Does anyone have any information on the S-type suspension.

No one seems to know the "Stock Shock Valving" and "Spring Rates" on these vehicles. Better yet, the working spring rate on the S-Type.

Even the aftermarket company's just say, they are stiffer than stock. How do they know if they cannot tell me the stock spring rate or their spring rate?

Same with shocks.

This is a little disappointing.
Shock Valving and Spring Rates need to be compatible.

 

Generally, the OEM or its supplier is tasked with matching up appropriate shock valving to spring rates,

Very few platforms out there have publicly available data on factory spring rates, and even fewer still have information on factory damper valving/damping curves,

Specialty motorsports/suspension shops have equipment to measure dampers and spring rates, this is usually represented on a graph typically referred to as a 'shock dyno',

Agreed, springs need to be matched to appropriately valved dampers, but unless this is in a motorsports context, it's usually impractical to develop or mod around this; 99.99% of the market for something like the STR platform just wants to lower the car an inch with a 10% stiffer spring which usually a stock damper can handle,

Anything else needs some serious development that few can tackle, so its best to stick to what the factory deemed appropriate in regards to pairing up dampers and springs,

 

When I called Mina, they said they were for stock struts. Stock Sport or non-sport. They also said that they were copies of Arden Springs. Arden uses it's own shock built by bilstein. Is that shock closer to the Sport or non-sport?

Do I just blindly order the Mina Springs and the Bilstein Sport Shocks? I am not even sure anyone has even run that combination.

Maybe the MINA springs match the comfort shocks better?

Ideally, I would want the ride quality and performance of the Sports non-Cat Suspension, with a 1" drop.

Given our S-typs (non-R) have such a bad resale value for its performance, I would have thought the Aftermarket would have grown.

 

Ok, After talking with Bilstein here are the valving specs.
Front:
24-067287 (160/50)
24-067430 (171/63)

Rear:
24-067430 (169/109)
25-067720 (185/131)



Bilstein tech line, 858-386-5900 option 2

 

Sport 29436
drop: 1.3 / 1.2
Spring Weight Unknown

STR 29300
Drop: 1.4 / 1.3
Spring Rate: 87nm / 82nm
converted: 497lbs / 470lbs

 

I haven't tried them in this platform yet, but Bilstein is good at what they do.

Good at making a car handle with out making the ride bone jarring. Which is not what you want in a car like this.

 

Yes they are, they are really our only option given they make the OEM Struts.

The only other replaement struts I know of are Monroe and KYB, and I don't see why you would install these in a Jag. You could go to a very expensive coil-over setup, but not sure it is worth it in a non-R S-Type. Then there is Arden, have their own spring along with there own custom Bilstein, but that is another 3K setup.

As far as affortable performance increases. We have H&R and Mina (Arden Copies) Springs. Along with 2 options of Bilstein Struts (Comfort and Sport).
Unless you were lucky enough to purchase a car with CATS.

 

And as far as I can tell, we are kind of like the "Redheaded Step-child" with companies like Eibach and Koni leaving us out of the mix. I am sure there is another vehicle that use a similar setup as ours that have similar specs for strut lenget and mounting points. Possibly an Audi A4, then we could get the valving correct on an adjustable strut, maybe even a reasonable coil-over suspension setup for Koni.

 

Koni Coilover for the A4 B6

 

Brian, did you ask the Bilstein tech about why they have two part numbers for the sport? Front: 24-067430 AND 24-067447 ("from 4/02")? Rear: 24-067720 AND 24-067454 ("from 4/02" (same time as production update for U.S. 2003 MY))?

What do the valving numbers represent? Is the first number compression damping and the second number rebound damping? What is the index based on? 1 being just the friction with no damping, and a 171 being 171 times more resistance than friction alone? Or is it some kind of measurement of force?

From these numbers it is looking like the "sport" dampers are only about 7% stiffer (in the first number) than the non-sport, and about 9.5% stiffer in the rear. For the second number (rebound??), 26% front and 20% rear.

 

There is also Spires in England. They mostly seem to offer things for the XF and newer XK: Spires :: Engineered Performance for BMW and Jaguar But they do offer what appears to be a more moderate sport suspension set with springs with a 13 mm nominal (they say 10-18 mm) drop (about 1/2") and dampers they say match the springs (nothing about who makes them -- I wouldn't be surprised if they were off-the-shelf Bilstein sport B4s). They sell the set for 699.99 GBP without VAT for export. Last July they quoted me that price plus 160 GBP for shipping to the USA, bringing the total to 859.99 GBP. The current exchange rate is around 1GBP:1.5USD, so the price is US$1,050 plus $240 shipping, for a total of US$1,290. That's only a little more than the Mina springs at $499 plus about $500 for the Bilstein dampers from a discount online dealer.

Spires seems to do good work on the XF and XK Jags, and their exhaust for the S-type is known on this forum, but no one in America seems to have anything to say about their suspension packages for the S-type. I am considering being the first (in 2014 -- yes, thinking ahead).

 

No, I did not ask about the earlier version of the dampeners as it seems like everyone runs the new versions with any spring change. If I was to guess, they probably tightened everythig up a little with the springs and shocks. Similar to what the other vehicle manufactures were doing at the time.
But yours is a 2005, built after April of 2002.

 

I would like to stick with parts that are available in the USA. It would suck to have an issue with a spring or a strut and have to wait months to get a new part. You can get the Mina Springs much cheaper than $500. They are also getting me the spring rate for their arden copy. I will post it once I get it.

I will probably run the Mina Spring, Matching Bilstein, and new bushings and isolaters.

And hopefully this tire on my stock RIM:
Conti DWS 245/50R17

 

It's not clear which are the earlier versions and which are the later versions of the Bilsteins. The "from 4/02" description seems to suggest it was made for the 2003+ S-types (revised suspension), yet everyone seems to be talking about the part numbers without the "from 4/02" descriptor for their 2003+ S-types (including you).

I guess if and when I am ready to buy new dampers I'll call the Bilstein tech line and try to clear that up.

 

What they hey, I blow enough time on all this already, so I just called Bilstein to clear up this question on the proper part numbers. I talked to a very knowledgeable Bilstein tech, and here is what he said:

PN 24-067430: CORRECT shock for a 4.2 wanting the "sport" higher damping rates. He said the damping values for this PN are 1710 rebound, 630 compression (different than what you got/wrote, Brian). The tech also mentioned that the B4 for the S-type is already a monotube, more like a B6 and that the B4 line was simply the OE replacement/match line and didn't denote twin-tube versus monotube. The B6 and B8 lines are Bilstein's own damping rates, while the B4 line is the OEM/factory damping rates. He said BMW uses a twin-tube in their base suspension and so the monotube is a significant upgrade; and that Jag already specked the better monotube for all suspensions. He also said that if there was enough demand, Bilstein would make B6s or B8s for the Jag S-type, but he questioned how much demand was there really? I said not much, apparently, especially in comparison to BMWs, and that most of the interest was from STR owners and they have the CATS electronically controlled dampers.

PN 24-067447: WRONG shock for a 4.2 -- this is for the 2.5, 3.0, and 2.7TD. The tech said he was in the process of correcting the US database overall, and that Bilstein Germany's database had the correct info and he had to look there.

Same story for the rears: PN 24-067720 is CORRECT for V8 sport, PN 24-067454 is for the V6 2.5 (not sold in US), 3.0, AND 2.7TD (also not sold in US as we all know).

Comparing damping strength:
PN 24-067287 - the OE standard/comfort damper for our 4.2 NA V8: 1550 rebound, 540 compression damping values.

N 24-067430 - the OE SPORT damper for our 4.2 NA V8: 1710 rebound, 630 compression.

Difference: Sport is 10.3% stronger in rebound damping, and 16.7% stronger in compression damping.

 

The Bilstein techs are pretty good and know a lot about their product.
The tech I talked to did not mention that the B4 for our vehicle is a monotube, but that is nice to know.

The number I got are for the 2006 S-Type 4.2 (given it is the vehicle I own)
for both the Sport and Comfort Struts they have listed.
I did not ask about the older models, and/or six cylinder models.

Here is the reason your numbers are so large.
Here is what Valving in a shock means.

EXAMPLE: Valve rating: 275 / 78
Rebound force is 2750 Newtons at 0.52 m/s
Compression force is 780 Newtons at 0.52 m/s

Now, It looks like we got the same numbers for the Sports, but not for the comfort suspension, not sure why we have a difference there.

 

This thread is a little dated, but I figure I will add some more shock/spring information here because it is the only coilover thread I’ve found that has some rate data posted.

I pulled the Right Rear CATS Coilover off my 2000 S-type Sports project car this morning after I gave up on finding a coolant leak in my STR.
My plan is to build up adjustable rear coilovers for my sub-frame build.

Attached is an image of the coilover taken apart.

Here are some measurements that someday may help others wanting to build their up their own.

Coil Spring:
Free length: 12”+
Compressed length: approx 10”
Coil OD Top: 4.5”
Coil OD bottom: 4”
Number of Turns: 8.5
Spring wire Diameter: 15mm
Spring Rate : ?

Stock Coilover Shock
Style: CATS
Brand: Bilstein
Length: 20” (Top of thread to center of lower mount)
Bottom Mount: Fluid filled Mono-ball bushing
Top mount: Threaded shock shaft to upper coilover mount
Spring Mount: Spring sits 5” below top of shock, plus bottom spacer. Approx. ½”

design wise, nothing unique . Pretty typical for a factory coilover. It should be easy to piece together my own rear coilovers.

Someday, if I ever have nothing better to do, I will pull the rear coilover from my 04 STR and compare the parts.