GT6 mk3 Sports Exhaust

[Acole]

Hi all,

I’m looking to fit a sports exhaust to my GT6. In the past, I have been warned off this from a classic car restorer as “it wasn’t original therefore the engine isn’t designed for it and will impact the running, performance, efficiency and reliability of the engine”. Surely this isn’t true as many GT6s have the sports exhaust.

Does the engine require to be set up for a sports exhaust? The car has a stainless steel 6-3-2 manifold. Any tips or advice would be greatly received. 

Thanks

Andrew 

[Clive]

The manifold (especially a 6>3>1) will already impact fuelling at higher RPM. A sports exhaust may make a little difference, add maybe 2-3bhp.

Strongly recommend the single sports exhaust (sold by canleys and others) as it works really well, and avoids the issues associated with the twin "wheelbarrow" system. 

If you have not done so, a quick session on a rolling rod will get the carbs set up correctly, possibly a needle reprofile etc. And from experience, the tuning transforms the car.

[Acole]

Thanks for the advice Clive. 

I’m wanting to switch to a wheel barrow sports exhaust as I prefer the look of it to the single sports or the side twins.

Thanks

 

[Nigel Clark]

2 hours ago, Acole said:

Thanks for the advice Clive. 

I’m wanting to switch to a wheel barrow sports exhaust as I prefer the look of it to the single sports or the side twins.

Thanks

 

The wheelbarrow twin exhaust is loud, loud enough to leave one's ears ringing after a long run.

You have a good manifold. Couple that with a standard centre silencer and semi sport back box from the club shop, and you have a system that sounds purposeful without causing ear ache!

As for setting up, fit the rich carb mixture needles recommended by some suppliers for use with sports exhausts and air filters, retune the carbs and you should find the engine runs fine. Standard ignition timing should be okay.

That's how I ran my GT6 Mk3 for many years.

Nigel

[Acole]

Hi Nigel,

Thanks for the advice. As for the ignition timing, I’ve actually converted mine to an electronic system. 

I think changing the exhaust is something beyond my capabilities so I will get it done at my local Classic car restorer. 

Thanks

Andrew

[Mathew]

I know with mine I started with a virtually straight through, it sounded very loud but not much go! Got a sports system twin pipe with a centre box. Transformed the drive. Good sound and went very well.

Picture before, now sadly sold about nine years ago.

[rlubikey]

On 30/05/2021 at 18:23, Acole said:

Does the engine require to be set up for a sports exhaust?

Andrew, if you change the amount of gas coming out of the engine, it changes the amount sucked in. That means you have to modify the fuelling to accommodate this.

On 30/05/2021 at 21:54, Nigel Clark said:

The wheelbarrow twin exhaust is loud, loud enough to leave one's ears ringing after a long run.

I can confirm this is true. I took to using ear plugs on longer runs to keep my sanity until I managed to change to a standard system. Some poor fool (sorry) enthusiastic driver wanted to swap for a sports exhaust. He's probably not on such good terms with his neighbours now.

Cheers, Richard

[thescrapman]

When a friend purchased his TR6, it was loud, VERY LOUD, a previous owner had opened up the twin boxes and emptied them out, and welded them up again.

It had to come off, and a standard system was fitted ( in fact my standard system, need to get it back at some point) And he mentioned he had swapped it on a forum, and someone contacted him really keen to have the loud one, despite us telling him it was noisy. 

Saw the guy a year or so later, and he had been forced to admit defeat and the exhaust had been changed again, I think pressure from his other half and neighbours had a lot to do with it.

anyway, GT6 are sensitive to loud exhausts as the resonate in the cabin.

[Martin Marrison]

Nigel in my view not all wheel barrow exhausts are the same. I ran a 2.5 spitfire for a number of years with wheelbarrow exhausts and it wasn't that loud. I think it was a Phoenix system.

Martin  

[dougbgt6]

Martin,

I agree, I went to the club meeting last night, 8 cars and a variety of exhausts, wheel barrow, semi, standard, straight through. No two wheel barrows were the same and the loudest exhaust was easily the semi. You have to hear them and ask the manufacturer to decide which is the one you want.

Doug

[thescrapman]

I have 3 different wheelbarrow systems, a Phoenix on the Mk3 Spitfire, that is quite refined, I had a Bell on my Mk2 ( with Mk4 engine) and that was loud and popped and banged, great fun round the lanes, too noisy on a run.

The TR6 has a Falcon system (I think) and that is LOUD. But sounds great, and does quieten a bit a cruising speeds.But boot it and it sounds fantastic.

[Clive]

17 minutes ago, Mathew said:

The puma spitfire has a bell twin at the back and a custom made front. I was toying with the idea of putting a mid box on to quiet it down but its not too bad. It does raw with the pedal planted but with normal driving its not too loud, probably as there is a cat just after the manifold. A previous spitfire of mine had a full bell sports and that was not too loud, i think the larger 2 plus litre engines benefit from a mid box though.

I have found six cylinders to be less "offensive" in terms of noise with the same exhaust. The note is always smoother, less bark.

I ended up making my own system, it has 5' of exhaust box in it, all straight through 2 1/4" bore. When tested at Castle Combe it was 85db at 4000rpm, well within the limit of 98. The twin wheelbarrow system I had on there initially just about scraped through the test at 98.... and I got pulled in and asked to reduce the sound (I had a couple of db killers that got it down a bit)