Corvette C3 X pipe installation

[westlothianvette]

I recently acquired a 1971 convertible. At the moment it has two separate exhaust pipes. I was wondering if fitting an X pipe would create the offbeat burble I am looking for or is this a cam thing that creates the sound. I couldn't see any off the shelf parts for this installation. If I get an exhaust shop to make up this system what sort of money could I expect.

 

[teamzr1]

Good way to go, installing an X-Pipe over an H-pipe
Sound will change for sure, will add some torque if installed close to the engine so that the exhaust pulses will
help extract all exhaust from cylinders, so the next firing of a cylinder will be clean air/fuel
I had a shop build mine the way I wanted the exhaust makeup for my C5 and the X-pipe installed as close to the exhaust manifolds
To work best is where the 2 pipes meet of the X is as wide as the pipes' diameter, so it does not limit flow or cause
more back pressure

In my case since I had long tube headers with 3 inch collectors so X-pipe and whole exhaust system is also 3 inch including
the inlet and outlets of mufflers

Any decent shop could take 90 or 45 degree pipes, cut them to the shape needed and weld that up
I would not know in your country what they would charge for this

Sound likely what you want that also may need a bit richer carb setting and timing change so when lifting
off the gas pedal (decel), the slighter richer AFR causes the sound you want

 

[Roscobbc]

I have an 'X' pipe on the 3" system on my big block. It does tend to minimise the typical jackhammer like thump of a large capacity V8 at lower rpm. Mid range rpm and it seems to be much the same, perhaps a little quieter - at higher revs I'm told it sounds like it's revving at far higher revs than the 5 or 6 thousand it might be at. They are supposed to aid torque at specific rpm levels.

 

[Forrest Gump]

The problem on a C3 is that there is not enough space to fit an x-pipe in close to the collectors. The gearbox is in the way and then the exhausts go through the crossmember. Ross has managed to get an x-pipe is by sitting the exhaust lower so that it doesn’t pass through the crossmember. It works but of course the exhaust is close to the road. If you stay with the conventional exhaust route, the first suitable location for an x-pipe is after the crossmember- but that it is getting too far away from the collectors to be effective from any performance gain (noise perhaps might be changed, I’m not sure). It is possible to fit an H pipe in front of the crossmember however. Performance gains of an H are debatable, but sound will be changed.Plus many have found it will reduce droning.

 

[Roscobbc]

It seems that it is very difficult on most V8 powered vehicles to install an 'X' pipe in the optimal position..........it is generally accepted that one fits it in the closest to ideal position. The main issue really is with header design. The need for a efficient header design may larger diameter primary tubing, less restrictive bends with equal length and longer primaries. If you have a/c and perhaps other engine/transmission combinations you may it difficult to source a suiable 'off the shelf' header.

 

[Roscobbc]

Going back to the OP's first question about whether an 'X' pipe will give that off-beat burble he requires...............no it won't.....as such. You'll still have the burble but it will perhaps be a little less noticeable at idle.......at higher rpm the exhaust will still have the sound he wants but it will be more intense.......some say more like the sound of a race car.

 

[teamzr1]

Couple of examples of C3 exhaust system with X-pipe after the tranny

1974 Corvette C3 2.5 Inch Crossmember Back Exhaust Kit With X-Pipe 409 Stainless | Pypes Performance Exhaust

www.pypesexhaust.com

74-79 C3 Corvette Small Block X-Pipe Chambered Mufflers Kit Version

Up for sale is our 2.5" aluminized small block C3 X-pipe chambered kit. This system DOES NOT include headpipes and is aimed toward people using headers. This is designed for the C3 body with frames with the holes through the crossmember from 74-79. We use our custom xpipe going through the...

highfloperformance.com