IPD Plenum - best performance mod?

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Originally Posted by DanD04

Does anyone have experience with the LN Engineering IPD Plenum? Is their claim true - best performance mod you can install on a Boxster?

Well "Best performance mod" is a tough question because it all depends on where you want to improve performance. Straight line performance is a different goal from lap time performance on a closed course.

My own "best performance mod" priorities for a track focused car:
1. Remove weight from the car. This improves acceleration, cornering, and braking. 200lb reduction is a huge bump in performance. It is also cheap or free.
2. Excellent Tires. The most overlooked performance upgrade that makes a huge difference in lap times.
3. GT3 A-arms. Allows you to use ALL of your contact patch.
4. Coilover suspension or lowering springs. Allows precise corner balance and quicker weight transfer.
5. Underdrive pulley. Practically free HP and improved reliability.
6. Exhaust. Mostly for weight reduction but there is a bit of high RPM HP available.
7. 3rd Radiator. These cars get heat soaked fairly easily in continuous lapping and HP falls off as temps rise. Keeping water temps below 220F makes a noticeable difference in performance.

After all of these things have been done I have shaved 5-8 seconds off a typical lap time. The car is now a formidable track weapon. If I needed a bit more top end for the long straights I *might* consider the plenum, TB, and tune, knowing I will have to pay stiff penalty points in my car classification for very little improvement (maybe 2/10ths) in lap times. Cost/benefit is really quite low on this so it would be a low priority.

YMMV