Richard: Extractor manifold

[Stephen Grellet]

I would agree. The only time an exhaust will give this power is if the one you are replacing is that bad that it is strangling the engine. An exhaust only needs to pass whatever the engine produces, any more than that is wasted. A slightly modified standard manifold would allow 210 HP in the works Sprints, so even with mufflers fitted should allow 200 hp, and then the restriction is not the manifold, but the muffler.

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[LathamF2]

I've not seen a TR7 sprint manifold, so can't say whether it would fit or not.<br>
I know for sure that a standard TR7 manifold won't fit, because I used to have a TR7 engine in the car and had an 1850 manifold on it.<br>
<br>
The problem is a diagonal chassis tube about 1/2" from the standard manifold by No.2 cylinder, and another only 1/4" away by No.4<br>
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A tubular manifold could be made to fit, but only if it used the width of a standard manifold to direct the tubes straight down and back. It won't fit if it's any wider than a standard manifold.<br>
<br>
Latham(RIP) used to make one specially, but for £800 quid you got a manifold which paired 1-2 and 3-4 and was actually less powerful than the standard sprint one....

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[mp]

A standared manifold suitably flowed is quite adequate for any modified sprint, the only time you may see an advantage is if you rev your engine to 9000 rpm and then it would not be anything to shout about

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[angelomachairasthetriumph]

I'm afraid there's more to an exhaust system than the restriction to the hot gases .<br>
The different lengths of the primary pipes of the standard manifold tune each cylinder to deliver its <br>
max torque at different rpm . <br>
This is good for power spread , but not for max torque . That also means that some cylinders work harder <!--EZCODE EMOTICON START >: --><img src=http://www.ezboard.com/intl/aenglish/im ... ns/mad.gif ALT=">:"><!--EZCODE EMOTICON END--> than others at any given rpm .<br>
This tuning effect comes in to play from way down in the power curve . In big single cylinder motorcycle engines I have worked on , an inch longer/shorter exhaust could shift max torque point noticeably . I can live with the restriction , as long as all the pistons/valves/conrods ect. are equally stressed .

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[triumphdolomiteuk]

Out of interest,did anything come of the idea to produce extractor manifolds?<br>


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[Richard]

<br>
Andy, we never came up with a design that everybody was happy with as some didn't mind cutting the body to get a good design whereas others didn't want to cut the body which would make a less efficient design.<br>
cheers, Richard.<br>


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