fabricating a turbo manifold
Turbo Mini Forums

OK, OK, point taken. I'll climb back into my hole.

I'm not getting enough daylight which seems to be making me grumpy and miserable.

Handbags away.... i was enjoying what i thought was a healthy debate

On 8th Jan, 2016 Paul S said:
The winners use tuned lengths.

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

Excuse my dumbness here... but n/a in theory is the '3 branch into 1' manifold better/equal length compared to the lcb type?

Edited by D4VE on 8th Jan, 2016.

Vizard states LCB has more torque from 3-6k rpm. After that its pretty even, but with a slight advantage to 3 into 1 when using long duration cams.

And this is my point. There's been a shit load of research and testing by DV and others to work out how to make the best NA exhaust. No single person here could recreate that if it wasn't already known and it's no different for a turbo manifold. Knowing a few simple rules like "equal length is better" is a long way off actually proving that you can make decent gains.

Until someone presents a VE map comparing the two manifold types, no one knows.

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

i agree simple is best for 90% of people if you want that last bit you'll really have to work for it

i really regret making mine over complicated! simple is easy to work on, easy to build and much cheaper

Thanks for your input guys. I guess it's important to know the restraints of a build.
I won't in any circumstance chop the bulkhead. The project is my old cooper so I really don't want to ruin it.
I've got some budget but want to spend on some omega pistons and parts I cant make myself
I fabricate things in stainless steel for a living so I'll certainly be making my own manifold. Bad job if I can't

What size tube and thickness flanges are regarded as the best?

Thanks for all input!
Cheers

IMO I'd always like 1/2" flanges or more, but thinner have worked for people.

As for pipe diameter, no reason at all to go for anything bigger than the readily available 1.5" OD

If goals are low-moderate you could even go a little smaller without any concerns

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

No bigger than 1 1/4" OD or the pulses will be next to non-existant.

I use 28mm bore Schedule 10 stuff.

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 use 29mm ID for mine. It's just as important to have smooth joins and smooth welds internally otherwise yours just going to cause turbulence everytime the gases pass over a weld.

Edited by matty on 10th Jan, 2016.

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www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

Agreed, it's the same on the food grade production lines I fabricate. We tend to purge the gasses on the inside of pipes and tanks.

Out of interest,, how much do you charge for a manifold for a gt1752 that requires no bulkhead mods.
Had a look on your site but failed to find it.

Thanks

Ben

They are £250 Ben for the manifold.

On this page

http://fusionfabs.co.uk/stainless-range

Edited by matty on 10th Jan, 2016.

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www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

Yes, back-purging will help with the inside of the weld.

I also have some blocks that I use to stop the flanges from curling. Saves a lot of time later sorting the flanges out.

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 was going to bolt it up to a head before welding to try and stop it pulling too much.

I'll attempt making one as all it will cost is time, if I make a hash of it, I'll be getting my cheque book out!

Cheers Ben