E30 Rear Subframe - What Springs?

[Hatchman]

Hello,

 

This is partially an introduction thread. I recently picked up someone else's headache in the form of a botched and rusted '74 shell.  This thing definitely falls under a category of '02 that Rob Siegel would warn to stay the hell away from. However I am a fool, it was cheap, and I'm looking to improve my metal working skills and kill some years of my life.

Any who, the previous owner swapped in an e30 rear sub frame before ditching it. While I am still wrapping my head around the install (hacked off e30 bushing mounts and retrofitted a bolt to hit the '02 mounts) it has one major glaring flaw in that the stock '02 springs are not enough to keep the car from bottoming out and keeping the "roller" from "rolling".

 

So my question is.
Those that have swapped in an e30 rear subframe, what springs did you use and/or what modification to spring perches did you do?

I've searched the subject however the most unfortunately the more useful thread seem to be dead and/or the thread never really discusses the springs.

For now I just want to get the thing rolling as cheap as possible, I may just have to troll the junkyard for something the right diameter.  However it would be great to see what others have successfully done.

Pictures later.

Thank you.

 

[TobyB]

I think the unfinished thread may be as much as was ever discussed here.

I can't recall anyone ever showing it successfully finished.

You can use any spring bigger than the 2002 body 'nub' and 

it'll work, as the e30 trailing arm just has that little pin for location.

Jeez, do the upper and lower perches even line up?  The geometry's

pretty different between the 2.

 

There have been e30 diff retrofits, but those were on 2002 subframes, or custom subframes.

 

Good luck- pictures will help!

 

t

 

[Hatchman]

Thanks, will definitely get some pictures up, as I said I'm still absorbing it all, and bracing myself for the onslaught of messages that will tell me abandon this rust bucket when I do post some pictures.

The perches are close, but definitely do not line up 100%. Being that the e30 is as you said, just a nub I feel there is some opportunity to fab a better perch.

Ultimately, I'm sure rear coil overs will be the answer, but I'd like to come up with something better than a block of wood in the mean time so I can at least roll it in and  out of the garage. 

Edited May 22, 2018 by Hatchman

[evil02]

I went coil over on my E30 rear suspension swap. Ground Control made them.

Edited May 22, 2018 by evil02

[Mike Self]

Have you considered going back to an '02 rear subframe, or did the PO irretrievably booger up the mounts on the body?  

 

'02 subframes are pretty easy to come by, and will get your car back among the living much sooner.

 

cheers

mike

[Hatchman]

Its not out of the question, would definitely make life easier and I don't plan to throw too much power at the thing if I ever to get it on the road.  

But its there and it has discs soooo... might as well go down this path until I come to my senses.

 

The sub frame mounting location on the body is also shot so I may end up going down a whole other path in the end.

Really wish the Vintage at Saratoga was happening this year! I need to stare at some 02's!

[Hatchman]

Evil02 I'd love to see a picture of your sub frame mount.


Some images to go along with it, so the spring angle isn't... terrible?

 

A very rigid mounting system, essentially the E30 busing was hacked off and a tube for the stock '02 pin was welded on its inside.  Need to learn up on this mounting point. My understanding it is a pressed in sleeve with a  pin/bolt pressed in from the top?

Some square tubing was someone else's attempt to get it rolling.

Edited May 23, 2018 by Hatchman

[tomorrowcalling]

I used a custom wound spring, as it ends up quite long the wire diameter needs to to be a bit bigger. I also lengthened the "spigot" the spring sits around to get the bump stop in the right place

[Hatchman]

Interesting, I'll be honest I never even thought of a custom spring being an option.
Looks like you used the "stock" geometry of the two pieces, other than the bump stop mod, any issues there?
Would be curious to hear any specs you may have, length, gauge spring rate ect.  Would be fun to try to hunt down a set of springs from some other vehicle that fit the part.

Thanks for the post!

[evil02]

Hatchman,

 

 I'll send you a pic tomorrow morning. I don't have any pictures on this laptop. Basically, the end of the E30 subframe was cut off and a spherical type bushing was welded on the end and the same 02' subframe bolt was used.  It will make sense when you see it.

 

Another thing to think about if you want to use the big spring is, ground control sells a spring plate that allows the spring to "tilt" when the spring is relaxed. Maybe you can have them make the proper spring plate to use a 02' spring and adapt it to the subframe??

 

Dave

[tomorrowcalling]

2 hours ago, Hatchman said:

Interesting, I'll be honest I never even thought of a custom spring being an option.
Looks like you used the "stock" geometry of the two pieces, other than the bump stop mod, any issues there?
Would be curious to hear any specs you may have, length, gauge spring rate ect.  Would be fun to try to hunt down a set of springs from some other vehicle that fit the part.

Thanks for the post!

 

I basically took an E30 and a 2002 spring into a local spring maker, explained what I wanted and picked them up  a week later. From memory price was around NZ$250 for the pair.

Current rear spring, is 101mm ID, 15.98mm Wire, 9.25 turns, rate is 250 lb/in, which gives 176 lb/in at wheel, This is stiffer than stock which is around 130 lb/in at wheel

Only issue is the arm doesn't quite swing far enough down to remove the spring without using a spring compressor.

 

 

[evil02]

The ends are E39 hub carrier mounts welded on to the subframe.

[TobyB]

If it helps, stock car springs in 5" diameters can be had cheaply in almost any length and spring rate.

Also, the adjusters they use are pretty cool, and cheap, too.

They call them 'spring spacers'.

 

https://www.speedwaymotors.com/Search?query=spring spacers&facet=GA_Nav_Part:Coil Spring Spacers

 

hth

 

t

 

[Hatchman]

tommorowcalling thats great info to go off of thank you! good to know I can make the stock points work for the time being. 

 

evil02, thats great to see thank you. I was curious what others had used there since the trailing arm bushing is so damn close to the '02 mounts. Looks like that low profile one off the e39 is a great solution.

 

however toby I think you nailed it for a get this thing rolling cheap and easy option.

So much to do, so much to learn. Thank you all.

 

Edited May 24, 2018 by Hatchman

[Blackwhiteandblue]

On 5/22/2018 at 8:12 PM, Hatchman said:

Evil02 I'd love to see a picture of your sub frame mount.


Some images to go along with it, so the spring angle isn't... terrible?

 

A very rigid mounting system, essentially the E30 busing was hacked off and a tube for the stock '02 pin was welded on its inside.  Need to learn up on this mounting point. My understanding it is a pressed in sleeve with a  pin/bolt pressed in from the top?

Some square tubing was someone else's attempt to get it rolling.

 

I now feel A LOT better about how my E30 subframe swap is looking! Granted mine is not done either...