the koni stuff is all liniar (unless they have changed stuff recently)

so probably not much diiference for the same valving specs, except the bilstiens will dampen better over short hard hits.
Click to expand...
They are both digressive: http://www.koniracing.com/images/File/30force.pdf
The 20.65"/s is close enough to Bilstein's 0.52m/s. Just convert units.

Maybe I should have titled the thread "Affordable performance rear shocks" because that's what I was going for. Obviously there are better options, but with a premium that may or may not be worth it to the buyer.
 
woodrowstar said:
These and change out the lower eyelet bushing sleeve or put in a larger shank bolt. ;-)
Or you can get really fancy for the remote reservoir ones.

http://www.summitracing.com/parts/HAL-TS403/

or cheaper option good for 320 spring i believe.
http://www.summitracing.com/parts/BSN-24-184588/

I should mention.... click on the link in signature to see how i'm sitting on them.
Click to expand...
One of those shocks has 3 inches of travel and no valving information, and is probably made for a drag car, and the other has neither length nor valving information... :e-shrug:
 
ill be very interested to hear how the bilsteins work out for you as i will be running the same spring rate and have been looking for a suitable cheap shock option for awhile.
 
blkaplan said:
I doubt it would really out perform it, they are both steel bodied monotubes. The koni is adjustable, the bilstein isn't

I don't see any reason the Bilsteins dampening performance would be inheriantly better then Konis
Click to expand...


The Koni's will foam overheat with a moderate springrate, especially on bumpy surfaces. The Bilstein is all around a superior quality damper (outside of adjustability, but really, when custom-spec'ing a damper - there is no need for adjustability. If the valving needs to change - revalve it).

In my application, in the rear of my 960 wagon, I'll either be using one of the Bilstein circle track shocks like the OP purchased, or something from ProShocks (who happen to be local, about 15 minutes from my house).
 
kendogg, the Koni shock Ben is talking about is also a high pressure gas shock. Also for your 960, not sure if you are aware, but most of the Bilstein motorsports shocks have linear valving. The ones are an off-road shock and have digressive valving. Not sure what the purpose of your 960 is, but a motorsports shock with digressive valving starts around $170 each and doesn't include the valve stack, and linear valving may suck on the street.
 
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