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960 IRS II Rear Coilovers Part 1: Boy, I sure hope this works

I guess this is mostly rear suspension, so it'll go here. Part of the "eh, I guess I might as well" school of thought:

85448460.jpg


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And although not related to rear suspension really much at all, here's more goo:

85448462.jpg


We'll see how long that holds up. Ideally, it should hold up indefinitely, seeing as that shouldn't be seeing much flex at all. If it pops out, something terribly odd is happening under the car.
 
And although not related to rear suspension really much at all, here's more goo:

85448462.jpg


We'll see how long that holds up. Ideally, it should hold up indefinitely, seeing as that shouldn't be seeing much flex at all. If it pops out, something terribly odd is happening under the car.

Well this is certainly doing something. The car has a wicked shimmy at about 70mph. Am I right in thinking that the stiff CSB should be fine if the DS is very well balanced? Meaning, before I gooed it, the vibration was worked out by the very flexible support? Because I'd much rather just get the DS balanced then figure something else out to keep the driveshaft from wandering about under the car...
 
could be a bad bearing too....can you be any more specific about the shimmy that is wicked?

It just vibrates like hell at 70 mph. It didn't before I gooed up the CSB. It was perfectly smooth actually. When i pulled the driveshaft to do the fuel lines though, I found the middle u-joint was contacting the tunnel. Although...I don't know if thats recent. I'll probably just remove the urethane and try it out--I put some tape on the tunnel where the mark was. If it still does it, I'm not quite sure what to do...
 
OHHHHH. I kinda forgot about that slightly important detail.

This may "only work" on Nivo cars! The composite leaf is still in place, with it's nebulus spring rate (which I could, for the life of me, not determine). The 80lb spring is in addition to the normal spring.

For non nivo cars, the spring will maintain the stock ride height. Increasing the spring rate would reqire raising the car with the CO springs enough so the spring rate doesn't suddenly change on droop.

I'm not sure the non-nivo cars will maintain stock height. Pretty sure my car's rear shocks are toast and the rear end sags a decent amount. I should detatch them and put the car on the ground to see.

As for the vibration in the rear - have you cleaned/greased the 'CV joint' on the rear part of the driveshaft?
 
Hi, could I get a thinner coilover and not have to cut with anglegrinder?
I'm paranoid the car wont be approved if they see I cut on the suspension components.
 
Hi, could I get a thinner coilover and not have to cut with anglegrinder?
I'm paranoid the car wont be approved if they see I cut on the suspension components.

Make it look stock:-D A narrow coil will work fine (my original 80 pounders fit without clearance). I think eibach makes springs with a smaller OD than others.
 
Sorry for spamming with questions, lol.

I see on http://store.summitracing.com/partd...art=HAL-DR5855B&N=700+400026+115&autoview=sku that the shock is 2", so I guess this means you cant fit a 2" spring over this shock? I guess it needs some clearance?

What length spring/comp rate did you end up with?
Also, do the "buckets" for the DR5855B support different diametre springs? like 2.5" 3" etc? or did you have to swap the "buckets" (upper and lower) on the shock it self?

The only experience I have with coilovers is with my downhill bicycle :p

Also you never put back the swaybar, right? wasent just removed for assembly of the shocks?

Edit: this spring looks OK, right?
http://store.summitracing.com/partd...925130+4294839061+4294846689+115&autoview=sku
 
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It's a 2" body, but it's made for a 2.5" spring. The spring seats are machine for 2.5in springs, but if I remember correctly, they could be turned down on a lathe to fit a smaller spring, but just barely. A 2.5" spring is snug around the shock body. The swaybar comes off for assembly, but once the shocks are in place, you can bolt it back on. I put mine back on.
 
I know I'm resurrecting a dead thread here but did you settle on 170lb springs on the rear or did you go for something stiffer?. I'm gonna be doing this conversion myself in the coming weeks (along with fitting a nivomat leaf) and I'm trying to compare the struts from QA1 to AVO shocks as they're available over here.
 
I know I'm resurrecting a dead thread here but did you settle on 170lb springs on the rear or did you go for something stiffer?. I'm gonna be doing this conversion myself in the coming weeks (along with fitting a nivomat leaf) and I'm trying to compare the struts from QA1 to AVO shocks as they're available over here.

Good point, I should probably update this!

I upped the spring rate to 450lbs, after sitting down and doing the math. Ride rate for 2.1hz, 2.0hz rear, using 450hz springs on all four corners! It handles great now, but I had to space out the spring to clear everything (the 450x7 springs are super thick). Pictorial:

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123176238.jpg
 
Thanks for the update, that's a hell of a jump in spring rate!, mine is a seddan so not sure if I need the same poundage or not now...mmmm (just had a look and I can only get 450l/b in a 12" length)..
 
Waits for bolt to shear off. You fix that single shear ****tyness yet?
Also, 450lbs not HZ. noob

I mean ya it's technically in single shear, but its not like its just hanging off a bolt, it's a phatty 19 mm pin thinger. It's hasn't busted off yet. And I don't know what you're talking about, they only weigh like 5lbs, psh.
 
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