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Suspension limiter

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Old Aug 16, 2008 | 04:57 PM
  #1  
AlkyIROC's Avatar
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From: 51°N 114°W, 3500'
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Suspension limiter

Finished making a front suspension limiter. I won't know if it'll be strong enough until I get to the track to test.

Lower mount. I used the tab on the A-arm for a sway bar end link. 6" of 3/8" NF grade 8 threaded rod with a 3/8" clevis yoke leaving about 4" of adjustment. 1/8" aircraft cable. This is adjusted to full extension travel and will probably be never used like this.



The upper mount is simply an eye bolt drilled through the upper strut plate.



Here's the bottom mount adjusted to allow roughly 2" of suspension extension. Full extension travel from a neutral position is about 4 to 4-1/2" measured from the bottom of the fender lip to the spindle.



Flipping it over and adjusting from the top would work except the threaded rod would probably extend up enough to hit the hood.
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Old Aug 16, 2008 | 09:30 PM
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Re: Suspension limiter

the threaded rod may bend some, but other than that it will do what you want it to do.
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Old Aug 16, 2008 | 09:50 PM
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From: 51°N 114°W, 3500'
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Suspension limiter

It would bend if I had it adjusted just before full extension but when adjusted to that shorter setting, the rod is almost straight up.

That's why I was thinking of flipping it over with the rod at the top. With the eye bolt at the bottom, the adjuster at the top would always be pulling straight down. The angle changes by the a-arm won't affect the eye bolt the same way it will the rod. Flipping it over would also allow adjustment from under the hood instead of under the car.

Maybe I'll try that tomorrow anyway. I found that when I turn the wheels sharp, the bottom of the strut hits the yoke. Not that I ever have to turn that sharp.

I'll have to do some measurements to see how much clearance there is from the top of the strut mount to the underside of the hood.
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Old Aug 16, 2008 | 10:07 PM
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Re: Suspension limiter

I have found that to make a difference I had to really limit it down below 2 1/2 inches, with it adjusted that short that setup would probably be fine anyway, once you find the happy spot it will stay there anyway.
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Old Aug 16, 2008 | 10:13 PM
  #5  
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Car: 1983 Camaro Z28
Engine: 383
Transmission: TKO 600
Axle/Gears: Strange S60
Re: Suspension limiter

so what does this do? does it just make it so the suspension doesnt want to fly apart when the front end lifts off the ground?
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Old Aug 16, 2008 | 10:27 PM
  #6  
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Re: Suspension limiter

a front end limiter is used to contol front extension if your car tends to over rotate, or in picture terms, does this
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Old Aug 16, 2008 | 10:48 PM
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AlkyIROC's Avatar
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From: 51°N 114°W, 3500'
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Suspension limiter

It can also be used for road course racers. Powering out of a corner, the front end can come up a lot or at least one corner of the front. Using a limiter, you could control how much extension the shocks will get. Holding the front end down can get more power to the back wheels. I've seen some cars go around corners on 3 wheels. That isn't good stability. A front sway bar also helps prevent that.

As in the above picture, it also controls how far the front end comes up on a dragstrip launch. Currently my car doesn't have that problem but I've also been running for years with my front shocks adjusted to full soft. This allows the front end to extend quickly before the rear suspension starts to react. I've been fighting poor 60' times for some time now because of it. Changing the shock extension (rebound) to firm will allow the rear tire to plant before the rear suspension starts to pull the front of the car up. If it pulls up enough to drag the bumper, these suspension limiters will decrease the amount of lift.

There's 2 kinds of front lift. Shock lift and rear suspension lift. Mine was all shock lift and by the time the suspension started to lift the car, the front shocks were already fully extended and it unloaded the rear suspension. Also when the front end came down, it would bounce and further unloaded the rear tires.

Although I may have to play with 4-link settings again, I expect to now pull the front wheels past the 60' timers (currently going about 20') and wanted the limiters just in case it gets too out of control. Chances are I'll probably not even need them but if I do, they'll be ready for use.
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Old Aug 17, 2008 | 11:30 AM
  #8  
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Car: 1983 Camaro Z28
Engine: 383
Transmission: TKO 600
Axle/Gears: Strange S60
Re: Suspension limiter

so its kind of similar to the rock crawlers, except they use a winch to extend or compress the suspension...
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Old Aug 17, 2008 | 04:16 PM
  #9  
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From: 51°N 114°W, 3500'
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Suspension limiter

OK, I flipped it over today. Now it can be easily adjusted from the top. This is adjusted to allow 2-1/2" of extension. It doesn't stick out the top as much as I expected. I suppose if I remove all extension, it may touch the hood. Full extension and the threaded rod will be right to the end of the threads.





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