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      08-18-2008, 11:07 PM   #1
MINI135i
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Hardcore spring rates....what is the consensus?

So any conclusions on some good hardcore autocross spring rates yet?

What about front to rear ratio?

I have seen limited data so far: 350/500, 400/400, etc. Most of the others seem to be runing the progressive springs/coilovers.

Some competitive E36's in the area are at 600/600. Don't now if that is a safe start for the 135i?


We used to run Miatas at 800/400 lbs. with a 1.25 inch front sway to counteract body roll and dynamic camber/alignment change. I figure the 135i might benefit from the same approach??

Any thoughts?
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      08-19-2008, 01:01 AM   #2
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You should be concerned with wheel rates, not spring rates.
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      08-19-2008, 09:37 AM   #3
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The Bimmerworld One Lap of America 135i used 1100 front and 700 rear. James Clay said after the event (5000 miles of driving between events) that it was too much spring for the street. He suggests 550 front and 350 rear at the end of the article in the August Roundel.
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      08-19-2008, 05:28 PM   #4
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Quote:
Originally Posted by mikeo View Post
The Bimmerworld One Lap of America 135i used 1100 front and 700 rear. James Clay said after the event (5000 miles of driving between events) that it was too much spring for the street. He suggests 550 front and 350 rear at the end of the article in the August Roundel.

That combo is sounding more reasonable, meaning more spring up front than rear. My common sense experience keeps telling me more spring up front coupled with a bigger front bar. So depending on how aggresive one might want to go: 550/350, 600/400, 700/450, etc.

I pick up my 135i in a couple of weeks in Germany but then have to wait for them to ship it back so I can only theoretically test it in my mind until then.

I had another supercharged Miata setup at 550/350 and a 1 inch front bar. Interesting that Clay suggested a similar setup.... I think the 1 series is generally going to follow suit to what I experienced with the Miata. I guess we will see.

Someone out there try it out then I will know for sure...:wink:
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      08-19-2008, 06:18 PM   #5
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Man, MINI135i, you will have a great time doing the ED. I'm envious! Those rates sound about right to me for a serious street/auto-x dual purpose car. It's the linear springs rates on C/O setups that beat me up. I guess KW v1 and v2 are progressive, but you can't order custom spring rates.

Over the winter I'll do a very mild spring, shock, and front sway on my car. Looks like STU for me in '09.

I'm know a guy in the Rocky Mtn. Div. of SCCA, Mark Smith, that is an autocrosser. His mom campaigns an R32 in DS down here in Santa Fe.
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      08-19-2008, 10:33 PM   #6
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Quote:
Originally Posted by mikeo View Post
Man, MINI135i, you will have a great time doing the ED. I'm envious! Those rates sound about right to me for a serious street/auto-x dual purpose car. It's the linear springs rates on C/O setups that beat me up. I guess KW v1 and v2 are progressive, but you can't order custom spring rates.

Over the winter I'll do a very mild spring, shock, and front sway on my car. Looks like STU for me in '09.

I'm know a guy in the Rocky Mtn. Div. of SCCA, Mark Smith, that is an autocrosser. His mom campaigns an R32 in DS down here in Santa Fe.

I know Mark very well...I like to school him in my STX 07 Cooper S on the auto x course...actually in all fairness the last time we went head to head he nugded me out of 1st place by three thousandths of a second. It wasn't driving related, he just had more dust on his front bumper and tripped the light earlier. Got to remember not to keep my car so clean.:wink:

I also should fall into STU next year. Should be fun.
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      08-20-2008, 12:37 AM   #7
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Quote:
Originally Posted by MINI135i View Post
That combo is sounding more reasonable, meaning more spring up front than rear. My common sense experience keeps telling me more spring up front coupled with a bigger front bar. So depending on how aggresive one might want to go: 550/350, 600/400, 700/450, etc.

I pick up my 135i in a couple of weeks in Germany but then have to wait for them to ship it back so I can only theoretically test it in my mind until then.

I had another supercharged Miata setup at 550/350 and a 1 inch front bar. Interesting that Clay suggested a similar setup.... I think the 1 series is generally going to follow suit to what I experienced with the Miata. I guess we will see.

Someone out there try it out then I will know for sure...:wink:
Why does such a high front spring rate "sound reasonable" to you?

You know the front motion ratio is basically 1:1, right? And is nothing like a Miata, right?
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      08-20-2008, 09:45 AM   #8
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Hello all,

This all seems a bit off to me...

The stock spring rates are as follows

From our tests...
135
Front 120-125 lbs.
Rear Progressive 300 - 350 lbs.

M3
Front 160 lbs
Rear around 550 lbs

Please note wheel rates and spring rates are very different.

I am currently running 400/600 and don't see an advantage to reversing them. I guess only lots track time will tell.

Sent from an iPhone.

Charles
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      08-20-2008, 10:01 AM   #9
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I don't have the specific engineering answers but I think compensation for the Mac Strut comes into play once again.

Like Charles says, testing and time will tell, but I have found in auto X what is good on paper sometimes doesn't play out as the fastest on the auto X course or track for that matter.

I still find it interesting that Clay, an experienced BMW racer, suggested the same direction and implemented it on his OLOA car...

Charles, is the 400/600 feeling just right or do you still find you want more spring at this point? (If I recall you started at 400/400) How is the current ride comfort? Have you messed with sways yet?
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      08-20-2008, 10:42 AM   #10
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Supposedly, the H&R Sport springs (NOT OE Sport) are:

H&R Sport Spring Set
Lowering Front 30 mm / Rear 20 mm
Spring Rate Front 42 N/mm (240 lbs/inch)
Spring Rate Rear 65 N/mm (370 lbs/inch)

Found via a few internet searches, so might not be 100% accurate, as H&R keeps their rates very hush-hush.

I have these springs, and I do get a good bit of compression still on the autox course. I added a UUC front sway set to full stiff on Saturday, that I'll be testing at an autocross on Sunday. I hope that will be a good combination, but we'll see...
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      08-20-2008, 11:23 AM   #11
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The motion ratios (used to get wheel rates) for e36 are approximately 1:1 (.96%) in the front and 1:2 (.46%) in the rear and I've read they are almost the same for the 1-series.

H&R Sport and OE Sport springs have had the same spring rates in past same car applications, just different heights.

T.C. Kline early on suggested 450/300 spring rates for a mostly street 135i with some autocross. He told me if you keep the rear rates lower the ride is much improved, which I am concerned about with linear spring coilovers.
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      08-20-2008, 11:28 PM   #12
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Quote:
Originally Posted by mikeo View Post
The motion ratios (used to get wheel rates) for e36 are approximately 1:1 (.96%) in the front and 1:2 (.46%) in the rear and I've read they are almost the same for the 1-series.
Those are motion ratios, not wheel rates........................
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      08-21-2008, 07:12 AM   #13
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That would be correct, thanks, I'll edit it.
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      08-21-2008, 09:04 PM   #14
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Quote:
Originally Posted by mikeo View Post

Over the winter I'll do a very mild spring, shock, and front sway on my car. Looks like STU for me in '09.
That sounds like a very slippery slope....:biggrin:

Chris
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      08-21-2008, 09:28 PM   #15
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Yes, I went down that slippery slope with my E36 M3. And I hope I've learned my lesson, as it was an expensive one.
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