Bilstein HD vs. DRM Bilstein
Thread Starter
Burning Brakes
Joined: Dec 2009
Posts: 816
Likes: 40
From: Sacto Calif
Bilstein HD vs. DRM Bilstein
For my 08 Z51 equipped Corvette which of these 2 shocks makes the better choice for my weekend driven Corvette? there's about $100 difference between the 2 the Bilstein HD being the cheaper so is the DRM worth the extra $100 ?
Thanks Boonie
Thanks Boonie
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From: Washington Township Michigan
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You may want to check out Cultrag Perfomance, a forum sponsor for information on 2013Z06 shocks to replace your current set-up. They should be able to provide additional information regarding ride, handling, and performance, and I believe the price for them is also lower. Just my opinion.
Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,629
Need to back it up.
The Z51 shocks are not bad (smooth course auto cross shocks), but do have problems with slight road chop on a corner when into the throttle on the way out (dampening problem). Its not like the back end breaks free all at once with the correct amount of throttle used, but you can feel the back end not tracking/responding correctly in the light chop, and the back end breaks out in small chops instead.
If its just this problem that you want to solve, then the Koni fsd shock are close to the same stiffness, solves the dampening problem, but will drop the car down slightly since the are under less charge than the Z51 shock.
Bilstein shocks, HDs and Sports have been verified with Bilstein representatives multiple times as having identical valving, the HDs are simply optimized for stock ride height and the sports are for cars with sports or aftermarket lowering springs.
As for the DRM shocks, they are Bilstein shocks, but have been valved to DRM specs for better performance in the vets.
So this bring up back to why you are swapping the z51 shocks.
If for DD driving for the most part, then the Koni FSD do better in light chop for DD driving, solves the light chop out of the corner tracking problem, and about at stiff as the Z51 shocks over all.
If you pushing the car more, then the drm's shocks shine a little better here instead (little more firmer that the FSD shocks over all). Also to point out, you can get the DRM's with poly bushings to increase the road feed back to the driver, but means a slightly rougher ride as well.
As for the sport and HD shocks, again, their is a reason that DRM came up with spec's to have the Bilstein shocks valved to improve them, so they are more valve tuned to the vets better than the sport/HD valving.
As for the final question, do you have the talent to push the car to the edge and keep it there to fully understand the difference of the shocks.
I'm a fan of the non adjustable DRM shocks for what they offer when pushed hard, but in someones car that is being used for mostly just DD crusing instead, they will ride too stiff/give too much road feed back for most peoples tastes instead (guys looking for the smoother Buick ride instead).
Trust is, if the Z51 shocks are fine on your car now, and your looking for better handling, then just change out the OEM tunnel cover to a 3/8" plate. The plate will stiffen the chassis, and makes a huge difference on it's own without causing the overall ride to become too stiff isntead (push you into the stiffer Z06 ride with say DRM shocks).
http://www.eliteengineeringusa.com/3...-tunnel-plate/
The Z51 shocks are not bad (smooth course auto cross shocks), but do have problems with slight road chop on a corner when into the throttle on the way out (dampening problem). Its not like the back end breaks free all at once with the correct amount of throttle used, but you can feel the back end not tracking/responding correctly in the light chop, and the back end breaks out in small chops instead.
If its just this problem that you want to solve, then the Koni fsd shock are close to the same stiffness, solves the dampening problem, but will drop the car down slightly since the are under less charge than the Z51 shock.
Bilstein shocks, HDs and Sports have been verified with Bilstein representatives multiple times as having identical valving, the HDs are simply optimized for stock ride height and the sports are for cars with sports or aftermarket lowering springs.
As for the DRM shocks, they are Bilstein shocks, but have been valved to DRM specs for better performance in the vets.
So this bring up back to why you are swapping the z51 shocks.
If for DD driving for the most part, then the Koni FSD do better in light chop for DD driving, solves the light chop out of the corner tracking problem, and about at stiff as the Z51 shocks over all.
If you pushing the car more, then the drm's shocks shine a little better here instead (little more firmer that the FSD shocks over all). Also to point out, you can get the DRM's with poly bushings to increase the road feed back to the driver, but means a slightly rougher ride as well.
As for the sport and HD shocks, again, their is a reason that DRM came up with spec's to have the Bilstein shocks valved to improve them, so they are more valve tuned to the vets better than the sport/HD valving.
As for the final question, do you have the talent to push the car to the edge and keep it there to fully understand the difference of the shocks.
I'm a fan of the non adjustable DRM shocks for what they offer when pushed hard, but in someones car that is being used for mostly just DD crusing instead, they will ride too stiff/give too much road feed back for most peoples tastes instead (guys looking for the smoother Buick ride instead).
Trust is, if the Z51 shocks are fine on your car now, and your looking for better handling, then just change out the OEM tunnel cover to a 3/8" plate. The plate will stiffen the chassis, and makes a huge difference on it's own without causing the overall ride to become too stiff isntead (push you into the stiffer Z06 ride with say DRM shocks).
http://www.eliteengineeringusa.com/3...-tunnel-plate/
Team Owner
Joined: Sep 2005
Posts: 20,352
Likes: 568
From: Ventura County, Calif
The DRM's are pretty stiff.
Take a look at this recent post:
https://www.corvetteforum.com/forums...ough-ride.html
Take a look at this recent post:
https://www.corvetteforum.com/forums...ough-ride.html
Pro
Joined: Apr 2012
Posts: 521
Likes: 14
From: Denham Springs Louisiana
I, nor my wife, feel the DRM's are too stiff. I just asked her again and she gave me the "are you stupid" look.
We paired our DRM's with zo6 bars front/back (on a base c6) and, although much stiffer, it isn't that bad at all. Wife uses as DD and me for fun on the weekends.
We paired our DRM's with zo6 bars front/back (on a base c6) and, although much stiffer, it isn't that bad at all. Wife uses as DD and me for fun on the weekends.
Team Owner
Joined: Sep 2000
Posts: 25,015
Likes: 2,709
From: Far NW 'burbs of Chicago
St. Jude Donor '13
Need to back it up.
The Z51 shocks are not bad (smooth course auto cross shocks), but do have problems with slight road chop on a corner when into the throttle on the way out (dampening problem). Its not like the back end breaks free all at once with the correct amount of throttle used, but you can feel the back end not tracking/responding correctly in the light chop, and the back end breaks out in small chops instead.
If its just this problem that you want to solve, then the Koni fsd shock are close to the same stiffness, solves the dampening problem, but will drop the car down slightly since the are under less charge than the Z51 shock.
[B]Bilstein shocks, HDs and Sports have been verified with Bilstein representatives multiple times as having identical valving, the HDs are simply optimized for stock ride height and the sports are for cars with sports or aftermarket lowering springs.
[/B
]As for the DRM shocks, they are Bilstein shocks, but have been valved to DRM specs for better performance in the vets.
So this bring up back to why you are swapping the z51 shocks.
If for DD driving for the most part, then the Koni FSD do better in light chop for DD driving, solves the light chop out of the corner tracking problem, and about at stiff as the Z51 shocks over all.
If you pushing the car more, then the drm's shocks shine a little better here instead (little more firmer that the FSD shocks over all). Also to point out, you can get the DRM's with poly bushings to increase the road feed back to the driver, but means a slightly rougher ride as well.
As for the sport and HD shocks, again, their is a reason that DRM came up with spec's to have the Bilstein shocks valved to improve them, so they are more valve tuned to the vets better than the sport/HD valving.
As for the final question, do you have the talent to push the car to the edge and keep it there to fully understand the difference of the shocks.
I'm a fan of the non adjustable DRM shocks for what they offer when pushed hard, but in someones car that is being used for mostly just DD crusing instead, they will ride too stiff/give too much road feed back for most peoples tastes instead (guys looking for the smoother Buick ride instead).
Trust is, if the Z51 shocks are fine on your car now, and your looking for better handling, then just change out the OEM tunnel cover to a 3/8" plate. The plate will stiffen the chassis, and makes a huge difference on it's own without causing the overall ride to become too stiff isntead (push you into the stiffer Z06 ride with say DRM shocks).
http://www.eliteengineeringusa.com/3...-tunnel-plate/
The Z51 shocks are not bad (smooth course auto cross shocks), but do have problems with slight road chop on a corner when into the throttle on the way out (dampening problem). Its not like the back end breaks free all at once with the correct amount of throttle used, but you can feel the back end not tracking/responding correctly in the light chop, and the back end breaks out in small chops instead.
If its just this problem that you want to solve, then the Koni fsd shock are close to the same stiffness, solves the dampening problem, but will drop the car down slightly since the are under less charge than the Z51 shock.
[B]Bilstein shocks, HDs and Sports have been verified with Bilstein representatives multiple times as having identical valving, the HDs are simply optimized for stock ride height and the sports are for cars with sports or aftermarket lowering springs.
[/B
]As for the DRM shocks, they are Bilstein shocks, but have been valved to DRM specs for better performance in the vets.
So this bring up back to why you are swapping the z51 shocks.
If for DD driving for the most part, then the Koni FSD do better in light chop for DD driving, solves the light chop out of the corner tracking problem, and about at stiff as the Z51 shocks over all.
If you pushing the car more, then the drm's shocks shine a little better here instead (little more firmer that the FSD shocks over all). Also to point out, you can get the DRM's with poly bushings to increase the road feed back to the driver, but means a slightly rougher ride as well.
As for the sport and HD shocks, again, their is a reason that DRM came up with spec's to have the Bilstein shocks valved to improve them, so they are more valve tuned to the vets better than the sport/HD valving.
As for the final question, do you have the talent to push the car to the edge and keep it there to fully understand the difference of the shocks.
I'm a fan of the non adjustable DRM shocks for what they offer when pushed hard, but in someones car that is being used for mostly just DD crusing instead, they will ride too stiff/give too much road feed back for most peoples tastes instead (guys looking for the smoother Buick ride instead).
Trust is, if the Z51 shocks are fine on your car now, and your looking for better handling, then just change out the OEM tunnel cover to a 3/8" plate. The plate will stiffen the chassis, and makes a huge difference on it's own without causing the overall ride to become too stiff isntead (push you into the stiffer Z06 ride with say DRM shocks).
http://www.eliteengineeringusa.com/3...-tunnel-plate/
Our 2009 Z51 car was getting annoyingly harsh on the ever-worsening roads of the Midwest. I replaced the factory Z51 shocks with stock base model shocks, the ride got a lot nicer but the handling was too loose and floaty for me.
I test-drove a C6 that had identical tires and suspension but Koni FSD shocks, they still felt pretty stiff to me.
So I looked into the Bilsteins. We had a set of the Bilstein Sports on our C5 Z51 and they were about as stiff as the factory Z51 shocks. I phoned Bilstein about our C6, the guy told me the Sports are definitely valved stiffer than Heavy Duty, eventually he swore me to secrecy but gave me their actual compression/rebound numbers for both shocks and indeed the Sports are stiffer. He did not mention anything about either shock being made for a non-standard ride height, which makes sense because there were at least 3 different factory ride heights over the years of C6 production.
After that I bought the Bilstein Heavy Duty and had them installed, they are firmer than the base C6 shocks but softer than the Z51/Bilstein Sports. I'd rate them as about 1/2 to 2/3 of the way between base shocks and factory Z51 shocks, and I like them a lot.
Last edited by Gearhead Jim; Dec 21, 2015 at 12:00 PM.
Team Owner
Joined: Mar 2008
Posts: 21,502
Likes: 461
From: Southern Utah
To me, the magic of Bilsteins is that they improve the handling of the car, especially on rough corners, but they do it without simply making everything stiffer. More stiffness is the standard way that aftermarket suspension components improve handling. Somehow, Bilsteins do this without adding lots of stiffness. I put a set on my '74 Trans Am in 1978 and they are still working perfectly. They are like magic on my '07 Vert.
Drifting
Joined: Feb 2010
Posts: 1,527
Likes: 34
Here are my butt meter experience on the OEM equipped Z51 fair weather toy:
1. No comment on Bilstein HD - never used, no first hand.
2. As recommended by Bilstein for Z51 combination, got the Sports - great compliment for the Z51, quicker response, smoothed out all the rough edges and a great ride. On stock spring, ride height was lower.
3. Rubber, poly and Delrin Spherical Pin Top bushings - Tried the bushing came with Sports, they were deformed from the get go. Poly bushing was firmer, but both rubber and poly bushing gave Sports a sluggish pivot articulation. Changed to Delrin Spherical Pin Top bushings - immediate free'ed up the shocks pivot and shocks were free to articulate at their designed perimeter.
4. Lastly, DRMs are on car - it is certainly, although subtle but remarkably improved in all aspect over the Sports...at a price...came with a instant firmer/quicker feel...most people might not like them the way I do. Lower ride height remained same as Sports.
5. Tunnel Plate - curiosity lead me to made my own with 3/8" thick aluminum....but at the moment while OEM plate was off to use as template...realized that no matter how thick the replacement plate is...existing thin gauge pressed sheet metal flange mounts + tiny mounting screws...it will be a futile effort...but I got the raw aluminum stock already...went ahead made it...afterward, my butt meter confirmed it was a wasted futile efforts.
In conclusion, these Delrin Spherical Pin Top bushings can contribute instant articulation improvements, enabling shocks to perform without hindering compression/damping strokes - experienced no increased NVH as well...:
...in the end, you will still ended up getting what you feel is best!
Good luck and have fun!
Last edited by victorf; Dec 21, 2015 at 01:41 PM.
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Instructor
Joined: Aug 2015
Posts: 185
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From: Maui, Hawaii
Can the Koni FSD be used on C5 which has been lowered .75" F&R (down on bolts on front, and replaced longer bolts in rear), and re-set to stock alignment specs?
This will be for DD and a little drag racing. Also we are removing the F45 system w TechII reprogramming.
This has been very confusing between Bilsteins and Koni's so any feedback would be appreciated and you seem to understand the various differences.
Happy New Year 016,
professor jim
510-219-7400 text ok too.
This will be for DD and a little drag racing. Also we are removing the F45 system w TechII reprogramming.
This has been very confusing between Bilsteins and Koni's so any feedback would be appreciated and you seem to understand the various differences.
Happy New Year 016,
professor jim
510-219-7400 text ok too.
Melting Slicks
Joined: Jul 2005
Posts: 2,649
Likes: 863
I went with the DRM valved Bilsteins on a 2012 GS. I haven't had them on long enough to have a firm opinion - but after less than 100 miles of driving, I can tell you the DRM valving feels QUITE different from what was in the Sachs shocks that came on the car from the factory.
I've used DRM valved shocks on a tracked C4, and I firmly believe that DRM knows their stuff. I spoke to the guys at DRM before I purchased these C6 shocks, and while they didn't give me their compression / rebound rates - they did talk a little bit about what they did that was different from the factory - and my posterior agrees that the car feels better controlled.
The car is hibernating right now - but come spring time (and after some new rubber) I hope to be able to give a better review.... But so far - no buyers remorse...
BTW - doing the full shock change out took quite a bit more time than I was expecting. I wasn't killing myself - and was taking a break (or two) every wheel - but I'd say it took me 5 - 6 hours to change the full set of shocks out....
I've used DRM valved shocks on a tracked C4, and I firmly believe that DRM knows their stuff. I spoke to the guys at DRM before I purchased these C6 shocks, and while they didn't give me their compression / rebound rates - they did talk a little bit about what they did that was different from the factory - and my posterior agrees that the car feels better controlled.
The car is hibernating right now - but come spring time (and after some new rubber) I hope to be able to give a better review.... But so far - no buyers remorse...
BTW - doing the full shock change out took quite a bit more time than I was expecting. I wasn't killing myself - and was taking a break (or two) every wheel - but I'd say it took me 5 - 6 hours to change the full set of shocks out....
Drifting
Joined: Jul 2006
Posts: 1,786
Likes: 93
From: Charlotte N.C.
Everyone's butt meter is different....so you will need to weed thru...
Here are my butt meter experience on the OEM equipped Z51 fair weather toy:
1. No comment on Bilstein HD - never used, no first hand.
2. As recommended by Bilstein for Z51 combination, got the Sports - great compliment for the Z51, quicker response, smoothed out all the rough edges and a great ride. On stock spring, ride height was lower.
3. Rubber, poly and Delrin Spherical Pin Top bushings - Tried the bushing came with Sports, they were deformed from the get go. Poly bushing was firmer, but both rubber and poly bushing gave Sports a sluggish pivot articulation. Changed to Delrin Spherical Pin Top bushings - immediate free'ed up the shocks pivot and shocks were free to articulate at their designed perimeter.
4. Lastly, DRMs are on car - it is certainly, although subtle but remarkably improved in all aspect over the Sports...at a price...came with a instant firmer/quicker feel...most people might not like them the way I do. Lower ride height remained same as Sports.
5. Tunnel Plate - curiosity lead me to made my own with 3/8" thick aluminum....but at the moment while OEM plate was off to use as template...realized that no matter how thick the replacement plate is...existing thin gauge pressed sheet metal flange mounts + tiny mounting screws...it will be a futile effort...but I got the raw aluminum stock already...went ahead made it...afterward, my butt meter confirmed it was a wasted futile efforts.
In conclusion, these Delrin Spherical Pin Top bushings can contribute instant articulation improvements, enabling shocks to perform without hindering compression/damping strokes - experienced no increased NVH as well...:
...in the end, you will still ended up getting what you feel is best!
Good luck and have fun!
Here are my butt meter experience on the OEM equipped Z51 fair weather toy:
1. No comment on Bilstein HD - never used, no first hand.
2. As recommended by Bilstein for Z51 combination, got the Sports - great compliment for the Z51, quicker response, smoothed out all the rough edges and a great ride. On stock spring, ride height was lower.
3. Rubber, poly and Delrin Spherical Pin Top bushings - Tried the bushing came with Sports, they were deformed from the get go. Poly bushing was firmer, but both rubber and poly bushing gave Sports a sluggish pivot articulation. Changed to Delrin Spherical Pin Top bushings - immediate free'ed up the shocks pivot and shocks were free to articulate at their designed perimeter.
4. Lastly, DRMs are on car - it is certainly, although subtle but remarkably improved in all aspect over the Sports...at a price...came with a instant firmer/quicker feel...most people might not like them the way I do. Lower ride height remained same as Sports.
5. Tunnel Plate - curiosity lead me to made my own with 3/8" thick aluminum....but at the moment while OEM plate was off to use as template...realized that no matter how thick the replacement plate is...existing thin gauge pressed sheet metal flange mounts + tiny mounting screws...it will be a futile effort...but I got the raw aluminum stock already...went ahead made it...afterward, my butt meter confirmed it was a wasted futile efforts.
In conclusion, these Delrin Spherical Pin Top bushings can contribute instant articulation improvements, enabling shocks to perform without hindering compression/damping strokes - experienced no increased NVH as well...:
...in the end, you will still ended up getting what you feel is best!
Good luck and have fun!
Le Mans Master
Joined: Jun 2011
Posts: 8,049
Likes: 330
From: Charlotte NC
St. Jude Donor '14-'15
When I bought my 08 Z51 I was disappointed with the ride as this is my DD, it SUCKED!
I installed the Bilstein HD shocks and dumped the run-craps and now my car rides soooooooooo much better.
My opinion is that the bilstein shock itself is pretty good, the things you get with the shock are garbage. I bought GM shock mounts for the front and rear and reused the boot & bump stop from my Z51 shocks.
I installed the Bilstein HD shocks and dumped the run-craps and now my car rides soooooooooo much better.
My opinion is that the bilstein shock itself is pretty good, the things you get with the shock are garbage. I bought GM shock mounts for the front and rear and reused the boot & bump stop from my Z51 shocks.
Last edited by ls1121; Jan 2, 2016 at 04:42 PM.
