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Length st170 exhaust manifold pipes
Rena - 2/4/17 at 07:38 AM

Hi,

Have already cutted my st170 exhaust manifold but need the lenght of the secondaries.
Anyone?

big_wasa - 2/4/17 at 04:04 PM

I would just make it fit where it's needed.

SPYDER - 2/4/17 at 07:10 PM

A quick search on LCB suggests the following for a similar XE motor...

31" Primaries 1 7/8 header dia
15" Secondaries 2 1/4"


But also the following...

27" primaries 1 7/8" dia
10" secondaries 2 1/4" dia

And a well known exhaust maker suggests 8"- 10"

There are calculators online which compute the lengths from pipe diameters, valve timing etc.

Get Googling "Exhaust length calculator"

There's no one answer but unless you are chasing the last hp I wouldn't get too hung up on it.

snapper - 3/4/17 at 06:08 PM

It's not just the primary and secondary lengths but also the inlet lengths.
Specific to the engine, rods, stroke, cam duration etc etc
There are different harmonics that give different pipe lengths and still provide benefit
It's not just the lengths but also diameters of tubes
Trust me the more you look in to it the more complicated it gets
There is not a single answer to your question
And your question is not simple

Rena - 3/4/17 at 08:05 PM

Quite easy, I have asked for a length, not anymore.

SJ - 4/4/17 at 06:58 AM

I think he just wants to know the length of the standard ST manifold as he has already chopped his up.


Stu

Rena - 4/4/17 at 07:01 AM

quote:
Originally posted by SJ
I think he just wants to know the length of the standard ST manifold as he has already chopped his up.


Stu


Correct!