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MG Midget and Sprite Technical - 1500 4-1 Exhaust

Some may have seen this on FB, but for those that haven't I've been bored and designing and making stuff again!

Yesterday I picked up the tubes for my custom 1500 4-into-1 exhaust manifold. My own design - all runners are within +/- 10mm of each other in length and theoretically, according to my maths, tuned for an ~5200rpm peak. All beautifully CNC mandrel bent by my supplier.

Obviously some work to do to get it trial fitted and welded to the (soon to be laser cut) face plate. Then the proof of the pudding will be in the driving and (one day) dyno figures.

I need a catchy name for it... "Maliflow"? Ha ha.

Cheers,
Malc
Malcolm

Pictures help...

Malcolm

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Malcolm

Looking very impressive Malcolm. As you say a trip to Peter Burgess but maybe before and then after you've fitted it?
Jeremy MkIII

Surely - Malcolmflow or Flowmalcolm.
Nigel Atkins

A thing of beauty, well done
R.A Davis

Last time I was at Peter Burgess' place, it was running on a single DCOE, with a Piper 270 cam, a Spitty Mk3 manifold into a 1.75" downpipe and exhaust and an electronic dizzy. 88 hp @ the wheels, approx. 101 hp @ flywheel.

Now I have the injection, mapped ignition, 285 cam, new inlet and exhaust manifolds (almost!), plus some other trick bits.

I think I can fairly accurately guesstimate power output by looking at data logs and injector opening times. Power is proportional to fuel injected which is proportional to injector opening time. I was at, I estimate, ~104 flywheel hp with the old exhaust. I can certainly calculate the % gain by the new system by looking at % increase in injector time once it has had chance to recalibrate itself.

But I would one day like to get the fuelling, ignition and output verified on a R.R.

Malc.
Malcolm

Malc

Always great to see your ingenuity and craftsmanship. All power to your elbow (or to the rest of your exhaust system!)

In terms of names, apart from something along the lines of Chevalier Classics, how about a homage to a long-gone but high respected manifold builder in Surrey - Mike the Pipe, so you could be ‘Malc the Pipe’. I do like Malcflow too!
Something related to collecteur d'échappement perhaps?

Must find an old issue of Cars and Car Conversions magazine for a Mike the Pipe ad as he had a great logo with his name and a great bunch of bananas manifold with a slogan something like ‘Be exhausted by Mike the Pipe!’. Apparently when he retired and the business closed all his manifold jigs ended up in a skip.

Talking of old small manufactures, wonder what happened to the jigs and drawings and detail of manufacturing methods and process for the Barry King wishbones?

Cheers
Mike
M Wood

Malc,
for your actual RR figures there might be variances for current fuel (f'an'ol or not) and additives if used and if you were previously on the the er, previous rollers against the present rollers.

Also if you've changed anything else, lubrication, transmission, wheels, tyres, aging and/or lack of use slippage/stiffness for you, Peter and the car. How many decimal places are you working to. 😄

Pipemalcolm - the manifold is a Pipemalcom 4 in 1. 😄
Nigel Atkins

Now now Nigel - let's leave the effin-ol out of this! I always use premium anyway. :-)

Malcolm

Very nice Malcolm. I have to ask, why the extra bends in pipe #3, rather than keeping it parallel to pipe #2? Isn't the extra quite acute bend going to disrupt gas flow? Or is it to do with balancing the lengths? Not that I know anything about it, but it does look good!
I assume your carbs (injectors) still fit! ;-)
GuyW

Hi Guy, yes, it was to even up the lengths. Otherwise it ends up about 3" shorter than the other three. Even with the wiggle it is still the shortest one.

I spent ages messing round with different configurations in CAD, and I always got three that looked good and the last one was a wiggley compromise to squeeze in.

Malc.
Malcolm

This thread was discussed between 17/09/2021 and 18/09/2021

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