Dolomite 1850 - Tubular Exhaust Manifold

[David Embery]

Hi,

I’ve recently acquired a 1972 Dolomite 1850. The exhaust manifold is the original ‘log’ type and I feel much better can be achieved in terms of engine efficiency and additional horsepower if I had a tubular exhaust manifold fitted.

Although, I’ve found my view has many supporters, actually getting hold of a tubular manifold for an 1850 as opposed to a Sprint has proven to be near impossible. The only options I have found are that I spend £2k+ for a stainless steel bespoke complete exhaust system to be made or have the existing ‘log’ ceramic coated.

I would be grateful for any alternative suggestions/help. I.e. does anyone know where I can get a tubular manifold for my 1850?

Any help will be gratefully received.

Cheers

David

[new to this]

There was a tubular exhaust manifold for a Tr7 on ebay would that fit

Dave

[David Embery]

Cheers Dave. My understanding is that a TR7 manifold would not fit as it is on the large size for what is needed on the 1850 cylinder head.

[cliftyhanger]

They used to be available, but I think some ran under the subframe, reducing ground clearance.

TR7 wont fit, at least the std cast one.
But, on the plus side, I am not convinced a better manifold will make much difference by itself. This is from the figures comparing a TR7 engine to dolly 1850. Approx 90 to 100 bhp, so call it 10%. From an engine with bigger carbs, nearly 10% larger cc and a better exhaust manifold.
There may be better ways of getting more power. TR7 engine is a straight swap, and does give better torque, and does feel perkier to drive (so power figures not everything). And very capable of 3 figure speeds.

[DoloWIGHTY]

Again to confirm that a TR7 one won't fit, the 7 has much more space around the engine than a Dolomite so the down tube is sloped whereas the Dolomite tubular one would be much more upright to match the exhaust system below.

Good luck with your search, I think (maybe) that SAH had one listed in their catalogue when the cars were current so perhaps there might be one (somewhere) out there.

[Carledo]

The 1850 is a bit of a "poor relation" to the Sprint engine these days, the Sprint motor has so much more to work with and you are fighting against a 37BHP deficit from the start. So normal practice for those seeking more horsepower from an 1850, is to use a bigger/better engine rather than modding the stocker.

With that said, I have seen an 1850 with a VERY pretty stainless tubular manifold on it. It's on a Mallard car that often wins "best 1850" at the annual TDCIR show, but I don't know who owns it. Like the bespoke Sprint ones i've seen, it curves UP and over the head before disappearing back down the usual way. I've always assumed it was bespoke (there are several West Mids based companies that will make you one - for a price) but, IIRC, there WAS once a Triumphtune option though I doubt it's still available.

Even on the Sprint, a tubular manifold isn't a popular choice, the tight space available limits what is possible (and pushes the cost into the stratosphere) and the log, for all that it LOOKS hopeless, doesn't flow THAT badly! Most Sprint tuners opt for the opened out log and bigger downpipe as a more cost effective vs horsepower gained option.

Steve

[GlenM]

Steve/Clive,

You are quite right. SAH tuning used to sell a tubular manifold for the 1850, before Sam handed over the business to Terry and it became Triumph Tune. I got into Dolomites in the late 80s, by which time it was Triumph Tune, and they didn't list the 1850 manifold then. I was offered a used one in the early 90s but by then I had a Sprint, so it was of no use to me.

If any one did want a stainless manifold made up for an 1850/TR7 engined Dolomite, the guy who made my CA18 DET manifold would be able to do one. He's based in Reading and he also did a fantastic Sprint one recently, for a race car, that retained the ability to change the plugs, and also exited the engine bay in the normal place, rather than at the front and under the sub-frame.

Glen.

[Carledo]

.....The only options I have found are that I spend £2k+ for a stainless steel bespoke complete exhaust system to be made........

Cheers David

You don't need an entire bespoke system made, Rimmers, (who, TBF, I normally scorn) produce a reasonably competent "straight through" sports exhaust in stainless steel. It's designed for the Sprint, but if you buy all but the down pipe, it can be used on any model of Dolomite. I've fitted and used several since 2012 and they've been OK in service though often need tweaking/fettling to fit correctly.

So all you'd need making is a 4 branch that reaches back to where the tail end of the downpipe would be.

Steve