turbo M50/2

[bigkev]

has anyone or is anyone thinking of turbo'ing an M50/2
it looks like i'm going to go down this route but i am presuming the comp ratio will be in the high tens on this motor so i am thinking of fitting some offset small end bushes to get the comp right and keep the cost down,anyone tried this on a beemer motor?
i remember reading a thread about manifold flanges and somebody said they could CNC some but i cant find their user name so if anybody remembers could they please let me know

cheers guys

[Toby_Unna]

cool, that should make a really nice conversion

can you maybe use one of those tubular m50/t3 manifolds on ebay.com, fairly cheap as i remember.

easier than making your own anyway

[bigkev]

i have'nt actually looked on ebay yet as i was planning on building my own toby as i am getting cash together so i can get started as soon as i buy a 316 shitter to be stripped out as its going to be track/daily hack car
also been reading about the comp reducer plates but never actually seen one,i would be happier with the standard gasket to be honest and have found an engineering shop that can machine the rods and knock up the bushes

[Turbo-Brown]

Personally think you'd be better off getting the pistons dished so that you maintain some kind of squish band rather than moving the whole piston down in the bore.

Would however need to check on the thickness of the crown before going that route.

[bigkev]

i presume the pistons are convex seeing as its a multivalve so i could machine the tops off (if its feesable strength wise)
whats the general rule of thumb regarding comp ratios for multivalves can they take a bit more than 2 valvers

[Turbo-Brown]

Wouldn't assume they're convex, the majority seem to be flat with cutouts from what I've seen.

I imagine that the more efficient breathing of the multivalve engine would raise the dynamic CR over that of a 2v so perhaps even less would be in order.

However, I very much stand to be corrected on that!

Probably not a bad idea to look at what multivalve turbo production engines run. Seem to recall that the VAG 20vT engines have about a 9.5:1CR which is pleasingly close to what I've got on mine, however careful mapping is a necessity with such a relatively high CR.

Having said that, the Mi16 turbo my mate and I have been working of for the last millenia still has a 10.4:1CR....but we're absolutely not going above 5psi on that!

[jmc330i]

Ebay manifold

TBH, for the price I dont think you could go wrong. I doubt you could make one like that yourself for that sort of price.

[Turbo-Brown]

I've never seen a more bizarre looking manifold!

It's like a combination of a log manifold and a multi branch and look at the way the pipe for cylinder 4 is squashed where it joins the log.

You can make a 6 branch manifold for about Ԛ£250 if you can weld and have basic hand tools to fit up the pipes!

How could all those different lengths and styles of runners possibly flow equally too?!

[jmc330i]

You can make a 6 branch manifold for about Ԛ£250 if you can weld and have basic hand tools to fit up the pipes!

Im not saying its a great manifold, but for 99 notes vs 250...
Not many people can or have the tools though. As Toby said, it would be easier than making one.

How could all those different lengths and styles of runners possibly flow equally too?!

Would it really be that different from using a log style manifold?

[WillG]

not really just thats got abit higher backpressure on 456 then 123, it depends on rest of setup , probly wont be to bad if turbo isnt big

[Turbo-Brown]

Would it really be that different from using a log style manifold?

It's just that they say

Each manifold is ported on each cylinder for even flow

which seems a bit unlikely.

As you say though, for Ԛ£100 it's probably worth it.

Like the way they make a big thing of using thick walled tubing as though that's somehow a good thing too!

[leftcoaste30]

i presume the pistons are convex seeing as its a multivalve so i could machine the tops off (if its feesable strength wise)
whats the general rule of thumb regarding comp ratios for multivalves can they take a bit more than 2 valvers

on a pickup I built, we machined a square into the top in an oval in the middle of the piston that went around the indents for the valves. This setup works awesome, www.auburnautomachine.com has a picture of a setup where they machined the top of the piston out like we did with mine, I think it's under engines.

[e21Jason]

Hi

If you use an 84mm bore m50 you could use m40 1.8 pistons? they have a dihshed profiel unlike the 4V which has a raised centre section and valve pockets

Jason

[bigkev]

Hi

If you use an 84mm bore m50 you could use m40 1.8 pistons? they have a dihshed profiel unlike the 4V which has a raised centre section and valve pockets

Jason

i supose that would work but whats the chance of the deck height being spot on ?

that manifod does look pretty good (shiny at least) but i have to agree with turbo-brown i cant see it flowing very well,i am looking at a fairly small turbo as i dont need huge HP at the moment another 50-60 to start off with will be fine so i want to get it right from the off so i can upgrade at a later stage turbo wise so it would make sense to pay more for decent stuff and then maybe look into bigger turbo's

[bigkev]

just been thinking about what leftcoaste30 said ,if i machined the parts around the valve pockets so they are flush with the existing cutouts that should drop the comp a fair bit
shit i have'nt even started and its all getting a bit confusing

[Turbo-Brown]

Would definately investigate the crown thickness before looking at what to machine off.

Afterall, less material is not in a good position to deal with more load.

[bigkev]

i guess i cant really make a decision until the heads off and the pistons out really will post some pics once its stripped then we can make a collective decision on comp ratio,and then when it goes bang we can make a collective collection of cash for another go

[WillG]

cant you get thick MLS gasket for it, might only get it down to 9:1 but thats ok for turbo anyway, what is it as standard?