986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - IPD Plenum

husker boxster · 08-06-2021, 07:31 PM

Nice video MP. Now we have some actual numbers vs all the butt dynos.

In some regards I'm not surprised by your results. I have an IPD on my CSS and my butt dyno didn't feel any HP advantage. I did feel some mild mid-range grunt, which your #s show. You don't mention doing any software tuning in your experiment and I don't have a tune either. I think that's why the HP #s look like they do. With no tune, you're just adding air to the equation. The fuel injectors are still performing at their previous levels. I'm not an expert and I didn't stay at a Holiday Inn, but I would think diluting the fuel / air mixture with addl air explains the loss of HP. The factory mixture Porsche chose would hopefully be the best ratio possible. With a tune, you could get the fuel side richened to match the extra air and produce a more explosive cocktale. Somebody with more knowledge than my guesses can chime in.

When my engine rebuild is complete, the shop that pulled my engine is going to do a tune and dyno pull on it to maximize the setup after a proper break in session. I'm looking fwd to that (hopefully sometime this month).

Sure don't miss the Kram days.

08-06-2021, 07:31 PM	#45
husker boxster Registered User Join Date: Sep 2006 Location: Omaha Posts: 2,911	Nice video MP. Now we have some actual numbers vs all the butt dynos. In some regards I'm not surprised by your results. I have an IPD on my CSS and my butt dyno didn't feel any HP advantage. I did feel some mild mid-range grunt, which your #s show. You don't mention doing any software tuning in your experiment and I don't have a tune either. I think that's why the HP #s look like they do. With no tune, you're just adding air to the equation. The fuel injectors are still performing at their previous levels. I'm not an expert and I didn't stay at a Holiday Inn, but I would think diluting the fuel / air mixture with addl air explains the loss of HP. The factory mixture Porsche chose would hopefully be the best ratio possible. With a tune, you could get the fuel side richened to match the extra air and produce a more explosive cocktale. Somebody with more knowledge than my guesses can chime in. When my engine rebuild is complete, the shop that pulled my engine is going to do a tune and dyno pull on it to maximize the setup after a proper break in session. I'm looking fwd to that (hopefully sometime this month). Sure don't miss the Kram days. __________________ GPRPCA Chief Driving Instructor 2008 Boxster S Limited Edition #005 2008 Cayman S Sport - Signal Green 1989 928 S4 5 spd - black Last edited by husker boxster; 08-06-2021 at 07:36 PM.