Why Lowering Springs May Ruin Your M3

[Trier Germany]

Originally Posted by Trier Germany

I have H&R and felt a dramatic difference in handling on the Nordschleife. Alot less body roll! sharper turn ins! better felling at the limit. The stock setup is for M3 drivers that will never leave the public roads!

I'm still waiting for the aftermarket companies to come out with coilovers that adapt too EDC. Hopefully they are not too far away i will definately go KW!

[rzm3]

Originally Posted by ThorPR

I was looking into buying some Eibach springs. Would you recommend these or will they push the limit of the stock setup? I know that Dinan includes a shorter bumpstop and Eibach does not. I assume that Eibach believes that a shorter bumpstop is not necessary for their springs, and by adding one it will alter the overall spring rate.

Thanks...

The key to Dinan's solution is 1) shorter bump stop (-0.2") and 2) shorter upper guide support (-0.3"). These combined maintains the suspension travel while dropping the car by 0.5".

[808MGuy]

Originally Posted by Lemans_Blue_M

Very interesting analysis about the effects of installing lowering springs.

I have a suggestion that will give your theory a little more factual 'weight'...

Your calculations should factor in the progressive spring rate of every aftermarket lowering spring on the market.

The current crop of lowering spring for the M3 will all have different progressive spring rates, so they will all behave a little different with the OE shocks and struts.

From my perspective, Dinan and Eibach got it right...and everyone else got it wrong.

I agree. Its a good starting point but there are so many other variables that need to be included to make a solid argument.

I was a little confused with the numbers though. If total available compression is 2.875" but the bump stop is 2.375", then compression prior to contacting the bump stop is 0.5". So with a 1" drop you're already compressing the bump stop 0.5". Now you said that at 1" the bump stop will act like "rock bottom" although according to your graph, it looks like the non-linearity of the bump stop is closer to 20mm which is more like 0.75". Anyway, if we go with the 1" number and we're already at 0.5" compression, we only have 0.5" left and not 0.875" per your calculations. If we go with the 0.75" rock bottom number, we actually would only have 0.25" left right?

[rzm3]

Originally Posted by 808MGuy

I agree. Its a good starting point but there are so many other variables that need to be included to make a solid argument.

I was a little confused with the numbers though. If total available compression is 2.875" but the bump stop is 2.375", then compression prior to contacting the bump stop is 0.5". So with a 1" drop you're already compressing the bump stop 0.5". Now you said that at 1" the bump stop will act like "rock bottom" although according to your graph, it looks like the non-linearity of the bump stop is closer to 20mm which is more like 0.75". Anyway, if we go with the 1" number and we're already at 0.5" compression, we only have 0.5" left and not 0.875" per your calculations. If we go with the 0.75" rock bottom number, we actually would only have 0.25" left right?

First, what I said is when the bump stop compresses to 1", the bump stop rate will shoot up.

Second, the graph is just an illustration of a similar bump stop.

Hope this helps.

[aus]

Originally Posted by Poppin Fresh

But couldn't you buy those bump stops separately and have them shaved to lowering specs? I remember someone doing this before.

You should even need to shave/cut them since they E36 M3 bumpstops are shorter than the stock ones.

Originally Posted by Splinter4784

I agree, i would trust Dinan because they are the official bmw aftermarket supplier and they make it all work out in the end

And from what I have heard, springs are only for cosmetics, it does not affect performance

There is NOTHING official about Dinan anymore. That relationship ended long ago.

[Evan_RS]

Damm, and I was just about to order the RD Sport springs.

[alex310]

Originally Posted by Lemans_Blue_M

Very interesting analysis about the effects of installing lowering springs.

I have a suggestion that will give your theory a little more factual 'weight'...

Your calculations should factor in the progressive spring rate of every aftermarket lowering spring on the market.

The current crop of lowering spring for the M3 will all have different progressive spring rates, so they will all behave a little different with the OE shocks and struts.

From my perspective, Dinan and Eibach got it right...and everyone else got it wrong.

I agree with my old buddy Lemans here, Dinan includes a camber plate that has been cut down by .3" and uses the e36 M3 bump stops which are shorter, this gives the shock more travel then a stock camber plate on the front.

I noticed on my buddies car his EiBachs didn't even really drop it too much so I guess that's good too.

My H&R Coils are just amazing, the handling on the car is much better then stock.

I know your going to make fun of me later Lemans, but here is a question for you, when I went from my 285/25/20s in the rear to 295/25/20s it feels as if the handling wasn't as good as before, could this be? I am running 255/30/20s on the front.

[dawgdog]

I've had my H&R springs on for over 10,000 miles and 8 HPDEs. I do not feel the handling on the track has been compromised, but I do feel it is not an ideal situation. For me this is not intended as the final solution; eventually coilovers will be the anwer.

[Lemans_Blue_M]

Originally Posted by alex310

I agree with my old buddy Lemans here, Dinan includes a camber plate that has been cut down by .3" and uses the e36 M3 bump stops which are shorter, this gives the shock more travel then a stock camber plate on the front.

I noticed on my buddies car his EiBachs didn't even really drop it too much so I guess that's good too.

My H&R Coils are just amazing, the handling on the car is much better then stock.

I know your going to make fun of me later Lemans, but here is a question for you, when I went from my 285/25/20s in the rear to 295/25/20s it feels as if the handling wasn't as good as before, could this be? I am running 255/30/20s on the front.

The reason your handling seems a bit off, is that the larger 295/25/20's have a larger section width, and they weigh a few pounds more per tire. Also, the larger differential width between the tires on your front axle (255/30), and rear axle (295/25) are causing little more understeer than you had with your previous setup.

That's why your handling feels different now, since you bought the larger rear tire size. (to fill up the rear wheel well)

Larger tires and wheels will affect the way your suspension responds under compression and rebound. Keep in mind that our stock suspension was designed and tested with the stock wheel and tire sizes during R&D.

[MMMorish]

Do the chamber plates come with the Dinan spring kit, or is it an additional option? I know they have a few levels of spring kits.

[Jaypod]

Originally Posted by MMMorish

Do the chamber plates come with the Dinan spring kit, or is it an additional option? I know they have a few levels of spring kits.

The camber plates are a separate option. However I don't believe it will work with the stock suspension so you need to run their suspension to use them. (Although I think they make work with other aftermarket suspension set ups as well..

[rzm3]

Originally Posted by Jaypod

The camber plates are a separate option. However I don't believe it will work with the stock suspension so you need to run their suspension to use them. (Although I think they make work with other aftermarket suspension set ups as well..

They will work with stock upper guide support, meaning you can add them to your stock suspension w/o their spring kit.

[Bluechipper]

My Eibach springs have been absolutely spot on.

Mild drop, oem ride quality, edc works perfectly.

Best mod I have done. I wouldn't change a thing.

[JC919]

Originally Posted by Trier Germany

I'm still waiting for the aftermarket companies to come out with coilovers that adapt too EDC. Hopefully they are not too far away i will definately go KW!

Amen to that

[Lemans_Blue_M]

Originally Posted by Trier Germany

I'm still waiting for the aftermarket companies to come out with coilovers that adapt too EDC. Hopefully they are not too far away i will definately go KW!

Originally Posted by JC919

Amen to that

Hmm...

I think there's some lingering perception among M3 owners, that an aftermarket suspension setup can be fully compatible with the factory EDC option.

Unfortunately, that's virtually impossible the way the EDC suspension is designed by BMW.

[rzm3]

Originally Posted by Trier Germany

I'm still waiting for the aftermarket companies to come out with coilovers that adapt too EDC. Hopefully they are not too far away i will definately go KW!

From what I've read from industry insiders, this will probably not happen because 1) the EDC system is quite complex (hence not justifying the R&D) and 2) there are IP protection surrounding the OE design.

[Technic]

Originally Posted by rldzhao

From what I've read from industry insiders, this will probably not happen because 1) the EDC system is quite complex (hence not justifying the R&D) and 2) there are IP protection surrounding the OE design.

... and probably the most important reason: the M3 market that will pay for EDC in the first place and then replace it with aftermarket EDC is insignificant.

[Reedomn]

Very informative...another reason this is the best BMW/M3 site!!

[sehrgut]

Originally Posted by Technic

... and probably the most important reason: the M3 market that will pay for EDC in the first place and then replace it with aftermarket EDC is insignificant.

+1 but when I got my M3 I had no intention of dropping it so now after some time i want to drop it and I should just have bought it without the EDC but then again, it works so awesome. But as far as looks go, it could need a drop and because of aftermarket springs works with EDC I will look over the bumpstop issue anyways, i mean, who cares? Just buy shorter once or simply replace them youself every other year or so.

[adc]

Originally Posted by MrHarris

My eibachs feel "right" unlike my H&R's.

Would you mind elaborating a little more please?


Not sure if I can afford any drop in ride height at all (driveway-related), but I was considering the Dinan springs... even so, I'd like to know what it was you didn't like about the H&R's...

[adc]

Originally Posted by Lemans_Blue_M

I think there's some lingering perception among M3 owners, that an aftermarket suspension setup can be fully compatible with the factory EDC option.

Unfortunately, that's virtually impossible the way the EDC suspension is designed by BMW.

Well, both the M3 "Edition" package and the upcoming ZCP have a 10mm drop in ride height - and are available with EDC.

[Moxie]

Originally Posted by adc

Would you mind elaborating a little more please?


Not sure if I can afford any drop in ride height at all (driveway-related), but I was considering the Dinan springs... even so, I'd like to know what it was you didn't like about the H&R's...

Put a 2X4 across the lowest part of the dip in your driveway

May have to sandbag it down