making my own exhaust manifold
Turbo Mini Forums

bored of waiting for the mirage manifold ive been toying with the potentially dangerous idea of making my own manifold

im about to have a read of maximum boost, but does anyone have any top tips on what to do, im presuming keeping back pressure to a minium and keep the pipe work to simialr lengths which could be a bit hard

any advice is appriaciated

I am buiding a manifold myself at the moment. Its for my left hand side steering midget. I am using standard exhaust bends bought at the local halfords. Thoughts were to keep it as simple as possible and with large 42mm diameter pipes and smooth bends.
Dimensions have been sorted and work has only just started, however, I shall shoot a foto tomorrow.

Why don't you harrass them day in day out, twice a day if needs be...

I've pm'd you by the way...

Guys - you need to be using at least 2.5mm wall thickness hi-grade steel for this... Anything else will last a matter of hours before cracking and failing. Been there.

Grey - if you tip the engine more forward, and use an adaptor plate, you can just get a T2 in there without cutting the bulkhead...

Edited by turbodave16v on 4th Jun, 2004.

if you guys really do go ahead with building your manifolds then plese post up some pics for me to see :)

'I swear to use the Boost, The whole Boost'
'And nothing but the Boost..... So help me God'

thanking your for the assistance

the only trouble there dave is that i dont have a turbo manifold either! may be able to lay my hands on one though
did you get some conversion plates made up?

grrrrrrr I WILL MAKE IT TO AVON PARK THIS YEAR! 1st year car stolen, 2nd got the car finished but the engine was dead, 3rd it looks like it wont be ready, oh poop deck!

thank the lord! got through yesterday and the manifolds and turbo WILL be ready this coming week!!wahoo

YAY!

alex

AlexF

Here's mine sofar:
http://upload.altrezia.com/imageviewer.php?i=210

The piping has a wallthickness of 2mm, I am not sure if its enough, ill proceed anyway. lets see what happens.
They say its tubing with some content of aluminium, hence the difficult welding.
I have to make me own inlet manifold as well, if the exhaust comes along fine I will continue.

wow lets see what yours look like greypride :)

'I swear to use the Boost, The whole Boost'
'And nothing but the Boost..... So help me God'

Arno...

It looks good but you are going to run into expansion problems with that design of manifold. Were tubes 2 and 3 join (the longer ones) you going to get much more growth than the 1st pipe!

Alex

AlexF

Alex???????
Please explane???
I am full of question marks.

as in thermal expansion and contraction of the pipes may cause cracking. i think thats what he's saying. Makes sense to me anyway

Arno - add some triangular webs onto the flange that the turbo mounts to.
Adding large sections of flat plate between the individual runners will also increase reliability (these must be fitted at the 'mid height' of the runners so the flat plane is in line with the centre-line of the tubing) but weld them top and bottom to ensure they are well fixed and expand/contract with the runners as a whole.

I'd also make the flange at middle ehaust port a pretty close fit between the studs. Make #1 runner around 2mm clearance, and give around 3mm clearance on the #8 runner. This will allow the manifold to grow and contract.
I would also make a braket to take the weight of the turbo. Make from rose-joints or similar to allow for slight movement.

Lastly - DONT' use any lagging on the tube. If the heat wants to escape, you must let it escape!

Edited by turbodave16v on 8th Jun, 2004.

Yup thats the idea...

It would probably have been better to try and equalise the lengths of the runners, its possible a long centre runner would be benifical...

But you certainly can work with what you have started :)

alex

AlexF

Thanks for the input, its highly appreciated. i shall make the alterations it makes sence to me.
I have no choice in positioning the turbo, this is the only place to put it, otherwise it fauls with the steering rod and shock absorber.
Also I have to keep in mind that the down pipe has to go down somewhere.
Thanks people, I shall post another picture after more progress.
Arno

I did wonder if they were the deciding factors for the lengths... everything with cars is always a compromise!

Keep us posted, its a great project!!

Alex

AlexF

Turbo dave,
i think I understood what was said, exept for the lagging bit, please explain.

By now I have welded in some triangle webs between the runners of 6mm thick plate, i was not to weld in large plates as I need to sort the intake lateron.

lagging...

when you wrap the manifold in heat insulating material.

Like you cover water pipes in foam to stop them freezing in winter.


Alex

AlexF

so wouldn't you guys reccommend wrapping my exhaust in heat wrap :(

'I swear to use the Boost, The whole Boost'
'And nothing but the Boost..... So help me God'

i know of the advantages but what are the disadvantages?

'I swear to use the Boost, The whole Boost'
'And nothing but the Boost..... So help me God'

I would have thought if you're using the standard Metro Turbo cast iron exhaust manifold it will be fine to wrap it, as the manifolds a fairly hefty job.
On the other hand a thin tubular manifold will be more prone to cracking especially when hot, it will keep cooler if you don't cover it.

Phil.

WWW.TURBO-MINI.COM

manifold errosion is the disadvantage!

alex

AlexF

Its a masterpiece by now. such thing shall not be wrapped.

LOL

I should hope not...

it looks ugly...

sorry Jon!


alex

AlexF