Rebuilding my race car, multi link rear suspension, fg gt flairs Options

[slugmika]

Thanks Timo
As you can see, i did it as we planned the other day.
Thanks for your advises.
I'am still sick so progress is quite slow.

Mika

[914Timo]

Oh, really. I am glad if my thoughts help you.

Hope you´ll get well soon.

Have you heard anything about those parts coming to me ?? As soon as you get them I could come and see your project. I can hardly wait to see those suspension arms in live. They are ..... (IMG:http://www.914world.com/bbs2/html/emoticons/drooley.gif)

[turbo914v8]

Your work is off the hook. When it’s all done, I think you all your troubles and hard work will pay off. I for one would pay you to supply me with parts, finished product as an upgrade for my 914. I think that a lot of 914 owners here probably feel the same. Keep up the great work and just remember when you’re famous that I am first in line for your products. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif)

[Jeroen]

QUOTE (turbo914v8 @ Jan 30 2006, 09:47 PM)

I for one would pay you to supply me with parts

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif)
put me second in line (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

(IMG:http://www.914world.com/bbs2/html/emoticons/pray.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/pray.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/pray.gif)

[biggy72]

I was just wondering if you have the steel heim joints threaded directly into the aluminum. If it is it may cause some gauling, and may not be the easiest thing in the world when you go to adjust it.

Generally you want to keep your rear track width a little more narrow than the front as this allows the rear of the car to pivot easier and it will follow the front better. This might not be possible depending on how big of a motor you're running and how wide of tires you need to keep traction, but generally it's what I've seen as a rule of thumb to try to keep with.

it looks like your lower control arms are shorter than your uppers and that's the right idea there, but I'm not a big fan of keeping both of the a arms parallel. It doesn't have an instant center and so the roll center does weird things (from what I've read). I just got done designing some suspension geometry for a formula sae car and I put the rear roll center right at ground level when it's static, and it goes more below ground under bump. From what I've read this helps eleviate the need for a sway bar. Over the next couple years I'll get to experiment with a few different geometry set ups and we'll see what each change does.

Almost everything I just said is only from research and I haven't put it on a car yet.... well except the aluminum a arm thing. I'm in the process of building steel a arms that are lighter and won't fatigue like the aluminum does.

[slugmika]

Thanks for your comments guys.
"I was just wondering if you have the steel heim joints threaded directly into the aluminum. If it is it may cause some gauling, and may not be the easiest thing in the world when you go to adjust it."

-Yes those are threaded directly into the aluminium. I am using Castrols anti corrosion lubricant with those. I haven't had any problems with same kind of connections earlier with this Castrol stuff. If we have problems with gauling, we'll add steel insert to the arms.

"Generally you want to keep your rear track width a little more narrow than the front as this allows the rear of the car to pivot easier and it will follow the front better. This might not be possible depending on how big of a motor you're running and how wide of tires you need to keep traction, but generally it's what I've seen as a rule of thumb to try to keep with."

-Thats true, i will try to keep the original difference in my car. Last season we had much wider rear than front and it was working better than original set up but that was because of other problems in rear.

"it looks like your lower control arms are shorter than your uppers and that's the right idea there, but I'm not a big fan of keeping both of the a arms parallel. It doesn't have an instant center and so the roll center does weird things (from what I've read)."

-Actually upper are shorter (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) . Reason for parallel arms is that it's easy starting point. Now i can adjust roll and instant center just by changing the upper arms inner pivot point. I'am sure this is not the best way to do it but i think this is zillion time better than my cars original set up.

"I just got done designing some suspension geometry for a formula sae car and I put the rear roll center right at ground level when it's static, and it goes more below ground under bump. From what I've read this helps eleviate the need for a sway bar. Over the next couple years I'll get to experiment with a few different geometry set ups and we'll see what each change does."

-So you must have nice software to design these things? I really should have found someone with suspension software before i started this project. I'we been checking those sae formulas and those seem to be really well thought machines. I'am sure your design is in totally different level than mine but i'we done my best. My design might not be "optimal" but i think it is nice starting point for testing.

"Almost everything I just said is only from research and I haven't put it on a car yet.... well except the aluminum a arm thing. I'm in the process of building steel a arms that are lighter and won't fatigue like the aluminum does."

-I'am not worried about the fatigue of these aluminium arms but i'am also building steel a arms to test few things.
Thanks for your comments, keep em coming

-Mika-

[biggy72]

ya I meant the top arms were shorter, don't know why I said that.

Well the software I've got isn't really suspension software, it's just solid works, just a cad drawing program. It lets you set points on top of other points and then adjust one thing or the other to see how the articulation works. Makes it really easy to see the camber curve, instant centers, roll centers, and you can draw up any parts and test them under different conditions to see where the weak points will be. I'm not a pro on the program at all. I've just been teaching myself so I can apply the things to the formula car since there aren't any classes offered here for it.

While your car's not exactly a formula car alot of the things are just common to a double a arm set up. With our current car we've got the front roll center right at ground level at static height, and the rear pretty far below. The car's handling really neutral without a sway bar, but it feels really lazy when turning, and I think the roll center along with a couple other problems is causing it. We'll see how next year's car works out.

Good luck with your set up, the z link in the rear should work really well from everyone else I've seen with it, and I'm building something really similar for our new a arms.

[racerx7]

WSU Formula SAE Drivetrain Lead/ Suspension Team
http://www.mme.wsu.edu/~sae/

(IMG:http://www.914world.com/bbs2/html/emoticons/pray.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/pray.gif)


Please for this arm chair want to be designer, could you recommend books, software for me to look and read about.

I have always wanted to go to school just so I could enter
that contest. Maybe in my next life time.

[slugmika]

ok i'll make one set of brackets which makes the rc radically below ground level so we can test that too.

Mika

ps. there has been lots of interrest about front spoiler. that is copy of Opel Omega Lotus part.

[biggy72]

QUOTE (racerx7 @ Jan 31 2006, 12:31 AM)

WSU Formula SAE Drivetrain Lead/ Suspension Team http://www.mme.wsu.edu/~sae/ (IMG:http://www.914world.com/bbs2/html/emoticons/pray.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/pray.gif) Please for this arm chair want to be designer, could you recommend books, software for me to look and read about. I have always wanted to go to school just so I could enter that contest. Maybe in my next life time.

I really wouldn't go that far... It's only my second semester here, and we're a first year fsae team. I think our car is decent, but there's a steep learning curve going on right now for just about everyone involved.

As for books, there are lots, but the best overall book that we use quite a bit is Race Car Vehicle Dynamics ( http://www.sae.org/servlets/productDetail?...K&PROD_CD=R-280 ) and for programs we mostly just use solid works.

Really at this point I don't know much, but I'm learning quite a bit about this type of stuff right now, and hopefully I'll only pick up more as I go.

[racerx7]

Cool. Thanks. I am placing a order right. Don't tell the wife. I spent
the last two weeks selling over 150 books to make room for the
kids books. Just one little book should not make a difference right:)

[Mueller]

QUOTE (racerx7 @ Jan 31 2006, 01:31 AM)

WSU Formula SAE Drivetrain Lead/ Suspension Team http://www.mme.wsu.edu/~sae/ (IMG:http://www.914world.com/bbs2/html/emoticons/pray.gif)  :worship: Please for this arm chair want to be designer, could you recommend books, softwarefor me to look and  read about. I have always wanted to go to school just so I could enter that contest. Maybe in my next life time.

this software has been recommended by a few people in the know (IMG:http://www.914world.com/bbs2/html/emoticons/smash.gif)

Mitchell suspension software programs

[racerx7]

QUOTE (Mueller @ Jan 31 2006, 11:58 AM)

this software has been recommended by a few people in the know (IMG:http://www.914world.com/bbs2/html/emoticons/smash.gif) Mitchell suspension software programs

Very nice. thanks for the link.

[Mueller]

QUOTE (racerx7 @ Jan 31 2006, 01:10 PM)

QUOTE (Mueller @ Jan 31 2006, 11:58 AM) this software has been recommended by a few people in the know  :smash: Mitchell suspension software programs Very nice. thanks for the link.

no problem....I wonder if he'd offer a group purchase discount or a networked version for multiple people (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

I'd like a copy, but I have a hard time justifing the price for something I'd only use a few times a year if even that much......

[stock93]

Great looking fab work!

The microstub setup BrettW was talking about can be found at http://www.kartek.com This setup is commonly used in off road buggy racing.
I've attached a picture as well.

John

[biggy72]

I'm borrowing a book that the guy that invented the mitchell software wrote. I've heard about his program as well, but haven't ever used it since you can do everything on solid works, just have to set it up first. And since we're college students we've been kind of running on the minimalist approach.

If you don't want to learn how to use a whole program and you want to do more of a plug and chug kinda deal his program is probably much better.

[slugmika]

Hi Again
I'we been sick for over month but now i'am getting better (i hope).
I don't know if i should call this progress but here is what we did last weekend.
(IMG:http://www.914world.com/bbs2/uploads_offsite/photos1.blogger.com-179-1274376551.1.jpg)
(IMG:http://www.914world.com/bbs2/uploads_offsite/photos1.blogger.com-179-1274376551.2.jpg)
I was thinking that i just make a frame out of the 30*50mm square tube which i
use to tie the front and rear attachment points together. Then i raise the whole setup
1" and weld roll gage tubes to it. How does it sound? Do you think there is something else
i should do to make the front better? When i have the frame part ready i will put it on a table and then measure that all are square with rear axle.
Here is the rear
(IMG:http://www.914world.com/bbs2/uploads_offsite/photos1.blogger.com-179-1274376551.3.jpg)
i'am trying to get the suspension ready so i can lift the car over it. This should happen in a next 3 weeks.
Then i should have the car ready for Callicott Motorsports quarter panels (thanks Dan) as they arrive.
After those are on a car, i'll paint the car using a Jeroen's design with main sponsors colours.
Then of course i still need to rebuildt the engine and gearbox.
Oh, and finish a new trailer (thanks lurker Pekka)

Mika

[alpha434]

Did Harris have anything to do with this?!?! (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

[slugmika]

Harris?

[Jeroen]

way to go Mika! I like your plans!

but since you're at it... why not make a double a-arm front suspension as well?
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