I have an older Ohlin single-adjustable coilover suspension on my Evo VIII. I purchased it used and it came with the standard (I presume) Ohlin springs and a set of Swift springs for track duty.

I am trying to install the Swift springs. Two of them are 070's; 65mm inside diameter and 200mm tall. The others are 080's ; 65mm inside diameter and 260mm tall.

The rear Ohlin springs appear to be slightly shorter than the fronts, so I initially presumed that the shorter Swifts would mount there. But, the Swift springs are so much shorter than the Ohlins, it appears that there are not enough threads on the strut to adjust the Swift springs to suspend the car as high as before. Or, I am just looking at it wrong.

Can someone tell me which Swifts go on the front and which on the back? What else (besides a spring compressor, which I have) do I need to make this work?

Your advice will be accepted with undying gratitude!

Thanks,

Steve Moe

 

You won't need a spring compressor....just lower the perches down so you have enough slack to work with things. Then raise the perches to play with ride height. They do have helper springs correct (little soft short springs under the main springs)?

First....the better spring rates would be the 7k up front and the 8k in the rear. This will handle better AND you would probably want the longer spring back there anyway.

A 200mm spring is good up front. 260 in the rear should be fine, might be too long.

Good luck, and enjoy a good set-up.

- Andrew 1

 

The front springs slide down the bottom of the shock. The backs slide from the top, after taking the knob off and using impact gun to take of the nut holding the plate.

This may help
http://www.rx7club.com/showthread.php?t=816238&page=2

 

LOL!

Ok, 1st of all which Ohlins single adjustable coilover do you have? The old Ohlins Road and Track or the Ohlin Sportline with DFV? The Ohlins R&T are single height adjustable (meaning preload and height are simultaneously controled via the lower spring perches). The Ohlins Sport are seperate height adjustable (meaning height can be controled without affecting spring preload). Depending on your answer you may or may not run out of threads trying to put on the Swift springs. The stock Ohlins spring are usually rebranded Eibachs.

Remember spring rates also affect ride height, so depending on whether the spring are softer of stiffer will also affect how much you have to adjust the lower perches to get the ride height you are aiming at. Either way you most likely want the shorter springs in the front and longer ones in the rear due to tire clearance issues. What are your current spring rates and what rates are you trying to switch to?

You don't need a spring compressor to mount or dismount the springs on a coilover and you do not need an impact gun to undo the nut on the top (if everything was put together properly). You should be able to undo the nut using a 6mm hex and a 21 or 22mm wrench (sorry I forget).

 

Guys,

Thank you for the help!

My "Ohlin suspension kit" model numbers are MIS 7B00 (front) and MIS 8B00 (rear). The only adjustments for the springs are the single lower perch/preload adjuster rings (with lock rings). The springs that were (on the back) and are (on the front - still trying to disassemble) are the ones that came with the kit. The springs I am changing from are branded as Ohlins 05671-01/48 L274 (rear) and 05371-07/40 L274 (front). The struts have the 20-click damping force adjusters.

On both front and rear, the springs have to slide up to be removed, unless I am missing something obvious. The preload rings prevent downward removal on the rear struts (the outer housing ring threads only go partway down the strut) On the fronts, both the rings and lower mounting brackets would prevent downward removal.

I have been receiving conflicting advice on which spring goes on which end. English Racing advises that the Swift 070's are for the rear and the 080's for the front. They are also thinking that the 070 and 080 designations are the spring rates.

The Ohlin front springs are 290mm with a slight amount of preload. If the 200mm 070's were installed on the front, the adjusting rings would be at the very top of the of the strut housing threads (there are 85mm of threads), which would prevent adding any preload or adjusting ride height upward. So, I am planning to install the 260mm Swifts there. At least, that is where I am headed at the moment.

I had been avoiding using an impact wrench as I thought I had read somewhere that it could damage the strut. However, I just received an email from Joey at Ohlin verifying that an impact wrench can be used for removal of the of top mount nut, but not for reassembly. He also speculated that the mechanic who installed the Ohlin springs on the struts may have used locktite, thus the need for the impact wrench. The struts have been replaced since I have had the kits, so that is certainly a possibility.

Looking at the RX7 site, it appears that the springs on those Ohlins would have to slide up also to be removed. Again, the external threads appear to prevent the lower seats from being removed and the external reservoirs are in the way. Wouldn't that prevent the springs from sliding off downward?

My impact wrench battery probably has enough charge to get that nut off now (if it is going to happen) so I guess I will go try it. I'll report back on what happens.

Thanks again,

Steve

 

290mm is more than 11 inches long....that's a huge spring. Like rally-x big. 260mm is a bit big.

200mm is fairly standard and from what I remember Ohlins used 200mm (8 inch) springs front and rear as standard on at least the kits I've used.

Impact wrench to remove the top mounts is okay.

I see no reason why the 200mm springs wouldn't work up front. You do have helper springs correct?

The better spring rates would be the 70s up front and the 80s in the rear.

- Andrew

 

The impact wrench turned out to be the key to replacing the springs. After that, the rest of the job was a piece of cake.

I went with English Racing's advice and put the 260mm 080's on the front, 070's on the back. I guessed at the height/preload adjustment. I was bang on in the rear and 5/8" high in the front. I made it to the track a half-hour late and ran it with no changes. I went full stiff on the front struts, all 20 clicks, 15 on the back.

The stability of the car was transformed! The track is Pacific Raceway near Seattle, a 2.3 mile circuit with significant elevation changes. Turn 1 at the end of the straight is hardly a turn, just a few degrees to the right, but catches some drivers (usually novices) off guard because of the high speeds.

Last time at the track, after a dyno tune by English following addition of a turbo-back 3" exhaust, I was at 140mph by the turn-down to 1. That is a true 140, established validating my speedometer by timing through state-measured freeway 5-mile speedometer checks at constant speeds ranging from 60 to 90mph. Because of the uneasiness of the suspension, I had to lift before the turn.

Not today! After the first couple of laps to get a feel for the new springs, it was pedal to the metal with confidence into the braking cones for turn 2, a left-hand sweeper. Because this was a late afternoon-evening event and we were driving west directly into the setting sun, I didn't have a chance to check the speed.

The attitude of the car can now be completely controlled with the throttle through turns. I think there is a little more speed to be coaxed out of the setup by stiffening up the front a bit. I am definitely going to drop the front that 5/8". Also, a long time ago, I drilled adjustment holes in the front sway bar for a stiffer setting but I didn't like it with the stock suspension. It might just be the refining touch with this new arrangement. That, and I may move one hole back from full stiffness on my Hotchkis rear sway.

Again, thanks to everybody for your help, especially you, Andrew. And, to answer one of your questions, there are no helper springs in this arrangement. And, yup, the front Ohlin springs previously described are 297mm, removed.

Drive fast and safe!

Steve

 

Andrew: Sounds like he is using the older Ohlins R&T. Those used to come with 10" spring as standards, the newer Sportlines and Flags use 8" springs standard.

Steve: Sounds like you figured everything out. As Old English suggested, most likely the 070 and 080 are 7K and 8K spring rates. What spring rates you decide on will depend on all the other suspension mods you have done to your car. If you hadn't done sway bar mods, 7K front and 8K rear would've work nicely. With a larger rear, 8K front and 7K rear will work well depending on the sway bar setting. It seems like 254mm - 260mm length springs will work well for your setup, in case you decide to do spring rate changes in the future.

BTW 140mph is crazy fast!

 

Makes sense....good to see everything working out then!

Agreed on a rear swaybar working well with those spring rates, depending on driver preference.

- Andrew

 

Sounds like it's working well. If your sway bar is set stiff you should be good with those rates. I run my setup with the stiffer springs in the rear and the rear bar on the softest setting.

Turn one can get a little nervous for sure, I'm going through at about 135 right now because I want to have a little more seat time before I hold it pinned. I think my car will go through there at 150 + if I hold the throttle to the floor.

If you ever want to put my data logger (Traqmate) in your car for a session let me know - then you can see your speeds everywhere without needing to look at gauges.

Here's my car from the same night.

http://www.vimeo.com/5365021