hi there need 2 know a question as above what is a wastgate and what job does it do i know its a silly question 2 ask also what is an acutor 2 and what does sorry 4 silly qustion can u tell me in very easy terms

 

http://www.turbobygarrett.com/turbob...nter/faqs.html

 

essentially a actuator controls the wastegate, normally by pre set boost pressures via a boost controller

 

what u do u mean by that u have ur work cut out here have 2 start at the start and go from there am sorry mate

 

ok mate;

lets start with the basics, do you know how a turbo works?

 

yeah wiv gases from the exhaust the spins the turbo its self and after that i am total lost wiv wastesgates and acturors i know know how a dump valve works thats just a spring does up and dwn when the turbo is on and off pressure

 

OK, you've got the basics

now; you've got to control the amount of boost, this is done by the waste gate and actuator.

the actuator basically controls the opening and closing of the wastegate by overcoming spring pressure

so if you're car/turbo is set 20psi peak, the wastegate will remain closed until 20psi is reached; then then spring will open the wastegate to allow exhaust gas to escape to stop more boost from being made.

does that make sense?

the actuator is calibrated or set electronically via a boost controller

 

a dump valve is basically a way of venting built up pressure to the atmosphere

so; when your turbo is making boost you have pressurised air, now once you come off the throttle; the pressurised air needs somewhere to go.

if you dont have a dump valve the pressurised air can only come out of the turbo (which is why you get that lovely fluttering noise) this is better known as turbo stall, because essentially the air is stalling the turbo. However if you have a dump valve the presurissed air will come out through the dump valve which is why you get the ptshhhh noise.

This is why with a DV fitted the turbo doesnt have to spin up again which will in turn make the car feel faster between gear changes

Hope that helps; i'm crap at explaining things!

Matt

 

thanks 4 that whats peak psi then and a -31 autour

 

peak is the most amount of boost a turbo will make; usually a turbo will peak then tail off towards the top end of the rev range

a -31 actuator has a base lift pressure of 8psi
a -34 actuator has a base lift pressure of 14psi

cheers

 

holding presure u mean? and whats a amel valve ur doing very good here thans a lot

 

so wiv a 3dr wiv a 330bhp it would b use a - 31 then?

 

Not quite true there, if you put a dump valve on a S2 for example, when it vents all the pressurised air,making the phsssst noise, im crap at making noises,the turbo WILL have to replenish all that air thats been vented thus making turbo lag and will be slower through gear changes.

If you have no DV the air stays in the system and as soon as you come back on throttle, the pressurised air is already there, so no lag.

Although this would depend on the psi and turbo i would imagine.