Through Tunnel Exhaust

[Jayrz]

Anyone have any pictures of a well executed "through the tunnel" system. I'm planning on my car being pretty low and it's probably going to have to be either this or Ala "Super Seven" down the side.

 

[Bugeye58]

Jay, do you just want a picture of an uninstalled exhaust?
I've got a 1275 thru tunnel hanging in the garage, and one installed on the race car. There's not much to see if I take a pic of the installed setup, but I'll snap a few if you want.
You'll have to come up with a different trans mount if your system is similar to mine, and I don't think you may be prepared for the heat in the tunnel if it's going on a street car.
Both my systems are from Huffaker Engineering.
Jeff

 

[Jayrz]

Jeff,

Yeah i guess either would be better than what I have now which is no idea how this is done. just doesn't seem to me there is room but I know it can be done,,, obviously.

Lots of heat,,,,, yeah, was afraid that was going to be a problem.

 

[kcbugeye1275]

I think what you are coming to realize, this is a race car set up. On the cars I have seen, they have the battery box area cut out, they are race cars.

 

[Tim Hollister]

(Disclaimer -- I purchased a Spridgetech through-tunnel exhaust system though I have yet to install it -- something to do this winter...)

In addition to the Huffaker unit Jeff mentions above, Spridgetch also builds through-tunnel systems including the transmission mount. Spridgetech does have a web site with pictures of the systems he builds.

Regarding heat, I am told the best thing you can do is to have the header and the through-tunnel pipe coated inside and out -- supposed to drastically reduce the heat in the car versus an uncoated system.

Battery shelves? One race car with, one race car without. The one without is much easier to service and work on in general. And moving the battery to the passenger compartment on both cars helped the weight distribution and corner weights.

Best wishes and happy holidays!!

Tim

 

[Hap Waldrop]

You do not want to do this on a street car, you have to deal with alot heat in the tranny tunnel. Tim, on your race car, it will take more than just some coating on the pipe, it will also take some serious heat insulation on the tranny and tranny tunnel. This is kinda silly for a street car in my opinion, becuase you need to be below 3-3 1/2" at the rocker rail on ride height to need it, and at that height you would bottom on a speed bump on the street, just not pratical for the street in my opinion. Here's a shot of the pipe coming out of the tunnel on the Huffaker Bugeye I used to drive.

 

[Bugeye58]

Hap, is that one of the old Hussey cars? It looks awfully familiar from that angle.
Jeff

 

[jlaird]

That's preaty isn't it.

 

[Jayrz]

That really does look slick. My car is going to have the battery tray cut out of it as the distributor would hit it anyway. Down the side with a tube tunnel through the left front corner of the footwell/ rocker may be the way to go.

 

[Hap Waldrop]

Hap, is that one of the old Hussey cars? It looks awfully familiar from that angle.
Jeff

Yep, it was the second one built for Rob, super trick car that we could never get to handle, best and worse race car at the same time I every sat in. It was my first 948 experience, I remember the first session when I got out of it, I was a bit confused and mad all at the same time, my thoughts was, why in the heck would anyone spent so much to have so little /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

 

[Bugeye58]

I thought I recognized it. Huffakers and I go back a LOT of years. I built my thru tunnel exhaust there, using their jig. Just as I finished it, LJ got a phone call from somebody back east that needed one immediately, so LJ asked me if he could sell mine! I let it go, and built another, but they took a picture of me holding the first one, and had it up on the bulletin board with the caption "The One That Got Away". /bcforum/images/%%GRAEMLIN_URL%%/grin.gif
Great group out there.
Jeff

 

[tony barnhill]

Hap - is the muffler also up in the tranny tunnel?

 

[Bugeye58]

Tony, there's barely enough room in the tunnel for the exhaust pipe and the prop shaft.
Something no one else has mentioned is the fact that you have to remove a portion of the left side of the transmission case for clearance.
Jeff

 

[Bugeye58]

Here's a few snaps of the 948 car. The bolts you see through the side of the footwell hold the scattershield. I had to bolt it inside, as there wasn't enough clearance to put it in the engine bay.
Jeff

 

[tony barnhill]

I'm thinking my '68 MGB GT race car

 

[JPSmit]

I'm trying to get this straight in my head - why would you not weld a tunnel in the passenger compartment? As long as it were tall enough for the supension, would it not be cooler and easier? Or would this violate the rules? And, while we're discussing this at all, Is it simply a clearance issue that this is done (through the tunnel) or are there aerodynamic reasons as well?

TIA

 

[Bugeye58]

JP, it's primarily a clearance issue, trying to get the car as low as possible. Rules don't allow the exhaust to be run through the cockpit.
Jeff

 

[JPSmit]

Figured - thanks (can you widen the tunnel?)

 

[Bugeye58]

JP, I suppose you <u>could</u> widen the tunnel, but don't see why you would want to. There's enough room in there to get the exhaust and the propshaft in. Remember, the tunnel is essentially the backbone of the chassis, so the less fiddling with it, the better.
Additionally, the SCCA rule states that "Floor pans shall be altered only to recess mufflers. All other parts of the exhaust system (i.e., headers, tailpipes, etc.) shall not be recessed, nor shall any modifications be made to the bodywork for that purpose."
Jeff