Thoughts around SLC as a race car.

Hi from the other side of the world.

I have looked at GTM and SLC as a rolling chassis base for a race car.
I don't want a old car that everything costs blood and/or have to be made when things fall apart.
Both have positive and negative aspects after what i can read and several people concluded that the end price is about the same.
I want a newer car, medium priced but with a great chassis that i can develop.

I like the SLC best, but one thing concerns me at that is the alloy chassis.
Is this stif enough?

This is from the series i want to drive, race start 13.30 :
It is a fast series, to put it in perspective there is a Corvette C5 GT1 ending 5 place.

Any other thoughts about the cars?
 
I'd go for the GTM personally, having followed these guys for a while: https://www.factoryfive.com/whats-new/team-pdg-scores-podium-finish-at-25-hours-of-thunderhill/

But that's just because of familiarity and the fact it's Vette-based.

I have seen that there is some adjustments that is needed. And if that means change out vette parts, then it is back to start.
That is why i asking about chassi stiffness. The biggest negative aspect i can see is al the bodywork.
 

Randy V

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Well, this is why I'd go for GTM - a space frame chassis is far easier to modify.

I agree, but I think the advantage with the stock parts then is gone if it must be modified.

Photo from a red Gtm.
I do also weld aluminum
 

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I'm sure others with direct experience will weigh in. But...the SLC chassis is plenty stiff, especially when you incorporate the required full roll cage. Yes, chassis damage is easier to repair on a GTM since it's tube frame. However, the GTM was adapted to use the corvette suspension, and it's an open question whether the geometry is truly optimized for a mid engine car. SLC designed that way from the start. Finally, look at the ease of body removal for service/maintenance/adjustment. You can take the whole front/rear end off the SLC, don't think that's the case with the GTM.
 
We use ours for open road racing. The chassis is STIFF as chassis go. We have several other tube frame cars and we regularly have to do repairs and replace chassis.

It would not bother me to fix moderate damage on the SLC. If more than that I’d be on the phone with Fran working out a deal for a new tub.

if you’ve not looked over both cars closely, you need to. I’m not going to share my thoughts on that other chassis other than to say you won’t see my ass in it running the speeds we are used to.
 
I'm sure others with direct experience will weigh in. But...the SLC chassis is plenty stiff, especially when you incorporate the required full roll cage. Yes, chassis damage is easier to repair on a GTM since it's tube frame. However, the GTM was adapted to use the corvette suspension, and it's an open question whether the geometry is truly optimized for a mid engine car. SLC designed that way from the start. Finally, look at the ease of body removal for service/maintenance/adjustment. You can take the whole front/rear end off the SLC, don't think that's the case with the GTM.

After i started this thread i found photos of the cage, that looked good. Good point about removal of body, after what i have seen racers modify that on the GTM.
 
We use ours for open road racing. The chassis is STIFF as chassis go. We have several other tube frame cars and we regularly have to do repairs and replace chassis.

It would not bother me to fix moderate damage on the SLC. If more than that I’d be on the phone with Fran working out a deal for a new tub.

if you’ve not looked over both cars closely, you need to. I’m not going to share my thoughts on that other chassis other than to say you won’t see my ass in it running the speeds we are used to.

Im am looking, and asking :) Thanks for answer.
 
I have been working on my SL-C build since early February. I have my chassis sitting on four jack stands at the furthest out points on the chassis you can place them. Since the first day five months ago that I placed the chassis on the stands it has only rested on three of them, one is about 1/32” shorter than the other three. In five months time the chassis has not shifted or settled and is still up off of the one jack stand. This is even with the motor and transaxle now in place, they were not originally!! The SL-C chassis is VERY stiff.

With the past success it has experienced on the racetrack and it’s custom race designed suspension I would call the SL-C the better choice over the GTM but I am partial since I am building one (I considered both before pulling the trigger on the SL-C).
 
I have been working on my SL-C build since early February. I have my chassis sitting on four jack stands at the furthest out points on the chassis you can place them. Since the first day five months ago that I placed the chassis on the stands it has only rested on three of them, one is about 1/32” shorter than the other three. In five months time the chassis has not shifted or settled and is still up off of the one jack stand. This is even with the motor and transaxle now in place, they were not originally!! The SL-C chassis is VERY stiff.

With the past success it has experienced on the racetrack and it’s custom race designed suspension I would call the SL-C the better choice over the GTM but I am partial since I am building one (I considered both before pulling the trigger on the SL-C).
Your first part means nothing. Only it’s own weight stil stand.
Part two, yes I hawe read that to. But I know nothing about the competitors. List or links?
 
Your first part means nothing. Only it’s own weight stil stand.
Part two, yes I hawe read that to. But I know nothing about the competitors. List or links?

Fran has a summary on the Superlite website of his success with the factory car on the track. If you give him a call I am certain he would be happy to answer any questions you have.
 

Scott

Lifetime Supporter
The SL-C's chassis is very stiff. The Superlite website provides the following table and you'll note that the only car with a stiffer chassis on the list is the Ferrari F50. However that number doesn't include the dropped seats which adds triangulation and is now a standard feature. More importantly that number doesn't include a cage so it's for the Le Mans (i.e. a convertible) not the SL-C. The standard 6-point cage will make things stiffer and Superlite can fabricate a FIA-compliant or whatever type of roll cage that you need. I don't think you can get that from FF.

1593916120044.png


Before the SL-C was registered in Australia it was subjected to a chassis torsion test. It's my understanding that the test rig's bolts tore out of the concrete... I guess that's a pass, right;-)

If you look at the video below you can see the flex points in the tube section in the rear. The roll cage hoop between the cockpit and the engine compartment connects to two tubes that extend back into the engine compartment which significantly stiffen things up in the rear.


There are pros and cons to every car. I live less than an hour from FF. I look closely at the GTM and it would have been really convenient to buy from them, but I'm a biased SL-C owner. Superlite sells proven race upgrades and there is at least one company, Agile Automotive, that has built multiple SL-Cs for endurance races (e.g., 24-Hour Thunderhill). They can provide you with proven race parts for the SL-C. For example, I recently installed their motorsport-grade SL-C steering rack which can withstand LMP1-level loads.
 
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Howard Jones

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That is a pretty advanced series as far as car spec is concerned. My guess is it would take $250-500K to build one of those cars from scratch here in the US and expect to win races. I would start with a very comprehensive study of the front running cars, rules package, and teams budgets.

I will assume you have raced in a similar series before. Maybe a rules package with less performance but you understand what is required to run a series.

Assuming you have everything else, trailer, tow vehicle, tools, place to work, and buddies to help, etc. then In all honesty I would start with a used relatively completive car that was for sale from the same series. Maybe a mid pack previous years car. That way you have a known performance target to work towards. If it ran more or less mid pack last year then until you are finishing in the same range I would hold off a new build and development program.

As far as the SLC being completive. It would be in the right hands and in a appropriate series. It have proven results to back that up in NASA here in the US by multiple teams.
 
That is a pretty advanced series as far as car spec is concerned. My guess is it would take $250-500K to build one of those cars from scratch here in the US and expect to win races. I would start with a very comprehensive study of the front running cars, rules package, and teams budgets.

I will assume you have raced in a similar series before. Maybe a rules package with less performance but you understand what is required to run a series.

Assuming you have everything else, trailer, tow vehicle, tools, place to work, and buddies to help, etc. then In all honesty I would start with a used relatively completive car that was for sale from the same series. Maybe a mid pack previous years car. That way you have a known performance target to work towards. If it ran more or less mid pack last year then until you are finishing in the same range I would hold off a new build and development program.

As far as the SLC being completive. It would be in the right hands and in a appropriate series. It have proven results to back that up in NASA here in the US by multiple teams.
Which car did you run?
This is a unlimited class with non pro drivers. Private team’s. I have mostly what I need, but the plan is to start up again with a car. No i check out things in the same time as I rebuild my workshop.
No mid engine car before. 4wd and turbo, and 800hp street car Bmw M3. The tube frame car’s ( Audi) problem seen with my eyes was flex in the frame. Also studying a lot of other cars that i can see this problem. That’s why this thread.
 

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Howard Jones

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Ok got it. You seam to know what is required and are skilled enough to do it. Great! An SLC can be made to run a lap time at GT3 pace. If you add enough power I would think it could be made to go significantly faster. The only limitation is that the car is not a ground effect car. It does however make quite a bit of downforce if setup correctly. It won't run IMSA P2 pace but then its a hell of a lot less money.

I have personally witnessed a very well prepared SLC run the 24 hrs of Thunder Hill NASA event and run lap times at or faster than a Flying Lizard prepared and crewed GT3 Porsche and that was on Hoosier R7's with the Porsche on IMSA series Dunlop's. This was in 2017 or 18 I believe.

So the car can be made fast enough to win armature "open class" races as long as someone doesn't show up with a pro built prototype on race slicks, a big budget and a ringer for a driver.

I don't worry about the Aluminum construction. If you shunt it, it will be the same process to fix it. Cut off the bent stuff and weld on new stuff. Same as steel, just different material and welding process.
 

Howard Jones

Supporter
Oh...…...and the GTM you are looking at won the 25 hour race at thunder hill...………….then the team sold it and built the SLC I mentioned above...……..it was faster...…………...
 
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