More power from 2000

[andyborris]

Would like some more power from my 2000.

It already has a big bore exhaust, I'm thinking that one of Chris Witor's 6-3-1 manifolds should be the next thing?

Am I right in assuming that the carbs (SU HS4) will need re-jetting after fitting the manifold?

I see Chris offers a re-worked Stromberg manifold, does the SU manifold suffer from the same problem (unequal airflow)?

Is it worth changing the very thin air filter for some fat K&N with ram pipes, or is the cool/clean air feed to important?

I know I'll have to change the jetting with K&N filters, so will fit filters (if needed!) and manifold together.

I've posted on both boards which deal with big sixes, so apologies if you've already read this!

Andy

[kevinw]

I spoke with Chris Witor a while ago about changing the filters for either K&N type or some gling chrome ones. Mine has got later Strombergs (the last type used before the change to SU's) with the thick filter box fitted on the carbs that is a bit of a bu&&er to remove due to lack of room for fat fingers. I was going to change them for ease of maintenance more than anything else.

His advice was to stick with the original design to ensure a supply of cold air. The bigger exhaust on mine has made a huge difference. It's only a "semi-sport", being an automatic, but probably got twice the cross sectional area of the original drinking straw fitted. Doesn't blow any longer, either.

Kevin

[Allen Walker]

There are plenty of cold air feed kits available. It wouldn't take too much effort to route a length of 80mm diameter ducting from the front valance intakes and point it at the K&Ns.
Some come ready made with radiused alloy trumpets either end of the ducting.

[Mike Stevens]

Although these things will increase power a little, perhaps a more effective modification would be to uprate the camshaft and gas flow/skim the head. Together with suitable carbs and needles - and free-flow exhaust - that will make quite a difference.

Of course, fitting a 2.5 engine gives a big step too, but with lower maximum revs.

However, is this what the 2000 is all about? The engine would have been designed for smoothness, economy etc. Doing all the above will make it less smooth and probably drink more fuel.

But, yes, I have done it all before! I fitted an early TR6 engine in my Mk1. With twin CD150s, suitably needled, it went like a rocket! Having the original 4.11 final drive helped of course!

Cheers,
Mike.

[andyborris]

I'm not looking for mods which will just throw petrol into the engine, but ones which burn the petrol more efficiently.

Then if I can resist the temptation of a heavy right foot, it should have slightly more power for the same fuel consumption.

That's the theory anyway !

Andy

[Mike Stevens]

but ones which burn the petrol more efficiently

Well, gas flowing and improving the breathing is the obvious choice then. Camshafts come into that category. In fact, I would have thought anything that increases the power is likely to help improve the economy - if you can resist the temptation of using that extra power! Not an easy task though.

Don't forget to keep the tyres at the correct pressure too!

Cheers,
Mike.

[dallliiisss]

I'm told fuel injection (of some sort) works well with the 2000, as it's oversquare with a shorter stroke than the 2.5. Or twin SU's with suitable cam, higher compression ratio, etc..

[Jonathan Lewis]

I'm told fuel injection (of some sort) works well with the 2000, as it's oversquare with a shorter stroke than the 2.5

Triumph's own first thoughts on the matter... Someone wrote-up a '2000PI' conversion in Six Appeal years back (it's reprinted in the first volume of the Service Notes). Using a standard early PI cam, the result was apparently not as good as a 2.5, but perhaps with a TR5 or one of CW's own-spec cams, things might be different?

Regards,

[andyborris]

After speaking to Chris Witor, I have a slightly clearer idea of my first step.

A 6-3-1 exhaust manifold coupled with a “long” twin carb manifold. He says that not only does the long manifold flow better, it is the only one you can use with the 6-3-1 exhaust manifold, because the short one doesn't fit!

Interestingly he suggests using Stroms, rather then SUs, according to him, the Stroms have better response, pick up and are less fussy about needle choice, while SUs will give a bit more on the top end.

So, if I go with Stromberg's, which ones should I look out for?

Andy

[Alec]

Hello Andy,

I think Chris's comments about Strombergs are subjective. My biggest dislike of Strombergs are that diaphragm.

There is also a much bigger range of needles for S.U.'s so you have more chance of getting it right (Albeit S.U. needles can be adapted to fit Strombergs I believe?).

There is always fuel injection?

Alec