My new favorite SLC YouTube video...

Kyle D · Apr 19, 2015

[ame]www.youtube.com/watch?v=-mIv7WOdTAQ[/ame]

Lookin good Stu! :thumbsup:

Al Wohlstrom · Apr 19, 2015

Would love to know what that cost the customer. Big bucks.

Eric McClellan · Apr 19, 2015

Didn't the owner just post ?

Al Wohlstrom · Apr 19, 2015

he doesn't have one yet.

Eric McClellan · Apr 19, 2015

No, the owner of this red car in the video.

Al Wohlstrom · Apr 19, 2015

The guy talking sounded like the shop rep

Keith1 · Apr 19, 2015

It was clearly a commercial production for Bilstein...

Not very complimentary about the shocks as supplied...

Eric McClellan · Apr 19, 2015

Al Wohlstrom said:
The guy talking sounded like the shop rep

Yes. I got that.

I'm talking about the owner of the red SLC. I believe he has recently posted here.

Annnnny ways,

The shop guy said something that I remember reading differently about... the rear ride height adjustment. I thought the wiki said NOT to use that adjuster bar and only use the coil overs but in the video he points right to it?

gt40fran · Apr 19, 2015

You use both when setting up the car
We do offer Penske shocks as our track shock package.
In both double 8300 series and 8760 triple adjustment options

Stu , the owner is a regular poster on the forum
This car was filmed recently for an Australian gear head TV show , looking forward to seeing it!

P-nut · Apr 19, 2015

Eric McClellan said:
Yes. I got that.

The shop guy said something that I remember reading differently about... the rear ride height adjustment. I thought the wiki said NOT to use that adjuster bar and only use the coil overs but in the video he points right to it?

Here's what the wiki says, and I think it's consistent with what Fran says:

"One thing to repeat here, is not to use the pushrods in the rear suspension to make adjustments to ride height. The pushrods need to be adjusted so that (1) they don't hit the upper control arm on full droop, and (2) so that they are the same length. Different length pushrods on each side of the car will cause the effective wheel rate to be different on each side on a bump, or in a curve, which will lead to a squirrely car. Set them to be the same length, and adjust the ride height with the spring collars on the coil overs."

IOW, you set the pushrods to the correct length, and use the collars for ride height. I saw the same thing in the video, and if he was adjusting ride height by making the pushrods different lengths, he was introducing a side-to-side difference in the way the car handles. Except for oval track cars, this is normally not desired in a road or track car.

To clarify, if the pushrods are adjusted so they are the same length, and don't cause interference on full droop, initial ride height can be set with them in a pretty limited range. Once they are set properly, the rest of the ride height and balancing must be set with the shock collars. The warning in the wiki is mostly to try to stop people from adjusting ride height with the pushrods and ending up with different lengths- that's the grievous error!

gt40fran · Apr 19, 2015

Correct...I should have posted more detail myself, sorry.

prothct · Apr 20, 2015

Gotta love the number plate "WTF 376"

StuM5 · Apr 22, 2015

Kyle you beat me to it. I didn’t want to post yet because I was waiting for the technical details to go with it.

Let me set the background to the change to the Bilstein dampers/shocks:
The car was being filmed for a TV show and part of that included race track focus with both myself and a professional driver. The feedback from the professional driver (not me, I’m still a novice on track) found the weight wasn't transferring to the front of the car under braking and the wheels were sitting up in the guards which prevented him from turning into the corner properly. The suspension engineers dyno’d the QA1's and found they were very stiff in their first range of movement. They couldn’t adjust out this stiffness.

I showed the shock engineers the posts in this thread and this is the quick response they provided:
…basically adjusting the spring seat height and the push rod does the same thing. The only difference is the clearance issue, which we sorted with the damper lengths. Raising or lowering the car on the push rod (or the spring seat) will not adjust the effective wheel rate, as the cars geometry hasn’t changed. The only thing that will change is the ride height and the corner weights.
The “rules” they talk about may only apply to cars with standard dampers.

Fran added this comment to the above (hope you don’t mind me including it Fran): The wheel rate will not change with the pushrod length as that's a function of control arm length and effective spring rate dependent upon the chosen frequency.

This is what the suspension engineers have told me they did to the car:
We moved the tie rod ends away from the steering arm to reduce the bump steer. When we did our initial dimension work we noticed that the front tie rod ends and the rear toe adjuster were binding (running out of articulation) on full droop, this was actually the droop limiting factor in the vehicles standard suspension. When we built the new dampers we reduced the open length and used this as the limiting factor help stop the tie rod ends binding on full droop.

With the standard suspension, if you remove the tie rod ends from outer toe adjustment, on the rear end, the suspension will droop (hang down) a further 20mm (approx.). Hence there was no need for the dampers to open as much as they did.

We used 800lb/in Eibach coils on the rear. The Eibach coils gave us more travel and a firmer rate than the standard coils.

cheers
Stuart

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jac mac · Apr 22, 2015

Just a heads up, avoid using Penske shocks as a travel limiter on full droop, use check straps or wishbone stops to do this. We had a couple fail internally at the piston end due to not doing this. Probably applies to most shocks, cause appeared to be the unloaded inner front when running over ripple strips etc at corner apex which acted like a shock hammer on the extended shock absorber.

StuM5 · Apr 22, 2015

Thanks for the commentary jac mac, i will throw that comment to the Bilstein guys and see what they say. They use this exact same MDS Bilstein system in  car #6 with the advertising skwirk/beechwood homes starting from the front in this race. The driver of this car is the professional driver that gave the SLC the shake down at the track.
https://www.youtube.com/watch?v=ftSlN2PM_BQ.

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Kris · Apr 22, 2015

^ that was an incredible drive -- thanks for sharing

prothct · Apr 22, 2015

StuM5 said:
We moved the tie rod ends away from the steering arm to reduce the bump steer.

Hi Stu, I was trying to see that in the video, I am looking at the 4:13 mark on the video. If I understand correctly it appears they added a spacer under the steering arm between the arm and the tierod. Is that what they meant by moving it away?

I can't wait until the track video gets posted!

gt40fran · Apr 22, 2015

Stu and I have discussed this at length and the feedback from another pro driver has been great.
All the stock SLC components are being used with the exception of the shocks.
The guys have put their own set up on the car and have been really impressed by the grip, feel and performance and they are just getting started on street tyres..

So all you SLC guys have the same opportunity to drive like Stus pro...maybe not the talent but at least the car...:thumbsup:

YerDugliness · Apr 22, 2015

That red car looked HOT! I am becoming more of a fan of the SLC as time goes on...love the way the tires fit into the wheel openings!!

Just curious...are most of the SLC's being built for track use (i.e. is that the intended purpose of the car)? It seems to me that a lot of the "southerners" are building for street use...but, I could be wrong about that.

I ask b/c whatever sort of mid-engined GT I get to build (if that really does happen) will need to be fit for street use. I am encouraged by the comments about the SLC being so much easier to build than an RCR40, just want to make sure I am not considering a car that will not fulfill my intended purpose.

Gotta admit, the SLC really is growing on me!!!

Cheers!

Doug

StuM5 · May 5, 2015

prothct said:
Hi Stu, I was trying to see that in the video, I am looking at the 4:13 mark on the video. If I understand correctly it appears they added a spacer under the steering arm between the arm and the tierod. Is that what they meant by moving it away?

To be honest I'm not sure how they achieved this. I have asked but haven't received a response as yet. The only comparison I have is this photo taken before any work was performed.

My new favorite SLC YouTube video...

Kyle D

Al Wohlstrom

Eric McClellan

Al Wohlstrom

Eric McClellan

Al Wohlstrom

Keith

Eric McClellan

Fran Hall RCR

Will Campbell

Fran Hall RCR

P Roth

Stu Coleman

Jac Mac

Stu Coleman

kris

P Roth

Fran Hall RCR

Doug S.

The protoplasm may be 72, but the spirit is 32!

Stu Coleman

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