Alignment settings and more from a new owner

[Christopher Lewis]

Hi everyone,

New owner here. Bought an already built SL-C from the family of a guy in Hailey, Idaho. Unfortunately he is deceased and the family knows nothing about the car. It is currently a track only car but plan on getting it street worthy.

https://sunvalleyautosales.zenfolio...AhzgQYBSCdZyZfNL3V1Da0jUCcHgd6eRqcF_Zgq3KhQC4

I intend for this to be a track car that can transit to various tracks via it's own power for a certain event that occur's every year around the 2nd week of May.

Questions are going to start coming hard and fast over many areas of the car but let's start with some basic stuff.

Since I don't have a manual, What are the recommended alignment settings and what are the track guys running?

Have any of you mapped the toe curve on the rear of the car by varying the rear caster?

For those of you with the Ricardo gearbox, do you have a cooler and if so what size? Is anyone monitoring gearbox temps?

Where is the chassis serial number located?

Much, much more to come....

A bit about me, I'm a endurance road racer, builder and principle of Shaky Dog Racing.

https://www.facebook.com/ShakyDogRacing/

Thanks in advance for your help
Chris

 

[Chris H]

Have you tried contacting RCR for a manual?

 

[Cam]

Welcome! Talk around town is yours is an earlier chassis, one of the first. It would be best to get in touch with RCR for that particular information.

The track guys will chime in but it may be good to know what tires you’re planning to run for alignment settings.

Best of luck! Looking forward to hearing more about your car and experiences with it.

 

[Will Campbell]

There's a pretty comprehensive discussion on alignment in the SLC wiki. Here's a link.

Good luck with the car!

 

[Christopher Lewis]

Has anyone calculated the motion ratios and bounce frequencies for their car? Just wondering before I do it so I’m not reinventing the wheel here.

 

[Cam]

Forgot to mention - of the folks who post here, Howard Jones, Paul Robertson, and Frank Clark seem to be the most track/race focused and somewhat active. You should reach out to them directly for more info.

 

[Ken Roberts]

I have a Ricardo and a transaxle cooler. I'm using a Setrab 625 cooler and a Improved Racing FSM-165 thermostat. I installed a GM temp sensor on the drain plug fitting. Unfortunately my car is still not road ready.

https://www.gt40s.com/threads/kens-slc-build-thread.38446/page-24#post-466837

 

[Howard Jones]

So first what tires, sizes and wheel widths will you run. Then call RCR and get the static caster washer stack number and use it. This will get you about 5 degrees of caster on the front. I forget the rear. But in any case caster is set with the washer stack number in front and to the rear of the inboard rod ends of the a arms. I set caster to Frans recommendation and have never changed it. Seams OK that way.

Ride height. set F to 3.75 if you really want to go for it and 4 otherwise. Set rear 1/2" higher than the front. The rear MUST have this 1/2 positive rake.

Toe. Set car up dead straight no toe either end for now. We'll come back here later.

Now camber. If you run Hoosiers minimum 1.5 - front and 1.0 - rear. I started that way and have now progressed to -2F -1.5R

Setup the lower a arm inboard rod ends at both f & r so that you can get good tire clearance to the wheel openings and with minimum number of threads showing. This will set the lower arm as close to the chassis as possible. Now adjust the top outboard rod end 75% into the a arm and the top inboard rod ends about all the way in (minimum threads showing) and measure what you have (both F & R). adjust as much as possible with top outboard rod end leaving the inboard ones as is for now.

If you get to your target camber setting with the top rod ends with a MINIMUM of 33% (50% is better) of its thread into the a arm then good. If you still need to move the bottom of the tire outboard to gain neg camber then you will need to turn the lower inboard rod ends out a bit. The bottom a arms are the most loaded suspension parts on the car. Keep as many of the rod end threads in the a arm as possible but no less than 50%.

All inboard rod ends are always moved the same number of turns as it's sister rod end (two per a arm) when making adjustments.

The idea is to be able to make camber adjustments on the top a arm rod ends without having to take the inboard lower rod ends loose once you get close. It will make life easier from then on.

last toe. Reset toe to 1/16 inch toe in per side on the front. Rear can be very close to 0 but NOT toed out. Call it 3/64 per side. This car does not seam to gain toe with suspension travel. BUT I have very stiff springs and therefor very little roll under load. These are what I like. BUT I am ok with a bit twitchy at high speed if I get crisp turn in. If you like the opposite then add more toe at the front.

My springs are 650F 850R. Would like to try 850s on front and 950s maybe even 1000 on rears. Shocks are set to about 75% full stiff both compression and rebound. Currently at 6 degrees angle of attack on rear standard wing with large canards set to about 35 degrees on the front.

Hope this helps.

 

[Howard Jones]

Chris, You might also benefit from reviewing the thread "SLC hubs/race worthy" in the SLC clubhouse section.

 

[Mesa]

Welcome Christopher,
Your car was one of the first 5 chassis produced, it was built for a fellow in Scottsdale by a NASCAR and offroad race team fabricator/crew chief. Our cars are "sisters" as mine was the first sold, but this car was actually delivered before mine. The car was subsequently sold to a guy in Idaho who unfortunately had the engine block freeze and crack in storage there. (IIRC) It was rebuilt/replaced by CLP Motorsports in Martinez Ca. Ironically I took a picture of it while it was there with Howard in the foreground (which I cannot locate at thee moment).

As I was in contact with the original owner, I have a lot of build documentation the builder shared with me. Let me know if you are interested in getting a copy of that info.

 

[Christopher Lewis]

Hi Mesa,

Thanks for the info. I called CLP and they are looking for the exact info but they believe it was a Mast Motorsports LS7 SS motor. This is what I suspected it was after I looked at it. If you have any more info I would appreciate it.

 

[Mesa]

Chris,
Got your PM, I don't have any info on the engine itself. What I do have is build pics and component lists. I'll get a CD together for you, please send a mailing address.

 

[Christopher Lewis]

Chris, You might also benefit from reviewing the thread "SLC hubs/race worthy" in the SLC clubhouse section.

Already checked it out. This car has Racelogic TC in it so I'm assuming it has some passive wheel speed sensors picking up wheel speeds somewhere. I haven't had time to really dig into the car yet as I am in the middle of a new endurance racecar build that has to be ready in 2 weeks. After that I will have some time to sort out the SL-C. I would like to use the C6 hubs with the active sensors built into them since I want to add the Teves Mk60 ABS system. Just have to figure out how to get both active and passive together for the 2 different systems.

 

[Frank Clark]

...
My springs are 650F 850R. Would like to try 850s on front and 950s maybe even 1000 on rears....

I have 800F (2.25" x 4") and 900R (2.5" x 7"). I will probably go to 1000 rear at some time. I probably spend more time at high speed (>120) than most tracks allow. I'd think 800/1000 is about right for COTA, though I've not driven there. I run the CF rear wing and Street Splitter. Need to step up to the Race Splitter, but I've already beat the tar out of the street one. Hate to see how long the race one will last me.

Minor machining required for 2.25" springs. If you DO have a front lift kit then you likely need to go to the smaller diameter springs (there is very limited selection in 2.5" x 4").

I run ride height at 4"F/4.5"R. At speed it still peels the road markers off the highway (I'm sure TxDOT loves me). I may try 5" in the rear.

If someone is looking for springs lighter than I run, hit me up. I have a stack, some have been used for mock up, some have half a dozen laps on them.

 

[Christopher Lewis]

OK, couple of questions. Still haven't had a chance to get to the SL-C yet. (Hurt an engine on one of the racecars at Barber) As far as the lift for the front end is concerned.

Which lift system are you running? It seems like the SL-C crowd uses the Ramlift Pro but which one? 1.25", 2.5" 40mm?

With the lift is the longest spring you can use a 4"? Why the 2.25, because of a lack of 2.5" x 4.00" springs?

What wheel rates are you shooting for and what tires are you running? (i.e. a wheel frequency rate of 2.5 with a 200TW BFG Rival S)

What are the front and rear motion ratios for the spring/shocks?

 

[Howard Jones]

Here: you will need to measure things yourself :

https://eibach.com/us/p-101-suspension-worksheet.html

 

[Christopher Lewis]

Thank Howard, I was just wondering if anyone had already measured and was willing to share.

 

[Frank Clark]

Which lift system are you running? It seems like the SL-C crowd uses the Ramlift Pro but which one? 1.25", 2.5" 40mm?

With the lift is the longest spring you can use a 4"? Why the 2.25, because of a lack of 2.5" x 4.00" springs?

What wheel rates are you shooting for and what tires are you running?

Yes, RamLift Pro. I believe it's the 2.5" lift, but I would have to double check that.

The longest spring you can use with the lift is 4". If you are running the car high, you could fit a 5" (but I don't think that is a common size). Also, you need to run helper springs (google HELPERSPRG-2.25) and the mating adapters that keep these in line with the main spring.

Reason for the 2.25" conversion is the lack of availability in 2.5" x 4.00 springs. A while back Hyper had heavier rate 2.5" springs (800 and 900lb) in their catalog, but they told me they had never actually produced them. Availability changes, so see if what you want is available.

Reason for the helper springs is at full droop, the 4" springs will be loose, so if you unload the suspension (or jack up the car), it may not re-seat correctly.

I am running PS4s. Not targeting a specific wheel rate, just looking to get the car to drive well at speed. The standard springs are probably a good starting point for a street car. But a track car, or high speed back road car they are too soft.

Had my car out at the TMS infield road coarse Sunday. With the wing off, the spring rates were in the right ball park for that track. With the wing on it probably would have been fine as well as the corner speeds there are not high.