Coilover Recommendation

[Ob917]

Seems the Euro tuners like softer spring rates and bigger bars than most is tuners but 571 and 800 seem pretty reasonable for something that’s not dedicated track only. Maybe I’m off on my rate guess.

[maupineda]

My setup is pretty average, for not saying poor. it is H&R street coils, which ride very poorly, I am going down the path of the flat ride concept and will make some changes this weekend to test the foundation of it (wheel motion frequency) and see how it feels before committing to a complete solution including the stage 2 damper service

I am going with

Front Swift Springs 250#
Rear TCK springs 600#

I am using OE hardware with some extra hardware to tie everything together. I can tell you I hate the way the car rides, so if this flat ride concept is anything to go with, I certainly should see an improvement with the settings above.

[r4dr]

Seems the Euro tuners like softer spring rates and bigger bars than most is tuners but 571 and 800 seem pretty reasonable for something that’s not dedicated track only. Maybe I’m off on my rate guess.

It's not so much the absolute rates, but the ratio of them. My understanding of progressive rates (which could be wrong) is that the number (e.g. 800 lbs/in) is achieved toward the end of the compression. So for small/moderate bumps, the effective spring rate in the back will be even lower since it's in the softer portion of the compression stroke, leading to even more pitch.

Of course, this is all peanut gallery commentary based on the descrption on Turner's site.

[Tbonem3]

Any idea on the spring rates for H&R street coilover set vs the RSS clubsport set? Price is barely different. Wouldn't be surprised if dampers were the same, but springs were 10% stiffer or something.

Also, in case it helps anyone, after some research today, it seems the Vogtland coilovers are KWs (same as ST) with vogtland springs (even -1.2" drop). The springs actually get great reviews (esp on cutters, bigger in uk/europe), but haven't seen much about the dampers.

The STs, H&Rs, Vogtlands all seem to be decent budget sets around $1000 with no adjustment besides height. Biggest drawback is the progressive, stock style spring imo, but that can be rectified, though it raises costs.

[r4dr]

Biggest drawback is the progressive, stock style spring imo, but that can be rectified, though it raises costs.

I considered going this route as my car came with KW V2s. By the time you do just the front-end conversion to linear, I was a hundred or two bucks from just buying TCK SAs. HPA down in SoCal put a kit together that they sell specifically for the KWs.

[Tbonem3]

It's not so much the absolute rates, but the ratio of them. My understanding of progressive rates (which could be wrong) is that the number (e.g. 800 lbs/in) is achieved toward the end of the compression. So for small/moderate bumps, the effective spring rate in the back will be even lower since it's in the softer portion of the compression stroke, leading to even more pitch.

Of course, this is all peanut gallery commentary based on the descrption on Turner's site.

If the front is also progressive, theoretically, it too will have a lower effect rate over a small bump. If the manufacturer matched the range and progression of rates between F&R, there shouldn't be an issue, esp if they chose higher rates in the rear vs front (like our stock springs 143lbF/385lbR). Keeping in mind that the rear springs' location would lower its rate at the wheel.

The hardest part about picking a set is knowing what the rates really are :/

[Tbonem3]

I considered going this route as my car came with KW V2s. By the time you do just the front-end conversion to linear, I was a hundred or two bucks from just buying TCK SAs. HPA down in SoCal put a kit together that they sell specifically for the KWs.

I saw that HPA kit (they're in Santa Barbara I think)! Looks cool. But you're right, it's not really worth it unless you're fixated on a certain set of dampers.

[r4dr]

If the front is also progressive, theoretically, it too will have a lower effect rate over a small bump. If the manufacturer matched the range and progression of rates between F&R, there shouldn't be an issue, esp if they chose higher rates in the rear vs front (like our stock springs 143lbF/385lbR). Keeping in mind that the rear springs' location would lower its rate at the wheel.

The hardest part about picking a set is knowing what the rates really are :/

Here's the TMS language:

This package is supplied with a base set of springs - 100Nm (571lb) front and 140Nm (800lb, progressive) rear.

Makes me think the fronts are linear and the rears are progressive. I know appearance of springs isn't conclusive, but that matches the photos too.

IMO not sharing spring rates is a bad sign to me, and means the product is intended for people who don't think about spring rates.

[Tbonem3]

Ya, looking at it now, I think you're right. That said, now you'd only need to buy 1 pair of linear springs for the rear. So just add another $50-100 (easily find sets of race coils on ebay, etc). Run the FCM calculator with the 571 front + figure out the rear + chose a coil close to that = profit?

[maupineda]

If the front is also progressive, theoretically, it too will have a lower effect rate over a small bump. If the manufacturer matched the range and progression of rates between F&R, there shouldn't be an issue, esp if they chose higher rates in the rear vs front (like our stock springs 143lbF/385lbR). Keeping in mind that the rear springs' location would lower its rate at the wheel.

The hardest part about picking a set is knowing what the rates really are :/

Agree! That is why I went with swift and tck. Also lowering the car beyond the stock height screws travel if not done properly. With HR I have 1.5 to 2.0in of bump travel, but I am at stock height. If I go down to the lowest setting, at 1.0in drop, you basically have one, or less, inch of travel (and that is considering the bump stop). At least on the Z4M, but i dont see the M3 being much better. No surprise why most aftermarket system can ride very poorly.

[Tbonem3]

Yes, that's what mostly happens when people (usually younger guys) "upgrade" their susp. Track cars can get away with it because they don't need much travel with super stiff springs and mods to mounting that can recapture travel. We all want a "track car" on the street, at least in our minds, but you have to do it carefully!

[maupineda]

Seems the Euro tuners like softer spring rates and bigger bars than most is tuners but 571 and 800 seem pretty reasonable for something that’s not dedicated track only. Maybe I’m off on my rate guess.

I’d not say these rates are street friendly.

[r4dr]

Ya, looking at it now, I think you're right. That said, now you'd only need to buy 1 pair of linear springs for the rear. So just add another $50-100 (easily find sets of race coils on ebay, etc). Run the FCM calculator with the 571 front + figure out the rear + chose a coil close to that = profit?

It takes 1000 lbs/in in the rear just to get up to a 1.01 ratio. You would probably want something like 1200 back there which is insane, and probably way beyond the damping capabilities of that shock. Crazy.

[Tbonem3]

Oh ya nvm lol

[maupineda]

For what it is worth, the H&R and Bilstein coils use a 60mm perch in the front, which drives the use of 60mm ID springs only, for which there are not as many rate options in the Swift catalogue. So I bought some adapters from Eibach to mount 2.5in springs to a 60mm perch. These are made off aluminum and are fairly cheap ($20 each)

These may even work with KW coilovers as their perches are 61mm



I hope the springs are not an exact 2.5 (63.5) or it will be a very tight fit :P



Not much is added to the stack height



These will go with turner 2.5in spring perches up top to seat on the OE top mounts