fabricating a turbo manifold
Turbo Mini Forums

Hello all
I'm looking at fabricating my own manifold in stainless. I want to produce a similar version to the mirage one so I don't have to modify the bulkhead. However I'm somewhat confused. On my N.a mini engine, it's important to get the exhaust manifold pipes all similar or the same lengths. How does the mirage one get round this as the centre port has very little length to it at all compared to the outer ones

Hope someone can explain this to me!

Many thanks!

it dosent,

its compromised due to the packaging, but it still works,

to look at it another way, whats going to make more power, a 1 litre engine with a tuned exhaust, or a 2 litre with a cast log type production manifold,

Turbo manifolds do not have to look pretty to be very functional.

It's nice if they are...but in no way needed.

Even a horrible looking manifold will still have the engine making tons of power

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I know people on here are looking at longer, equal length runners and I don't doubt there're gains to be had; But until they're built, tested and proven, you won't go wrong copying the Mirage.

Edited by PhilR on 7th Jan, 2016.

There are easy gains to be had with longer and equal length branches, but when you can easily over perform the engine as far as grip and handling is concerned, the log type manifolds are more than adequate.

The Turbo Minis tenth comandment is a load of bollox, its just bragging rights.

I'd really hope a better manifold would give better off boost performance and boost sooner.

If the gains were just at peak bananas, then I can't see the point either.

Metro turbo manifold seems more than adequate for most folks with over 200bhp available - and with less time spent in the workshop it means you are on the road quicker and enjoying that great feeling as the boost comes up.

Also,

unless your doing this for the engineering exercise, Matty on here now does manifolds, and would be able to sort you out.

https://www.facebook.com/fusionfabs/

http://www.fusionfabs.co.uk/

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Edited by PhilR on 8th Jan, 2016.

No data, just an opinion.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Wintersurfers car makes much more power than mine (when running the same boost). The only major difference is the long exhaust manifold (a chopped about LCB). He even has less cc's than me.

Same cam, similar head, similar CR, same inlet, carb etc.

Edited by theoneeyedlizard on 8th Jan, 2016.

In the 13's at last!.. Just

Even F1 cars have used log manifolds to good effect in the last few years.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

The winners use tuned lengths.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I fail to understand how people who recommend using a well modified cylinder head don't seem to see any benefit in a well designed exhaust manifold. It all works on the same principle and they are well proven.

The idea that more boost will compensate is not correct because you introduce more heat and more stress on the engine. And it will be less efficient.

Of course, it can be more complex and costly to use the better design but the argument here is that it's not important. And that is not true.

http://www.jbperf.com/

Case in point of why no one posts on this forum anymore. Just my opinion.

That's the v6 f1 engine I believe, so Hamiltons

Not in the first year they didn't



And they weren't the only ones. There was a very good reason to use the log manifold, but this year they changed if for other equally good reasons I'm sure. I could go and dig out the reasons a log manifold has advantages, but I can't be arsed.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

http://www.jbperf.com/

I could reply with a come back, but I can't be arsed

By the way I'm not arguing against a fancy manifold. But cost and packaging etc may mean a simpler manifold is the best solution in many cases.

more power at less boost is great. But the same power for £500 less and slightly more boost is still a result!

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

wait a minute why argue about the type of manifold rather than the guy is wanting to keep the turbo behind the engine and not cut the fire wall
so its really a matter of first if he wants to make it or buy it and then if he makes it how fussy he wants to be id think they should be a way to add some length in the center runner if you wanted it bad enugh but honstly getting the center runner to the same length as the outters probaly whont make much diffrance the gains you get from the length is to do with pressure pulses caused buy the valves as wel allready know so to get the advantage we need substansaly longer runners than can be fit behind the block this is the reason you go for a side mount or top mount creation and my self in my opion going side mount was a mistake i should have gone behind the block and keep things as simple as i could as ive made everything far to tight and difficault to work on

i think you can get good off boost power by useing a decant compression ratio like 10-1 or maby more depending on fuel and boost after all the metro ran 9.75 and what 7 pound? a good head and cam choice can produce varry good resolts with out getting all compcated