Omega Owners Forum

Chat Area => General Car Chat => Topic started by: The Red Baron on 09 May 2010, 21:42:36

Title: inlet manifold switchover valve
Post by: The Red Baron on 09 May 2010, 21:42:36
on a v6, can anyone give a simple explanation as to what it does please. :y
Title: Re: inlet manifold switchover valve
Post by: Elite Pete on 09 May 2010, 21:43:56
It operates the zeeko flashback system :D
Title: Re: inlet manifold switchover valve
Post by: The Red Baron on 09 May 2010, 21:51:08
Quote
It operates the zeeko flashback system :D
sensible answers on a postcard please. ;)
Title: Re: inlet manifold switchover valve
Post by: TheBoy on 09 May 2010, 22:00:14
flattens the torque curve
Title: Re: inlet manifold switchover valve
Post by: dbug on 09 May 2010, 23:28:16
I thought it operated the zeeko flashback system  :o
Title: Re: inlet manifold switchover valve
Post by: feeutfo on 09 May 2010, 23:31:04
if not working, increases fuel consumption and loses power below 4k, basickly alters the inlet flow to give low rpm torque and, in conjunction with the second multiram at back of plenum, gives good top end power as well. Fools the inlet flow to give best of bith worlds. :y
Title: Re: inlet manifold switchover valve
Post by: The Red Baron on 10 May 2010, 08:35:40
Quote
if not working, increases fuel consumption and loses power below 4k, basickly alters the inlet flow to give low rpm torque and, in conjunction with the second multiram at back of plenum, gives good top end power as well. Fools the inlet flow to give best of bith worlds. :y
thanks for that chris. :y
Title: Re: inlet manifold switchover valve
Post by: 2woody on 10 May 2010, 09:34:16
this is a bit of a test.......

it's all to do with Organ pipes really.

any air in a pipe will have a resonant frequency, which depends on (amongst other things) the pipe's length.

IF you can organise the pipe so there's a slight high pressure at the ends, then that pressure can spill out

the idea in an engine is that the inlet tract is switchable into three lengths, and at certain speeds the slight high-pressure spills into the cylinders past the valves, causing a mild "supercharging" effect. Longer for lower revs, shorter for higher revs (just like organ pipes)

its exactly the same theory as used for the tuning of exhaust manifold lengths.

that's about the simplest I can make it. Actually, I dod one of my dissertations on this subject - three months of slog, and I only just scratched the surface. One day I'll run all of the calculations for the Omega
Title: Re: inlet manifold switchover valve
Post by: TheBoy on 10 May 2010, 09:40:02
Quote
this is a bit of a test.......

it's all to do with Organ pipes really.

any air in a pipe will have a resonant frequency, which depends on (amongst other things) the pipe's length.

IF you can organise the pipe so there's a slight high pressure at the ends, then that pressure can spill out

the idea in an engine is that the inlet tract is switchable into three lengths, and at certain speeds the slight high-pressure spills into the cylinders past the valves, causing a mild "supercharging" effect. Longer for lower revs, shorter for higher revs (just like organ pipes)

its exactly the same theory as used for the tuning of exhaust manifold lengths.

that's about the simplest I can make it. Actually, I dod one of my dissertations on this subject - three months of slog, and I only just scratched the surface. One day I'll run all of the calculations for the Omega
Hmmm, sounds like fun. Not ;D
Title: Re: inlet manifold switchover valve
Post by: Kevin Wood on 10 May 2010, 09:41:51
Quote
One day I'll run all of the calculations for the Omega

It'd be interesting to look at what can be done with the exhaust on the V6. Having crafted quite a nice induction system, GM seem to have bolted a carbunkle of an exhaust manifold on it.

Maybe it's for packaging reasons, maybe they knew there was little to gain, or maybe the bean counters "engineered" that bit, but it would be nice to know what a nice tubular manifold would do for the engine.

Kevin
Title: Re: inlet manifold switchover valve
Post by: 2woody on 10 May 2010, 11:11:16
cast iron manifold and lagged primaries all there for emissions reasons...
Title: Re: inlet manifold switchover valve
Post by: 2woody on 10 May 2010, 11:12:13
Quote
Quote
this is a bit of a test.......

it's all to do with Organ pipes really.

any air in a pipe will have a resonant frequency, which depends on (amongst other things) the pipe's length.

IF you can organise the pipe so there's a slight high pressure at the ends, then that pressure can spill out

the idea in an engine is that the inlet tract is switchable into three lengths, and at certain speeds the slight high-pressure spills into the cylinders past the valves, causing a mild "supercharging" effect. Longer for lower revs, shorter for higher revs (just like organ pipes)

its exactly the same theory as used for the tuning of exhaust manifold lengths.

that's about the simplest I can make it. Actually, I dod one of my dissertations on this subject - three months of slog, and I only just scratched the surface. One day I'll run all of the calculations for the Omega
Hmmm, sounds like fun. Not ;D

sesigned a cylinder head for my second one !
Title: Re: inlet manifold switchover valve
Post by: TheBoy on 10 May 2010, 11:28:42
Quote
cast iron manifold and lagged primaries all there for emissions reasons...
I seem to recall on the 2.6/3.2 that they did away with the cast iron manifolds...
Title: Re: inlet manifold switchover valve
Post by: 2woody on 10 May 2010, 13:41:01
yes - that's when they went for the four-cat system. Again for emissions reasons. ( even tighter emissions legislation )