Thread: coilover shock setup

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I am building a 1933 chevy five window coupe with a 671 blown 409 chevy with a 4 speed and a gear vender overdrive ,with a dana 60 and 354 gears. the drive shaft will be less than 2 foot. The car will be a street car .with a trip or two down the strip.
Do I need to mount my coil overs at a 15 or 20 degree angle or straight up?
What should I set my pinion angle at?
Should I mount my shocks as far apart as possible?
Your help is greatly appreciated
Marc.

I like 3 degrees down on the pinon with the intake manifold set level. To help with stability coilovers should be spaced wide as possible with the bottom out no more then 20 degrees, I prefer keeping them around 12 to 15 degrees. Speedway Motors has a chart in their catalog (on line and in print) that explains the why's and coil spring rate selection. Couple years back I switched to AFCO coilovers, great quality and selection!!!

Originally Posted by Dave Severson

I like 3 degrees down on the pinon with the intake manifold set level.....

That's the drag racer in Dave sneaking out, tilting the pinion down a few degrees to offset the "wrap" at launch. The OEM setup, and what you'll see from the driveline vendors is that the pinion angle should be equal and opposite to the engine/tranny angle. If your tailshaft is two degrees down then your ideal pinion angle is two degrees up, keeping the U-joint angles parallel to minimize vibration. For a cruiser the charts say it's best if the angles are three degrees or less.

With a blown 409, think I'd be for setting it up like a drag car, probably going to be used that way more then once or twice!!!!! As long as the U Joints aren't straight, vibration and premature wear has never been a problem for me on a driveline... especially with such a short driveshaft, may be difficult to set things up like OEM is...... Heck with that kind of torque coming down the shaft, might as well set it up like a drag car so that the car will launch smooth and straight!!!!!

With decent power, also going to be important to get the bars right on the rear end. If not, you can end up with a really squirrely ride when you stand on the power!

What type of rear suspension is on the car? Please be specific.

By the way, this might be the best money you will ever spend.....
http://www.ebay.com/itm/Chassis-Tuni...-/270991882467

First thing I would do with the car is to install a video camera underneath with plenty of light on the U-Joints. Make a few easy launches and see what the driveline and joints are doing. That will actually tell you more than a library full of books. As you launch harder and harder, keep filming and making adjustments. The shorter the driveshaft, the more I'd be concerned with U-Joint angles.


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Thanks guys for your information. I hope to have the car on the road this summer.
Marc.

by the way ,the rear sup consists of 42 inch S&W ladder bars ,panhard bar and 14 inch QA1 coilovers

On all the 4 link and ladder bar cars I've been around, the coil overs are usually as straight as they can be. But each build is different. Where are the pics is my biggest question?

Most coil over setups are built pretty straight vertical but that really comes as a result of the commonly used mounting brackets on the rear end --a combo bracket for the links and shocks will be located together-----However, the mosr effective and tunable is a setup that is mounted wider on the housing and then tipping in at the top---this allows the spring/shock action to be closer to the tire and the top tipped in gives clearance fot the tire-----------


the more vertical and closer to tire gives a much more direct ratio of spring rate and schock valving/dampening, however probably 99% of the bracketry out there will place them closer together which causes the spring rate/schock damp to end up being a complicated percentage factor further complicated by what is a leveraged dealie-------

[IMG]C:\Users\schecter\Pictures\my 33 coupe build\my 33 chevy coupe-6.jpg[/IMG]
[IMG]C:\Users\schecter\Pictures\my 33 coupe build\my 33 chevy coupe 5.jpg[/IMG]

If the rear end will be narrowed, you may want to stick with straight-up shocks. Otherwise, 15 degrees seems to be real common, just remember that you lose 7% of the rated load with the angled spring. My '37 fiberglass car has 200lb/in springs in the rear.

With coil-overs, it's common to set the pinion angle parallel to the engine. In my car, I set the engine dead level and did the same with the pinion angle. Tilting the engine more than .5 degree up at the front is about the limit in my car. Any higher and the transmission could not be removed with the engine in place, unless the transmission cross member was rebuilt to lower the tail of the transmission, to create more angle. The actual angle of my driveshaft is just over 1 degree.