Turbo help needed

[Tom-os]

Hi all.
I'm going to up boost and have been told that I need to block off a couple of the pipes, one off the turbo, but not sure about the which other one.
I've tried a search but not sure what these pipes are called.
Can somebody please tell me which ones to block and the best way of doing this please?
I've got a rev2 turbo.
Cheers for any help guys
Tom-os

[Slarty]

As you look down on the turbo, it will have two small bore pipes. One will go from the turbo to the actuator and one will go off around the side of the block towards the underside of the inlet manifold to the TVSV (Toyota Vacuum switching valve).

This is the pipe that you need to cut and seal both ends. Best way is with a small bolt wound into the inside of the pipe and a small jubilee clip over it to make sure it doesn't come back out.

There is another method whereby you unplug the electrical connection to the VSV which stops it from working.

This post should help you if you decide to go the above way;

http://www.imoc.co.uk/forums/viewtopic. ... t=vsv+plug

[Tom-os]

Cheers for the help.
Just want to make sure for something first before i start taking things off.
I noticed that on the posts i've been looking at to sort this problem out, they all say that they are using MBC/EBC to sort out the extra boost, however i'm not using either of those at the moment.
I've got extra boost as i've got a straight through exhaust, gutted cat, airfilter and hks bov. This alone has raised my boost to around 12psi.
So just wanted to double check that i should still disable the TVSV?
Tom-os

[Slarty]

I've got extra boost as i've got a straight through exhaust, gutted cat, airfilter and hks bov. This alone has raised my boost to around 12psi.
So just wanted to double check that i should still disable the TVSV?
Tom-os

Right, with you now. You should have mentioned it in the first place but hey ho

If the turbo is producing "extra" boots with the stock boost management in place, then you certainly do NOTsteed to remove the VSV from the equation.

The most likely source of your issue is the free flowing exhaust/downpipe that you have. It could be one other issue that I can think of, but I'll come back to that later.

The CTxx series turbo have a very poor flowing wastegate by design. What this means in laymans terms is that the wastegate cannot really flow enough exhaust gas away from the exhaust turbine to control its speed and hence the boost that the turbo will produce (as the inlet turbine is attached to it by the shaft). In stock set up, this seems to be hidden by the fact that the CAT and exhaust are a little restrictive and they slow the exhaust gases down. This has the side effect of slowing the exhaust turbine down and "holding" it at stock boost.

When you remove these restrictions (by way of fitting a downpipe and free flowing exhaust) the true problem comes to light in that the wastegate alone can no longer divert sufficient gas to control the turbine speed.

The VSV works by bleeding a small amout of boost away from the actuator under certain conditions (when the engine is warm, in certain gears, as long as there are no serious malfunctions detected by the ECU). This has the effect of raising the boost produced. You could, if you wanted to, dissable the VSV but all that would do is prevent the lower amount of boost being acheived under the opposite of those conditions, it wouldn't prevent the extra boost that you're seeing.

Lastly, the one other condition that could raise the boost being produced is if the timing is so far out that part of the combustion is taking place outside of the cylinder (hot gases flow fast and make the exhaust turbine spin faster).

So it might be worth you checking your timing is correct as a start off point.

Sorry for the rather long post, I'm bored lol.

Edit: Made a boo boo on the description of the VSV.

[Tom-os]

Is there any easy way to check my timing?

Also I'm running a HKS BOV not the standard unit so does the above post still apply? (I am going to put a recirc unit back on but until then need to know what's best?)

Tom-os

[Slarty]

Is there any easy way to check my timing?

Well, if you have a timing light, yeah, use that

If not, any decent garage should be able to do it for you in a matter of minutes. Just make sure that E1 & TE1 are bridged in the diagnostics box (as you would for checking error codes) and the timing should be 10 degrees BTDC (I think, not 100% on that)

Also I'm running a HKS BOV not the standard unit so does the above post still apply? (I am going to put a recirc unit back on but until then need to know what's best?)

No, I can't think of any reason why the BOV would make the turbo produce more boost, only less if it's leaking etc and the obvious over fueling.