Funky exhaust on GD T70

[davefiddes]

Just been having a read at the GD T70 article on the front page (www.pistonheads.com/doc.asp?c=112&i=7130).

Spotted that the exhaust on their Chevy is a bit different from the Ultima one (or any other performance V8 I've seen). There seems to be some sort of balance pipe that connects the banks just after the collector on the header.



Does anyone know what this does? Does it improve performance or reduce the noise somehow?

[chief-0369]

IIRC, it uses a v8 with a 90 degree crankshaft. these work best with 180 degree crossover headers.

however I very much doubt you could fit those under the bonnet and so the best way to get around this is to fit a balance pipe between the standard headers

edit to say i dont know why its not used on the ultima though.

>> Edited by chief-0369 on Wednesday 13th August 14:09

[gtrclive]

The balance pipe does exactly what it says on the tin... And yes it does reduce noise and increase horse power alittle. It's an old Muscle Car Idea that still works. Best way of useing it is to have a Single Cross-over Exhaust Box, so the perferated pipe in the box is in a X shape. My GT40 had one and was Quite enough to get on at Castle Combe etc. 98db. Also sounded like it was reving it's nuts off, will have this system in my next Car, just wish I had waited at the time and fitted it to this one.

[davefiddes]

Interesting. Now you mention it I do recall seeing pictures of the system on a GT40 and wondering how it was plumbed.

Would be interested to hear the results when/if you get around to getting your new system made. I'm afraid I can't really mod mine now either...just sent the system off to be ceramic coated .

[Alan 2]

Have a look at this www.ultimaspecialedition.com/photo5.html

[k wright]

Thats a really nice crossover pipe but what was done with the silencer?

[Alan 2]

Ken. The car is a Canam built about a year ago. It has a sbc enlarged to 434 ci. There are no conventional silencers but apparently it has detachable baffles in the tailpipes. I understand that extra baffles can be added to meet trackday noise regulations. How they fit and how well the system works, I don't know but there is an article on the car in the August 2002 edition of "Kit Car".

[tuffer]

GT40 exhaust can be seen here www.findit.co.uk/cars/kitcar/parts/777414.htm not sure if thats like the original but looks funky!

[andycanam]

Using this idea and adding some extra length to the exhaust (within the car!) I managed to reduce the cars noise by over 10db's.... and it's got straight through silencers, excellent for both power and flame outs!

[davefiddes]

10dB is quite some reduction!!! I'll bet that takes your system well under 95dB??? Do you have any pictures of the system that you'd be happy to share? The pictures on your website look like the normal factory system...

Anything that encourages flames to come out of the back has to be a good thing too!

[ultimaandy]

If you mail me I'll send you a pic.... don't have one on my site as my PC doesn't like uploading stuff as it's useless. Also can't send them through your profile as you can't add attachments.

Only have one of it off the car... probably easier to see though with it off.

Incidently my car was 108db's without and came down to 98db's....

I think I was burning the wadding out of the originals as it always popped so the flames were odviously being kept in the silencers.