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marky
Msport Veteran
| Joined: 13 Jun 2004 |
| Posts: 4014 |
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| Posted: Sun Aug 12, 2007 5:36 pm |
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This is the easiest thing to do, and will solve sooo many problems in a lot of cars, especially turbo ones that have been apart at some stage. People keep spending money when this can fix so much in 10 minutes.
Reason behind it causing so many issues - if you have an air leak after the turbo, when you come on boost your trying to pressurise the engine bay. The ECU still sees this air go through the air flow meter, puts in fuel to suit, your car will run richer than it should, retard timing more than it needs to, your turbo will have to work harder than it should (heating the air more), and you will hit fuel cut much sooner than you think you should. Off boost it will go a bit leaner, but it isn't that major - it will have a lumpier idle than it should and may have stalling issues though.
If its between the AFM and the turbo inlet, the problem can go the other way - unmetered air is sucked in on boost, car goes leaner than it should.... 
What you need -
Something the diameter of your intake piping. A baked beans can is about the right size (feel free to rename it "Pressure test special tool") for a 2.5" pipe. A bigger can suits 3" hahaha. Anything airtight will do.
An air compressor, or at a pinch a bike pump... wont work well but better than nothing.
Some kind of nozzle you can vary the air flow with, just makes it a bit nicer to work with.
A second person to be a second pair of ears
How to do it -
Blank off the intake of your car, airtight. Thats what the can is for. Preferably do it before the AFM (most pod filter adaptors are 3"), if that cant be done then the turbo inlet will have to do.
Now find a point to pressurise the piping at. This can just be any of the vacuum ports on the intake manifold, or where your wastegate gets its signal from. Whatever works.
Now pressurise it all. Ideally get it up to 15psi or so (2nd person handy to watch that). And listen carefully. In a perfect world you wont hear much air anywhere - there will be a tiny bit (wastegates all leak, even $1000 ones, tiny bit past rings in cylinder etc) but it should fall at maybe 1psi per second. If its any faster, you have a leak somewhere. To find the leak just listen around the place, if you think youve found it try to put your hand over it and you'll hear if your right or not.
If piping leaks - simple fix, either tighten it up or get silicon that fits the point better. Remember it is meant to bridge a gap between metal bits, NOT take up strain of parts that don't line up properly. If piping wants to come apart before you even get 20psi through it, your always going to have issues with pipes popping off and leaking.
Intake manifold gaskets are a common one as well, as are injector O Ring seals. Easy fixes but ones you would never have even known were a problem before :).
Doing this has heaps of good results - cars will come on boost faster, boost will be more stable once it does come on, you will get better economy, you can run more boost safely, you'll make MORE POWER on the same boost as before (or the same power with less boost, whatever), the car will run smoother when driving and idling, the BOV stalling issue will be lessened in a big way, and a lot of the time it can help solve misfires and other stupid stuff cause the car is now running like it is meant to.
Enjoy :)
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Current -
03 Airtrek Turbo
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