Fiat, Second Time Around

Thats the method I use too Bob, little slow but it gets the job done. Looking great!!

wendle said:

Grab yourself a cheap holesaw tube notcher. Harbor Freight do a cheap one in your hemisphere which works well.
I use them for full tube rockcrawler chassis, realistically it takes about a minute to clamp the tube in, notch it, and remove it.

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That's good info - I need one of those!

Looking very nice bob - gonna be a great car!

looks really good to me, i can't wait to see more progress[cl[P

Even More Tubes


All the tubes are now in the front end. Added two pipes from the dash rail to the bottom rails and diagonals as seen in the pic.
[I'm now thinking about rear suspension. Here's where I call on the vast resource the RRR members are. I'm considering a 3 link arrangement and need pictures of how the third link attaches at the front.[

bob w said:

Here's where I call on the vast resource the RRR members are. I'm considering a 3 link arrangement and need pictures of how the third link attaches at the front.[

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Are you thinking along the lines of parallel lower links and an upper wishbone?

Plain old rubber or poly bushings at the frame end with a spherical bearing at the axle end works well in that case. Try not to use a flanged style bushing as the side load can sometimes slice the flange off over time.

Really cool car! Keep the updates coming!

wendle said:

Grab yourself a cheap holesaw tube notcher. Harbor Freight do a cheap one in your hemisphere which works well.
I use them for full tube rockcrawler chassis, realistically it takes about a minute to clamp the tube in, notch it, and remove it.

Click to expand...

You can also notch pretty easily with a chop saw.
Here are a couple links from a less friendly site:
(notching's a way down on this one) http://www.pirate4x4.com/tech/billavista/Links/
http://www.pirate4x4.com/forum/showthread.php?t=456800

-Chaz

Bob, why not just go with a regular 4-link like most drag cars run? What's the advantage of going with a 3 link?

Here's a pretty darn good article on drag race suspension designs and theories that may or may not help: http://www.baselinesuspensions.com/info/Launching_A_Drag_Car.htm

Here's an Art Morrison 3 link rear clip for an early Camaro. How long do you think the bars are? I don't have much room but want the bars long enough to be effective.[S

The reason for a 3 link is, I haven't done one & I want the car to work good in Autotross. Also, the top bar can go in the driveshaft tunnel where there is some room.

Wendle, thanks for the guideance. Ordered & recieved 3/4" moly rod ends today and ordered some urethane bushings for the other ends of the bars. Looks like a trip to the steel yard Monday.

Just my 2 cents. ..if I wanted a dual purpose car, autocross and drag strip use I would want the front mount of lower bars to be adjustable vertically so I could adjust the instant center for best weight transfer on the strip. But I think a 4 link would be more adjustable and still work at autocross. The watts link would be best for autocross and still do its job at the strip. So guess what Im saying is , I wouldn' use the 3 link cuz it looks to me to be just a street crusier setup. ...[P your project is looking good.

Was hoping to make it handle something like this:
http://www.youtube.com/watch?v=Pq5LjV4lnV0

Fuzz & 62ChevyII, I really appreciate your interest and input. While I agree a Watts link would be excellent, I have been looking at a NASCAR track bar arrangement for its adjustability. Even though I haven't got a clue how to adjust one.

I had intended to have adjustability in the lower bars. The G body cars lower the bar mount I understand.

Here's the bar arrangement. It would be horizontal for normal driving.

would be interesting to see how the Nascar guys set the panhard bar for a road course!

Fuzz, Maybe they put a Watts link in for a road course??? Is there any video of your coupe (in your avatar) at the strip? Your coupe is faster than I expect the Fiat to be. Pics of how you built it would be nice to see.

bob w said:

Wendle, thanks for the guideance. Ordered & recieved 3/4" moly rod ends today and ordered some urethane bushings for the other ends of the bars. Looks like a trip to the steel yard Monday.

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No problem, but the 3-link in that pic is different to the setup I was talking about

I assumed you meant a wishbone style 3-link, not a parallel 3-link with a panhard.

Poly bush on one end of the links and rod ends on the other works very well. It's kind of the best of both worlds, the bushing takes out most of the vibes, and the rod end gives you some adjustment.

Try and keep a decent amount of vertical separation at the axle end of the links. That will help the bushes longevity.
Also, as someone else already mentioned, building adjustment into the chassis mounts is a very good idea.

Started building rear suspension pieces. The axle/spring pad brackets are done. As are the lower bars. The bars are 21" long.

Lots left to do as there is no structure behind the main hoop of the roll cage.[ Still haven't figured out if the bars should be horizontal and parallel with the top third link, or if they should aim at some selected instant center, like a drag four link. Advice gratefully accepted.[cl

bob w said:

Fuzz, Maybe they put a Watts link in for a road course??? Is there any video of your coupe (in your avatar) at the strip? Your coupe is faster than I expect the Fiat to be. Pics of how you built it would be nice to see.

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Sorry Bob, I built that coupe around 1989, long before I new about videos or even computers.

bob w said:

Lots left to do as there is no structure behind the main hoop of the roll cage.[ Still haven't figured out if the bars should be horizontal and parallel with the top third link, or if they should aim at some selected instant center, like a drag four link. Advice gratefully accepted.[cl

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IMHO...the 3 link is going to work like a ladder bar, the instant center will have to be set by the position of the lower bars. The upper bar will just keep the rear from rotating but should be mounted close to parallel to the lower bars to maintain pinion angle. That being said, I perfer a ladder bar suspension because they helped prevent body roll during hard acceleration. Don't think you will have that advantage with the 3 link. You may want to consider adding a sway bar at the rear to control body roll.

I would make it all as adjustable as possible. Looks like you could get two more holes in the spring brackets above the hole already there. I think Fuzz is right although I'm not sure roll will be that big of a problem as narrow as the car is? Not sure? You gonna race this or street it?