87350IROC

iTrader: (2)

Hi folks,

CTW Motorsports was kind enough to send one of their wheels out to me to check fitment with a bunch of Perdoch brake kits. The idea being both companies will learn and benefit from this experience.

In case you are not aware, CTW Motorsports offers a direct bolt on (no spacers/adapters) 17x9.5" wheel that is affordable, lightweight, and has great brake clearance. We will be putting that to the test. Check out their website:
http://ctw-motorsports.com/

Perdoch is a design, engineering, and manufacturing company specializing in high end parts, service, and consultation for the gen III F-body. They do not have a website yet, but can be contacted at: john@perdoch.com

Here are the components we plan to test.

Rotors:
4th gen F-body - 12x1.25"
C5 / C6 - 12.8x1.25"
C4HD - 13x1.1"
C6 Z51 - 13.4x1.25"
SS Camaro - 14x1.20"
C6 Z06 - 14x1.25"
gen II CTS-V - 14.6x1.34"

Calipers:
4th gen F-body - 2 piston
C5/C6/C6Z51 - 2 piston
Wilwood FSL - 4 piston
SS Camaro - 4 piston
gen II CTS-V - 6 piston

And the caliper/rotor combinations we plan to test.

Caliper-Rotor
4th gen - 4th gen
C5/C6 - C5/C6
C5/C6 - C6Z51
C5/C6 - C6Z06
FSL - C4HD
FSL - C5/C6
SS Camaro - C5/C6
SS Camaro - C6Z51
SS Camaro - SS Camaro
CTS-V - CTS-V
CTS-V - SS Camaro

We are curious to know if any of the members are interested in seeing any other combinations? We are open to considering other rotors and calipers.

Testing should commence this weekend.

Thanks,

John

paul_huryk

John,

We at CTW Motorsports appreciate the opportunity to send you a wheel for testing fitment with your many brake systems.

At this point, with our previous fitment testing, everything but the 14.6" CTS-V setup should clear our wheels (and it possibly might fit too) - we have had cars here in the shop with various aftermarket kits up to the Baer Extreme+ 14" 6 piston setup and everything has fit with space to spare so far.

While sometimes expensive (at least some aftermarket kits), upgrading your 3rdgen brakes is one of the best safety enhancing (and also performance) things you can do. Stock 10.5" front brakes are seriously underpowered and today provide poor stopping performance. Even a basic 2 piston 12" kit can drop 20' off your 60 to 0 stopping distance and will not fade like factory brake do. Considering a lot of stock 3rd gens can top 140mph stock, running bigger brakes is a really good idea.

87350IROC

iTrader: (2)

I couldn't agree more. Please feel free to add any pictures you have for brake kit fitment.

I am quite excited to try the CTS-V setup on both the 14.6" and 14" rotor.

paul_huryk

Here the Baer Extreme Plus 14" with 6 piston caliper shot:

Nelz

Hmmm...do you think the SSBC Extreme 4 piston caliper will fit?

http://ssbrakes.com/i-10093251-extre...brake-kit.html

I was looking at that upgrade (after my currently upgraded Hawk Pad and slotted Rotor with stock caliper)

But then I saw the Baer Extreme Plus 14" kit from above...

87350IROC

iTrader: (2)

That caliper should fit just fine. Its all about how much performance and looks you need, and how much you want to spend. There are a lot of great brake kits out there.

87350IROC

iTrader: (2)

Ok, I got a nice package from CTW today. Here are some pictures. Paul, I have to suggest that you fire your photographer. I like these wheels much better in person than in pictures.

For all pictures, right click - view image for a larger picture

Nice packaging






Very nice looking wheel.

87350IROC

iTrader: (2)

These wheels carry the JWL standard, which is a good sign.




And with the center cap installed

paul_huryk

John - thank you for the glowing compliment of my photography skills!

And the black in person looks 10x better than the silver compared to pictures...

Can't wait for your brake kits to be stuck under the wheels. Keeping fingers crossed on the CTS-V 14.6" setup!!!

87350IROC

iTrader: (2)

I finally made it home before dark today. I few pictures in more natural light.

87350IROC

iTrader: (2)

And the contenders. Please right click - view image for largest possible image.

iansane

iTrader: (1)

Definitely interesting! Thanks for doing all this legwork for fitment information. I have the c6z06 calipers/rotors if you want to try a test fit on that as well.

87350IROC

iTrader: (2)

That would be awesome. Did you want to stop by, or should I come to you? I should be free most of the weekend.

John

iansane

iTrader: (1)

Well the car won't move under its own power for another few weeks so you'd have to stop by here.

87350IROC

iTrader: (2)

Sounds like a deal. If you don't mind, send me a PM for when you have some free time.

paul_huryk

This is something I can't wait for!

InfernalVortex

iTrader: (4)

Any JWL wheel is going to be a good piece.

Zach/90\irocZ

iTrader: (6)

I agree black looks 10x better I wish I can see them in gunmetal been eyeing them for awhile thinking of changing my wheel setup again lol for theses more I look more it grows on me looking at the silver ones I wasn't a big fan of them at first hmmmmm gunmetal also 18 would be interesting

paul_huryk

The black wheel looks awesome in certain cases - I love it on my white GTA, but on my blue Camaro - silver looks better to me.

At this point, we only offer the wheels in silver and black. But you may strip them (they are painted) and can paint the wheels (and centercaps) any color you like, including gunmetal.

Zach/90\irocZ

iTrader: (6)

I guess I'm bias I have white iroc lol

87350IROC

iTrader: (2)

A special thanks to Iansane for letting me test the wheels on his car. Beautiful car with lots of unique touches.

The brakes fit inside the wheel. There is about a 1/8" gap between the wheel barrel and the top of the caliper. And lots of space between the face of the caliper and the back of the spokes. I must say, it does look awesome with the entire wheel filled by the brakes.

As always, right click - show image for a larger version.



About a 1/2" between the tie rod and the wheel


Tight fit, about 1/8" clearance


Again about an 1/8" clearance


Lots of spoke clearance




And its not pictured, but there is clearance between the strut body lip and the wheel. I didn't measure it, but would estimate around 3/8" or so.

John

paul_huryk

I like!!!

87350IROC

iTrader: (2)

I am sad to report that the 14.6" CTS-V setup does NOT fit inside the CTW wheel. It is close. My plan is to try it again at some point with a slightly different bracket that brings the caliper in just a smidge on the rotor. I am also going to try the CTS-V calipers on the 14" SS Camaro rotor, which should fit well, and look awesome. Progress continues.

Zach/90\irocZ

iTrader: (6)

Looks very nice those brakes fill the wheel up nicely

Nelz

It looks good. I guess my question would then be, is 1/8" inch enough space to add a wheel balancing weight? (You know, the ones that stick inside a wheel when you balance a tire?)

BumpaD82

off brake fitiment topic, BUT why is the center cap(s) so "TALL"

~DaVe

paul_huryk

DaVe,

Excellent question - here is the answer:

The wheel has a very shallow mounting face - when you place it on the car, the hub sticks out a few inches out of the middle of the wheel, just like a 1982 to 1987 15" Z28 wheel. As you can't leave the hub exposed on a street car, I had to get a center cap that would both cover the hub and also looked good - the one we chose is the only one that accomplished both. We were actually going to build up the center portion of the wheel to cover the hub (like an IROC wheel), but it added a lot of weight and looked very awkward. Believe it or not, our cap measures almost the same as a 1987 and up lace Trans Am center cap.

paul_huryk

I figured with the tight Z06 fit, the 14.6" CTS-V setup would not fit. The good thing is that the 14" Z06 one fits our 17", something some manufacturers need a 19" to clear - GM uses a 18" OEM wheel.

paul_huryk

Yes you should use them - just don't hae them placed on the wheel where the caliper will contact them and rip them off the wheel barrel...

87350IROC

iTrader: (2)

Yup, no doubt. For the wheels on my personal car, I added a lot of backpad in order to completely cover the spindle pin. And I also cut off the unused spindle threads and run a modified dust cap. That bought me around 3/16".

I will take some measurements, but obviously with an aftermarket brake kit, the center cap could theoretically be about 0.3" to account for the rotor hat thickness.

Another really great option is to use an aluminum hub that has a pretty machined aluminum dust cap. These are the kind I include in my kits. With this option you could run no center cap and probably look decent. I will take some pictures later with the dust cap removed, and the hub poking through.

87350IROC

iTrader: (2)

Very cool. I think this is a pretty good solution for people who don't like the larger center cap. Of course you could paint them silver to match the wheel. The caps are machined aluminum.

This is with the CTS-V 14.6" rotor by the way. Looks nice in there.

As always, right click - view image for a larger version.

paul_huryk

Very nice! Even better view behind the wheels...

Twin_Turbo

iTrader: (25)

Those CTS-V rotors, are they 32 or 36mm thick???

iansane

iTrader: (1)

Do the Camaro SS rotors show a left and right part number? (As opposed to the Z06 stuff that use the same part number for both sides...)

And is the CamaroSS pattern 5x120 or 5x120.65? Reason I ask is that I'm pretty sure 14" G8GXP rotor I have on the shelf is a 5x120.

Twin_Turbo

iTrader: (25)

camaro should be 5x120.65 the Opel OPC stuff uses the same brake system but the rotors are 120, they are 2pc rotors (and even stupid expensive here)

Those caddies, they are a different bolt pattern yes? Or was it just the center bore that is different? I'm loving that rotor and I think its 1.25 or so wide, almost 15 in diam.... perfect for my z06 calipers.

87350IROC

iTrader: (2)

The Camaro SS rotor is non-directional. Same part number left and right.

The SS rotor is 5x120mm. And the center bore is 67.3mm. So to get them to fit, I open up the center hole to 70.3mm. I make that a snug fit so the rotor is well located by the hub. Then the difference is bolt pattern is insignificant. The holes in the rotor are large enough to allow 1/2" studs on a 120.65mm pattern to pass through them no problem.

87350IROC

iTrader: (2)

The gen II CTS-V rotors are 370x34mm.

87350IROC

iTrader: (2)

Just measured them and they are 5x120mm.

The V rotors are also 5x120mm. And just like the Camaro SS rotors, the center bore is 67.3mm and needs to be opened up to 70.3mm.

The thickness of the V rotor works out to 1.34". I'm not sure if the Z06 caliper will fit over that rotor.

Twin_Turbo

iTrader: (25)

Don't think so, need a 1.25 rotor

87350IROC

iTrader: (2)

It might be worth a look though. I know the CTS-V brembos have extra thickness. With the pistons all the way in, there is about 1/16" gap between the new pad and a new rotor. Most calipers do not have that much extra thickness. Or depending how much thinner you really need, you may considering turning down the rotor slightly. Depends how adventurous you want to get.

iansane

iTrader: (1)

Or shaving the pad itself down a hair? ~.05" on both the inboard and outboard pad isn't an incredible amount...

paul_huryk

For the most part, GM had gone to 5x120mm bolt patterns - my 2011 LaCrosse is 5x120... And even though it is a FWD, BMW 5 series wheels fit it - both in terms of BS and also center bore - no hub centric spacers are needed. Believe it is 67.3mm also.

peterc005

Subscribed.

@87350IROC - yes, much neater centre caps!

rlewi771

Jon- How do you feel about those kore3 aluminum hubs in a road race application? Should there be concern in regard to their strength?

InfernalVortex

iTrader: (4)

Is there a legal reason you cant leave the hub exposed? Or is it an aesthetic one?

87350IROC

iTrader: (2)

Great question. I have spoken with Tobin, the owner of Kore3, many times. I am a mechanical engineer in my day job, he is mechanical engineer. Now that is just a title, it doesn't guarantee you actually know anything. I can say from speaking to Tobin, he definitely knows what he is talking about. I have talked to him about hubs, materials, brakes, calipers, rotors, etc... He understands the stresses involved and the load paths.

I have not seen the specific numbers on his design.

Now with that said. Lets take a look at the material properties. His standard hubs are 6061 T6 aluminum with a yield stress of around 40,000psi, or 40ksi. Now of course our stock brake rotors act as our hubs. So our hubs are made from gray cast iron.

Gray cast iron is good for rotors because:
- high thermal conductivity
- adequate strength
- inexpensive to cast
- vibration/noise damping
- machinability
- good wear resistance

Now the lowest quality cast iron used in rotors is G1800. This particular grade has a yield stress of only 18ksi. Less than half that of 6061-T6 aluminum. By comparison, if you look at the highest grade of rotor iron, G4000, its yield stress is about 39ksi. You would have to assume GM designed the rotor/hub to the lowest quality iron that an aftermarket rotor maker may use.

Now static strength is not the only consideration. You also have to look at the fatigue performance. I would have to assume the hubs are designed for infinite life which means the material must have an endurance limit where further cycles do not reduce the strength of the material. G1800 has an endurance limit stress of about 10ksi.

Now aluminum technically does not have an endurance limit as the strength continues to decrease as cycles increases. However 6061-T6 has a strength of about 14ksi after 500,000,000 (500 million) cycles. Now remember, 99% of the cycles in a car will be well below the maximum load. So I think its same to assume 14ksi is a good infinite strength for this application.

There are assumptions in there and I didn't bother talking about a few of the considerations. However based on that information I am pretty happy with 6061-T6 as a hub material. Add to that the Kore3 hubs are thicker than the stock iron hubs and have stiffening ribs. I think we are good to go.

If that is not enough, Kore3 will also make them from 7075-T6 aluminum which has a yield stress of over 70ksi. And they are no heavier than the 6061 hubs. This is what I have on my car. They are quite a bit more expensive however, as 7075 is quite expensive.

I am working with Tobin on a modified version of the Kore3 hubs to include in brake kits. My version will have the larger 1LE SET3 outer bearing and will be drilled for both our stock 5x4.75" bolt pattern and the BMW / modern GM 5x120mm bolt pattern. Hopefully this will be a good solution for people who want to run BMW wheels but are not willing to put up with the incorrect bolt pattern.

As with any part, particularly in a road race application, I would make an effort to check them occasionally for any damage. I would do this with iron hubs as well.

Let me know what you think,

John

87350IROC

iTrader: (2)

I don't have an answer for your questions.

I can say, as I'm sure you are aware, the stock hubs and dust cap is just plain ugly. Not to mention, if you are still running stock brakes, the spindle pokes out of the wheel ~0.3" more than what I am showing.

paul_huryk

No legal reason at all - but I wouldn't want and road debris getting into there regardless.

Aesthetic reason - yes as the factory dust covers are very ugly. If you ever seen a 3rdgen with caps that are missing on factory wheels - you know what I'm talking about...

paul_huryk

John that is good information for everyone here about the materials. As a engineering school grad myself (never worked as one), I understand the materials and stresses, but can throw in an additional bit of data from over 20 years experience with the 3rd gens:

I have heard of stock hub failures happening in a street car, but they are very rare if the car is maintained in a decent fashion. In terms of road racing, there of course have been failures for various reasons, but for the most part they are due to other catastrophic events - as racers maintain their cars meticulously (otherwise they would become unreliable). Stock iron hubs are adequate for 99% of street applications and 90% of race ones.

Materials are important - GM used cast iron - as John pointed out its pros above, aluminum also has advantages and disadvantages as a replacement material. Also important is the design of the replacement part - more material in key places and strengthening ribs should push a 6061 hub to ever higher strength after fatigue is factored in.

Plus aluminum is lighter and helps in the unsprung and rotational mass reduction. As an example, the Baer kit I put on my Camaro has 13" rotors (vs 10.5" stock), aluminum hubs, and PBR 2 piston calipers and dropped 20lbs off the front end with no other changes - never had a problem with those hubs, even though Kore3's are a more modern design I'm sure.

87350IROC

iTrader: (2)

Paul,

Those are aluminum hubs that came with the Baer kit? How many miles do you have on them?