Intake pipes theory

[speeding-g60]

on my 35R i run 2.5" from turbo compressor to intercooler and 3" from intercooler to 70mm TB.

here is a quote from VWVortex, from Frederick. it gets kinda technical.... but its the mathematics of it....

Did some fast calculation myself.
Could be incorrect due to all conversion from Lb/min to litre per min and from meter per second to mph etc.

BWTF .... Books say do not exeed MACH 0.4
Mach 1 is ~761Mph
So MACH 0.4 is ~304Mph

304Mph is ~136meter per second .

So this is the aim to be below


At wot/redline My turbo boost ~56Lb/min = 25.4kilos a minute
1 kilo of air is ~ 1m3 or 35,3 cubic foot.

So its 25.4M3 or 896.6cubic foot per minute.

To get Mach 0.4 or 136m per second at 896cmf that could be anything from 500-590Hp depending on temp and fuel
So 56Lb/min * something between 9-10,5 = Hp

60mm/2,36inch INNER diameter piping will result in 148meter per second.
This is normal thin whall stainless piping ...alu piping is often have thicker walls so its comparable to 2.75 inch outer.
So thats not what we whant for our 500hp project.


So what piping will keep ME under Mach 0.4 ?
A 63mm inner diam a.k.a 2.5 inch inner diam piping will do Mach 0.4 at 56lb/min.

So im going for 2.75 outer with ~65mm inner for HOT side
And 3 inch for Cold side .


No temp etc is in this calculation.
Max Hp before it goes way to high!
So its better to make a bigger dimater pipe with smarter shorter routing with less bends and less difference in area.
If you use alu piping make sure its required inner diameter.
Stailess steel is often in thin wall

500-550hp = 3inch piping with atleast 2,75inch inner diam
450-500hp = 2.75inch piping with atleast 2.5inch inner diam.
400-450hp = 2,5inch piping with atleast 2,3 inch inner diam
350-400hp = 2.25inch piping with atleast 2.1inch inner diam
250-300hp = 2inch piping with atleast 1.8inch inner diam


http://www.eesiflo.com/flow_calculator_01.html
http://hemsidor.torget.se/user...ength
http://www.turbobygarrett.com/....html

[gnutz2]

@ speeding-g60

According to that info the air in your turbo to IC pipe is exceeding 0.4 mach. You need to replace this with 3" tube.

[|Maku|]

To get Mach 0.4 or 136m per second at 896cmf that could be anything from 500-590Hp depending on temp and fuel
So 56Lb/min * something between 9-10,5 = Hp

60mm/2,36inch INNER diameter piping will result in 148meter per second.
This is normal thin whall stainless piping ...alu piping is often have thicker walls so its comparable to 2.75 inch outer.
So thats not what we whant for our 500hp project.

So what piping will keep ME under Mach 0.4 ?
A 63mm inner diam a.k.a 2.5 inch inner diam piping will do Mach 0.4 at 56lb/min.

So im going for 2.75 outer with ~65mm inner for HOT side
And 3 inch for Cold side .

500-550hp = 3inch piping with atleast 2,75inch inner diam
450-500hp = 2.75inch piping with atleast 2.5inch inner diam.
400-450hp = 2,5inch piping with atleast 2,3 inch inner diam

Exactly, shouldn't you go for at least 2,75inch inner diam?

What size is your 35R cold side outlet?

EDIT: From what point speed must not exceed 136 m/s? Is it before intercooler, after intercooler or before intake manifold?

[quattro84]

the 'mach 0.4' is already a guess, so i wouldn't take this too seriously.

its better to make a bigger diameter pipe with smarter shorter routing with less bends and less difference in area

that always goes

[|Maku|]

Exactly, shouldn't you go for at least 2,75inch inner diam?

What size is your 35R cold side outlet?

EDIT: From what point speed must not exceed 136 m/s? Is it before intercooler, after intercooler or before intake manifold?

speeding-g60, enlighten please.

[speeding-g60]

i want to say the 35R cold side outlet is 2.5" OD. and i run SS or CS piping, not aluminum. the thin wall of aluminum tubing can crush easily with good t-bolts.

[|Maku|]

But have anybody thought of two step intake for 2.2t?