A Few Specific Questions For An SL-C Build

Ok, I know there are several "newbie" threads looking for info on building an SL-C. This thread is similar, but different, I hope. I have done extensive research for a GTM build, which also includes a very detailed parts/price list unique to my build desires. Based on that experience, and what I have been able to pull from these forums, several of my questions have been answered. However, not all of them were answered so I will try to make my questions as specific (and not as repetitive) as I can.

The purpose of the car is a street car, with all of the creature comforts of a street car, that can be used at the track occasionally. As a point of reference, I currently track my "mildly" modified 2005 BMW M3 which is still very much a street car (and more than enough for me at the track at my skill level). My thoughts are that a "street" SL-C will run circles around my M3, thus I do not intend to do any of the race upgrades available for the SL-C as that seems like overkill for me and not money well spent for my build. For me, going to the track with this car would basically entail only changing tires and brake pads (and possible brake fluid if necessary) to make the car "track ready".

Now on to my questions.....

1. Plug-n-Play Engine/Trans Advice. I found a thread that discussed various engine/trans combos - good info. As the GTM is LSX based, my planned combo for that build after taking several factors into consideration (LS376 w/G50-20) seems right at home in an SL-C. I don't have any desire to modify the engine, I just want simple reliability and performance and be able to just "plug-n-play" in the car with little to no modifications from the kit as designed. So the question is, as the SL-C offers more engine/trans options than a GTM, are there any other good plug-n-play engine/trans combos for the SL-C in the 400-500 HP range that may be less expensive than the combo I listed above (I know some money can be saved by using a LS1/2/3 or a different G50 box, but I want to know if there is some other good combo out there that might have similar performance)? Also, my current preference is for a new vs used/rebuilt engine for cost and reliability reasons.

2. Headers and Exhaust. I have not found a lot of info here, maybe because there several engine possibilities for the SL-C. Again, I am not looking for anything fancy here. My basic requirement would be a system that has headers, CATs of some sort (to make it street legal and cut down on exhaust smell), and mufflers. Again, the plug-n-play principle applies as I have no desire to make any radical body or frame modifications to support the exhaust system. Any recommendations? Are there any "kits" available or is it all custom exhaust work?

3. Air Intake System. So far I have only seen designs that encompass a filter open in the engine bay (not a fan due to the heat build up) or a tube that is snaked to one of the side vents. I am actually willing to be a little creative here, as I was planning to do so for a GTM build which can be seen here. I saw a pic of something similar for the SL-C here on the forum, but also looking for other intake ideas as well.

4. Engine and Transmission Coolers. Are they even necessary for an SL-C (they are for a street GTM after my research IMHO)? If so, what is the best and simplest setup (the plug-n-play principle applies to the max extent possible here, but I understand there may be some fabrication involved if RCR does not already have a solution)?

5. Air Conditioning. From my searching I could not confirm if a Vintage Air Gen II or Gen IV was used in the current kits. I know how to integrate a Gen IV, but want to know if I need to bother researching about the Gen II, which is slightly different.

6. Power Steering. Has anyone done this and would it be helpful for a street SL-C? I saw this as an option, but only for the racing steering column (which is too spartan for me in a street car build). I planned to do this upgrade for a GTM build (which uses an OEM Vette steering column) and it basically consists of a Ford Mustang based steering rack (the GTM rack does not have the plumbing, but the Ford rack is a direct swap), an MR-2 electric power steering pump assembly, and a programmable controller. Definitely not plug-n-play, but I feel is within my install capability after my research (at least for the GTM). More info can be seen here?

I guess that is all for now. Hopefully I was not too repetitive. Oh yeah, pics are worth a thousand words here, especially for any air intake or oil cooler setups.
Hey there...

I have read many of your post over on the FFcars site...

As for your engine and transaxle choice , as a value for money option you have chosen the most realistic pairing....presuming that you want a 6 speed, readily serviceable unit and being cost conscious...the LS3 with a new ECU wiring and EC/Harness is the best value and the G50 family same again....they really are very plug and play...With ISIS being a standard DP kit component the integration of the tilt power column etc is very easy. We even included the lift kit wiring pigtail as a standard ISIS circuit as many guys use the lift kit from day one.

Headers and exhaust...even on our race SLC we use factory LS7 exhaust manifolds ..they support upto 700hp , they are double walled stainless and hug the block very well....GM spent millions of dollars developing them and as they are the same ones fitted to the LS9/ZR1 they support plenty of power and are available very inexpensively....headers are available but at a price...Tailpipes...we have standard side exit units but they are more track focussed ...and as each customer wants something a little different we cannot build a one size fits all and keep everyone happy...sorry

Air intake...depends upon your choice of street or race tail ...with a baffle to stop hot air being sucked/blown dirrectly into the air cleaner the open filter is very effective...again we race with this exact set up and we monitor intake temps with very little/no power drop off...
An intake plenum could be configured to draw air from the side scoops but as you have mentioned, we have many different engine/trans choices and with each requiring a different length/size/location its impossible to make one size fit all... with choice comes a little compromise I guess.
Shanes rear window looks great and it that much more effective at removing hot/radiant air too...which is never a bad thing.

Engine trans cooler...we have had success with an oil filter sandwich plate adapter...and a Mocal cooler(location depends upon drivetrain once more) but they are not absolutely necessary for street use...any transaxle will live longer with a pump dropping oil ontop of the RP/gearsets , ...a cooler may not always be necessary if the oil is circulated well...again a tested item in race conditions(no cooler, pump only)

Air con..Vintage air is standard with the DP kit ..they have a custom evap box for the SLC and we make a custom plenum that distributes air under the dash and to the dash/windscreen vents.

Power steering...not really necessary as the steering is not heavy at all...the electric units we use could be fitted with a street column but require the chassis to be modified for packaging...I am sure there will be guys in the future doing some inventive things with power steering if they feel its necessary...the only reason we run it on the race car is due to VERY high downforce and wider slicks...plus to keep the drivers fresh during a race.

Hope this helps and I know many guys will share their opinions too...
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I'll give it a whirl:
1. LS3 in any flavor/G50 gearbox. Call Erik at GBOX.
2. LS7 exhaust manifold and cats/SPF mufflers, fabricate connections.
3. I'm liking the GTM solution with a little different styling.
4. Better to have than have not. Fairly easy to do.
5. Current Vintage Air for the car is SL-C specific. All electronic including the
heater water valve.
6. I don't think it is necessary, go for it if you must have.

Advice: Don't overthink solutions. Don't go out and make a bunch of purchases until you have to. You may change your mind about some things that you'll find are not needed.
Thanks for the replies so far guys. And Fran, I didn't know my reputation preceded me from over there. Hopefully that is a good thing :) .

To provide a little more clarification based on the initial info provided.....

I intend on using the street tail as far as the air intake is concerned. Not sure if that makes air intake options/fabrication easier or harder than the race tail.

My question about the A/C unit was more about the electrical interface. I intend to use ISIS and I know ISIS has a direct interface for the Gen IV. The Gen II is similar, but I wanted to know if I would have to make my own ISIS interface or if the SL-C variant used the same interface as the standard Gen IV.

I am still keeping an open mind on the power steering. I had the opportunity to sit in a GTM and was surprised at how heavy the steering was. When I saw the mod that was created for adding power steering, it seemed like a no-brainer. I would like to have an opportunity to sit in an SL-C as I would also expect the steering to be light as you have mentioned. I would like to learn more about the feasibility of adding power steering to the GM column, or the ability to modify a race column to add some street capability (i.e. a turn signal switch at a minimum).

One other new question, what about ABS? I have seen some race standalone ABS systems, very pricey. Has anyone been able to incorporate it? For my GTM build I was planning on using a self contained ABS system taken from another car.
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So have you decided against a GTM ?

Street tail has two large vents that allow more intake air options

ISIS is supplied as part of the kit and the harness is specifically made for the SLC. and its systems....all the lights/switched circuits on the supplied tilt/telescoping electric steering column are fully operational functions with the ISIS system provided...very plug and play whe compared to multiple relays etc .

Stationary steering does not equate to steering feel or weight when driving...

ABS from Bosch as a race system is on the cards to install this season in the SLC race car but nobody as yet has installed it in a street car...
If you have already designed /re-engineered another system to fit a GTM then it can certainly be fitted to an SLC...the chassis/dynamic parameters must be tuned to the CG/weight bias etc etc of each car individually or it will be worthless...and potentially very dangerous...dont expect a Corvette or similar to be tuned to work in a mid engined car ..

Ken Roberts

I just received my backordered AC unit. It is neither a Gen IV or Gen II. It is basically a "mini slimline" from Vintage Air. The only thing custom about it is the front panel has been left blank. It is up to the owner to cutout the outlets to match up with the holes in the aluminum panel that is located above it's mounting point. There are no "blend doors" or seperate "defroster outlets". If you want to defrost your windshield then you simply close the dash outlets and the air then gets forced down the defroster piping only. The included servo controlled water valve is the only way to control the temperature. Well that and the fan speed settings.

So...as far as the electrical interface goes there are 3 fan speed settings (one knob) and AC on or AC off (the other knob). Also there is the servo controlled water valve to control how much coolant is allowed to flow through the heater core.
Fran, I haven't completely given up on the GTM. However, after looking more at the SL-C, I like the fact that the body work and interior of the SL-C seems more "shade tree mechanic" friendly than the GTM (for a guy that has never done any body or interior work).

The ABS is still a bit of a research project, for some of the reasons you mentioned. However, it is still on the table for me based on the research I have done thus far.

Regarding my A/C question, what I really need to know, I guess, is can I interface the SL-C A/C system with ISIS so that I can use the ISIS touchscreen interface.
The optional ISIS interface to Vintage AC is only for Gen 4 systems, which don't fit in the SLC or the GTM.

You can use ISIS to control the fan (I am planning to do this), to turn the AC on and off (ditto), and possibly to control a servo to control heat.

The actual AC adjustment is mechanical and would need a servo to convert a signal to a rotary mechanical motion.
Ok thanks for the A/C info guys. I now know what I need to do to make it work with ISIS the way I want. It would be similar to the way Will mentioned, incorporating some type of servo motor to control the manual AC knob.

Ken Roberts

Here is a link to pictures of one installed in Grants SLC (see post 15). He has the same unit but without the heater core. The evaporator has been flipped so that the inlet/outlet pipes are on the drivers side of the AC unit.

He made a new aluminum box (with the holes in it) to match up with the holes in the SLC. The one supplied from Vintage Air is just left blank. I'm just going to make a flat aluminum panel for the top with holes in it then bond it to the blank one.

Mike your SLC is actually using a Gen II Mini. It has seperate defroster and foot well outlets controlled by a servo motor. :thumbsup:

Ken, You are correct and it seems to work pretty well. I don't have a compressor in yet so the jury is still out on the A/C.
I believe the Gen3 had an interface as well but I don't think that was ever used with ISIS.

The ISIS inVIRONMENT control module interfaces directly with the controller on the Vintage Air GenIV evaporator units.

The optional ISIS interface to Vintage AC is only for Gen 4 systems, which don't fit in the SLC or the GTM.

You can use ISIS to control the fan (I am planning to do this), to turn the AC on and off (ditto), and possibly to control a servo to control heat.

The actual AC adjustment is mechanical and would need a servo to convert a signal to a rotary mechanical motion.

The GTM's Vintage Air system is the GenIV and works the inVIRONMENT control module.
The GTM's Vintage Air system is the GenIV and works the inVIRONMENT control module.

Vidal, is that right? I didn't think that the GTM used a GenIV unit. The ones I have seen were all previous versions, or so I thought...

If so, that's great for the GTM crowd.
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Vidal, is that right? I didn't think that the GTM used a GenIV unit. The ones I have seen were all previous versions, or so I thought...

If so, that's great for the GTM crowd.

Yeah. It's a GenIV unit with a set of lines/fittings adapted for the GTM.

Quite a few Guys, using the ISIS Multiplex, have added the inVIRONMENT module (Two of them were completed in the last month).