IDEAL Rear Suspension - No Holds Barred

Suspension, including wheel, tire and brake.
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JordanTr
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IDEAL Rear Suspension - No Holds Barred

Postby JordanTr » 16 May 2017 21:45

What would you do improve on the rear suspension design of a 510?
1. Eliminate toe out on bump
2. Minimize unsprung weight
3...

What would the rear camber curve look like?
1...

What would the rear toe curve be? How aggressive (or not) would the changes be?
1...

Would there be antisquat? How much is too much? How much is stock?
1...

I'm playing with the design of a double wishbone rear suspension and would appreciate some input.

Hoping to hear from Keith, Byron, and anyone else with great experience to share.

Thanks.

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Jordan | '72 2 door KA project | '94 240sx RB26DETT | '97 Silvia RB25DET | '90 Audi 90 Quattro 20V (DD)

datzenmike
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Re: IDEAL Rear Suspension - No Holds Barred

Postby datzenmike » 17 May 2017 06:32

Solid axle and leaf spring.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

Three B's Racing
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Re: IDEAL Rear Suspension - No Holds Barred

Postby Three B's Racing » 17 May 2017 07:01

datzenmike wrote:Solid axle and leaf spring.

I second that!!!! simplify simplify simplify,,,,make it easy :shock:
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510wizard
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Re: IDEAL Rear Suspension - No Holds Barred

Postby 510wizard » 17 May 2017 07:34

Are you willing to highly modify the rear sheet metal where the gas tank now is ? IMHO the reason Datsun used the trailing arm and also BMW is the low package height of said suspension. When you start talking double wishbone and "A arm" type suspensions you need height. Also realize that all types of suspensions are all about compromises, may it be in packaging size, camber/toe changes,etc. If you are willing to modify the body sheet metal/structure and all the the stuff the will come up when doing that, then the it opens up a lot of possibilities. I think that the 240sx, Miata, or similar type of rear assy. would work nicely, but that also that brings up the width and height problem. I choose the Miata because of it's racing back ground, why reinvent the wheel? When I started the SSE wagon project, I couldn't believe how much narrower the track is on 510 is compared to the Miata which is a small car, (5.5" the amount that I had to narrow). Also the wagon has more height than the sedans and trust me its still a problem if you want to keep the cargo area, which I am trying to do.

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JordanTr
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Re: IDEAL Rear Suspension - No Holds Barred

Postby JordanTr » 17 May 2017 07:42

510wizard wrote:Are you willing to highly modify the rear sheet metal where the gas tank now is ? IMHO the reason Datsun used the trailing arm and also BMW is the low package height of said suspension. When you start talking double wishbone and "A arm" type suspensions you need height. Also realize that all types of suspensions are all about compromises, may it be in packaging size, camber/toe changes,etc. If you are willing to modify the body sheet metal/structure and all the the stuff the will come up when doing that, then the it opens up a lot of possibilities. I think that the 240sx, Miata, or similar type of rear assy. would work nicely, but that also that brings up the width and height problem. I choose the Miata because of it's racing back ground, why reinvent the wheel? When I started the SSE wagon project, I couldn't believe how much narrower the track is on 510 is compared to the Miata which is a small car, (5.5" the amount that I had to narrow). Also the wagon has more height than the sedans and trust me its still a problem if you want to keep the cargo area, which I am trying to do.


Monte, I agree. Modifying the floor and fuel tank is fair game for this one here.

I actually read through a big part of your thread looking for motivation for this so I totally understand what you mean and your whole journey.

Do you have any idea what the suspension dynamics are on the Miata subframe you've been playing around with?
Jordan | '72 2 door KA project | '94 240sx RB26DETT | '97 Silvia RB25DET | '90 Audi 90 Quattro 20V (DD)

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510wizard
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Re: IDEAL Rear Suspension - No Holds Barred

Postby 510wizard » 17 May 2017 10:42

I measured 1/4 degree of camber per inch of bump on my designed subframe. I think that you could save some height in the sedan by fulcrum links on the coilovers laying them horizontional like an indy car/open wheel car, but makes the thing more complicated. But, as you said modifying the structure/cargo area is fair game, that opens up a lot of possibilities which I didn't have. Also something to consider, is how low do you want the car? The lower the car, the higher the suspension package has to be in the car/frame to maintain the correct camber at static. The Miata race guys seem to run 1/4 to 1 degree at static, so if you use that as a range then it kinda dictates where the subframe is mounted in the chassis as far as height and then there is the subject of roll centers, which is other ball of wax. Happy suspension designing! You might Google locost, which is a home built lotus 7, those guys do some amazing suspension builds and might give you some ideas. But, remember suspensions are all about compromises .

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broke
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Re: IDEAL Rear Suspension - No Holds Barred

Postby broke » 18 May 2017 18:08

I'd pretty much copy what Gibson Motorsport did with George Fury's 910 Bluebird. Except because this is "no holds barred" I'd have it all in alloy or magnesium or something.

One of the main issues with the rear suspension on lowered 510's seems to be the crappy roll centre - obviously this setup gives you lots of adjustment to fine tune it.

furybird.jpg
furybird.jpg (454.04 KiB) Viewed 597 times
The IDx 10 concept is based on the 510 in the same way that the urinating I was doing last night was based on a 30 yr old single-malt scotch.
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Re: IDEAL Rear Suspension - No Holds Barred

Postby Byron510 » 19 May 2017 08:06

Broke; You posted more photos of this suspension design somewhere on this site. Do you have more photos of this complete set up you can post here? - specifically the modified LCA's used and changes to their links/attachment points at the X member - which is still in place.

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broke
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Re: IDEAL Rear Suspension - No Holds Barred

Postby broke » 20 May 2017 01:46

Hey Byron, yeah I think I might have ages ago. The best pics I can find are here http://www.performancegarage.com.au/blo ... -turbo-vid

Annoyingly, I lost the magazine I had that had a full writeup about this car and some close up pics of the rear. I remember in the article they were saying that they just sliced off the inner control arm mount and left the outer one, their argument being that this still constituted using the factory suspension pickup points (just not ALL of them) which the officials weren't too happy about.

It's very similar to the old E36 BMW rear suspension, which always seemed to work really well, and on this particular car it obviously worked VERY well! I've been wanting to copy this for a long, long time!
The IDx 10 concept is based on the 510 in the same way that the urinating I was doing last night was based on a 30 yr old single-malt scotch.
-McWicked


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