E34 rear suspension on E28? Rally-x tough suspension?

[dsmith]

Not an e28. A Ford Aspire! I posted a pic in your build thread.

Rally cars generally need a sway bar for body roll and use softer springs for compliance. So, I wouldn't eliminate it. You could make some better attachments instead of the stock garbage.

[95maxrider]

Not an e28. A Ford Aspire! I posted a pic in your build thread.

Rally cars generally need a sway bar for body roll and use softer springs for compliance. So, I wouldn't eliminate it. You could make some better attachments instead of the stock garbage.

Ahh yes, that car, I remember now!

By better attachment points, do you mean the frame mounts for the sway bars, or something to do with the end links? I have one of the nice sway bar mount reinforcement kits lying around that I haven't gotten around to installing, and I'm using some Meyle HD (non-adjustable) end links.

[ElGuappo]

I haven't built a rally car, but I did stay at a Holiday Inn Express last night, so I've got that going for me.
I was going to propose something like dsmith wrote, attach a sleeve over the rear shock body with the perch welded to the top of the sleeve.
E34 & E32 shocks are the same dimensions, and of course different valving. I have both E32 & E34 rear shocks kicking around if you want measurements.
They also have different valving, and Bilsten has been pretty helpful when I've spoken with them on the phone about determining stock valving numbers to get a feel for what I have before sending something in for a rebuild.
So you could run the longer e32/34 shocks wtih their longer springs for increased ride height, or the longer shocks with long coilover style springs from circle track cars.
Tons of options.

[dsmith]

By better attachment points, do you mean the frame mounts for the sway bars, or something to do with the end links? I have one of the nice sway bar mount reinforcement kits lying around that I haven't gotten around to installing, and I'm using some Meyle HD (non-adjustable) end links.

Well, I just think the way the rear bar end links were designed makes it tough to fab up better links.

[95maxrider]

I haven't built a rally car, but I did stay at a Holiday Inn Express last night, so I've got that going for me.
I was going to propose something like dsmith wrote, attach a sleeve over the rear shock body with the perch welded to the top of the sleeve.
E34 & E32 shocks are the same dimensions, and of course different valving. I have both E32 & E34 rear shocks kicking around if you want measurements.
They also have different valving, and Bilsten has been pretty helpful when I've spoken with them on the phone about determining stock valving numbers to get a feel for what I have before sending something in for a rebuild.
So you could run the longer e32/34 shocks wtih their longer springs for increased ride height, or the longer shocks with long coilover style springs from circle track cars.
Tons of options.

My co-owner doesn't want to spend the $350 to get new E34 rear Konis And putting together my own coilovers is rather intimidating

So I found a used set locally, and the guys is asking $100. Andy can get me E34 rear springs for about $50 shipped. In the interest of keeping things simple and cheap, I'm leaning towards this option. What do you guys think? Who do people use to get shocks re-valved, and how much did you pay?

[95maxrider]

Back to the drawing board!

The $100 used set of E34 Konis were completely beat up, so I need to figure something else out. Ugh. I'm putting these links here for my future reference...

450# front 2.5" springs, $42 each
http://www.jegs.com/i/QA1/122/7HT450/10 ... ProductId=

350# rear springs, $45 each
http://www.jegs.com/i/QA1/122/7HT350/10 ... ProductId=

A1 7" Koni coilover kit, $47 (each corner?) They say: FITS KONI 30 SERIES 46mm (1 7/8" O.D.) SHOCK WITH LARGE WASHER STYLE SHOCK END. Does anyone know if that means they will fit E34 Konis?
http://www.a1racing.com/cok12433.aspx

I need to figure something out, and soon.

[95maxrider]

Well, I ended up getting new E34 rear Konis and used E34 springs, and put them together using the beefy Moosehead Engineering upgraded rear strut mounts (thanks Paul!!). The Koni's shock body is quite a bit thicker than the E28 Bilsteins, so I hope they can withstand some rally abuse. Thankfully, they have a welded on lower spring perch.







You can see how freaking high this thing sits.


Sure enough, they raised the rear end of the car about 2", which I thought would be a good thing. Boy was I wrong. At the first rally-x of the year this Sunday, the car was miserable to drive. It just would not go straight. I was fighting with it every turn to make sure it didn't spin out. Going through the slalom was a series of me reacting to the rear end stepping out. Before, one of the best aspects of the car was how recklessly you could drive it without really thinking about what it would do, because it was just so planted. That is now gone, and I need it back. I ended up in 2nd place for the day, some 6 seconds (out of about 600 total) from my main rival Josh in his M42 E30, who I had beaten the prior 5 races in a row.

I'm thinking the culprit is the raised ride height, and not the increased spring rate. Josh said that when he lowered the rear of his E30, it was much more planted and put power down much better. I'm thinking the same applies to me. Since coilovers are out of the question ($$$), and lowering springs are too (would require buying two sets- one E34 and one E28, also didn't work well when we had them on the car before), I'm pretty sure cutting coils on the stock springs is my best option. Due to weight reduction on the front (battery moved to trunk, no AC or heat, dash, etc) the car sits higher than stock in the front. The same is true for the rear, but it's due to the E34 rear suspension. It's for those reasons that I think I can lower the car about 1" without any of the negative effects of cut springs. I think I can cut two coils from the rear and one in the front, but I may start with half that and see how it works.

One problem that I'm already aware of is that putting lower/shorter springs on the rear E34 setup would require tender springs, as you don't need a spring compressor to assemble the rear suspension, as there is no real tension on the spring when the assembly is out of the car. If I cut rear coils, the spring could become unloaded at full drop, which is a bad thing if I want to go fast and make these struts last. I'm honestly not sure how E34s run lowering springs without the same problem, because it's not a result of E34 parts in an E28. I've read about plenty of E34 and E28 guys who cut front coils, but I don't recall if the front springs are heavily compressed at rest (out of the car but assembled), so I don't know if I'll need tender springs in the front as well. Can anyone advise or point out other things I need to be aware of? I found a great site with info about properly cutting springs, which I will be following:

http://www.eatondetroitspring.com/cutting-coil-springs/

Any advice would be appreciated!

[ElGuappo]

I've not seen stock springs, front or rear, not have pressure on the top of the assembly.
That's not to say I don't just zip the top nut off and let the spring decompress, rapidly on it's own, but stock springs should always have be fully seated top and bottom.
I cannot see the pictures right now, but I would have to think that raising the ride height will be the inverse for camber as lowering the rear end. You are probably getting more contact on the outer edges of the tires, and you'd have to do some serious camber correction to remedy this.

As far as cutting springs go, the naysayers are misinformed.
You can cut stock springs all day and have them work just fine. As long as you don't use a torch and heat the steel up too much, they won't lose their temper and will be just fine. Since the rear assemblies are so much easier to R&R, I'd start with 1 coil at a time and see how it changes things.
E32/34 springs should be easy and cheap to find used, I would like to experiment with some of the extra springs I have laying around to acheive different rates and ride heights.

[demetk]

I think if you cut the front spring you're going to have to bend the last 1/2 coil back flat again otherwise the spring will not seat right.

[95maxrider]

Can anyone comment on what happens when we install lowering springs on our cars? Are the shorter springs under compression even when pulled from the car (but still assembled)? Or are they only compressed when installed in the car and under load? We didn't even have to use a spring compressor to install the E34 rear stuff, which just strikes me as very odd.

I did a quick search and tender/helper springs are EXPENSIVE, so if I could avoid paying for them, I would really like to do so. Given that so many people put lowering springs on these cars, there must be something I'm overlooking here. What is it?

[ElGuappo]

E34 rear springs should definitely be in compression when installed. If they are rattling on a shock you know should be fo ran E34 then either the spring is the wrong one, or its been cut.

Some lowering springs can go in with little or no compression, they are all a little different.

[95maxrider]

E34 rear springs should definitely be in compression when installed. If they are rattling on a shock you know should be fo ran E34 then either the spring is the wrong one, or its been cut.

Some lowering springs can go in with little or no compression, they are all a little different.

Well, it's compressed, but not enough to require a spring compressor to get the top mount bolted on. You just have to push down a bit with your hands, which seemed a bit odd. I didn't look super closely, but they didn't appear to be cut. I'm also pretty sure it's the right spring because the diameter is correct, and I bought them from Chris/wkohler, and I'm pretty sure he knows what he's talking about/selling!

[95maxrider]

I've read about people removing springs pads to drop the ride height, and feel like they might be important for my car when doing rally-x, but I can't say for sure. What are people's thoughts on removing them to drop the ride height a bit? Or should I just stick with cutting a coil at a time and see what happens? Is cutting one coil in the front too much to begin with; should I start by cutting half a coil?

When cutting, can anyone tell me if I should be cutting the top or bottom coils off? Does it matter?

For reference, this is how low the car was when we bought it on Bavarian Autoworks springs:




So my buddy on R3v posted up this in regards to spring length:

"Before you look into tender/helper springs, do a quick check of this: Put the e28 springs on, install them in the car. They'll hang loose initially. Now hook up the swaybar. See if that reduces the droop in the rear suspension sufficiently to keep the spring seated.

On the e30, my rears will practically fall out at full droop with the sway detached, but the sway limits the downward travel enough to keep them seated when attached. May be the same case on the e28."

I know E30s have vastly different suspension design than E28s, but it's an interesting idea none the less. Can anyone comment on this off the top of their head?

[SilverBullet]

I have a home made adjustable perch in the rear of mine with e28 bilsteins. Its pretty much a bit of mild steel tube which has been capped at one end (with a hole drilled for the shocky shaft) and it been threaded on the outside. It sits over the shock, has a perch thats threaded to match the tube, and it takes standard springs, not the tiny coil overs.

When installing all I did was remove thw circlip, slide the tube over the shock, put the coil in and top Mount and install it in the car. Would give you your original shocks and springs which can be adjusted to any height you like, and give you a much beefier spring perch.

Sorry I dont have any pics but it is stupidly easy to figure out. Been running it for years without a problem.

[95maxrider]

I think if you cut the front spring you're going to have to bend the last 1/2 coil back flat again otherwise the spring will not seat right.

Can anyone confirm this, and is this only true for the fronts? How do you bend it back, with heat? That sounds like a bad idea from what I've read....

[bluej]

Nick, you can just cut them perpendicular to the coil. Use an angle grinder, or even a dremel. makes a nice clean cut and doesn't overheat the spring. If you look at this picture you posted above, you can see how there's a rubber looking seat at the bottom of new e34 setup that the coil slips into, so you don't have to worry about it seating at an angle. A whole coil may be more of a change than you realise. look up a coil spring calculator and get a rough estimate of what the current spring rate is, then see what happens as you reduce coils. Even if the actual spring rate as you measure it (remember, there's a slight bit of paint thickness to the coil) isn't perfect, it'll give you an idea of what percentage increase in rate you're getting for the lower height.

[demetk]

Cutting a square coil spring and turning it into a tangential coil spring will make the spring want to bow in the direction opposite the cut. Although this may be fine for leisurely street driving, I doubt you would want his on a rally-x car. Heating up the last half coil and bending it back down is the way I do it. That coil is a dead coil anyway and I don't rally-x the car.

Aren't there any rules in rally-x about cutting coil springs?

[bluej]

There aren't specific rules about cutting springs.

Like i said, looking at the picture, the stock e34 springs appear to be tangential w/ a seat to match at the bottom.

[95maxrider]

Cutting a square coil spring and turning it into a tangential coil spring will make the spring want to bow in the direction opposite the cut. Although this may be fine for leisurely street driving, I doubt you would want his on a rally-x car. Heating up the last half coil and bending it back down is the way I do it. That coil is a dead coil anyway and I don't rally-x the car.

Aren't there any rules in rally-x about cutting coil springs?

Are you referring to the fronts?

According to this:


It looks like the E34 rears are tangential, and thus safe to cut. However, judging by a picture of my old FRONT lowering springs:


The front appear to have square ends, and thus are unsafe to cut, unless you heat up an end and bend it back into place. The spring cutting FAQ states:

Tangential- where the end of the coil continues to twist off into space. A spring with a tangential end would fall over if you tried to stand it on its end.

Square – the last coil bends back down to touch the coil below it. This style end allows the spring to stand up when placed on this end

Is it me, or does it look like the bottom of the front springs are square cut, and the tops are tangential? Ideally, I would like to cut a little off the fronts to keep the spring rates relatively similar, but also just because putting it lower will make it handle better.

[demetk]

Both front and rear springs are square.

[95maxrider]

Both front and rear springs are square.

Oh. Well, according to the FAQ:

The only Coil Spring Ends that can be safely cut are Tangential Ends.

Because Square ends and Pigtail ends are designed to make full contact with their mounting points, they would have to be re-shaped after they were cut. But in order to re-shape them the steel would have to be heated and heat is a spring’s worst enemy.

So, Coil springs with Square or Pigtail ends can not be safely cut.

So....I can't safely cut any of my springs

[demetk]

Yes, according to that particular faq you would conclude that it would be unsafe to cut our springs because the only way to make them square again would be to heat the last 1/2 coil. There are other points of view that indicate heating the last 1/2 coil to make it square is OK because that last coil is a dead coil. It depends on which viewpoint you trust.

Are you sure coilovers aren't in your future?

[Flip_Side_the_Pint]

is it only the bottom of the spring that has square end? If so is there a reason one couldn't remove from the top?

[tn535i]

Is the fundamental problem here that your lifted rear resulted in positive camber and maybe some toe change? While many get away with lowering and increased negative camber I don't think these cars take kindly to the opposite of that. I think if you want to bring it up you need to deal with the camber and possible toe changes to keep the handling as it was. If raised it won't matter if it is e34 parts or coil overs.

[95maxrider]

Is the fundamental problem here that your lifted rear resulted in positive camber and maybe some toe change? While many get away with lowering and increased negative camber I don't think these cars take kindly to the opposite of that. I think if you want to bring it up you need to deal with the camber and possible toe changes to keep the handling as it was. If raised it won't matter if it is e34 parts or coil overs.

If not alignment changes, then center of gravity and weight distribution. I don't even need it this high, so I would like to drop it back down. I really wanted to avoid the cost and hassle of coilovers, but I'm starting to lean in that direction.