wastegate chatter
Turbo Mini Forums

at the moment i have a totally std turbo lump in my mini, i am going to wind up the boost to about 10psi, i have no bleed valve fitted so i will be doing it on the actuator rod, if i do this, as i have no dump valve fitted, will the wastegate chatter, cos i dont like the sound of a poxy dv, i would much rather hear wastegate chatter.
plz help cos if it wont i am goin fit me dv.
cheers

Shouldnt shorten the actuator rod, if you want 10psi get a 10psi actuator.

Ive done this before and it doesnt work that well.

You will hear turbo chatter as there is no such thing as waste gate chatter!!!

Its the chirping sound of the compressor wheel stalling in the reduced air flow.

Alex

AlexF

thats the thing

Trust me on this. Buy an actuator. And if you can't afford that buy a bleed valve. Do not preload the actuator to get more psi.

http://photobucket.com/albums/y139/Skinns46/

buy one and then pre load it

alex

AlexF

whats the difference in me buying a new actuator when the stanard one is adjustable and will raise the boost for me? can someone explain why i should buy a new one?

The standard one isnt adjustable, just the length of the arm is to suit specific applications.

A new one will control boost to the desired pressure accurately. Personnaly im just using an MBC but havent trialed it yet so not sure how good they are. Soon see!

Ive tried the shortening method and you get different boost all over the place, over boosting then not holding the boost etc.

By shortening the arm you are creating a higher point at which the wastegate opens but once it opens its effectively making the arm longer and therefore reducing peak boost. I.e. it will overboost then sit back bit quite a considerable amount.

Think that reads right!

In short, but an actuator!
I've got a 14psi one, with just 1.5mm of pre-load, and it opens at 12psi and holds perfectly steady all through the rev range (when the bleed valve isn't opened)!

Do a net search on prices - they vary considerably!!!

Yep

The trick is to get nice constant boost and shortening the rod will not do this.

How do you set up the length of the rod with an unknown actuator?

Can anyone explain?

I'm guessing feeding the actuator with compressed air is necessary.

oh!
i will get a bleed valve then.

Nope, just as dave says, you need a pre-load. I.e. how far you have to pull the rod to get it onto the wastegate with the wastegate fully closed.

1.5mm is quite a low figure although as dave points out you dont need a high preload for it to work effectively. I was told 5mm will do the job.

re:
You will hear turbo chatter as there is no such thing as waste gate chatter!!!

Its the chirping sound of the compressor wheel stalling in the reduced air flow.

You learn something new every day! So, does this mean that rally cars don't have a DV? I though the whole idea was for instant boost when you floored the throttle without waiting for the turbo to spin up again? Doesn't sound right for a rally car but I suppose with their budgets, they can find a way round it.

Dave

Speedster turbo under construction

yep, 1.5mm is low, but having tried a few things, it seems that using a 'higher' pressure actuator, but only putting a small pre-load into it seems to makes the boost control even more stable...

I have to use a foot pump for fitting my actuator - evn if you hold it in your hand, and pull on the rod with a pair of pliers, it's a struggle to move the rod!

Yeah well ive only played with the 4psi one so its easy to move

Probably a case of less pre-load the stronger the actuator or something, im not sure without playing. Im going to get a new actuator next year, try the mbc this year and see how it goes.

im also using that MBC you saw iain :)

Previous Engine: 1040cc Morespeed engine, 1275 turbo head T2 Turbo Mirage Manifolds Megajolt
Previous engine: STD metro turbo, megajolt
Drives: 399bananahp (flywheel) Honda Civic Vtec b18c4 T28 Turbo 1968 Mini

Megajolt maps to download: http://www.jamesfawcett.co.uk/cms/index.ph...&gid=3&Itemid=3

DVs protect turbos... not speed up gearchanges


alex

AlexF

repeatability on single acting actuators can only be obtianed by springs (general). you may try by adding a pull spring in line with the rod