Dump Valve For A 172/182

[rich[182]]

Can someone explain the technical reason why one cant be fitted on a normally aspirated engine or why they wouldnt work, Ive always wondered

Someone in the ECOTEK thread said the ecotek hissed like a snake so surely a dump valve could be fitted to make the noise, or am i talking crap ?

 

[Daz]

http://www.grahamgoode.com/dump.htmhttp://www.grahamgoode.com/dump.htm

It vents away excessive Turbo boost when throttle is closed.. so it wont work without a turbo, heh.

 

[McBunny]

some people

 

[David]

lol...no no no...although ive heard u can get fake ones off ebay ....if u like that sort of thing..

 

[Daz]

Quote: Originally posted by David on 17 May 2004

lol...no no no...although ive heard u can get fake ones off ebay ....if u like that sort of thing..

Yea, theyre called "Speakers" with a recording.. shocking items. heh.

 

[Clart]

bless him

 

[iPap]

I could post you a few pics but they may be a little too much for your brain to handle! Bless you...

 

[rich[182]]

Chill guys, I know what they are dammit, I had one on my fiesta rs turbo for 5 years, I also know my 172 hasnt got a turbo (LOL) but just didnt understand why a normally aspirated engine doesnt produce enough pressure etc to be able to be vented away and therefore make the noise, surely the fact that ecotek valves hiss means there must be some air pressure escaping from the breather system ??????????

Nicky B - Thanks for the your technical input


[Edited by rich172 on 17 May 2004 at 12:43pm]

 

[Clart]

Would u like to borrow a spade?

 

[BIGDAVE]

No hes well past spade,hes onto JCB.

 

[Roamer]

LOL

Ok Rich, without a turbo, an engine (call N/A for Naturally Aspirated) produces NO positive inlet pressure.... a dump valve on a turbo car releases the excess inlet pressure when throttle is closed as has already been said, but as an N/A engine sucks the air and fuel mix in by creating a vacuum as the piston travels down the cylinder then is no inlet pressure whatsoever....therefore none to release to atmosphere when the throttle is closed.

Erm... think that covers it dont it?

 

[Matt16v]

The reason for a dump valve is that the turbos still spining after you take your foot off and its trying to force air in to the boost pipe when the throttle is closed. So the valve opens and releases it. (Or waste gate)

On a N/A car when you take your foot off the go pedal then theres no air being forced any where. So you dont have any pressure to have a valve.

Hope this clears it up a little bit, I get the guist of what your trying to say, when I accelerate I get a hiss from my airfilter but thats nothing to base a dump valve on!

 

[CUP80Y]

Forget the dump valve, you want one of those turbo whistle simulators which are in fact just a whistle for your exhaust!! LOL.

Know what you mean though - it would be nice to have the tissssshhh noise.

 

[rich[182]]

Roamer

Thanks very much, A constructive reply that clears it all up, Thats all I wanted to know.

 

[iPap]

Quote: Originally posted by Matt16v on 17 May 2004


The reason for a dump valve is that the turbos still spining after you take your foot off and its trying to force air in to the boost pipe when the throttle is closed. So the valve opens and releases it. (Or waste gate)

The waste gate is seperate from the dump valve.

You have a wastegate on all turbo cars. Dump valves are optional, they are more efficient at high boost presure for releasing boost.

This is why you loose the "wastegate chatter" when a dump valve is added to an engine.

 

[turbo man]

Not if you run enough boost. I manage to get both! The wasteget is complete different to a dump valve my friends. It allows the exhaust gases that usually pass past the turbo exhaust wheel to flow out of the exhasut. There fore if you adjust you actuator, you can keep the wastegate closed and creat more boost pressure. You guys probably already knew that, just wanted to make sure that RICH 172 was clear on it all. Didnt want to confuse him!

 

[Jones]

The hiss you hear from an ecotec is air actually being sucked in, supposed to aid atomisation of fuel which is b****cks and can make your engine run worse or lean!!

 

[BenR]

Put very very simply.

Ecotek makes a hiss because as Jones said, its air being sucked in. Its not that there is a vacuum inside the inlet manifold, but that there is a lower relative pressure than outside it, and air flows from high to low pressure.

On an NA car there is always 14.7lbs of pressure acting on the throttle plate. At wide open throttle you have effectively 1 bar of boost, but thats only because its the natural ambeint air pressure.

Turbos have a dump valve to release excess pessure before the throttle plate.....it wont create any mechanical damage to the throttle itself or the engine, but it will annoy your turbo. So the hiss comes from the high pressure in the plumbing of a turbo engine, excaping to the outside which has a lower ambeint pressure. If you had a DV on a NA engine you wouldnt get a hiss even though there is a pressure on the throttle plate simple because the pressure inside the airbox trunking before the throttle plate is the same as that outside it. That equals no movement between those two areas.

simeple eh!

 

[Yugguy]

You can put a cut-up coke can into your inlet pipe to make a homemade turbo as well!