SLC technical questions

[Alexander M]

Hi there,

I have been playing with the thought of buying an SLC superlight for a long time. Before I go into the project, I would like to get a few more technical details, if anyone here has some answers, i would greatly appreciate it.

1) Aluminium frame rear: what size are these? They appear to be 50x50x2 but not sure. I have seen few frames now and noticed that some of these kit cars have really low torsional stiffnesses. Wondering what the situation is here with the SLC. Does "superlight" mean "so light that torsional stiffness is also very low"?

2) Aluminium grade: what grade ist that aluminium tub? Is this 6060? Can it be welded?

3) Accuracy after welding: how accurate is that aluminium chassis? Are we talking few millimeters out on the pick/up points, more or less?

4) Corrosion resistance with salt water: an issue in some places where salt is used on the road for half of the year. I noticed some are painting the frame, some not. What is the consensus here?

5) Why the choice of aluminium / imagine using 316 stainless steel / no corrosion issues anywhere. Wall thicknesses would have to be 1/3rd for roughly the same mass and the same stiffness.

6) What is the weight of the chassis including the suspension? I want to use a turbocharged motorcycle engine with 280 horsepower - the weight including gearbox and drivetrain is below 100kg. I want to get below 600kg with the build. Happy to make compromises on wheels (narrow wheels), etc.

Any input here would be greatly appreciated!

 

[Howard Jones]

6) You can't build a 1350-pound SLC............drop the mike. 1350 pounds is an early small motor Radical. A radical is a MUCH smaller car. Look at it this way. My SLC is about 2450 ish. To take 1000 pounds out of the car you would have to REDUCE EVERY PART ON THE CAR by more than 40%. Not possible. Period.

 

[Alexander M]

Thanks for the reply. This will be quite challenging - and result in probably a completely custom made car that has nothing to do with the SLC. One question: do you have a mass overview of your car? Some baseline that I could attack and actually ask "what would you need to do to get half the mass of every part"? That would allow me to move ahead. Thanks

 

[Fred W Ballinger]

Agree with Howard

Berlow is my mass spread sheet for my space frame project. Its not yet quite complete, and already I am over 1850 pounds. Most Items are verified masses, others are estimated and their might still be some bits to add.

Part	Qty	Mass kg	Total		pounds
Spaceframe chassis	1.00	115.00	115.00		254
Roll bar	1.00	13.00	13.00		29
Spaceframe chassis panelling	1.00	38.00	38.00		84
Engine to gearbox adaptor	1.00	4.00	4.00		9
Engine RV8	1.00	125.00	125.00		276
Gearbox Audi	1.00	70.00	70.00		154
Flywheel	1.00	7.00	7.00		15
Clutch	1.00	6.00	6.00		13
Exhaust Manifolds	2.00	6.40	12.80		28
Exhaust Silencers	2.00	3.30	6.60		15
Gear Lever assembly	1.00	1.78	1.78		4
Gear Linkage complete	1.00	5.00	5.00		11
Steering rack - cortina	1.00	4.00	4.00		9
Steering rack clamps	1.00	0.84	0.84		2
Steering rack lower bracket	1.00	0.60	0.60		1
Steering shaft upper	1.00	1.80	1.80		4
Steering shaft mid	1.00	0.80	0.80		2
Steering shaft U Joints	3.00	0.48	1.44		3
Shock support plate	1.00	0.65	0.65		1
Rear wishbone upper	2.00	0.72	1.44		3
Rear wishbone lower	2.00	1.27	2.54		6
Rear wishbone toe link	2.00	0.18	0.36		1
Ampep Silverline rod ends & spherical bearings.	24.00	0.35	8.40		19
Front wishbone upper	2.00	0.54	1.08		2
Front wishbone lower	2.00	1.28	2.56		6
Front push rod	2.00	0.29	0.58		1
Front upright with disc	2.00	10.60	21.20		47
Rear upright with disc	2.00	7.30	14.60		32
Wheels Front - 6 J Miniltite / 225/60 BFG	2.00	22.00	44.00		97
Wheels Rear - 7 J Miniltite / 245/60 BFG	2.00	23.80	47.60		105
Protech coilover dampers + spring	4.00	2.36	9.44		21
half shafts & CV joints	2.00	8.00	16.00		35
Front Brake caliper	2.00	4.33	8.66		19
Rear Brake caliper	2.00	3.60	7.20		16
Steering wheel	1.00	1.22	1.22		3
Pedal box,	1.00	1.62	1.62		4
brake / clutch cylinder	3.00	0.29	0.87		2
handbrake lever	1.00	0.60	0.60		1
Body rear clip	1.00	30.00	30.00		66
Body nose	1.00	25.00	25.00		55
Body scuttle	1.00	8.90	8.90		20
Body LH door	1.00	5.40	5.40		12
Body RH door	1.00	5.90	5.90	75.20​	13
Rear subframe	1.00	3.30	3.30		7
Rear clip support	1.00	1.70	1.70		4
Door mounts	2.00	0.23	0.46		1
Body panel catches, pit pins and fixings	1.00	5.00	5.00		11
Alloy fuel tank - foam filled	3.00	15.00	45.00		99
Fuel sender	1.00	0.00	0.00		0
Alloy flush fit fuel filler, neck, hose and fittings	1.00	0.00	0.00		0
Pro Fuel Filter	1.00	0.00	0.00		0
Braided hose kit chassis runs for brakes & clutch	1.00	0.00	0.00		0
Alloy radiator for US V8's	1.00	15.00	15.00		33
Cooling hose & Alloy chassis pipes	1.00	10.00	10.00		22
CF66 Twin Fan kit for high BHP	1.00	10.00	10.00		22
Coolant swirl pot & expansion tank	1.00	5.00	5.00		11
Body loom, relays & fusebox.	1.00	15.00	15.00		33
Front and rear light pack.	1.00	15.00	15.00		33
mirrors	1.00	5.00	5.00		11
insturmetns	1.00	8.00	8.00		18
Head Rests	1.00	0.00	0.00		0
Wheel nuts	1.00	0.00	0.00		0
harness	2.00	5.00	10.00		22
battery	1.00	12.00	12.00		26
total			839.94		1852

 

[Robert Jones]

buy a wolf or a radical and modify it like you want

 

[Chris Kouba]

One question: do you have a mass overview of your car? Some baseline that I could attack and actually ask "what would you need to do to get half the mass of every part"? That would allow me to move ahead. Thanks

Why attack Howard's list? You'd be better served to make your own instead.

 

[Jeff W]

To cut the SL-C by ~40%/1,000lb mass simply isn't practical or reasonable. You'd be better off buying something else or scratchbuilding your own car. That amount of reduction is like trying to unscramble an omelette. It's not possible, and even if you could, you'd need an engineering degree and years of work to figure out what parts could be cut, how much, where, and then the time and money to actually execute the reduction.

Off the top of my head the obvious ways to reduce weight is to strip all interior parts and exterior extras like wheel well liners, go for the smallest all-aluminum engine you can for the HP you want and slap some turbos on it, then remake the entire body in carbon fiber. That should knock off close to 500 lb or so. Oh, and skip the air conditioning. This is a car that will not be practical for anything other than racing, and it will be really expensive to get it there.

 

[Howard Jones]

I would be happy to provide you with a complete list of parts necessary to build a car with a target horsepower and weight target. Other requirements will necessitate additional costs. This will require you to provide a proposed contract for me to review and counter. Should you do so I will require you to agree to compensate me for the cost of review of your contract proposal including but not limited to legal review and drafting my counteroffer. Please include a proposed method of payment and payment schedule with proposed milestones. Please provide which jurisdiction you currently reside in and be prepared to provide background information including banking records.

Be aware that I intend to propose an escrow process at your expense as a method of ensuring timely payment(s).

Should you be willing to go forward you can send me your contact information via PM.

 

[Mesa]

"Superlite" is a marketing moniker. Representing a general desire to use light weight materials to build a reasonably light car at a reasonable price point. How unreasonable you are from there is entirely up to you.

 

[David mono]

I don't know why more people build a Lotus seven / Caterham seven style car, How to build a cheap sports car and Build your own sports car for as little as 250 are both good books. You want light weight this could be it.

 

[Hector]

agree with the above. now if you want to take it to the next level, the lotus seven based Donkervoort F22 checks all the boxes. 1654 lbs , 492 hp turbo Audi engine. insane power to weight ratio, 0-60 in 2.5 seconds. Truly amazing car performance wise because it is so light.

https://www.motortrend.com/reviews/donkervoort-f22-first-drive-review/

 

[Steven Lobel]

battery recommendations

www.diyelectriccar.com

Still too heavy because of current battery needs. 18 Pacifica batteries, cooling plates, and electronics will get this up to 2500 pounds. Still 2200 pounds lighter than the Model S.