Boxster S M96/21 overbore to 3.6/3.8 with stock DME?

[PaulE]

Originally Posted by Silber

Thanks for sharing your experience! Great to hear that Softronic will work with custom builds on their tunes. I have sent inquiries to a number of tuners, will see what they say.



Have a few mods that would influence a tune:
Cone intake
Headers w/o cats
High flow cats in rear position
Free flow muffler

Considering bigger MAF and throttle body, but since I’m using stock 5 chain 3.2 heads not sure how much gains to be had there...

Silber

FWIW my shop recommended against the IPD Plenum and 74mm throttle body-they said they haven't seen power increases on stock engines and in some cases have seen power decreases on their dyno. I have also read comments that a larger throttle body is like putting a bigger faucet on a pipe. You get more flow opening the faucet just a little bit (part throttle), but opening up the faucet all the way (full throttle) doesn't add anything, because the pipe diameter is the limiting factor. I don't know the real answer, but I already spent more than enough so I opted not to change my throttle body or plenum. If I ever get to the point on the track where I'm using all the power I already have and need more from this car, I'll think about it.