2.5 Boxster Tune/ header Improvements or Dyno numbers?
 

Does anyone have 2.5 Boxster Tune/ header Improvements or Dyno numbers?

FOr classing have to stick with the @.5 and seeing how I can pull a little more power out of it

Underdrive pulley and 74mm throttle body from 1999 996 will get you a bit more noticeable gain, less belt noise and more intake noise too, what I did on mine.

Since you want it to be legal in its class, ask the racers in that class. By all means AOS, deep sump with baffles, suspension updates before worrying about power. You want reliability and handling first for your safety. Once your ability has been tested to the max, then worry about power/speed.

When you went up to a 74mm TB, was the dme able to compensate or did you need a 996 flash?

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Plug and play, no messing around with DME. Runs great!

That's really interesting. When I went up to 82mm the dme could not adjust, not even close.

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Maybe because your car had e-throttle, not cable-throttle as mine?

Did you have to go to the IPD plenum with a 74mm? Could one just swap the OEM 996 plenum and 74mm in the 986?

That's an interesting point, it's certainly possible. I think though there is probably just an upper limit (like with fuel trims) as to how much they can adjust and my guess is it's somewhere between the capacity of a 74 and 82 mm TB.

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That's what I did on mine, I have another set i'll sell .

The 996 should fit a 74 no problem. There are different style plenums for the 996 though (cable vs ethrottle) and you may need to do a bit of work to make them match up. I did this on my build (ethrottle tb cable plenum)

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I just put the IPD and 82mm on the 996 so I have the factory plenum and 74 just sitting here.

They're off an '02 would be going to my '01 986

I thought the tube ID at MAF is 74mm so it’s the bottleneck if you use a bigger TB.

You are correct. I completely forgot about it until you mentioned it but I also went up to a larger maf housing size, 3.25 or 3.5 inches (Don't remember off the top of my head but I think it was the TB for a 4.4l bmw v8) when I redid my intake. In retrospect, the dme's problem was probably moreso that than the 82mm TB.

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