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Discussion Starter #1
I will be installing an ACT carbon plenum in a month or so, they have around 25% more capacity according to their site. Is it worth getting a high flow air filter to let it suck more air in?
 

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Are you going to use the original air mass meter? If you are, I would be grateful if you could do some datalogging before and after the plenum is fitted. Say a 3rd gear run from 20mph to almost the redline. Just plot revs and air mass meter output. Then we will know the improvement in airflow this plenum gives over standard.
 

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I dont think this will be the best way to measure the affects of the plenum alone. Its changing the cams that would allow the engine to take in more air. The plenum alone is only providing the air that the engine needs. Its not psychology drawing more air in. I think it allows the engine to get easier what it wants and this will not be showing in the airmass.
But still want to see the data...
 

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But it would at least show if there is a benefit to changing the plenum/TB on a GTA with an original engine, original cams etc. Not a whole lot of people want to change cams.
 

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I think It wouldn't thats the whole point. If you would take this as a reference then you can think this is just a shiny new plenum and thats it, and that would not be fair. I think the plenum can be a worthy investment but only in combination with cams etc... The plenum alone on a stock engine would not show any gains, but thats my point of view. Please feel free to show me wrong and i hope i am...
 

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I think It wouldn't thats the whole point. If you would take this as a reference then you can think this is just a shiny new plenum and thats it, and that would not be fair. I think the plenum can be a worthy investment but only in combination with cams etc... The plenum alone on a stock engine would not show any gains, but thats my point of view. Please feel free to show me wrong and i hope i am...
I would be very surprised to find zero change compared the original plenum. The original plenum is identical to the 2.5 plenum, which has a much smaller demand for air. It seems they just carried this plenum over to the 3.2 engine without any adaption to make it more suitable. Because of this I'd expect a larger plenum to produce different results, most likely an improvement in air flow but even possibly a reduction, but if air flow stayed the same I would be surprised.
 

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Discussion Starter #7
I have read that the 2 chambers farthest from the air inlet can get starved of air as the first four suck most of it in, hence the ACT plenum having that odd banana shape which channels more air into the end chambers. I am also buying multiecuscan software so I'll be able to log before and after to see what happens :biglaugh:
 

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Would like to see those data results also!
 

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I have both plenums, the ATC with F430 84mm throttle body, and stock GTA plenum with GTA throttle body.

I was planning on swapping them around a bit recently anyway so if I do get round to it, I will try and plot some graphs using the Torque app on android over OBDII bluetooth adapter.

She's currently off the road for a bit pending an MOT!
 

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Pud237 is right this test will at least show if the new plenum provides the same airflow as the stock one. It's alsow possible that such a big plenum is reducing airspeed and thus gas exchange in certain rev-range compared to stock - plenum design is quite a science on it's own.....
another test can be made after different cam's are in the car.... however it will shurely sound amazing :)
 
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