Kw update

[ulllose]

Ok to whoever is following this...

This is on a 03 viper with 19/20 forgelines and pirelli Pzeros

Set the backs from full firm to full
Soft and set the fronts at click 4 so on the soft side.
Car ride is much softer no question I didn't notice a difference when I went from setting 6 to 12(full firm) but did notice a huge difference when I went from 12 to 1. I do like the ride but the bouncy is still there and I can't get rid of it. I'm starting to think its the Pirelli tires. The car felt the same way when I had eibachs and factory shocks. Maybe it has to do with the stiff sidewall idk. The car felt much more
Planted on full firm so i will need alittle
More seat time and maybe start working my way back up
To the firmer end of the adjustment. Bottom line my bouncy feel I think is coming from the pirelli's

 

[Paul Hawker]

I put on a set of Pilot Super Sports and like my ride with KW's set pretty soft.

 

[AbsolutHank]

I put on a set of Pilot Super Sports and like my ride with KW's set pretty soft.

Of course...that's what 30 series sidewalls do for you

 

[bluesrt]

its not the tires, i also had eibachs and factory shocks with factory wheels and tires and it was bouncy as hell too- i have kws now and better but still bouncy do to its dropped front and rear, but better than the eibachs. only way to get rid of the complete bouncy feel is motons or maybe penske- dont know about penske, but have ridden in a slammed hard viper with motons and no bounce at all..

 

[bmw2nv2000]

Isnt your car really low? If so Bluesrt is right from what Ive read the KW's right great to a certain lowered height then they get bouncy too. But I have never ridin in a KW set up maybe Ryan will chime in on this. he has his car set up on KW's really nicely. But I can say the motons ride great slammed and I still have a big smile on my face since installing mine 2 weeks ago.

 

[ulllose]

Isnt your car really low? If so Bluesrt is right from what Ive read the KW's right great to a certain lowered height then they get bouncy too. But I have never ridin in a KW set up maybe Ryan will chime in on this. he has his car set up on KW's really nicely. But I can say the motons ride great slammed and I still have a big smile on my face since installing mine 2 weeks ago.

Yes its low......ground to front fender is 25" and ground to rear fender is 26 3/4'' I was reading my manual (the two pages in english) and it had some minimum and maximum heights for the shock body itself. I never measured where mine are and had the wheels off the car today but looked at the manual afterwards, So I cant say if i'm out of range or not.

 

[ulllose]

its not the tires, i also had eibachs and factory shocks with factory wheels and tires and it was bouncy as hell too- i have kws now and better but still bouncy do to its dropped front and rear, but better than the eibachs. only way to get rid of the complete bouncy feel is motons or maybe penske- dont know about penske, but have ridden in a slammed hard viper with motons and no bounce at all..

Damn it........lol I sure was hoping to give myself a reason to burn off the pirelli's ... Well maybe in the spring when i get the car back out of storage i will raise it up a few inches and take it for a drive on roads that i know the car bounces on. And Ive said it a thousand times its not that it bounces over bumps, the road can be smooth a hell but i feel this little bounce bounce bounce feel that makes me look little a bobblehead.

 

[Timnineside]

I can't follow most of your posts, but smaller sidewalls will obviously make the car ride much harder. You may even have a 25 series sidewall. I do. Also running Pirelli's and love the way the car rides.

 

[ulllose]

I can't follow most of your posts, but smaller sidewalls will obviously make the car ride much harder. You may even have a 25 series sidewall. I do. Also running Pirelli's and love the way the car rides.

Ok, not sure why you can't but anyways, I do have a 25 series sidewall.

 

[bluesrt]

yes lower profile tires ride stiffer, but not the bouncy feel

 

[ulllose]

Bluesrt----I believe everything you have said. I'm just trying to fine tune the set up I have (this ride height).

 

[2000_Black_RT10]

Just some food for thought..

Do your KWs have high and low speed compression / rebound adjustment capability? That bumpy feeling is needing to be absorbed by a higher freq valve damper, whereas I'm thinking the KW shocks on your car doesn't have that adjustability? You may also need to verify with KW that the spring rate is compatible with the shocks. Up to a 25% difference in a spring rate will have an impact on (and go beyond) the valve tuning range / capability of the shock if they weren't setup for the springs on your car, and internals of the shock may need to be changed. Ride height won't make much a difference, the relationship between the spring and shock is typically the spring rate, yet, the damping is also related to the mass of the unsprung weight, perhaps the mass of the previous wheel and tire combo changed? It doesn't seem related, but just to note that lower profile tires will also make a car feel more darty, having less of a slip angle.

Cheers,
Mike

 

[ulllose]

Just some food for thought..

Do your KWs have high and low speed compression / rebound adjustment capability? That bumpy feeling is needing to be absorbed by a higher freq valve damper, whereas I'm thinking the KW shocks on your car doesn't have that adjustability? You may also need to verify with KW that the spring rate is compatible with the shocks. Up to a 25% difference in a spring rate will have an impact on (and go beyond) the valve tuning range / capability of the shock if they weren't setup for the springs on your car, and internals of the shock may need to be changed. Ride height won't make much a difference, the relationship between the spring and shock is typically the spring rate, yet, the damping is also related to the mass of the unsprung weight, perhaps the mass of the previous wheel and tire combo changed? It doesn't seem related, but just to note that lower profile tires will also make a car feel more darty, having less of a slip angle.

Cheers,
Mike

Mike, I only have one adjustment for rebound. 12 different settings. The springs and shocks were a package deal right from KW, so I didnt pick my spring rates and I really dont know what they are. The ride height I wouldnt think would change anything either but what others have said it does. The wheels I have on it are the same Wheels I had when I had Eibachs and stock shocks and it did the same bounce bounce feel when rolling along on smooth roads. So the only common factor here are the wheels/tires. I like your thoughts but I still dont know. I have yet to call KW to double check that the right spring is on the car but have not. This is a suspension that many have used before, this is not something I put together myself and wonder why its not working good.

 

[Nine Ball]

I doubt it is a tire issue as long as your runflats are gone. I have the exact same 345-20 Nitto Invo tires on both my Z06 and my '06 Viper - and the Viper rides like total crap compared to the Z06.

 

[2000_Black_RT10]

If it helps, just some more suggestions, others may have some ideas also. I chatted about your situation today offline with an ol' pal Paul who a damper expert, race car stuff, from the UK (also worked on F1 stuff). He suspects that you may need to get the shocks retuned (mind you they call them dampers in the UK, as he always corrects me being in NA.. just some inside humor amongst us), and a question for KW could be; if they can soften up the high speed characteristics to make up for the lack of sidewall compliance and ask what tire did they use to setup the damper valving. Perhaps this is too obvious, but to also verify the tire air pressure. He also asked if the bouncing is felt just on the front, rear or all around?

It may be just a challenge you're facing because it is an aftermarket application on your 03, typically on OEM cars the shocks are specifically tuned to the tire selected for the car (and many other aspects), where as the KW setup was most likely setup for a specific tire (and obviously tuned front and rear) which you're not using and KW may have not communicated or provided tire criteria / recommendations / options to the buyer? I don't know, again these are just thoughts and some feedback to help, or some info for others to be aware of if no known. Yet I found that many on here are pretty knowledgable about this stuff.

Cheers,
Mike

 

[ViperGTS]

"19/20 forgelines and pirelli Pzeros" and lowered to the max.

The most ugly combination. Big tires, run-craps and max lowered. The only way to make a Viper handle like CRAP.

May I tell you a story I heard from a friend here in Germany? In short:
The owner of "KW" once attended a race event at the N'Ring and some Viper owners showed up with lowered cars. To the max lowered.
Un-drivable. Un-secure. Just plain stupid.

He (the KW business owner) did not let them drive away - the KW-equipped Vipers - before HIS mechanics raised the cars to the specs.

 

[ViperGTS]

You should do a real drivers training side by side with a stock car with good tires and see how it (your car) handles. For example an emergency breaking situation where you brake hard at +100 mph and have to avoid an "obstacle" while braking....handling!

 

[ulllose]

If it helps, just some more suggestions, others may have some ideas also. I chatted about your situation today offline with an ol' pal Paul who a damper expert, race car stuff, from the UK (also worked on F1 stuff). He suspects that you may need to get the shocks retuned (mind you they call them dampers in the UK, as he always corrects me being in NA.. just some inside humor amongst us), and a question for KW could be; if they can soften up the high speed characteristics to make up for the lack of sidewall compliance and ask what tire did they use to setup the damper valving. Perhaps this is too obvious, but to also verify the tire air pressure. He also asked if the bouncing is felt just on the front, rear or all around?

It may be just a challenge you're facing because it is an aftermarket application on your 03, typically on OEM cars the shocks are specifically tuned to the tire selected for the car (and many other aspects), where as the KW setup was most likely setup for a specific tire (and obviously tuned front and rear) which you're not using and KW may have not communicated or provided tire criteria / recommendations / options to the buyer? I don't know, again these are just thoughts and some feedback to help, or some info for others to be aware of if no known. Yet I found that many on here are pretty knowledgable about this stuff.

Cheers,
Mike

Mike thanks for the info. IF your asking me about tire pressure I do have them all at 29psi. Bouncing is felt mostly in the rear I would say. I talked with KW today about this issue and they did say I can send my shocks back to them if I want them to verify spring rates. I also told them that I didnt know if I have the car too low for these shock to absorb the imperfections of the roads. (ex. not enough shock travel). So anyways we came up with the conclusion that I have the front and rear 1" lower than what the minimum should be. My rear is from center of hub to fender is 14" and he said minimum is 15" and the front is set at 12 3/4'' and minimum is 13 3/4. So until I raise the car and take it for a drive I really cant say. Alot of people have told me on this forum to raise the car up but heck if I wanted basically stock height I would have left the stock coilovers! The car handles and take the bumps just fine, its the little annoying up and down movement I get on perfectly flat roads, so I dont see how raising the car height will get rid of it.

 

[ulllose]

"19/20 forgelines and pirelli Pzeros" and lowered to the max.

The most ugly combination. Big tires, run-craps and max lowered. The only way to make a Viper handle like CRAP.

May I tell you a story I heard from a friend here in Germany? In short:
The owner of "KW" once attended a race event at the N'Ring and some Viper owners showed up with lowered cars. To the max lowered.


He (the KW business owner) did not let them drive away - the KW-equipped Vipers - before HIS mechanics raised the cars to the specs.

I think the combination looks pretty bad ass.........lol
P-zero's are not run craps but I dont think they are the best tire either.

Not ******** about how it handles or that it takes bumps bad or Ive scraped the front end coming into a parking lot.
Im not attending the "ring" to try out how fast I can get around it. I Strictly have the car lowered for LOOKS.

Trying to get rid of a little up and down movement when driving down the road on flat surfaces......and if it makes it better, when im at high speeds i dont feel it..lol

 

[2000_Black_RT10]

Cool, hope all works out. I don't know the KW shock design specifically, but going too low you may be riding on or hitting the bump stops too early (are they above the damper tube on the shaft?), maybe something to look into, that could be one disadvantage causing issues. Other than that, raising or lowering the car doesn't change the spring rate, you're just losing out on some suspension travel to manage on big dips, etc.., but it does help aero a bit, but also changing the roll center of the car.

Good luck, interesting post, if you get the chance to keep us updated on the outcome, that'd be great.
Mike

 

[ulllose]

You should do a real drivers training side by side with a stock car with good tires and see how it (your car) handles. For example an emergency breaking situation where you brake hard at +100 mph and have to avoid an "obstacle" while braking....handling!

Uummmm, sure that sounds fun and would like to see what I would do, but in the real world im better off breaking at 60-70 and see what happens. Truly I think my lowered firmed up suspension would do better than a stock setup, but its just a guess. I also think I would get better traction if I soften up my rear shocks than a stock set up...(when accelerating)

 

[ulllose]

Cool, hope all works out. I don't know the KW shock design specifically, but going too low you may be riding on or hitting the bump stops too early (are they above the damper tube on the shaft?), maybe something to look into, that could be one disadvantage causing issues. Other than that, raising or lowering the car doesn't change the spring rate, you're just losing out on some suspension travel to manage on big dips, etc.., but it does help aero a bit.

Good luck, interesting post, if you get the chance to keep us updated on the outcome, that'd be great.
Mike

I will, I think a few of us were having the same issue. I may put on my factory wheels and tires and take it for a ride to rule that out for my own self

 

[2000_Black_RT10]

If you don't have the same issue with the factory tires, then it's most likely the internal shock valve setup for high speed compression damping characteristics, and since they're not externally adjustable for high speed damping (i.e. expensive high end race dampers have the adjustment capability for high and low speed), could try contacting KW afterwards, look into if they could modify the shock internals to be compatible with your tires. One thing I do find interesting, if KW recommended a compatible tire application when you bought the kit?

I came from an industry where dampers were designed for race cars & supercars, so many variables.. some F1 teams even paid up to $50k per corner for a custom damper setup (completely adjustable, depending on the track and conditions, rebuilt after each race, etc..), as they can surely get complicated to say the least.. but if you have sponsors like Red Bull, you can afford it!

Good luck,
Mike

 

[ulllose]

If you don't have the same issue with the factory tires, then it's most likely the internal shock valve setup for high speed compression damping characteristics, and since they're not externally adjustable for high speed damping (i.e. expensive high end race dampers have the adjustment capability for high and low speed), could try contacting KW afterwards, look into if they could modify the shock internals to be compatible with your tires.

I came from an industry where dampers were designed for race cars & supercars, so many variables.. some F1 teams even paid up to $50k per corner for a custom damper setup (completely adjustable, depending on the track and conditions, rebuilt after each race, etc..), as they can surely get complicated to say the least.. but if you have sponsors like Red Bull, you can afford it!

Good luck,
Mike

I did just email the guy at kw and asked him a few questions about re-valving and what tire was used when set-up originally. Will see what the reply is. I hope he doesnt get all technical on me because I will have to hurry up and post here to have a response...lmao

 

[Radu]

You don't by any chance have the Northwind seat-lowering kit do you?

I also have KWs on my '04 with HRE wheels (stock size) and Kumho tires, and I used to have the Northwind kit. I tried every suspension setting from soft to firm until I took a ride in the passenger seat one day and realized it wasn't the car that was bouncing but just the driver, because of that poorly-designed kit.

I've gone back to the stock seat mounts and the bouncing is greatly diminished though not completely gone. There is still a noticeable difference compared to, for example, my stock M3.

 

[ulllose]

You don't by any chance have the Northwind seat-lowering kit do you?

I also have KWs on my '04 with HRE wheels (stock size) and Kumho tires, and I used to have the Northwind kit. I tried every suspension setting from soft to firm until I took a ride in the passenger seat one day and realized it wasn't the car that was bouncing but just the driver, because of that poorly-designed kit.

I've gone back to the stock seat mounts and the bouncing is greatly diminished though not completely gone. There is still a noticeable difference compared to, for example, my stock M3.

No I dont have a seat lowering kit, but good thinking. Yeah I know for sure I will not get rid of it with the rebound adjustment. Now if I raise the car some I may get rid of it but I still dont think so. I will raise it in the spring and try it. But first Im going to bolt up my stock wheels and take the car for a drive, that may rule something out.
I also have a E46M3 and that car rides like a dream compared to the viper but its suppose to...lol, so I would never compare those 2 suspensions.
Im curious is it just a minimal bounce up and down when going down a nice smooth road? If im on it It never happens, only happens when driving along at a constant speed on fairly smooth roads (to the eye)

 

[bluesrt]

it has to do with rebound to slow, so its staying packed up and your now rideing on springs for the feel, drive it like you stole it and you will love it... thats the deal, if you could adjust compression,and rebound all alone by thierselves, you could dial it in and be happy.. but you cant, and even if you could, you have to know what your doing and understand it fully, and that takes time and exsperiance.

 

[ViperGTS]

making a Viper or any sportscar drive like **** for the LOOKS is not smart at all ... but it is your life! Hopefully, nobody else will be involved when something happens ...

 

[ulllose]

making a Viper or any sportscar drive like **** for the LOOKS is not smart at all ... but it is your life! Hopefully, nobody else will be involved when something happens ...

Your lost .....

 

[ulllose]

Sorry...."you're"