Wastegate

[Aler]

Hi,

from what i understand the wastegate helps with controlling the boost pressure generated by the turbocharger.

correct me If i am wrong please, the turbo generates boost and when it reaches the desired boost, the wastegate opens allowing the extra boost the leave the system which will keep the boost constant at the desired level.

if what i think is right then, what is the function of the Gp "gate pressure" in the E-boost 2 does exactly?

I have my GP set to 6 PSI and i get around 13 PSI. when i increase the GP value i feel that the car boost holds a bit and then suddenly jumps to a high lvl boost causing a boost spike. when i lower it down to minimum I get a strange flattering sound while boosting.

can anyone please explain to me what do these things mean? and how does it work?

I read the instruction manual and I still dont get it.

thanks in advance

Aler

[bubba]

http://auto.howstuffworks.com/turbo.htm

[Aler]

http://auto.howstuffworks.com/turbo.htm

thanks for the reply,

I got that from the link you've provided

"Most automotive turbochargers have a wastegate, which allows the use of a smaller turbocharger to reduce lag while preventing it from spinning too quickly at high engine speeds. The wastegate is a valve that allows the exhaust to bypass the turbine blades. The wastegate senses the boost pressure. If the pressure gets too high, it could be an indicator that the turbine is spinning too quickly, so the wastegate bypasses some of the exhaust around the turbine blades, allowing the blades to slow down."

so it actually controls the spining of the turbine itself.

I am still not sure about the GP function in the eboost2. my guess is that when I increase the value of the gate pressure I keeps the wastegate closed for a longer time which explains the sudden jump in boost. however, I still dont underestand why the boost come a bit late than a lower value.

example, if i set the GP value to 12.0.... i feel that the car is very heavy (feels like pulling another car) then at around 3800 jumps straight to 12 PSI.

but, when i set the value to 5.0 ...... i can feel the boost at lower RPMs starting from 2600 RPM and climbs gradually and hits 12 PSI at around 4500 RPM.

so the question is... why does the car become lighter at lower RPM with lower gate pressure value and feels like an elephant at lower RPMs when the value is higher? (boost kicks in earlier with lower GP value with a late peak)

[gotRICE?]

The wastegate doesnt sense boost pressure.

There is a vacume hose attatched to an actuator. Kinda like a valve thing with a spring.

The spring has a certain "PSI" to it. As in its stiffness. The spring is connecte to a rod, that is connected to the wastegate flapper.

When the turbo creates enough boost to move that spring (lets say, 10psi for an R32 Actuator), it pushes the rod away, therefore opening the flapper, in turn letting exhaust gasses bypass the turbine so it does not make any more boost and stays spinning at a non life threatening speed.

That, or you have a massive turbo and only want to run X psi due to other limiting factors

Hope that makes a little bit of sense. I suck at the explain. Someone can add or delete. haha

Infact, it might not even be a spring. Could just be some sort of diaphragm..

Edited March 25, 2009 by gotRICE?

[gotRICE?]

Oh my bad, and as to your Boost controller, id suggest finding the model number and trying to search for a manual online.

[tridentt150v]

This is just a guess but sounds like you've got the actuator or boost controller hoses mixed up, boost should act differently to how you described.

[Aler]

The wastegate doesnt sense boost pressure.

There is a vacume hose attatched to an actuator. Kinda like a valve thing with a spring.

The spring has a certain "PSI" to it. As in its stiffness. The spring is connecte to a rod, that is connected to the wastegate flapper.

When the turbo creates enough boost to move that spring (lets say, 10psi for an R32 Actuator), it pushes the rod away, therefore opening the flapper, in turn letting exhaust gasses bypass the turbine so it does not make any more boost and stays spinning at a non life threatening speed.

That, or you have a massive turbo and only want to run X psi due to other limiting factors

Hope that makes a little bit of sense. I suck at the explain. Someone can add or delete. haha

Infact, it might not even be a spring. Could just be some sort of diaphragm..

thanks for the replies guys

and BTW gotrice, to me your explanation is very clear and now i can imagine exactly how does these things work

Aler

[Aler]

The wastegate doesnt sense boost pressure.

There is a vacume hose attatched to an actuator. Kinda like a valve thing with a spring.

The spring has a certain "PSI" to it. As in its stiffness. The spring is connecte to a rod, that is connected to the wastegate flapper.

When the turbo creates enough boost to move that spring (lets say, 10psi for an R32 Actuator), it pushes the rod away, therefore opening the flapper, in turn letting exhaust gasses bypass the turbine so it does not make any more boost and stays spinning at a non life threatening speed.

That, or you have a massive turbo and only want to run X psi due to other limiting factors

Hope that makes a little bit of sense. I suck at the explain. Someone can add or delete. haha

Infact, it might not even be a spring. Could just be some sort of diaphragm..

thanks for the replies guys

and BTW gotrice, to me your explanation is very clear and now i can imagine exactly how does these things work

Aler

[r32_det]

so would i be wrong in saying that winding the boost up on a rb20 turbo is pointless without changing the wastegate spring value? because although you've changed the desired boost pressure it will still vent out like the factory wastegate was made to?

sorry just trying to clear it up

[debonaire]

Hey Aler,

I googled for some pics to help explain the info given by gotRICE?

http://www.plracing.com/T28Turbo-actuator.jpg - The gold coloured piece in this pic is the wastegate actuator. The nipple on the front of the cyliner in the foreground connects via a vacuum hose to either the compressor housing itself, or somewhere along the intake (at a point after intake air has passed through the turbo). As gotRICE? said, there is some sort of diapragm inside which bends/moves toward the rear of the picture when pressure is experienced by the front side (i.e. when you are on boost). When the diaphragm moves, is pushes the long gold rod, swinging the lever that you can see where it connects to the exhaust turbine housing at the back.

http://www.flickr.com/photos/itsbrian/3322169272/ - Here you can see from the opposite end, looking at where the turbo bolts to the dump pipe. Exhaust coming from the engine flows through the turbine on the left here and out towards your face as you look at it. On the right you can see the wastegate and how it is connected to the actuator. You can't actually see the hole from this angle, but here the wastegate is open, allowing exhaust gasses to bypass the turbine and flow straight past the turbo into the dump pipe - preventing the turbo from speeding up any further.

The picture above is an example of an internal wastegate, because it is a part of the turbo structure itself. This is the norm, but for big HP where this small hole can't deal with the high airflow, an external wastegate is used, which is a separate unit.

As you can probably gather, it is the actuator that is responsible for when the wastegate opens, and this varies from turbo to turbo. It is common for people to transplant the actuator from an R32 Gts-t, which is set to 10psi, to and R33 turbo that ordinarily runs a dual stage 5,7psi. In cars with dual stage boost, the actuator works in addition with another control module.

Simple boost controllers like the turbotech and bleed valves are placed in the vacuum hose between the compressor and the wastegate actuator, and, without going into specifics, distort this pressure so that, even though the system may be running 10psi for instance, the actuator doesn't realise this so the wastegate stays closed and more boost is made. I'm not sure if ebc's operate exactly the same way, it might vary between models. Without knowing more about your product and how you have it set up, I'm as perplexed as everyone else in trying to figure out the reason behind the symptoms you are giving.

Sorry if I was at all patronising or insulted your intelligence, don't know how much you know and I have a lot of time on my hands so I thought I'd go with the basics

[Aler]

Hey Aler,

I googled for some pics to help explain the info given by gotRICE?

http://www.plracing.com/T28Turbo-actuator.jpg - The gold coloured piece in this pic is the wastegate actuator. The nipple on the front of the cyliner in the foreground connects via a vacuum hose to either the compressor housing itself, or somewhere along the intake (at a point after intake air has passed through the turbo). As gotRICE? said, there is some sort of diapragm inside which bends/moves toward the rear of the picture when pressure is experienced by the front side (i.e. when you are on boost). When the diaphragm moves, is pushes the long gold rod, swinging the lever that you can see where it connects to the exhaust turbine housing at the back.

http://www.flickr.com/photos/itsbrian/3322169272/ - Here you can see from the opposite end, looking at where the turbo bolts to the dump pipe. Exhaust coming from the engine flows through the turbine on the left here and out towards your face as you look at it. On the right you can see the wastegate and how it is connected to the actuator. You can't actually see the hole from this angle, but here the wastegate is open, allowing exhaust gasses to bypass the turbine and flow straight past the turbo into the dump pipe - preventing the turbo from speeding up any further.

The picture above is an example of an internal wastegate, because it is a part of the turbo structure itself. This is the norm, but for big HP where this small hole can't deal with the high airflow, an external wastegate is used, which is a separate unit.

As you can probably gather, it is the actuator that is responsible for when the wastegate opens, and this varies from turbo to turbo. It is common for people to transplant the actuator from an R32 Gts-t, which is set to 10psi, to and R33 turbo that ordinarily runs a dual stage 5,7psi. In cars with dual stage boost, the actuator works in addition with another control module.

Simple boost controllers like the turbotech and bleed valves are placed in the vacuum hose between the compressor and the wastegate actuator, and, without going into specifics, distort this pressure so that, even though the system may be running 10psi for instance, the actuator doesn't realise this so the wastegate stays closed and more boost is made. I'm not sure if ebc's operate exactly the same way, it might vary between models. Without knowing more about your product and how you have it set up, I'm as perplexed as everyone else in trying to figure out the reason behind the symptoms you are giving.

Sorry if I was at all patronising or insulted your intelligence, don't know how much you know and I have a lot of time on my hands so I thought I'd go with the basics

yup, thanks for the pictures mate.

I know alot about american muscle cars and i own 2 at the moment (2006 LS2 6.0L Corvette stock 320 rwhp, and a 99 Camaro SS 430 rwhp) but both of them are NA's and i've never used turbos and my knowledge about Turbo's and Superchargers are very little,, as you can see.

I'll be in australia for a couple of years,,, missed my sports cars,,, thought about a change, so i got my turbo charged skyline and i am having a wonderfull experience with that car so far "except for that small issue lol"

thanks for the replies guys

Aler

[4NTM4N]

if i put a wastegate on my 33 gtst would it be a smart move ie performance or would it just change the sound?

its pretty much stock got hks bov an a mushroom filta

fanx

[bubba]

You mean an external wastegate for your internally gated turbo?

No benefit whatsoever.

External wastegates are used with big non-internally gated turbo applications.