The Triumph Dolomite Club - Discussion Forum

Looking to source a tubular exhaust manifold. Just wondered if anyone had come across a product or is this a bespoke item. Hoping to improve on gas flow over the standard cast manifold.

Robi

I'm not gonna say it's impossible, cos i've seen one or two 4 branch manifold on Sprints.

But the ones i've seen were bespoke creations, fantastically convoluted, usually climbing UP over the cambox before exiting, and mostly requiring some relieving work on the suspension turret to get it in! And probably HORRIBLY expensive!

What the go faster brigade around here usually do, is open up the ports at the downpipe joint of the stock manifold and mate it to a Jigsaw racing or similar big bore downpipe. It's not a really good solution, but it's relatively cheap and does liberate a few extra horses.

Steve

I'll second the above.

I have a car with a tubular manifold on it, but the suspension turret has been cut and shut to give it room to fit.

Also, I have it on good authority that whilst the standard manifold is visually 'boxy' it is actually internally well engineered from a gas flowing principle. So much so, that unless you are putting out in excess of 185 bhp, a tubular manifold doesn't actually contribute anything.

xvivalve wrote: ↑Sat Jul 22, 2017 10:26 pm
Also, I have it on good authority that whilst the standard manifold is visually 'boxy' it is actually internally well engineered from a gas flowing principle.

I agree, the casting is well made in that ports 1 & 3 are internally seperate from ports 2 & 4 which is why there are two bores at the down pipe end.

Malc

I did look at having some copies made as a mate's wife's family own and run a large aftermarket exhaust manufacturing business, but when they saw the space available, they were unwilling to make them off a pattern or jig, saying each one would need offering up to a car during manufacture.

Thank you all for responding clearly there is no simple tubular option so will go down existing manifold option perhaps with a bigger bore exhaust

Robin