4 2 1 exhaust manifold upgrade 135 sport

[woody]

I have an S2 manifold here, but no down pipe. Welcome to it if the down pipe is available separately.

[Ferg]

That manifold from woody and a new or second down pipe would be a good plan. Wish I'd done that before buying a replacement standard down pipe for mine.

[robin]

The other thing to think about is the heat shield. Often S1 original heat shields have disintegrated by now; the bendy metal one that the S2 uses connects directly to the manifold/head rather than the bulk head and is more durable (though not indestructable). The S2 manifold to downpipe flange is a six stud design and appears more durable than the old S1 (though who knows whether it really is - anecdotally the S1 manifold breaks at the flange to the downpipe whilst the S2 does not). Finally the S2 O2 sensor boss is in the downpipe which makes it easier to replace the O2 sensor when it fails (compare to the S1 location, anyway).

If you just want it to work as well as it ever did before then the S2 would be my advice - if you're actually looking for more from the engine then it's much harder to come by relevant data that shows you what you'll actually get from a given zorst configuration on your particular car.

Cheers,
Robin

[KingK_series]

The other thing to think about is the heat shield. Often S1 original heat shields have disintegrated by now; the bendy metal one that the S2 uses connects directly to the manifold/head rather than the bulk head and is more durable (though not indestructable). The S2 manifold to downpipe flange is a six stud design and appears more durable than the old S1 (though who knows whether it really is - anecdotally the S1 manifold breaks at the flange to the downpipe whilst the S2 does not). Finally the S2 O2 sensor boss is in the downpipe which makes it easier to replace the O2 sensor when it fails (compare to the S1 location, anyway).

If you just want it to work as well as it ever did before then the S2 would be my advice - if you're actually looking for more from the engine then it's much harder to come by relevant data that shows you what you'll actually get from a given zorst configuration on your particular car.

Cheers,
Robin

Absolutely right

I would only add that the most important heatshield is one to sheild the alternator. - and Lotus didn't even fit the basic MGTF fit

as far as exhausts are concerned, the only way to design them is in sight of the whole engine spec, generic exhausts will never get the best out of an engine - that is why Sinclairs are so particular about their system for their 240bhp Honda with A3 cams, and do not supply that system in their basic £10,500 quote -

[KD88]

I recently fitted an S2 manifold and downpipe to my daughters S1, first cleaning/grinding the excess welding that block the tube bores.

MGTF items are the same and are usually cheaper, you simply have to move the hanger on the flexi section. The mg heat shield also fits straight onto the manifold so you don't have to make up your own.

Do a search on SELOC to see the difference the grinding does.

[robin]

The lotus supplied heat shield for the S2 also fits straight onto the manifold - item 19 in this handy picture:



Don't forget items 23 (as pointed out above, the alt heat shield is a must) and 34 if you're retro fitting to an S1 - otherwise the exhaust will be heating up your coolant and toasting your alternator.

Cheers,
Robin

[woody]

Ah.... I fitted the MG TF heat shield on my car when I did the bottom end swap. Kept the S160 Alt heat shield I think as it was larger, plus the small heat shield on the manifold at the front of the block Not shown), but I was quite concerned about the lack of length in the main heatshield. Luckily, I had a section of heatshielding from a very different type of engine around the same size as the original S1 part that I modified to suit.

You can tell the newer set-up works really well; with the rear window out of the S1 you barely get a heat from the manifold now, used to keep the cabin nicely hot on a cold day.