moremazda

iTrader: (4)

Has any one here setup a first gen (or any generation) with a "Lotus Link" 3-link setup?

I an looking for impressions and thoguhts. I have a first gen with a three link and panhard rod set up and I am looking at doing this to my turbo first gen. Before any one goes shooting off "check the rule book" I am not building the turbo car for a particular class. It is being built as a, for lack of better term, time attack car.

Ryan

jgrewe

iTrader: (1)

Are you refering to a lower "A" shaped arm with the rear end attached to the top of the "A"? I havn't seen one, probably because of those pesky rules you speak of. Off the top of my head I think the stock upper links will still cause problems, maybe not with binding but with roll steer. You would also need to reinforce the mounting points on the body to take a lateral load but thats pretty easy where they are. I'm sure it could be made to work but with a panhard rod your roll center is already pretty close to where the new set-up would put it.

tims

A "Lotus" link is not a three link setup. the lotus link has four control arms and no panhard rod. the typical stock car three link rear suspension has one arm/bar on top of the differential and two lower arms/bars located on the lower part of the axle tube at the farthest outside location, if that makes sense, near to the wheels as possible. then you use a panhard(most popular oval setup) or a watts link(favorite road race setup). this suspension is easy to setup and will work well for most situations. the four link lotus suspension in theory is better, but the connection mounts need to be reinforced and the setup can be very tricky. I would say any of these suspensions properly built would be light years better than the OEM setup.

sctty

http://www.yawpower.com/picture.html

Bottom of the page, pictures 35-37.

Nihilanthic

Lotus link is a 4 link for a live axle? lol

Um, when ford made one (guess where this is going) for their fox body mustangs, they were called "Quadrabind". The top two control arms control pinion angle (er, windup?) and lateral location of the axle, and would bind under hard conering. I somehow doubt that a 4 link is better than a 3 link or a watts-linked two or four link.

BTW, the 2K5 mustang uses 2 lower control arms and a PHB, and 82-02 camaros used a phb + 2 LCA (also just called 3 link) and could handle rather well for a live axle car.

Just FYI - a properly set up PHB arrangement has VERY little lateral movement, especially if the panhard bar is very long due to being mounted diagonally opposed, or more commonly parallel to the axle, just behind it with a bracket for where it connects to the chassis. IIRC, 1st gen RX-7s in racing for both circles and road courses used PHBs.

tims

the lotus link and 4 link setups have been used very successfully and then banned in catagories like Trans Am because the amount of testing required to make it fast was costing teams alot of money and forcing teams out of the series. this is why they now mandate the three link type suspension(Seven's Only uses the lotus link on their Super 7 cars with great results). In theory the properly setup 4 link and lotus link will perform better than the three link and a panhard or watts. comparing the mustang street car to a properly built and designed race suspension is just not fair. the links will be longer and made of materials that won't bind, bend, or flex. the three link with a watts link would be easy to build and for most drivers it would perform very well and again light years better than the stock setup. it is also relatively easy to get setup well.

Nihilanthic

How does the 'lotus link' actually not have the binding on the top two control arms while cornering?

M's

does someone have some good pictures of the watt's linkage, I saw a really nice super 7 replica with a very interesting rear suspension design. I was told it eliminated the need for a LSD. I don't completely understand how it worked but it was interesting none the less...

speedturn

iTrader: (1)

The Lotus link is pretty popular in SCCA GT-3 racing. The Chapman link must be put underneath the rear axle housing; the center pivot point becomes the rear roll center.

Most Watt's linkages have too high of a rear roll center (unless built horizontal, laying flat.) The stock 1st gen Watt's linkage has a horribly high rear roll center. That is why most road racers use a panhard bar instead of a Watt's link on their racing 1st gens.

The Lotus link does the job of rear axle fore/aft location + side to side location, thus eliminating the need for a Watts link or panhard bar. Colin Chapman was so obsessive to save weight that he was always very proud if he could make one part do 2 different jobs.

grantmac

Spherical bushings, regular bushings would have a small amount of bind.
Grant

RoadRaceJosh

So why not do an offset 3-link and Panhard rod? Once you do the math on the link locations it's easy to set up and gives equal tire loading on acceleration and 100% anti-squat. Jaguar used it on the LeMans winning C-type. It's easiest to do with two upper links and one offset lower link.

grantmac

Have any resources for designing one? The other problem is that these cars don't have straight upper links so you'd have to make new chassis mounts for pretty much everything, cool design from what I understand of it.
Grant