SLC Sanity Check

[Alex Webster]

Hi All,

I'm looking into building an SLC street car, which of course has given me plenty of opportunity to fantasize and get carried away with all the potential things I could do as a part of the build. I did have a few questions, to hopefully bring me back to earth:

1. Am I correct in assuming that you can't really finance the kit like you would a normal car?
2. As for engines, I want to get something higher revving than the traditional LS, so looking at either building a Ford 5.2 Coyote, or buying a crashed Ferrari F136. Can either of these options fit in the stock chassis as-is, and should I expect building custom exhausts/headers to be catastrophically expensive? Also, does RCR offer engine mounts for either of these options?
3. I want to go dual-clutch, and I see that there are third party kits/controllers now to run the Porsche PDK with a third party ECU - has anyone attempted to put one in a SLC?
4. Can I get hubs from RCR with a slightly different lug pattern? The wheels I've got a particular lust for are 5x120, rather than 5x4.75".
5. If I order my whole kit at once, minus a few things that I want to spec myself (wheels, brakes, pedals, and a couple other odds and ends), am I still eligible for the whole-kit discount?

I'm an experienced machinist with access to a full machine shop, and fabrication shop.

 

[Scott]

1. Am I correct in assuming that you can't really finance the kit like you would a normal car?

It's not a normal car so you can't finance it like one. You could obviously get a home equity line of credit or a personal loan. Keep in mind that you'll need to budget well past the price of the kit.

2. As for engines, I want to get something higher revving than the traditional LS, so looking at either building a Ford 5.2 Coyote, or buying a crashed Ferrari F136. Can either of these options fit in the stock chassis as-is, and should I expect building custom exhausts/headers to be catastrophically expensive? Also, does RCR offer engine mounts for either of these options?

There have been a variety of exotic engines installed in the SL-C. You can look through the forum, the wiki or call RCR.

3. I want to go dual-clutch, and I see that there are third party kits/controllers now to run the Porsche PDK with a third party ECU - has anyone attempted to put one in a SLC?

I'm aware of a SL-C that's just starting a build; Maserati engine, PDK transaxle, MoTeC engine management, custom engine harness, HGT GCU (Gear Control Unit) and HGT wiring harness for the PDK. This requires configuration and tuning. You'll also need a flywheel, adapter plate, and clutch, but that's something that RCR has a lot of experience with.

4. Can I get hubs from RCR with a slightly different lug pattern? The wheels I've got a particular lust for are 5x120, rather than 5x4.75".

Many SL-C builders replace the hubs with that come with the kit with higher quality ones. RCR is backed up with orders, so I doubt they're going to want to mess around with different hubs. The big questions are; will the hubs bolt up to the uprights and if the wheels have the correct offsets.

5. If I order my whole kit at once, minus a few things that I want to spec myself (wheels, brakes, pedals, and a couple other odds and ends), am I still eligible for the whole-kit discount?

In theory the kit is immutable with the standard options listed in the configutor. In the overall scheme of things, the items you've listed aren't that pricy so I wouldn't expect significant savings even if RCR provides a discount. They are a small fraction of the increased cost of an exotic engine, 3rd-Party ECU, GCU, custom engine harness and the associated fabrication and tuning vs an LS-based solution. Keep in mind that RCR will need hubs, wheels and tires to ship you a rolling car, so they would need to agree to install your custom parts. The foot box is really tight and the 600-series Tilton pedals that come with kit are nice. I know of an endurance SL-C that upgraded to the 900-series Tilton pedals, but those are over $2000. What are you trying to achieve with a different set of pedals?

 

[Alex Webster]

It's not a normal car so you can't finance it like one. You could obviously get a home equity line of credit or a personal loan. Keep in mind that you'll need to budget well past the price of the kit.


There have been a variety of exotic engines installed in the SL-C. You can look through the forum, the wiki or call RCR.


I'm aware of a SL-C that's just starting a build; Maserati engine, PDK transaxle, MoTeC engine management, custom engine harness, HGT GCU (Gear Control Unit) and HGT wiring harness for the PDK. This requires configuration and tuning. You'll also need a flywheel, adapter plate, and clutch, but that's something that RCR has a lot of experience with.


Many SL-C builders replace the hubs with that come with the kit with higher quality ones. RCR is backed up with orders, so I doubt they're going to want to mess around with different hubs. The big questions are; will the hubs bolt up to the uprights and if the wheels have the correct offsets.


In theory the kit is immutable with the standard options listed in the configutor. In the overall scheme of things, the items you've listed aren't that pricy so I wouldn't expect significant savings even if RCR provides a discount. They are a small fraction of the increased cost of an exotic engine, 3rd-Party ECU, GCU, custom engine harness and the associated fabrication and tuning vs an LS-based solution. Keep in mind that RCR will need hubs, wheels and tires to ship you a rolling car, so they would need to agree to install your custom parts. The foot box is really tight and the 600-series Tilton pedals that come with kit are nice. I know of an endurance SL-C that upgraded to the 900-series Tilton pedals, but those are over $2000. What are you trying to achieve with a different set of pedals?

Thanks for all the answers! Seems like it won't be too much of a science project. I was unaware the kit came with Tilton pedals - my interest was in those, as I have some family who live next door to the Tilton shop, and I thought it would be fun to have some of the local product. Ditto the Wilwood brakes I had in mind.

 

[Jeff W]

Hey, I’ve looked at lightning loans. Don’t know where you live, but they offer pretty hassle-free specialty car loans. Probably the direction I’ll go.

 

[Howard Jones]

If I absolutely HAD to finance a kit car like an SLC I would first consider doing a homeowners 2nd or otherwise known as a home equity loan. Those are tax-deductible. You may need to tell the bank you are doing a variety of updates to your home and not buying a kit car, however. That kind of loan is also probably the lowest interest rate available.

On headers: IMHO you can make your own, teach yourself to tig weld and pay for a very nice 250amp tig machine for the price of a custom shop set of headers. You will have the car at home and you can take your time instead of shipping the car to the header builder because he must have the car, more than likely for months. All the pieces are available. Header flanges, straight, 45, 90-degree turn tubing, and collectors in both stainless and mild steel. I like mild steel with inside and out ceramic coating myself better than stainless.

On custom engine tuning: Be absolutely certain you have a tuner that will be able to do the job BEFORE you commit to an engine and engine management system purchase. The question to ask is, have you previously done the exact kind of engine/ ECU combination you are considering and if so how many with references. IMHO there are VERY few really qualified tuners in the country that could do a really wild setup like a Ferrari, V10 Audi, BMW, etc. Be prepared to spend a lot of money on this. Really.............I'm not trying to scare you off just to make you aware of the issue before you have what can be a really serious problem in your garage.

The PDK interface and torque performance capability improvements are the same issues. Be absolutely certain you have someone that can and has made it work before and at the power levels you are considering. I would want to see a running car if it was me. You do not want to be the prototype for this.

The hub issue has been solved and I believe that RCR's current hubs are more than adequate even when used in a weekend track car with moderate hp levels and track tires. Talk to Fran about this and let him know what your power requirements are. Buy what you need the first time and spend your money once on the right stuff.

Wheels: SLC's require that the wheels you might want must be known to fit, be trial fitted, or purchase the wheels available from RCR. IMHO I would only use 18 inch diameter wheels if you intend to run slicks on track. 18 inch is the current standard diameter for most prototype racing series and there are a lot of used/ very good tires available in the correct sizes for an SLC. This can be a HUGE savings in track costs. Otherwise used corvette takeoff wheels and tires will work from the C6 ZO6 onward. Used C7 Corvette wheels seam to be plentiful on ebay and GM wheels are generally very strong and well made. I would stay away from cheap offshore copys. You know what I mean.

I looked at doing an RCR 917 with a Cayman S powertrain in it but pumped up to around 500HP at the time I was considering my SLC purchase. The $$$ required to do this was eye-watering at that time AND there were many unanswered questions related to electronics, tuning, and software. I was pretty sure I would need to have a wrecked but running Cayman to start with. I finally decided on my SLC instead.

Anything can be done with, TIME and $$$$$$, but IMHO I would recommend a current LS 525HPish crate motor and the RCR recommended transaxle. Compair apples to apples. Establish an all in price for the baseline setup LS/ Graziano with your preferred gear ratios and a TBD diff. Then begin to total the cost of doing your optional powertrain. When you reach twice as much sitdown and have a think.