Putting a IPD Plenum in a 991
02-20-2017 | 01:30 PM
#16
Three Wheelin'
Joined: Jan 2016
Posts: 1,552
Likes: 283
My purchase decision was based on that I've done sub-sonic velocity air mass flow modeling and design for piping systems. The features of the IPD design will increase volumetric air flow efficency into the cylinders feed tubes. Plenum has less turbulence with the flow diverter and dimples reduce boundary friction which can be quantified by fluid mechanics analysis.
With the increase air mass, some car's may need the air/fuel ratio adjusted to see power gains by increasing the fuel level injected and spark timing changed. Modern ECUs with performance driven maps can automatically optimize the AFR and spark timing for the minor plenum change. The COBB tuner maps does include IPDs plenum in the allowed hardware changes.
With the increase air mass, some car's may need the air/fuel ratio adjusted to see power gains by increasing the fuel level injected and spark timing changed. Modern ECUs with performance driven maps can automatically optimize the AFR and spark timing for the minor plenum change. The COBB tuner maps does include IPDs plenum in the allowed hardware changes.
More airflow from a single bolt-on part can mean less power just as often as it can mean more.
02-21-2017 | 09:02 PM
#18
Three Wheelin'
Joined: May 2010
Posts: 1,615
Likes: 14
From: Philadelphia
I know the Porsche tuning policy for the lower costs models vs. the high end vehicles. IPD has designed a plenum to improve on the standard model Porsche intake configuration. Any modification that changes the chemistry of the engines air fuel ratio needs regression testing and maybe re-calibration. In combination with cat back exhaust and an ECU re-calibration no more than 5 to 7% increase in power at red line RPM can be expect from a normally aspirated engine. The cost-fun benefit analysis for me favored the benefit of a little more torque power on sooner in the mid RPM range for low speed autocross competition. Maybe 0.2 - 0.5 seconds faster depending on the course layout. P.T. Barnum was a lot of things in business and good for the community creating jobs and one of the most famous Americans in the world. Another one of his quotes was ""A human soul, ‘that God has created and Christ died for,’ is not to be trifled with. It may tenant the body of a Chinaman, a Turk, an Arab or a Hottentot – it is still an immortal spirit."
02-22-2017 | 01:59 AM
#19
Rennlist Member
Joined: Jun 2004
Posts: 3,560
Likes: 868
From: The South
Great product, and nice you documented it.
As a more informative DIY, I'm sure many guys would like some helpful audio explanations as well.
This is no easy project on a 991, so nice job accomplishing it. Left mine to the dealer. Not as talented as you.
Very happy with the IPD. Did BMC air filters too.
As a more informative DIY, I'm sure many guys would like some helpful audio explanations as well.
This is no easy project on a 991, so nice job accomplishing it. Left mine to the dealer. Not as talented as you.
Very happy with the IPD. Did BMC air filters too.
02-26-2017 | 11:40 PM
#21
Rennlist Member
Joined: Mar 2014
Posts: 4,779
Likes: 1,368
From: SW Florida
Great post Dan. We have all worked hard to be here and stay here. Glad you can see the value in the brand and the cars themselves. Look feared to seeing what you do with your ride. Enjoy.
