Anyone on here running a real coil over rear setup?

[Beedub]

good input their from above.

yes i once saw a pic of the z4 with a ballooned Front turret using the kw club sport since having mine on I've made sure to run the underside reinforcement plates and the SB , between these two i feel pretty confident in the additional strenthening.

Do you have any more info on the reinforcement plates? SB.. Strut Brace?

It was these that I ran with my intrax on the e46m3
https://www.turnermotorsport.com/p-323-e46-strut-tower-reinforcement-plates-priced-each/
not sure if they fit our cars but I think so, beedub can confirm

thats them, they fit perfectly and spread the load As per the stock top mount, I've had them in since day one with non stock suspension. The KW CS setup is solid mounted with no rubber, and smaller mount plates which places more load in the middle of the tower, anyone running such setup really should do this for cheap insurance,

not sure its needed on those V3s, they running a progressive spring and appear to reuse the stock top mount.


Tom the car performs so well with the stock config and top end items i really wouldn't go down this route. But if you do cant wait to see how you get on!!

 

[TomK]

Thanks, appreciate your thoughts, you make a good case for the sensible option I guess. What still sways me the other way is that above and beyond the extra control in the spring is the ability to have access to a far wider range of spring rates than is available with a barrel style.
I thought the same about the rear brace and I'm seeking an opinion from a race shop, I suspect I'll hear the same thing.
I'm not sure though that the e46 subframe issue is such a great analogy for the forces involved here? I do though agree that getting access to fix any spot welds etc issues around that area is going to be an issue. Is it also really a potential issue that a load is subjected constantly as you suggest? I would have thought that would not be a problem as long as it is within tolerance?
It's frustrating as I'm sure there are owners out there with this set up that could maybe feed back to me, but not in the uk it seems.

 

[Beedub]

Thanks, appreciate your thoughts, you make a good case for the sensible option I guess. What still sways me the other way is that above and beyond the extra control in the spring is the ability to have access to a far wider range of spring rates than is available with a barrel style.
I thought the same about the rear brace and I'm seeking an opinion from a race shop, I suspect I'll hear the same thing.
I'm not sure though that the e46 subframe issue is such a great analogy for the forces involved here? I do though agree that getting access to fix any spot welds etc issues around that area is going to be an issue. Is it also really a potential issue that a load is subjected constantly as you suggest? I would have thought that would not be a problem as long as it is within tolerance?
It's frustrating as I'm sure there are owners out there with this set up that could maybe feed back to me, but not in the uk it seems.

FWIW their are actually lots you can do with the rear spring on this car, as long as you willing to switch out to a linear and have a good enough damper with adequate valving to suit....

 

[TomK]

Tom the car performs so well with the stock config and top end items i really wouldn't go down this route. But if you do cant wait to see how you get on!!

Thanks, you're probably right. I've got a few months before I'm going to do anything about it. Lot's of time to think about new shiny bits :lol:

 

[TomK]

FWIW their are actually lots you can do with the rear spring on this car, as long as you willing to switch out to a linear and have a good enough damper with adequate valving to suit....

My understanding was that most spring manufacturers like KW, Intrax for the barrel spring will do way way less spring options than they offer for the coil over. :?

 

[Beedub]

yeah your right so , however you can pair up a swift spring in correct diameter and length and the options are endless really.... as long as you have a damper that can support the spring rate... your not limited at all, its just abit of a wait to get the springs, they aren't even expensive!

 

[TomK]

yeah your right so , however you can pair up a swift spring in correct diameter and length and the options are endless really.... as long as you have a damper that can support the spring rate... your not limited at all, its just abit of a wait to get the springs, they aren't even expensive!

Ok thanks, I hadn't heard of this, will look into it.
As you say springs are generally pretty cheap, at least relatively

 

[Beedub]

yeah your right so , however you can pair up a swift spring in correct diameter and length and the options are endless really.... as long as you have a damper that can support the spring rate... your not limited at all, its just abit of a wait to get the springs, they aren't even expensive!

Ok thanks, I hadn't heard of this, will look into it.
As you say springs are generally pretty cheap, at least relatively

another one for springs are HYPERCO....

if you go with a a control control or the likes of TCK you can actually specify what spring rate you want at the back, and then they valve the damper around your choice nitron were also willing to do this for me when i was talking to them while deciding which company to use.

 

[TomK]

yeah your right so , however you can pair up a swift spring in correct diameter and length and the options are endless really.... as long as you have a damper that can support the spring rate... your not limited at all, its just abit of a wait to get the springs, they aren't even expensive!

Ok thanks, I hadn't heard of this, will look into it.
As you say springs are generally pretty cheap, at least relatively

another one for springs are HYPERCO....

if you go with a a control control or the likes of TCK you can actually specify what spring rate you want at the back, and then they valve the damper around your choice nitron were also willing to do this for me when i was talking to them while deciding which company to use.

For sure I'm going to go with Intrax again, the dampers will be custom valved accordingly to include both increase the increase in power and reduction in weight particularly the unsprung part(AP, APEX) over a regular M. I had their 1k2 setup before and I've been missing it ever since, this time I will add their ARC which allows even softer spring rates. Just need to save a few pennies now, it's £4k's worth around

 

[Beedub]

wow big money..... !!

 

[TomK]

wow big money..... !!

It's fantastic kit.
Ordering process

As you already know, all our shocks are custom made. We only start producing after we have enough information about the car, wishes of the driver and of course after order.
Things we would like to know are:
For what purpose will your car be used (street, trackday, race, rally etc. or a combination)?
What type and size tire will the car drive on?
What size rim do you use?
Any other change (compared to standard) on the car that can influence the handling of the car (weight, power, roll cage etc)?

 

[GuidoK]

I'm not sure though that the e46 subframe issue is such a great analogy for the forces involved here? I do though agree that getting access to fix any spot welds etc issues around that area is going to be an issue.

Its a fine example to show that load bearing issues are not always apparant in the first1-2 years or 5k miles.
And also a fine example of the possible extend of damage.
Its not said that the first signs of damage will be a small crack in the top of the shock perch easily welded up. It can just as well be a row of spotwelds somewhere down low where the side/shockperch is welded into the bottom plate which can be really hard to get to.

Is it also really a potential issue that a load is subjected constantly as you suggest? I would have thought that would not be a problem as long as it is within tolerance?

Well, the tolerance is just the issue isnt'it? What is the tolerance?
In the stock configuration the rear shock tower doesnt get any constant load. Its just there to hold the shock, that dampenes motion.
The shock doesnt resist the force of bumps and such; thats the task of the spring. The shock slowly dissipates energy.
In the normal situation the weight of the car sits on the spring perch underneath, not on the shock tower.
About the tolerance thats very very hard to predict. I'm sure bmw makes a computer model that stress tests all welds etc but based on the stock situation. If the coilover situation holds and doesnt break immediately that doesnt mean in a few years there wont be any issues.
I dont know if you know what a Wöhler curve is, but thats basically a curve that dictates that increased loads will accelerate stress fails. It's a life cycle curve (used in material sciences studies). And its logaritmic/exponential, so a linear increase in load will have an exponential accelerated failure rate.
But that makes it also very difficult to predict. There might be failure in 3 years or 30 years. It's a personal decision if one is willing to take that risc. There is no real user experience. There is no one saying: hey, I installed that kit 7 years ago and did 60k miles since then without any problems. People who buy those kits are low mileage users. Going to shows and trackdays.
But there are plenty of people who daily their car for years on normal coilovers like kw/hr/etc that did serious miles.
That is the only information you can go on really. Failure rate of others who've done serious miles.
Someone who's selling the product assuring its ok only has a value if he can give a no questions unlimited warranty on shocks and chassis for a representative time in relation to how long you want to hold on to the car.

 

[TomK]

I'm not sure though that the e46 subframe issue is such a great analogy for the forces involved here? I do though agree that getting access to fix any spot welds etc issues around that area is going to be an issue.

Its a fine example to show that load bearing issues are not always apparant in the first1-2 years or 5k miles.
And also a fine example of the possible extend of damage.
Its not said that the first signs of damage will be a small crack in the top of the shock perch easily welded up. It can just as well be a row of spotwelds somewhere down low where the side/shockperch is welded into the bottom plate which can be really hard to get to.

Is it also really a potential issue that a load is subjected constantly as you suggest? I would have thought that would not be a problem as long as it is within tolerance?

Well, the tolerance is just the issue isnt'it? What is the tolerance?
In the stock configuration the rear shock tower doesnt get any constant load. Its just there to hold the shock, that dampenes motion.
The shock doesnt resist the force of bumps and such; thats the task of the spring. The shock slowly dissipates energy.
In the normal situation the weight of the car sits on the spring perch underneath, not on the shock tower.
About the tolerance thats very very hard to predict. I'm sure bmw makes a computer model that stress tests all welds etc but based on the stock situation. If the coilover situation holds and doesnt break immediately that doesnt mean in a few years there wont be any issues.
I dont know if you know what a Wöhler curve is, but thats basically a curve that dictates that increased loads will accelerate stress fails. It's a life cycle curve (used in material sciences studies). And its logaritmic/exponential, so a linear increase in load will have an exponential accelerated failure rate.
But that makes it also very difficult to predict. There might be failure in 3 years or 30 years. It's a personal decision if one is willing to take that risc. There is no real user experience. There is no one saying: hey, I installed that kit 7 years ago and did 60k miles since then without any problems. People who buy those kits are low mileage users. Going to shows and trackdays.
But there are plenty of people who daily their car for years on normal coilovers like kw/hr/etc that did serious miles.
That is the only information you can go on really. Failure rate of others who've done serious miles.
Someone who's selling the product assuring its ok only has a value if he can give a no questions unlimited warranty on shocks and chassis for a representative time in relation to how long you want to hold on to the car.

Thanks, again all good points.
The only thing is in this case Intrax or Nitron sell both a full coilover rear and if you like a separate barrel/damper arrangement, there is no difference in price and no (monetary gain) reason to overly sell me one way or the other. They say the coilover is better for my situation, but like you say I will never get any kind of guarantee out of them for the chassis nor would I expect them to.

 

[GuidoK]

They say the coilover is better for my situation

Better what?
Better handling (I dont doubt that) or better life expectancy of your chassis welds?
Its a decision only you can make. Its your car. Everyone is willing to risk different things.
I'm usually willing to risk a lot of mechanical things because I know I can fix them easily and usually cheaply. But when it comes to the body/chassis, I have a totally different approach. Maybe if my pockets were really deep it wouldnt be an issue, but alas they aint :roll:

 

[gazpat]

Hi TomK,

Re. running 'real' rear coilovers, I posted the note below in a thread a while back, not sure how to link it to this thread. I haven't done loads of miles since the install due to working away from home and a recent hand injury preventing me from driving, but all good so far. I wasn't aware of potential design/loading issues with the rear strut towers (Centre Gravity didn't voice any concerns), i'll repost when the arse falls out of my car lol!

Cheers.

Gaz.

Earlier post:

Apologies in advance for my lack of involvement on here, I'm not a great one for posting on forums.

Just thought I'd reply to Muckinonthesofa's comment "These cars must be incredible with the top of the range coil over kits fitted!"

Well, I had a set of Nitron coilovers fitted to my roadster and set up by Centre Gravity last week. Done a couple of hundred miles since, and I can say it's completely transformed the car.

I found the standard setup harsh and crashy over bumps and poorly surfaced roads, and the front end was a bit vague especially during hard acceleration. Now, all the old cliches can be rolled out. It's completely planted, stable, on rails etc, I can feel exactly what the car is doing. It's still firm, but the crashing over bumps has gone. It's a different car.

I specified that I wanted to keep the standard ride height, and have it set up for real world road conditions, and Centre Gravity have delivered this requirement perfectly IMO.

Only 'downside'?....well... it did cost a shedload of cash....but was it worth it?... most certainly yes... the best money i'll ever spend on this car for sure....