Volvo 940 Coil spring length, coil overs with Koni 8610-1437
Posted by Magnum TE
Toby Eidelman Mod Moderator Location: Santa Rosa Join Date: 10/12/2011 Age: Midlife Crisis Posts: 57 Rally Car: '92 Volvo 940T (tarmac dweller) |
Hello again from a tarmac dweller. There are a few forums that I can post this question on, but I really would like to hear from the rally guys. This time my question is about spring length choices for my 940s front coilover conversion. I’m super new to adjustable suspension, I’ve been ‘wingging it’ for a long time with sport springs and whatever junkyard parts I could put together. Now, I’m trying to be smart about this. I know there are better choices of inserts but the Koni 8610-1437’s are what I have and that’s what I’m going to be using until I hit the lotto and get some 50mm JVAB boingers.
I’m interested in anyone’s opinion. I’d like to have an open discussion as to the pro’s / cons about spring length, pre-loading, and whatever else I should be concerned with. The car’s primary role is autocross, with some drift events. I drive it around town, purely for looks (I’m admitting it upfront John) the car is lower ~4†with the sport springs on it now. I’m planning on raising it at least to get the noise up higher than the rear (2â€). The rake is just awful for handling under braking, ass end gets LIGHT. I got some pretty hardware: Including a new weld in strut top that raises the tower height 2" and changes the bolt pattern to use a Corolla strut mount. http://i483.photobucket.com/albums/rr191/Magnumte/Volvo/Goldie/Suspension/IMG_0595.jpg 
But I didn’t put any thought into which springs I chose, I got caught up with people’s recommendations but didn’t do my own math. So now I’m trying to start to think and it hurts mah brain a bit. Here’s what I’ve come up with. First since Koni doesn’t publish it’s valveing numbers all I know is that I should run a 300-600lb/in spring. They have 153mm (6â€) stroke, The 7†400lb/in spring I picked has complete coil bind at ~2.4†(measuring the diameter of the coil and the number of turns). I corner weighted the car on the truck scale at work FL:1001 / FR:860 So with the 400lb/in springs that’s going to be ~2.5†of static compression when the car’s at rest, or there about, right? If I adjust the coil to the point where the coil bind happens .5†below the external bump stop that gives me about 2†of compression travel before it hits the bump stop. Sounds like a less than ideal situation. Should I pick a spring length that will be the same length of the insert when at static compression? Like a 9" 400lb/in spring will be preloaded down to ~6" when under the weight of the car. Or a 7" 500lb/in Basically too many choices and not enough knowledge. Anyone want to lend a hand to my education? I like to play with cars, it's very inappropriate. Edited 1 time(s). Last edit at 07/24/2012 10:36PM by Magnum TE. |
Toby Eidelman Mod Moderator Location: Santa Rosa Join Date: 10/12/2011 Age: Midlife Crisis Posts: 57 Rally Car: '92 Volvo 940T (tarmac dweller) |
Toby Eidelman Mod Moderator Location: Santa Rosa Join Date: 10/12/2011 Age: Midlife Crisis Posts: 57 Rally Car: '92 Volvo 940T (tarmac dweller) |
Out of this dumpster fire Professional Moderator Join Date: 08/15/2010 Posts: 1,236 |
Jorden Ultra Moderator Location: Baraboo, Wisconsin, USA, Terra, Sol, Milky Way Join Date: 01/24/2006 Posts: 372 Rally Car: whichever one i happen to be driving at the time |
How much does your 940 weigh? My corolla weighs 2463 with me in it. My corolla is basically just for AutoX, but I take it to HPDEs from time to time as well.
I use 8" 400 #/in on the front of my car, and I have 350 #/in on the back, but would rather have 310-320 for AutoX, but it's just fine for HPDE/drifting. Here's my corner-weighting: 
It sounds like your 940 is actually lighter than my Corolla, which I find a bit interesting, and need pictars! I'm pretty sure that the engine / front of your car is a lot heavier than mine though. It's tough to get lighter than the 4AGE 1.6L. My thought is you might want some stronger/longer springs in front, but that's just my gut, with no actual mathematics involved. Regarding the tire fitment issue, since you've got the camber plates at the top, could you find a way to add some positive camber at the bottom to make room for the tires? Something similar to the NCRCA that the AE86/510 use? Do the 940's use the same type of strut mounting as the 740? Wasn't there the whole front spindle swap from an S90 that lets you use "ear" type struts, in which your konis might just fit? or I think you can also put on the nissan S13 type spindles on as well, provided you get a way to make the balljoint work with the LCA. Extra neato would be if there could be a way to just extend the spindle from the strut housing by an inch. but then you've gotta think about it snapping off and killing you. you could always add some spacers, just check your wheel bearings more often. That's what I do on the corolla to make the extra-big meats for autoX fit on the front. Disadvantage is a wider track, a funky-ass scrub radius, and possible interference with the firewall/fender and trailing edge of the bumper. --sarge ---** To be in compliance with the Anarchy **--- Jorden R. Kleier Baraboo, Wisconsin, USA 1990 Mazdog Protege 4WD 1973 |
Toby Eidelman Mod Moderator Location: Santa Rosa Join Date: 10/12/2011 Age: Midlife Crisis Posts: 57 Rally Car: '92 Volvo 940T (tarmac dweller) |
Sarge, my 940 might be lighter than the 'Rolla if it were on the moon. There was a guy who converted s13 spindles in his 740, I looked at the pics and don't want to go that far (yet). It was a pretty nice setup with adjustable links.
Total: 3420lbs with me, 5/8th tank, and spare tire. F-Total: 1860 R-Total: 1580 FL: 1001 FR:860 (worse than I remembered it) I'm running 5x108 32mm spacer/adapters currently to adapt FWD Volvo wheels. The 940 struts are pretty much like the AE86 struts, with the tube kinda build into the knuckle. I'll get some pics together when I do the install. Eventually I'm going to want to switch bolt patterns to a 5x114 then I'll get some thicker spacers. Or maybe I'll go to a Corvett pattern. I'm only running 7.5" wide wheels so the 225x45x17 Direzzas are a good fit. Here's some pics of the gold tractor plowing some fields. http://i483.photobucket.com/albums/rr191/Magnumte/Volvo/Goldie/940IMG_0255.jpg 
http://i483.photobucket.com/albums/rr191/Magnumte/SonomaDrift01.jpg Don't know if this one will work. https://sphotos-a.xx.fbcdn.net/hphotos-prn1/470554_647288368160_1916797694_o.jpg I like to play with cars, it's very inappropriate. Edited 1 time(s). Last edit at 07/24/2012 11:03PM by Magnum TE. |
Jorden Ultra Moderator Location: Baraboo, Wisconsin, USA, Terra, Sol, Milky Way Join Date: 01/24/2006 Posts: 372 Rally Car: whichever one i happen to be driving at the time |
aah, gotcha.. I thought it was gutted or something, because of this quote:
So, I was thinking the car was only 1920lbs, lol! Carbon Fiber!! I think for that weight, 400# springs are WAY too squishy for the intended tarmac use, especially with binding so soon. That'll mess you up pretty good in the middle of a corner. I think the biggest issue you've got is the distance of the strut to the wheel. I think this is from a 940: 
(Do those use sealed bearings instead of tapered roller bearings?) I think somehow making the strut tube another inch (or maybe two) further away from the spindle would fix a whole world of hurt. Question is, how to do that? is the strut tube housing itself pressed into the knuckle? What about pressing in a chunk of metal that is the same diameter as the strut tube, but then is machined square, with a couple holes drilled in it, so then some strut housings with ears on them can be bolted on to that square piece? The ears could then give you the offset you want, and you might even be able to get rid of the spacers, between the spindle and FWD wheel, still use the same Koni inserts that you've got. I dunno, I'm just rambling now, hemmorraging useless ponderings. ---** To be in compliance with the Anarchy **--- Jorden R. Kleier Baraboo, Wisconsin, USA 1990 Mazdog Protege 4WD 1973 |
Jorden Ultra Moderator Location: Baraboo, Wisconsin, USA, Terra, Sol, Milky Way Join Date: 01/24/2006 Posts: 372 Rally Car: whichever one i happen to be driving at the time |
something like this:
I've obviously got no idea if it would even work, but it might be a useful fix for this type of hub/knuckle/spindle, I can see it being useful on both my Corolla and a Volvo. But there's gotta be some reason why it's not already been done (or it has and I just don't know about it.) ---** To be in compliance with the Anarchy **--- Jorden R. Kleier Baraboo, Wisconsin, USA 1990 Mazdog Protege 4WD 1973 Edited 1 time(s). Last edit at 07/25/2012 10:09AM by SgtRauksauff. |
John Vanlandingham Mega Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
But it has been done, of course. It was done specifically to allow "ears" both for quick service and the ability to move the strut inboard away from the hub face. Done on some Volvo 240s and on at least 2 Corollas who were switching to using 240 Volvo spindles with their relatively huge bearings, discs and calipers. The specific ears chosen were........ were............................ wait for it... Subaru. It doesn't have to be full round where it plugs into the bottom forging. Just rounded, kinda "double D" Want to guess where the idea was developed?? What piccies? John Vanlandingham Sleezattle, WA, USA Vive le Prole-le-ralliat www.rallyrace.net/jvab CALL +1 206 431-9696 Remember! Pacific Standard Time is 3 hours behind Eastern Standard Time. |
Jorden Ultra Moderator Location: Baraboo, Wisconsin, USA, Terra, Sol, Milky Way Join Date: 01/24/2006 Posts: 372 Rally Car: whichever one i happen to be driving at the time |
I thought I might've seen something like that somewhere, but couldn't quite remember if I had, or if it was other nifty suspender bits.
I'm guessing it was developed in the grey matter of a buncha peoples, but finally acted upon and put together somewhere in the Pacific Northwest. 
What size wheels were run on the Toilettas after that? Were they able to keep 13's by chance? Did it use the same 4x114.3mm bolt pattern, or did they go to a Volvo 5x108 bolt pattern also for the hubs? yeah, I remember seeing these, with the slot/tab thingy,: 
If there are pics of the ear-conversion, it would be neat to see! --Jorden ---** To be in compliance with the Anarchy **--- Jorden R. Kleier Baraboo, Wisconsin, USA 1990 Mazdog Protege 4WD 1973 Edited 1 time(s). Last edit at 07/25/2012 11:20AM by SgtRauksauff. |
John Vanlandingham Mega Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
Well the above was out of one guy only and it was a pain to make with the irregular shape and as you see it maintains the centerline of the original.. That looked like a good idea but as we've seen so amply that guy is not nearly as smart as all the 20 something, living at home geniuses. THIS idea was a cooperative dealio from some guy and Kevin Hawkinson specifically to get some offset 
Much easier to fab, although it still takes some time, but its very easy---that didn't prevent a couple of really smart guys from explaining that I should not be charging them anything for it.. And mutterings and a campaign of whispers because I think i charged --to them, early in guys---$35 each Since both ended up using Volvo axle (but even there they decided they were smarter---which they clearly are mind you---but there was some deal with the 740 axle they got for the second guy...1041? ring and pinion was it?---it's the normal 240 Dana 30 you want if you want affordable ring and pinion sets) they stayed with Volvo 5 on 4 1/4" PCD.. OEM Volvo used 14" and I think they got some.... Toby can look at the bottom of the strut assemble and see a MiG weld around the bottom.. Easy to cut. John Vanlandingham Sleezattle, WA, USA Vive le Prole-le-ralliat www.rallyrace.net/jvab CALL +1 206 431-9696 Remember! Pacific Standard Time is 3 hours behind Eastern Standard Time. |
Jorden Ultra Moderator Location: Baraboo, Wisconsin, USA, Terra, Sol, Milky Way Join Date: 01/24/2006 Posts: 372 Rally Car: whichever one i happen to be driving at the time |
John Vanlandingham Mega Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
Toby Eidelman Mod Moderator Location: Santa Rosa Join Date: 10/12/2011 Age: Midlife Crisis Posts: 57 Rally Car: '92 Volvo 940T (tarmac dweller) |
Albert Kun Professional Moderator Location: SF Ca. Join Date: 01/07/2008 Age: Possibly Wise Posts: 1,732 Rally Car: volvo 242 |
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