Let's say coilovers are out of budget, because $2000 Challenge. How do you get stiffer shocks? What about a second shock on each corner? Something universal and cheap, with bushing or spherical mounts so it doesn't cause binding. Could this be done in a way to predictably improve a E36 M3box's handling? Discuss.
Usually shocks are doubled up to add thermal capacity rather than damping, some factory pickups in the '80s-'90s came with dual shocks and the Ford RS200 used them. These days a big single shock with a remote reservoir would be used instead.
Doubling up for twice the damping should work work though. Another option would be to put a thicker viscosity oil into a twin-tube shock:
https://grassrootsmotorsports.com/articles/can-you-upgrade-your-dampers-replacing-oil-inside/
In reply to GameboyRMH :
In reply to maschinenbau :
Doubling up with dampers will work just fine. You may even be able to simply extend existing mounting studs. The other way I have seen it done is one forward of the a-arm and one aft. I suppose you could even cobble one to run parallel to a strut if need be.
Since they are velocity driven with respect to damping, you will effectively get slower attitude transitions. That may be a drawback in some cases.
all I know is that it's a well-known enough trick that it's specifically called out as not-allowed in several of the GridLife class rulesets
I feel like at least one challenge car in the past has done this? mustang GL maybe?
perhaps you could add a link to the control arm and body to amplify the force
Somebody help me understand...
Do shocks get stiffer, or springs?
sleepyhead the buffalo said:all I know is that it's a well-known enough trick that it's specifically called out as not-allowed in several of the GridLife class rulesets
I feel like at least one challenge car in the past has done this? mustang GL maybe?
IIRC some Fox body Mustangs had four rear shocks from the factory.
Off road race trucks and some buggies have doubles @ 4 corners.
In reply to L5wolvesf :
Not so much these days but it was common around the same time sportier production pickups were getting them.
A lot of the suspension tuning is done with the bump stops. Cheaper, easier, effective.
The biggest issue would be that doing it with just some random shocks could create some very "interesting" overall damping curves. If you have some knowledge of the damper internals or are at least using pairs of the same dampers you could probably come up with something decent.
Well, actually, packaging would probably be the biggest issue on most cars.
Well, Jaguar used multiple shocks with good results, so it's not out of the question.
Random internet pic.
Coniglio Rampante said:Well, Jaguar used multiple shocks with good results, so it's not out of the question.
Random internet pic.
Jaguar engineers: "Last version was too easy to change brake pads - how can we make it even harder?"
Double shocks was done on literally the first car to win a Challenge (the $1500 Challenge), so the theory is sound 
I did it on an RX-7 with blown struts.... found some eyeleted shocks of the right length, drilled a hole in the control arm, added a piece of angle iron inside the strut tower, and bolted it up. Worked fine.
SV reX said:Somebody help me understand...
Do shocks get stiffer, or springs?
Svrex:
The dampers don't get stiffer per say, that is a spring force constant analogy that most are familiar with and lean on too much. Dampers resist motion and that resistance increases with shaft speed (or wheel bump droop speed to get back out to the thing most of us are trying to control). Damper curves are usually displayed as force vs velocity in both compression (bump) and extension (droop). The plots usually have a very distinct "<" shape. The ends of the shape can curl up/down (progressive), be linear, or curl to nearly flat (digressive). Progressive means more resistive force with speed, usually accelerating. That provides very harsh reaction to big bumps. Digressive gives a less harsh bump and allows the droop/rebound to occur faster.
Think of dampers as time release devices for the input forces the springs are working against.
It is kind of common practice in Swedish folkrace;
This is like cheap European rallycross or banger racing, so rather slow and on a track with both gravel and tarmac. The rules dictate you have to sell the car if someone wants it, for a set price (around $1100 today). So you don't want to spend too much building the car (at least theoretically).
It seems to "work" but these cars are not driven with much precision, more aim and shoot. And pray.
MadScientistMatt said:sleepyhead the buffalo said:all I know is that it's a well-known enough trick that it's specifically called out as not-allowed in several of the GridLife class rulesets
I feel like at least one challenge car in the past has done this? mustang GL maybe?
IIRC some Fox body Mustangs had four rear shocks from the factory.
Technically correct, but the quad shocks on Fox through new edge mustangs were horizontal units that worked to prevent wheel hop / axle windup. Basically because of the large rubber bushings in all of the links.
My Challenge Corolla has Bilsteins from a Toyota Tundra bolted in to the Miata front suspension. They'll bolt right in except the lower eyelet is too large, so I welded on eyelets from the knackered Miata shocks. I have no idea if they'll work well. I did that because any usable Miata shocks weren't budget friendly, but the truck ones were $10.
In reply to DeadSkunk (Warren) :
The shocks I used on the front of that RX-7 were $20 cheapy Monroes for the rear of an ACVW, chosen because they'd fit in the space available.
They "worked", obviously not ideal, but better than nothing.
I also tried replacing the oil in the OE wet struts with ATF. That worked okay too. Not ideal, but better than doing nothing at all.
I was trying to see if I could find the GRM article about the MGVC that won the $1500 Challenge. Paraphrased, he said they put the second shocks on and moved the mounting points around until it felt right. Clearly it was good enough That was my inspiration in 2007-2008ish to try the second shocks in the RX-7. I had done the ATF oil in the previous car, and found that ATF turns to sludge in the winter, causing the front suspension to pack down to the bump stops on rough roads.Thanksgiving?
Edit: https://grassrootsmotorsports.com/articles/grm-vault-depth-look-our-first-2000-challenge-winn/
Pics aren't working for me, though
I've thought about, and maybe posted here about, adding rear of the axle shocks to an IRS set up to make a road car go in a straight line better.
I've thought about mounting some so they extend with bump as the rebound tends to be a little weak on OEM type shocks. And doing that one shock would use the compression side in rebound while the other is in extension.
In reply to nocones :
I wonder if that's the real reason why some stadium trucks mounted the shocks so that they worked backwards.
I mean, if you are valving them yourself, it shouldn't matter either way, but I thought it was curious that they did that.
Pete. (l33t FS) said:In reply to DeadSkunk (Warren) :
The shocks I used on the front of that RX-7 were $20 cheapy Monroes for the rear of an ACVW, chosen because they'd fit in the space available.
They "worked", obviously not ideal, but better than nothing.
I also tried replacing the oil in the OE wet struts with ATF. That worked okay too. Not ideal, but better than doing nothing at all.
I was trying to see if I could find the GRM article about the MGVC that won the $1500 Challenge. Paraphrased, he said they put the second shocks on and moved the mounting points around until it felt right. Clearly it was good enough
Edit: https://grassrootsmotorsports.com/articles/grm-vault-depth-look-our-first-2000-challenge-winn/
Pics aren't working for me, though
apparently that article (or the media) was originally on classicmotorsports, but now it's over on GRM. someone should go and update the links to grm.com links in the html.
Guess I remembered wrong 
Oh well, it still worked.
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