Turbo Porting

[Covesy]

Hi Guys,

just about to get a tune and just weighing up my options

will I get a sugnificant increase in doing the porting

what is the benefit if doing the turbo porting

is it realy worth it?

Thanks heaps guys

[straughsberry]

The porting is about boost control. It may be worth it if you can't control boost.

[xrturbomatty]

Yeah it's prob worth it in the long run you will prob need it if you have a good flowing exhaust and intercooler kit

[RXENG]

Definitely not a bad idea to do if you have fitted a larger exhaust. It will help a little with keeping the boost under control

[RAP1D]

As mentioned above, its done for boost control, but needs to be combined with a stronger actuator.

Basically, when the tuner trys to tune in a certain boost level, the accual boost may go higher than the desired level through the midrange, but fall away as rpm increases.

This is due to two things, first the wastegate port hole is too small to pass (waste) enough air to slow the turbo exhaust wheel, so what happens is excess air pessure builds up very fast inside the exhaust housing, which in turn causes the boost to go too high (spike/over boost).

When the wastegate port is enlarged (and larger flapper valve fitted) more air pressure inside the exhaust housing can be passed (wasted) so less pressure is inside the housing, resulting in lower boost for a certain comanded level.

So now your able to command 15psi and accually make 15psi, but falls away as rpm increases, so the stronger actuator needs to be fitted to bring boost up as rpm increases.

Fit the actuator and there should be flat, controllable boost.

that's the theory, in the real world, results will always vary depending on what hardware is fitted (exhaust system, intake & IC systems and how free flowing they are) and how the tune is set up.

The exhaust system has the biggest effect on boost responce, a big dump/cat/pipe system will flow alot of air, and releive alot of back pressure from the turbo, but if the port can't pass enugh air, the boost will just spike up faster/higher than on a lesser flowing exhaust.

Boost response can also be different from dyno to the freeway, so always fit a boost guage if you want your motor to live longer, but a good tuner can set it up to run very stable boost on dyno and street... the tuner just needs the correct mods to be fitted to achieve this.

Also alot of tuners use different approaches to setting up boost control, so always discuss with your tuner about what parts you have or may need for the desired result.

No point rocking up for a tune with high hopes only to find out boost cant be controlled, or theres a restriction somewhere that you didnt think about.

Hope that helps.

[Smoke them tyres]

Airflow through wheel = turbine rpm = boost. Remove airflow to control turbine rpm.

Why Garrett continues to use internal/integral wastegates is beyond me........they were crap years ago and still are. They also make the thermodynamics of the turbine housing poor as there are 2 heat paths close together with insufficient material between them....hence cracked housings.

The only reliable way to control boost is via an external gate. A good rule of thumb is a 32mm valve is good to 400hp, but a 42mm valve is good to control 900hp. Food for thought.

It is good to have precise control over boost as a major factor in the motor living at higher boost levels. What's the point in having electronic control of boost if the mechanical side of it can't do the job........cheap insurance compared to a new motor.

[datjas]

so ive got my aftermarket cooler pipe set up and pod setup causing overboosting,if I do the bigger wastegate port will that let my car run close to stock boost again nothing else is done at all yet