289/427 Can't make up my mind!

[DanEC]

Originally Posted by jcooper

Thanks Dan!
I will take a look at Chuck's site.
Do you have any pictures of how you ran your pipes?

Jooper - here is my 2 inch PVC mockup of my tailpipes. 2 inch PVC is a little smaller OD than 2-1/2 inch exhaust pipe but the fittings are just a hair larger than 2-1/2 pipe - so it works reasonably well for a mock up.









With my wheel/tire combination I have about 1-1/4 clearance as it sits right now at the axle rise. That has to be spit for both sides. My car will still come down about 2 inches to get the tire top about even with the top of the wheel opening. Because of the angle of the axle and control arm I will probably gain another 1/4 inch or so as the suspension goes to ride heigth. Right now I have 7 inches of clearance from the pipe to the top of the carrrier hub. Subtract 2 inches from that as the suspension settles and that leaves about 5 inches of clearance which is significantly more that the factory available suspension compression from normal ride heigth. I think it will be OK. My fall back plan would be to either flatten the 2-1/2 inch pipe at any tight points or go to a short section of 2-1/4 inch pipe above the halfshaft axle. I don't really want to use oval pipe do to all the various secitons and transtitions that have to be assembled. Next post I show the mufflers I'm using.

I think I mentioned I'm going to try to have a nearby shop bend me up some pipes from this mockups. Should work - I've heard of ehxaust pipe companies advertising to send them a mockup of a tailpipe in heavy guage solid wire, box it and send to them and they will build a set of pipes from that. I think this is a sight better for a mockup than that. Also, it's a straight shot out the back from the outlet of the muffler - only 2-dimensional. I can take this mockup off the passenger side and sling it under the driver side and it fits the same - pretty fortunate turn of events.

[DanEC]

I'm using 2-1/2 inch Spintech mufflers which are 3 inches deep. Here are a few pictures with them in the approximate position.











I plan on having them ceramic coated black.

If anyone has any suggestions or sees some potential problems I would be glad to hear them.

Dan

[jcooper]

Looks like a great way to run the pipes. Wouldn't that work with the ERA rear end?

[patrickt]

Originally Posted by jcooper

Looks like a great way to run the pipes. Wouldn't that work with the ERA rear end?

I just don't think the room is there.

[RICK LAKE]

DanEC Dan The bents are fine but you have not allowed enough clearance between body of car and exhaust system. Also need room for shields to protect gas tank and body of car. I think that this system might work with adding exhaust rap around the pipe that goes over the rearend and jet coat it. A second shield has to go between gas tank and pipe. The other issue is amount of heat added to the fuel with both rearend rotors, air coming down the tunnel and now an exhaust system all adding heat to this location. The other thing is getting the moister out of the pipes. You will need drain holes in the mufflers or the system will rot out in a year or 2. Been there, tryed this on another car with same problem for rear exhaust. Ended with tail pipes coming out in front of rear tires and angle tips down and back to reduce noise. I think it would be better to do like the vettes with going under the center of the car rearend and then going out to the tires and along the trunk floor. Either way you are going to needs shields. You might want to get a infared temp gun and check these temps before any long drive is tryed. Just a thought. Rick L. Ps Bob P is pretty good at engineering on ERAs. I think there is a good reason that he runs small pipe out the back. I want to say that somewhere I read an article about heat transferance and you need 2" for safe clearance. If noise is an issue go to a longer muffler or a 3 chamber one. I don't think that spin tech is too quiet.

[*13*]

Probably not enough clearance to run exhaust under the rearend. It's tough enough to get a jack under there.

[DanEC]

On heat - remember the inner panels on the newer ERAs are aluminum instead of fiberglass, except for the one at the front of the wheel well. I'm going to insulate them on the inside and if need be - I can apply a coat of Lizard Skin in the vicinity of the pipes. I also plan to fabricate a "L" hanger to install in the wheel well, weld a stud on the bottom of the tailpipe and run that through a grommet in the hanger to hold the pipe firmly in location behind the tire. I'll drill out a couple of the wheel well liner rivets for 3/16 inch rivets and secure the hanger with them. I will set the inner clearance at about 1/2 inch and allow the rest (about 1 inch) to the tire. The gas tank shouldn't be a problem - we are only talking about 1/4 less clearance than ERA's design and I plan on having all of my pipes ceramic coated inside and outside.

I've heard video clips of the Spintech mufflers and your right - they are not quiet. Fortunately the compression in my motor is pretty mild and the cam is not extremely aggressive. But, at least most of the noise will be back there, behind me. That is the biggest muffler that will fit within the recess that ERA has provided in the frame for a muffler. A bigger mufffler is not an option except for going to a 4 inch thick muffler.

[wolf k]

http://i298.photobucket.com/albums/m...n/DSC00407.jpg

ERA rear, the lower control arm takes away some space but routing exhaust is still do-able with narrowish tires.

PVC mock-up, brilliant Dan.

[RICK LAKE]

DanEC Dan don't want to break your bubble but there is alot of dead air behind a cobra and that noise will carry back into the car, the same as side pipes. Add down pipes on the ends for about a 45 degree down and out. I ran a 452 with a hydro camshaft and 9.2 compression the stock system worked great. I raced at New Hampshire track and pass the noise limit where others failed. This was with the ERA side pipes. MY race pipes are a different story. Just my own observation on my car. Rick L. I do also have heat rapon my headers under the hood to reduce heat along with the Hot-Jet coatings of the pipes.

[Dominik]

I would get a 289, because "everybody" has a 427 ;-)

[RICK LAKE]

Dominick Hey Dom, let's go orginial and get a 260 motor?? Now we are talking different. Rick L.

[*13*]

Now we're talking "Wife's Car". Don't listen to them, 289!

[Dominik]

Haha, yes, and the worm and sector steering...

No, serious, with a 427 you always need to win at the robot. You have a name to defend. A 289 "buys" you peace and you can enjoy the cruise. (I am exaggerating, but you get the idea).

You can still have a 427SB in it, of course ;-)