TJM

This will probably degenerate rapidly, but here goes.

I am going to build a specific purpose car for HPDE, no street, no drags, no aspirations.

Just a car that will go fast, be reasonably competent, be a Corvette, and be fun.

So, now the abusive part. It will be a 1984 model.

[ It will be reduced to parts and built up from there.]

I am a big fan of planned maintenance so I am willing to spend the money to have parts that last.

#1 priority will be making brakes. I was thinking C5 brake parts & good rotors. I know the swap is popular and fairly easy, but question is the ’84 geometry?

Any one done this?

TJM

Solofast

The 84 geometry is fine, not sure what brakes bolt on to it, but I've always held that the earlier front end geometry is very bit as good for a track car. The later zero scrub geometry has less kickback, but on a track car that is less of an issue. The early suspension weights up more in terms of steering loads, but it isn't really that much different, the power steering just works a bit harder. It doesn't need as much caster as the later cars. The early geometry doesn't lose as much negative camber in tigher corners, but that isn't as much of an issue with a track car as compared to an autocross car.

Our BSP autocross car had early front end geometry and a later (96) rear suspension and it worked just fine.

TJM

Thanks. it's a start. Road Atl, and the new track coming in Dasonville Ga will be the most frequented tracks.


Now the brakes parts issues?

Single piston '84 calipers are not to be considered.

So? C5 or later C4? ............ Or after market?

I have a bit of trouble selling myself on aftermarket calibers.

Pads and rotors yes, but calipers???

TJM

John Shiels

C5 calipers at a minimum

geerookie

How about some Wilwood SL6R full size calipers with T2 pistons.
They won't spred like the C5 calipers, won't taper the pads and speaking of brake pads, they are twice as thick and cost half as much!

You can buy a pair of SL6R calipers new for less than $590 delivered to your door and Gary Hoffman can make you some radial mounts or possibly VanSteel already has some for a C4.

jaa1992

Ok, I'm not going to laugh or even snicker at using an 84 as a dedicated track car.
I know one guy in Richmond that embarassed C5's at the track in his 84.

For brakes, I'd go with C5 fronts - remember some 17" wheels won't clear the calipers.
Get some air in there!

Please put a full cage in it!

TJM

Yes Si, without a doubt. Full cage for sure, I will have a 16 year old squid in the car.

Fire suppression as well, bay, cabin, and cell.



I have seen a lot of positive on the C5 set up, and I have a dedicated machinist [as as one of the driver's] to fab the small stuff so I think these will be the first sets ups and give them a few runs.

I assume I will need spacers for 17" wheels? Finding weights on these has been a challenge, so far.



TJM

Kubs

That sounds like a deal! If I have conversion brackets on my car for the C5/6 calipers, what else is needed to use the SL6R?

mgarfias

I'd get a dedicated C4 to SL6R conversion bracket instead of trying to monkey a C4->C5->SL6R bracket.

In fact, if you're willing to deal with the Narrow SL6R caliper, Wilwood has a kit already: http://info.wilwood.com/BrakeKitsSub...e=Front%20Kits

If you want to run the better (wide-5 caliper), you'll need a custom bracket. Call Van Steel and see if they have anything off the shelf, if not call Gary Hoffman, and get him to design a bracket. You will need to check your wheel fitment with these calipers, I know it'll be pretty tight.

Kubs

How does the SL6R compare to the stock C5/6 caliper? How does the Wide-5 differ?

mgarfias

SL6R = 6pot fixed radial mount caliper.
C5/C6 = 2pot slide rail.

Compared, the 6pots are going to be stiffer (better brake feel/higher pedal), and thus provide better modulation. Also, remember that aluminum has lost 1/2 its stiffness by 400deg. Those PBRs spread and end up taper wearing the pads. The T1 guys replace them fairly often due to this.

Ryan0 just put a set of the narrow SL6Rs on his car, and said he was able to go into the corners much deeper than with the PBRs.

The narrow SL6R is narrower. It uses a 16mm thick pad vs the wide version using a 20mm pad. The Wide-5 version has the exterior stiffening rib milled off. Its narrower than the full wide caliper, but still wider than the narrow caliper.

Oh and the narrow caliper will accept a 14" rotor, where the wide versions only go to like 13.8 or something.

BrianCunningham

have you looked into one that's already prepped?

might be cheaper in the long run
http://tccracing.com//joomla//index....id=3&Itemid=72

BTW here's real good primer

http://www.tccracing.com/gettingstarted.htm

geerookie

The SL6R's are much stiffer and have very little pad taper.
The C5 brake pads are about twice the cost of SL6R pads.
Using Cobalt Friction XR2 pads for a C5 caliper cost's $389 a set.
Same XR2's for SL6R's cost $189 per set.
C5's have about 9mm of braking material
SL6R's have about 15mm.
Won't take long to pay for the brake calipers and mounts with the savings in pads!
With my savings I'm going to fund a new set of CCW Corsair wheels,
Or maybe more track time but the wife is already complaining that 30 days a year is to much.

Kubs

This is good info. I am looking to use the stock C6 Z51 size rotor (13.4) and keep my 17" wheels. I like the fact that there is more pad too. Sounds like the narrow one would work for my application. time to start saving.

mgarfias

I don't think you'll be able to get the C6Z51 rotors under the 17". I was thinking I'd do the same thing, but measured at .125"-.200" clearance, which I don't think is enough.

Measure carefully (and do it 3-4 times).

geerookie

Just be aware, with the narrow ones you lose some of the stiffness/rigidity and the pads are only about 10.5mm of brake material.

geerookie

Also with Z51 rotors at 13.37" diameter the calipers will not fit properly unless you use the narrow ones
part# 120-8000-RS/8001-RS. They will work with up to 14" rotors but they have removed a lot of the caliper mass to make it work and be narrower.
Personally I wouldn't go that route for a track car.
Go with the full size, use standard size rotors (less money) and go to a more aggressive pad compound.
You may have to go to a 18" wheel on the front but maybe not. I will have mine installed in a few weeks and will try my 17" wheels and see if they fit.

Kubs

Im thinking .125"-.200" of clearance is pleanty. My dad and I put 12" rotors and calipers from a GMC Envoy on his '91 Camaro and only had about that much clearance with 15" wheels and it didnt seem to be an issue.

I like the idea of having more caliper for strength. I think my only issue now is I do not have room for a full width caliper on my current wheels. Ill have to wait to get another set so I might as well save for 18" wheels, full size caliper, and 14" rotors.

TJM

No, never considered a prepared car.

Reason #1 is to teach the 15 year old something and too make him work at it.

#2 Is we have some much racing stuff, heads blocks carburetors, most everything needed for drive line other than the transmission and flywheel it would be excess.

Plus being red neck greasers, we pretty much have to do it ourselves to get the real bragging rights.

No offense but I could spend $60,000 on a C6, but have car that is just that much more than I can handle!

TJM

TJM

Wheels will be determined by the brakes.

Lucky to start with a fresh sheet of paper.

Leaning towards 18"

TJM