What is the difference between the BILSTEIN 24184649 B6 Performance; For Stock Ride Height and the BILSTEIN 24184571 B8 Performance Plus; For Adjusted Suspension?

JT

 

B8 is stiffer and is a must for the rear if you have a fiberglass spring. Unless you have very stiff front springs the B6 work best for the front.

 

Thanks for the reply I have Moog 5762 Coil Springs on the front, not sure if they are stiff or normal?

JT

 

Unless your car is lowered , you want the B6.

 

Thanks, and no it's not lowered.

JT

 

This has been discussed here before. According to Bilstein there isn't any difference in the valving between the two stocks. Guys here say that there is. So who's word do believe? I went with the B6's as Bilstein recommends all around with my 340 rate composite rear spring, 480 rate front springs and I'm not experiencing any bouncing.

 

Thanks, I did a search and came up with this from Bilstein so you are absolutely correct.

And even evil google AI agrees LOL
Another mystery solved with facts.

JT

 

What????^ You have to ask yourself why would Bilstein offer B6 HD's (heavy Duty) and B8 Sports with the same valving? The answer is they are not the same. Read more below.................

There is a BIG difference between the 3 versions of Bilsteins: B4 (OEM Replacements)/B6 (Heavy Duty)-Slightly stiffer than stock shocks/B8 Sports-Much Stiffer than the B6 or B4's.

How do I know the difference? Well, I have currently 5 cars with 2 versions of the Bilsteins, either B6 HD's or B8 Sports.

1. 2008 Chrysler 300 3.5L V6 B6's-Replaced Stock Struts and rear shocks-B6's noticeable stiffer than stock Chrysler Struts and Shocks

2. 1994 Ford Mustang GT B6's-Replaced Ford OEM struts and Shocks-Noticeable stiffer than Ford Struts/shocks with better ride quality overall. Would prefer stiffer B8's but not offered 25 years ago when i put them on

3. 1978 C3 L82 4 speed with Gymkhana OEM suspension modified-OEM 550 lbs Springs in Front/360lbs VBP monospring in back-B6 heavy duty in front with B8 Sports in the rear 360 monospring-more below on this combo

4. 2010 C6Z06 with Doug Rippie Motorsports Specially Valved B8 Sport Shocks-The best of the bunch with incredible ride, stiff but not harsh, tremendous handling

5. 2016 Audi Q3-Bilstein B8 Sports, replacing the OEM struts and shocks--MUCH MUCH Stiffer than OEM struts and shocks.

Since the 78 C3 came with 550 front springs which are very stiff, I went with the B6 heavy duty front bilsteins which was the correct call. Improved front ride, with no increase in stiffness. The rear with the 360 monospring also originally had the Bilstein B6 Heavy Duty and the rear suspension would bounce continuously on the highway. 20 years ago I sold those Bilsteins B6 HD's to a forum member with 2k miles on them for $100 for the pair and installed the bilstein B8 Sports to quell the ride bounce. The B8 Sports completed eliminated all bounce. There is a BIG difference between the B6 HD's and the B8 sports.

Real life experience with Bilsteins versus incorrect specs and theory...........

 

What do you want me say? That you're right? Okay you're right, I'm wrong.

 

So you're saying that Bilstein is publishing incorrect specs?

JT

 

In the case of the C3 specific shock application: Yes, the info from Bilstein is wrong. For many applications the B6 and B8 is the same except the B8 is for lowered vehicles just like Bilstein says (I haven't tested B6 and B8 on other cars but I assume Bilstein does this for many applications). But the C3 B8 shock is much stiffer than the B6. How do I know? Because I ran the B6 rears at first with my fiberglass spring. It was ridiculously soft and any half decent bump in the road would make the rear bottom out. It was truly awful. I had used those same B6 shocks with a steel spring before and that combo worked fine so I figured I'd just keep the B6s. After I swapped the rears to B8 (keeping the front B6) the car felt great and it's almost impossible to bottom out the rear.

 

So what I found published by Bilstein is as I quoted above, so far no mention of dampening rates from Bilstein just shock length.

Quote:
BILSTEIN B6: Improved OE replacement for high demands
BILSTEIN B8: Perfect OE replacement shock absorber for lowered vehicles

JT

 

When to Choose Each

Bilstein B6 (HD)

• Ideal for those looking to maintain a comfortable ride while upgrading performance.
• Suitable for vehicles that are not lowered and retain stock springs.
• Provides better handling and stability without sacrificing comfort.

Bilstein B8 (Sport)

• Best for vehicles with lowering springs or those that have a sportier suspension setup.
• Offers enhanced performance and handling for spirited driving.
• Recommended for drivers seeking a firmer ride and improved responsiveness.

Both models are known for their durability and performance, making them popular choices among car enthusiasts.

I think that there may be some misconception here about the shock/struts descriptions and what they are doing for each application. The physical dimensions for fitment of each shock type are the same for the B6 HD versus the B8 Sports for any one car. The difference is the amount of internal valve dampening which restricts the length extension for a B6 HD versus B8 Sport, allowing the "shorter" B8 Sports to be used with lowering springs (tighter control with shorter springs ) OR MORE sportier suspensions by restricting the Shock/Strut's total movement ,over a fixed dimension. Using the Sport B8 in a non lowered car (which is also an application for the B8 sports) will result in a much stiffer ride, as described in multiple applications, previously, due to restricted valve dampening over a shorter rod length.

 

Just to throw a 'wrench in the works'.......I haven't noticed any mention in the personal quotes relating to Bilsteins as to whether the cars are running with OEM sized wheels and tires or larger diameter aftermarket wheels with low profile tires. Surely that would make a significant difference to how the Bilsteins operate?

 

Where did you find that? I've searched on and off for good information about the B6 vs B8 since I started rebuilding this C3 many months ago?

JT

 

All of mine are stock for all the cars mentioned. The 78 C3 originally had the OEM stock 255/60/15 tires with the Bilsteins, both B6 and rear B8 Sports. Later went to 255/45/17 UHP ZR's and the ride IMPROVED with the Bilsteins.

The 300, Mustang GT, Audi Q3, and C6 Z06 are all stock size tires.

 

AI search..........multiple sources listed including Bilstein.co.uk...................The Bilsteins on my 78 L-82 have been on the car for 20+ years.

Last call for me on this issue! The 2 applications I have currently for the B8 Sports (not custom like the Z06) are MUCH stiffer than the other B6 applications. The ride quality of the B8 sports are, very noticeably, different than the B6 Heavy Duties. Another words, none of the B6 HD's are extremely stiff like the B8 Sport applications, on my cars.

 

We have MANY shock absorber threads on this exact question on this forum. What seems to be missing here is an explanation of why Bilstein can't answer the question in the first place....they know NOTHING about how the shocks have been applied by countless Corvette owners and aftermarket retailers in the past. WE KNOW because we have done this many times times before over the years. The Corvette vendors and racers have "been there, done that" already for us. They provided us with recommendations that are "off label" to the manufacturers.

A low rate fiberglass monospring or a stock leaf spring can work well with a B6 rear shock while a high rate monospring works better with a B8 shock. The stock front springs work well with a B6 shock regardless. This comes from experience, not from Bilstein. Along the way, we have lost quite a few of the people who came to know these things, so the newer guys get to go to school all over again. The Corvette racing/service shop that schooled me on this 35 years ago is gone now and the owner has passed away. He told me this stuff, but I was too cheap to pay that much for shocks so I ended up with a bouncy ride back then. After I installed what he told me to buy in the first place it was like night and day. PERFECT! Wish that shop was still around because they were worth every penny. This was before I had internet.

Just a "cliffs notes" here - guys that are too cheap to buy better shocks refuse to believe the Bilsteins are worth the money, never try them, and swear the KYB's are great....

No smoke, just truth.

 

I'll say this just to muddy the waters.
I run factory gymkhana springs up front with one coil removed. I also have taken a LOT of weight out of the front end. I run a VB&P rear composite spring. 330Lb.
I've had my car since Christ was a Corporal.
I have tryed a few different shock set-ups.
I run B6 Bilstien's in the front. I've tried a few different ones in the rear. Even tryed cheap AC Delco shocks at one point.
(they were truly disappointing).
I personally can testify that on these less than wonderful roads over here. I was bouncing and bottoming out and hitting my pipes hard on the ground with B6's in the rear. Even worse with cheaper shocks.
The B8's tame my composite spring extremely well. Ride and handling is excellent.
So, for me, it's Bilstien B6 up front with factory aluminium wheels 255/60-15's tires.
B8's in the rear and YES THERE IS A DIFFERENCE. Also factory slotted aluminium wheels with 255/60-15's
For those running more modern wheels, I haven't a clue.

 

Not muddying the waters at all. Same experience that I and others that have actually tried both B6 and B8 have had.