Killing Wastegate Creep

[Z2TT]

Hello,

I read the article on Autospeed titled "Killing Wastegate Creep" :

http://autospeed.com/cms/A_1053/article.html

In a nuteshell the article says that :

The wastegates on turbocharged cars do not stay shut until maximum boost is reached, but slowly open, which means the turbochargers will spool up slower and max boost will be reached slower.

What the person has done is lenghened the hose from the compressor housing to the wastegate actuator, he's put a 2.5m hose there so it takes longer for the pressure to reach the wastegate actuator, eliminating wastegate creep. The graphs show that after the 2.5m hose had been installed, the turbochargers reached max boost much quicker.

I am thinking of doing this to my car, I have a twin turbo engine though, a 1g-gte. I wonder how the person fitted a 2.5m hose there, did he wrap it in circles and circles or run it across the whole engine bay and back to the turbocharger area?

I'd imagine if by doing a simple modification like this to get the turbochargers to spool faster, everyone must be doing it, yet I dont hear about it.

What are your thoughts on this people?

Thanks,
Z2TT.

[LeeRoy]

Its not the best idea because it gives a delayed reading to the wastegate meaning once full boost is reached it doesnt instananeously shut. This makes your boost spike and in most vehicles youll hit boost cut, which is worse than a a slow spool time.

If you want to test your wastegate hook up a gauge, a hose, and a bike pump and see what pressure makes the gate open.

[Z2TT]

Thanks.

Ah then it wouldn't be a good Idea to attach a very long hose then. Really would the only good way of getting the turbochargers to spool up better is to get an Electronic Boost Controller?

I read that EBC's bleed off a lot of air when you begin accelerating to keep the wastegates shut so the turbochargers spool up faster, then slowly begin bleeding less air as you reach max boost. Is this correct Leeroy?

[LeeRoy]

Wastegates use a spring which has a preset tension which is rated in PSI. When that psi is reached, the force of the air overcomes the spring and makes the gate open. However, since there is air (exhaust gas) pushing against the gate, once you get close to its opening pressure, it will begin to open (or creep). This also stops boost spiking as it slowly diverts the gas, rather than shut it off like a light switch.

Think of it like a set of scales with a bucket on one end filled with water which also has a hole in the bottom of it, and a big weight on the other end. Now if you had a hose pouring water into the bucket and you wanted to get it to balance (which is what the gate does), you would need to increase or decrease the water being added depending on which way the scale tips. The gate would pretty much reads what the scale is doing, and adjust the water going into the bucket to keep them level. Now its easier to keep the bucket level by slowly increasing/decreasing the water that to be turning it fully off or fully on.

An EBC uses an electronically controlled solenoid which holds back the signal to the gate and once set pressure (which you set) is reached, they open and allow air to go to the gate causing it to open. Once psi falls they close, and this process goes on and on.

They still work like a set of scales but they work alot quicker as they dont open until they hit the specified pressure, whereas manual boost controllers or wastegates slowly open as they approach this pressure.

[Toy77]

Hi mate,

There is another option for non electronic boost controllers.

Yuo can add a "pressure relief valve". this goes in line with your boost actuator line. this is an adjustable valve - that stays completely shut until a set boost level is reached - then opens and stays open until there is no boost on it, at which point the cycle is repeated.

I have used one of these in the past and the difference is huge. you can even set a boost spike into the system - ie you have you boost controller set at 15psi, but set the pressure relief at 17psi - this gives you a big hit in the mid range, then a slightly lower boost in the top end where detonation is more likely.

with this set up in my single turbo 1g - was fine on slicks down the track (lots of traction) i got the car home, put stockers on it to go to a mates workshop and change my good tyres back on the car - but with the pressure relief set as aggresive as i had it for the track, the car was so aggresive coming onto boost, i had to pull over and wind it down - and i was only 2km from the workshop!!

The good electronic boost controllers are a better option these days - BUT there are other options.

Cheers
Stew

[brett_celicacoupe]

$30 gets you a turbtech boost controller and you can set it to have no increase in boost but it will make the turbos come on slightly harder

[PlacentaJuan]

brett i dont really understand how this works, coz the burnotech has a bleed hole, so even on the lowest setting i still got 20psi+ (over 'standard' 16-17psi)

my only solution was to sticky tape over the bleed hole and then i didnt even notice any difference (i was running seq so that might have been why, plus i think my no1 turbo is fooked from the 20psi+)

[brett_celicacoupe]

i was referring to my experiences with the 1GGTE - it behaved exactly as described above.
the spring and ball mechanism is very hard to set like this but it can be done.

im not running any boost control on the 2JZ

[MS-75]

Be VERY CAREFL when actioning any of the retarded boost control advice dished out by Autospeed around that time............

I'd hate to think how many engines have been lost due to the garbage spouted by those clowns over the years.

[chris davey]

toy77: I don't understand what you mean with the pressure relief valve. I ran one previously as well and had no boost controller other than that and wastegate spring was 15psi. I was adjusting it to get closer to 15psi so that it would hold the pressure until about 13psi or so. I then turned it just a tad too far so it was over the 15psi mark and from that point on it was running as much boost as it wanted! Held all the pressure at the valve, wastegate never got any and hence never opened.

[Kyosho]

The turbo tech bleed valve is on the side of the wastegate, not the pressure source.
The turbo tech doesn't BLEED air, like a bleed valve does, it is a spring, with a ball blocking the flow of air.

A springs distance is equal to the force applied on it, and a constant. (D = kF)
You adjust k, by tightening the screw up.
Now the turbotech DOES creep, but the hole is a certain point along, that it takes a fair bit of boost before the wastegate sees ANY pressure, at which point it starts its MINOREST amount of creep, but the time this happens you hit full boost, and the turbo tech is full open, which completely opens the wastegate.

The whole system still has creep, but instead of the wastegate creeping, the boost controller does.

[Toy77]

Hey Chris,

a pressure relief valve is different to a flow proportion style valve though both can look the same.

The pressure relief valve stays closed until a preset pressure is there, then it opens and stays open until there is no pressure there, at which point it closes again.
where as a restrictor or proportional valve will allow a certian flow (or bleed off) at a consistant rate.

so the pressure relief set up if using the correct valve as described by you, should work like this.....

for example lets say you have an 11psi spring in your waste gate (no boost controller to raise boost) you waste gate starts to open at 7psi to give a nice, smooth (but slower) boost curve.

adding the pressure relief vallve on the boost signal line and setting it to 9psi will show the wastegate 0psi until 9psi is reached - then the valve opens and allows the wastegate to do its job - limiting boost at 11psi.

if you set your pressure relief valve to 13psi - the waste gate should see 0 boost until 13psi - then the pressure relief opens - the wastegate will then control the boost to 11psi until you back off - at which point the relief valve will close again.

This is how the set up worked with the "hyperboost controller" and i ran a prototype of this on my car, and worked very well.

DISCLAIMER - i am not recomending for people to run boost spikes or what affect this has on the longevity of your turbo. this is a set up i have used - and have found some benifits in certain situations and am putting this out there in the spirit of discussion......


Cheers
Stew

[Ribfeast]

I used the dual valve setup off Autospeed with no problems, pressure relief valve and pressure regulator combo. Brought boost on nice and quick, and then held it quite stable. I ended up going electronic so I could control levels from within the cabin.

[naten]

I have played around with various methods of trying to bring boost on quicker. (1jzgte)

1) turbotec T $25 off ebay. dodgy as shit no effect on boost time

2) turbo smart dual stage boost controller payed $50 second hand would have been so shitty if i paid the $200+ retail for it. Would cause boost spikes and for me to hit boost cut even when it was set on the lowest (most open) setting.

3) The pressure relief valves mentioned on here from autospeed website (also used in "hyperboost" controller)

I did not have success with these either, basically boost was either building too quick and it hit boost cut or it wouldnt have any effect. That being said multiple people in this thread have said they have had success with them so it could just be me.

Moral of the story. Something that claims to bring boost on quicker that is a ball and spring type dont waste your time with.

cheers
nathan

[Ribfeast]

Get rid of boost cut then I had no problem with the Autospeed/Hiperboost setup.