vincent ashton

Hey guys. Is there a good source for C4 spindle ducts? I know many C5 kits are available. I have a feeling that some guys just make their own. If so any pointers on how you did it? Thanks

astock165

I have looked for them myself and have had no luck. I think you're right in that most people fab them up themselves. I was thinking of trying to mod a C5 set as necessary to mount but haven't done anything with it yet.

If you do find something make sure to post the info here.

VanSpeed

Here are some pictures of what I made from aluminum sheet. I used my old front brake dust shields and made the tube from some .032”T aluminum sheet. They may not be to pretty, but they seem to work fine. I don’t know what year your C4 is, but the early ones like mine, 85, have little bosses on the knuckle to mount the dust shield, later C4’s may not have these so mounting the duct will have to be done differently, maybe using the wheel bear/hub bolts for attachment.





Brian

Sidney004

Contact ZR1 MK
He is fabricating some right now. I will getting some very shortly.

BrianCunningham

VanSpeed,
Nicely done!

MarkBychowski

http://www.cardomain.com/ride/418999/2

Mike definitely has a nice setup!

craig brian johnson

I ended up using (2) 2" ducts on my C4, as I wasn't able to fit the larger single duct in-between my control arms without it crushing when the car would bump and turn.

I ended up fabricating a dual 2" fixture that would blow the air into the center of the rotor, instead of at the rotor, so that the air would then flow thru the rotor vanes.

vetracer

Yes, that is the best way to do it. I posted this picture of my C4 setup back in 2003:



It has air scoops inside where the turn signal/driving lights would be and has inline blowers to force even more air through them:



The difference between mine and the other photos I have seen is that mine fit inside the rotor, not flush up against it. I got the fit almost perfect from the get-go, then I just let the aluminum wear itself away where I had minor rubbing.

One note is that my rotor hats had two sets of holes for use with two different hub sizes. Since the GM hub has 3 holes in it (including 1 large one for removing the bolts holding the hub to the spindle) the holes would line up and allow air to leak through. The A-mold wheels mounting surface would not cover these holes when installed on the car. I tried high temp tape but it would burn off the rotors as soon as they got up to temperature. I solved this by using Permatex high temp copper gasket sealer to fill the holes on the hub (not the rotor). I put tape on the back side of the hub to hold the sealer and filled the hole. I then flattened out the gasket sealer with a putty knife. After it dried I removed the backing tape, leaving 3 nice little plugs. Works great!

Never had any problems with excess heat from the rears, even with a 4-piston and good brake bias through adjusting the proportioning valve:

larryfs

the guy who has it aiming at the center of the rotor got it right.
the first picture where the air hits the inside rotor face will only help the inside rotor face, not the outside where most cracking occurs.

ZR1 MK

Im finishing my run. Im too busy in the summer to fabs these. So if anyone is thinking they might want a set, give me a buzz.
Thanks for the comp, Mark Bychowski.

BrianCunningham

vetracer,
You got one of the best setup C4's I've seen.
I like the feature article Vette magazine did on it.
http://www.vetteweb.com/features/030...t_corvette_c4/

Have you driven the car on the street with the rod ends?
I'm just curious as I want to do this mod, and want to know what it feels like.

vetracer

Thanks, Brian.

I assume you are talking about the rear trailing arms. I have driven it on the street, although it was with track tires and and a pretty loud exhaust, so I couldn't tell you how much noise it will transmit. A lot, I would think. Maybe just do the end that attaches to the knuckle and use poly on the end that attaches to the car?

BrianCunningham

What about vibrations?

DALE C

Hi Vincent,
We are getting ready to start fabing some up we need them for Mike and Kevin. Get with me at the test and tune and we will get you a set when we get them done. They will be water cut and tig welded.
Dale

ZR1 MK

Since I got quite a few PMs and emails, Im posting a pic of the plates with the abs sensor. My 1990 has abs, but I dont use it as shown in my webpage pic. Some C4s dont have abs, some have abs located in the tube area and some have it located in the rear of the knuckle. I have installation instructions for different brake setups. Plates are for one 3 inch ducting per side.

vetracer

I didn't notice any. BTW I am following your thread on wheel hubs, nice work. I just replaced all 4 of mine again.

SDF

Mike, nice set-up! Could you please e-mail me with some information about you spindle ducts? (s.frew@mchsi.com) Thanks!

ZR1 MK

Sent an email, but it was rejected twice. My end is working so it might be your end. I sent you a PM.

SDF

Mike,
Hey, thanks for getting back with me! I am new to the Forum, but not to motorsports. I am an ex midget and sprint car driver from the midwest. I am currently preparing my 96 for some HPDE events that I can find locally. I was very impressed with the craftsmanship of your aluminum spindle ducts. I wanted to check the availability (since your season has started) and the price.
I was very impressed with your ZR-1. An exceptional piece of equipment. I had a couple of e-mail addresses of yours too, however they to were rejected. I have received several e-mails today, so I don't know what the deal is. What is the best way to reach you in the future? I appreciate any help (suggestions) you can provide! Thanks again.

Scott

ZR1 MK

You can use the forum private message service. It keeps the unwanted traffic down for others and is private. Go to User CP at the top of the screen, then private messages. Youll see a message from me in the "in box". Work email is mrk@donaldsonacoustics.com, but you can also try me at my house email zr1mk@verizon.net. Thanks for the comps.