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Has anyone built a locost with a macpherson strut? Or has anyone Modified one to make a double wishbone? I'v only saw a picture of one cut off?

MacPherson struts might be a little too tall and a little too outboard for a Locost. But just about anything can be done.

I've looked into utilizing front knuckles made for macpherson struts with a double wishbone and coilover type spring/shock.

It has been done before. Your main issue is packaging after you figure out how to add a ball joint to the top of the knuckle. In addition, the ball joint must be appropriately centered. It is rather difficult, makes tuning the suspension awkward, does not look particularly good, and there are MANY cheap alternatives.

After having been through this, I recommend using miata spindles at a minimum (which is what I used). If you can find the part and have the room, I would look for a rear steer double wishbone knuckle. Best ackerman and good fitment...

I think the mr2 might be a good source... front drive cars also typically have rear steer...

There are Locosts around with struts, Google is your friend...

While this car isn't struts, the standard Mazda shocks he uses offers the same result visually .... for lazy people.

viewtopic.php?t=2486

Struts can be made to be very short with little effort, mine were down to 700mm from the ground (top mounts) with 100mm clearance (so 600mm from bottom of chassis) - I'll find some pictures later.

Don't believe the rubbish that will be posted about "can't get suitable camber curves, you need double Aarms" - it is rubbish and the comments are based on compromised passenger car geometries.

This is a lovely setup using a cutup McStrut for double Aarms...



http://www.whartonindustries.com/MacPherson.htm

That gave me ideas on what to do with the pair of MacPhersons I got for free....

I found a great website on what one guy did to use his Mac P. http://dmr-architect.com/~locouki/cambe ... ction.html
Im using a Datsun 280z for a donor. Now i noticed that the rear strut has the cartridge tube offset. Will and offset upper ball joint be of any harm in the rear of the car. I dont see how it would but what do you guys think? Thanks for the input

Rather than geometry I think the important point to this is that production cars are typically softly sprung and have high CGs so it does not take very high cornering Gs to generate large amounts of body roll. Since struts have poor camber characteristics in roll, the camber goes positive and traction is lost. If the roll stiffness was increased from stiffer springs and anti roll bars and/or the CG was lowered, this lack of camber gain would be much less critical.

The Locost already has a lower CG and lower weight so the roll moment is lower so its already moving in the right direction. I definitely think it is doable with the right considerations.

_________________
-Andrew
Build Log
Youtube

Check out "The Gecko Project" on this "view new posts" page.
viewtopic.php?f=36&t=3241&start=60

No.

Struts only have poor camber characteristics when compromised in cars designed to suit family needs. I have no problems at all getting required camber curves with "uncompromised" McStrut geometry and can offer you as much neg camber gain as you want and with negative or positive lateral slip as required.

Care to share your design?

I've toyed with using struts before since they seem very well suited to the rear structure of a 7. I shortened the instant center to increase camber gain by moving the top of the strut closer to the chassis center line. It was definitely better than the production car geometry (close enough that a degree or so of negative static camber would keep it in a reasonable range) but I could never get the camber gain numbers that other IRSs yield. It always ended up being a hard sell since even at its best the numbers were mediocre.

Numbers aside, modifying a strut to make this work wouldn't be extremely difficult as long as the strut bolted to the knuckle - leave the bottom bolt in place, pivot the strut about the bolt to the correct angle, and make a new bracket to match the top hole.

_________________
-Andrew
Build Log
Youtube

Can't find any pictures worthwhile at the moment so took some aproximate only measurements off one of my cars. You can take the measurements and juggle them around in Wishbone/"whichever" program yourself.

Static with 1 degree neg ...



Note the roll changes and the dynamic camber changes in the appropriate boxes, all at 1" dive aproximating roll axis and steered wheel drag (turning right hand corner, car coming at you)...







If you click rapidly in the picture viewer it's like a movie!

Oh the Internet is lots of fun ...

The caveat involved here is that using a strut type suspension on the front of a performance car requires a significant angle on the strut, both inward AND rearward. The implication here being that to get the desirable geometry in conjunction with desirable alignment out of most production struts will probably require significant modification/adaptation of the stock uprights to allow for an angle between the strut and upright well beyond any designed, intended, or recommended range of adjustment...Or a fully custom designed/fabricated/machined upright. And while one of the biggest advantages to struts is packaging on traditionally designed street cars, it is actually a significant obstacle on a sevenesque car. As with everything else, it's all a series of compromises and personal prioritization.

_________________
-Justin

"Orville Wright did not have a pilots license." - Gordon MacKenzie

As Driven5 says, it's all in the packaging and just by the nature of the beast the strut will have a less ideal camber gain curve than a properly designed dual A arm suspension.

That's not to say you can't make it work wonderfully for a particular application. They less movement you allow in the suspension the easier it is to make a strut work. Of course the same could be said about most suspension types.

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mobilito ergo sum
I drive therefore I am

I can explain it to you,
but I can't understand it for you.

In the following thread are some pics of an adapter to mate a bolt-on strut type upright with a ball joint to create a double wishbone:

http://www.locostusa.com/forums/viewtopic.php?f=35&t=5886&start=150

_________________
-Justin

"Orville Wright did not have a pilots license." - Gordon MacKenzie