Rally Suspension project

[Rallyho]

hiya folks.

Gathering a bit of info as I try and make some suspension upgrades on the Swedish rally tractor. I reached out to Luke but haven't heard back. I know he's done a bunch of stuff, but I'm most interested in his nearly stock setup...was that on the vintagie 99 NA? Anyway, looking for the spring rates, shock type/length/valving and any fab he needed to do to make it work. I'm currently running what I think are SPG springs with two alum spacers and stock HD Bilsteins running some sort of valving. I think Geoff remembers, but for the life of me I can't find the specs.

Goals are to get the car to ride a little higher, which may require stiffer springs and run larger shock body to deal with overheating/loss of performance on longer stages. Am ok going with a slightly longer than stock shock length as I'll just fab around it.

Thanks ya'll!

Mike

[Rallyho]

Ok, here are some things I'm looking for info on:
* OEM spring lengths and measured (vs calculated) spring rates
* Model and valving specs for the silver Bilsteins Luke was running in the historic 99 he ran a few times including up at NEFR with us one year.
* Any photos and/or specs & part numbers for converting front springs to smaller diameter or flat coil end racing springs, but keeping stock a arms. I
think someone on here made narrower lower spring perches, but can't remember who
* And, wondering if anyone has viewed/documented tripod depth in the inner driver at full droop and full extension.


Thanks folks!

Mike

[Crazyswede]

Hi Mike,

Luke had a couple iterations of suspension as he worked through the issues. The shell that Geoff has is the latest iteration with the reinforced upper A arms, the coil over mounting brackets, and the Jaguar ball joints. The silver car that Luke kept is back in the stock 99 suspension configuration. I don't remember whether it has S&R springs or SPG springs with spacers. I believe that there are still a couple threads on the forum that detail the suspension.


Also the setup on the shell Geoff has uses the jaguar style ball joint where the mounting bolts are over the top of the ball vs the saab style where the ball is cantilevered out from the arm. The problem with the Saab ball joints is that they were literally bending or the back of the ball was blowing out due to the extra force that having the shock mount on top arm was imposing.

[Crazyswede]

This was the earlier setup:



And one of the early results from the setup:



Here is the setup with the improved ball joint and mount design:

[Crazyswede]

A detail of the modified A arms

[Crazyswede]

I was playing around with some ideas for running a coil over spring but leaving the shock in the stock location. There are these circle track parts emulate a coil over but dont have a shock portion. they allow you to run the coil over springs and adjust the preload but have only a guide rod. I think they could be a great way to open up the world of suspension tuning springs without having to go crazy making a super strong top A arm.

[Crazyswede]

I believe Luke wanted to switch to remote reservoir shocks and we had also done some research on hydraulic bump stops for the car Geoff now has. I believe the Bilsteins are

https://www.bilstein.com/us/en/product/ ... n-b8-5160/

The guys who ran the old Beetle had pretty tricked out suspension front and rear and i believe they were running the remote reservoir shocks.

[Crazyswede]

Coil Spring Sliders

https://www.speedwaymotors.com/shop/coi ... -306-18233

[Rallyho]

Thanks Seth. This is good stuff and now I better understand the photos of the slider and how that might work. In your measurements did you ever look at max droop and compression and their effects on axle alignment or how far the tripods pull out of the inner drivers?

[Rallyho]

And, I think the direction I'm going in for the moment is springs in their stock location with larger shocks using fabricated upper mounts if needed to accommodate for longer overall shock length. And I kinda want to go back to an upper mount more like the 99 where the attachment point is inside the wheel well...Makes service soooo much easier and I think I can tie it into my cage instead of oem sheet metal. Then, play with the maximum droop I can safely get and look for a spring solution that is closer to base model length and SPG++ rate. As you guys found at Maine the year we both ran, the cars are always wanting more ground clearance and even an inch more travel (longer springs, shocks and revised top-out & bottom out points) would help big time.

I like the idea of the hydraulic bump stops...where would you mount those?

[Crazyswede]

Its been a while but the limitations as I recall come in the form of how far the ball joints will move without interference, the axle will hit the body, the tire will hit the inner fender, etc. Lukes latest revision on the coil over suspension had a lot of travel but with most of it in droop....kind of like a little trophy truck. I think the CV's have enough ability to support the A arm travel and you would have other issues before the CV has problems.

Ony airborne picture I have but you can get an idea on the max lower angle he had it set at

[Crazyswede]

You could go to a double eyelet style shock and move the mount up into the engine bay tower with a cross bolt. That would make life a lot easier if changing shocks was needed. one easy to reach cross bolt vs trying to get at two top nuts or working in the wheel well where rocks and mud can smash things


Strike that...I was thinking about coil over designs there for minute.

[Rallyho]

hmm, totally non scientific, but looks like we may have similar droop. And if I zoom in, I see space between the axle and the lower "hoop" in the body shell...maybe another inch.

And a snot pile of compression...

[Crazyswede]

Yeah I remember the front of Lukes car was pretty close to stock as far as droop and compression went, I believe the rear had a ton of droop....I feel like the rear had 9" of travel?

[Rallyho]

Your double eyelet idea is where my head is at...shock like this. https://www.summitracing.com/parts/bsn- ... EdEALw_wcB