Adj. Rear Sway Bar & Panhard

[msiert]

"Little Italian" has got me focused on my rear suspension now after buying his "Feigel adj. rear sway bar kit" I also bought a Panhard rod and upper link kit from Jack Beck this week. Do many of you guys use a rear sway bar and a Panhard Rod kit......... is this OK to do?

I'm exicted about being able to adjust the stiffness of the rear sway bar and I wonder if I need to get stiffer rear springs too? I'm running 180 lb springs now. It seems like 250 lb to 300 lb springs on Spiders are more common on the track but maybe way to stiff for a dual purpose car?

What do you guy's think.......... ?

Murray

[bianchi1]

750 inch. pounds front and 125 inch pounds rear, give good ride, and nice handleing, doe's not roll side to side very much.keeps tyres planted well to the ground.

[conedriver]

Hi Murray,

I have Jack's Panhard bar, as well as an old Shankle rear sway bar with additional link connection holes I added for adjustment. There's no problem using both of these, since they represent two different functions: the sway bar controls roll stiffness, while the Panhard bar controls side-to-side axle location (while lowering the rear roll center).

The Panhard bar mounting requires welding a mount on one axle tube. Did you have Jack do this?. Finally (for those who asked), the Jack Beck/Orion Panhard bar will allow use of the emergency brake components.

I use 300# rear springs, and have rear training arms modified by Jack to accept slightly larger standard industry sized rear springs. These are more readilly available, and cheaper.

Watch out for that "Little Italian". He gets to drive my Spider in next week's autocross, and will most likely want to do more to his car after this experience...heh, heh...

Quote:

Originally Posted by msiert "Little Italian" has got me focused on my rear suspension now after buying his "Feigel adj. rear sway bar kit" I also bought a Panhard rod and upper link kit from Jack Beck this week. Do many of you guys use a rear sway bar and a Panhard Rod kit......... is this OK to do? I'm exicted about being able to adjust the stiffness of the rear sway bar and I wonder if I need to get stiffer rear springs too? I'm running 180 lb springs now. It seems like 250 lb to 300 lb springs on Spiders are more common on the track but maybe way to stiff for a dual purpose car? What do you guy's think.......... ? Murray

[genericwood]

Murray, your ideal rear spring rate will depend on your front rate and the size of your front and rear bars. I wouldn't change anything until you drive it. Of all the things you have done, the Panhard bar may make the most difference. It dramatically lowers the rear roll center. George mentioned running larger diameter rear springs on modified spring perches he got from Jack. There are 2 other good alternatives. Left Hander chassis sells an adjustable spring perch that can be welded onto your trailing arms. It allows the car to be "scaled" and allows the use of cheap aftermarket springs. The other option is the one I chose. I welded Coleman shock mounts onto the trailing arms. Then I made aluminum adaptors to allow a 2.5" spring to seat into the normal upper spring seat. These two modifications allow the use of threaded coil-over shocks. It's not a true coil-over set up since the spring still seats on the body at the top. But having the bottom spring seat on the shock allows very easy scaling and ride height adjustment. Plus 2.5" coil over springs are cheap.

Erik

[davbert]

erik

does the smaller 2.5 springs have any rubbing issues with the shocks? any pics you can post on your of the modified shock/spring mount on the trailing arm? What rear rates are you running and how long are the springs?

cheers

davbert

[Little Italian]

Quote:

Originally Posted by msiert Ya, It's going to take Bud a lot to catch up to you in hardware cost but he's telling me he knows he could bet you with equal cars. Murray

[genericwood]

Murray, with the front end that stiff, I would guess that 250 would be a good starting point in the rear. Start with the rear sway bar full soft and see how it feels. If it pushes, stiffen the rear bar and try again.

I will try to find some pics of the semi-coil-over set up. My hard drive crashed so I might have to take new pics.

Erik

Quote:

Originally Posted by msiert Wow........ Erik, I will pay you a buck tomorrow if you figure what my ideal rear spring rate is today Front spring weight = 1,300 lb Front sway bar = 29 mm Front rate = ? Got Outlaw calipers though Rear sway bar = 1/2 adjustable I'm just thinking that if the rear axle if off anyway's sure would be easy to change the springs out. Mine I think is on Lt. side........ do you think as a shot in the dark maybe 250 lb would be closer then 180 lb to the ideal rate (Hint, Hint)? Your friend, Murray

[genericwood]

Murray, the roll bar won't really change the roll stiffness front or rear. To get good balance, you are ultimately looking to fine tune the amount of weight transfer you get in the front and rear. For a given track width (the car not the race track), center of gravity and speed, the amount of weight transferred in total can't be changed. However, you change how much of that weight is transferred at the front or rear by changing roll stiffness. You do it with springs and sway bars.

Your roll bar will help stiffen the chassis, however. That's a good thing for handling too!

Erik

[Max Banks]

250 is too stiff! i would start a couple lower!

[genericwood]

I'll defer to Max on the spring rates. He has a lot more experience than do I. But I'll be he hasn't ever run a 1300 pound front rate either! I'm guessing neither of us have ever run a 2700 pound 105/115 car on the track.
For what it's worth, I went to the Alfa convention time trial with the following set up. 1200 front springs with the stiff Beck tubular sway bar. 250 rear springs with a 5/8 Shankle type rear bar. The car pushed pretty bad. At the BRIC I increased the rear spring rate to 300 pounds and it was balanced.

Let us know what feels right when you get to it on the track!

Erik

[conedriver]

Hi Erik,

Been there - done that!. The Beck tubular front swaybar is stiff!. I first installed one without considering the other changes needed, and turned a well balanced car into an understeering pig!. BTW, I am using 900# front, 300# rear with a 5/8 Shankle rear bar with the arms drilled for shorter leverage (additional stiffness).

Quote:

Originally Posted by genericwood ...For what it's worth, I went to the Alfa convention time trial with the following set up. 1200 front springs with the stiff Beck tubular sway bar. 250 rear springs with a 5/8 Shankle type rear bar. The car pushed pretty bad. At the BRIC I increased the rear spring rate to 300 pounds and it was balanced. Let us know what feels right when you get to it on the track! Erik

[Little Italian]

Does any one know what the front / back spring rates are for the red International Springs? This car I bought from Kevin Smith in Tenn. last fall came with them but I haven't the foggy-est idea what they are.
Murray, I think I'm going to the Solo this coming Sunday without a rear sway bar. I put my Spider up on stands yesterday and low and behold, the drop links were dangling loose again. I guess I drove the Tulsa events with a loose sway bar. Maybe that's the trick for me now. Think I'll just remove it completely today and while its on the bench, I can test it against the other two - the stock 5/8 inch, the 1/2 inch GTV bar, and George's Jack Beck adjustable bar. Might make some interesting discoveries. Ahhh...Science! George says I should try a bigger front bar. I removed my chassis stiffener yesterday and put it on ebay. I'm going to put my other stiffener on this week so I can start the rear mounted front tubular bar "experiments". Fortunately, I can always get reliable expert advice from George ever now and again to help me tune along the way.

[Max Banks]

Quote:

Originally Posted by genericwood I'll defer to Max on the spring rates. He has a lot more experience than do I. But I'll be he hasn't ever run a 1300 pound front rate either! I'm guessing neither of us have ever run a 2700 pound 105/115 car on the track. For what it's worth, I went to the Alfa convention time trial with the following set up. 1200 front springs with the stiff Beck tubular sway bar. 250 rear springs with a 5/8 Shankle type rear bar. The car pushed pretty bad. At the BRIC I increased the rear spring rate to 300 pounds and it was balanced. Let us know what feels right when you get to it on the track! Erik

[genericwood]

George, I'm not surprised you need the rear so stiff on an autocross car. A little oversteer is more than acceptable! Even though my car is still pushing a little, I am probably going to stay with 1200/300. I have drilled the rear bar for shorter arms, but haven't made the new drop links they are going to require.

Max, I suspect our tracks are smoother on this side of the pond. That may be why we can get away with much stiffer set ups. Most of the 105/115 cars I race with here run around 1200/250 or 1200/300. The more limited suspension travel also helps to compensate for less than perfect suspension geometry. Most of our vintage racing groups will not allow your improvements!

Erik

Quote:

Originally Posted by conedriver Hi Erik,Been there - done that!. The Beck tubular front swaybar is stiff!. I first installed one without considering the other changes needed, and turned a well balanced car into an understeering pig!. BTW, I am using 900# front, 300# rear with a 5/8 Shankle rear bar with the arms drilled for shorter leverage (additional stiffness).

[conedriver]

The new links were easy. I bought solid steel rod, and tapped each end for Heim joints (I may have posted this earlier)

Quote:

Originally Posted by genericwood ...I have drilled the rear bar for shorter arms, but haven't made the new drop links they are going to require...Erik