Make your Prius quieter mod

Ever felt that your Prius was too loud? A run of weather seal tape around the doors can reduce road noise.

I used Moroday MWS4 open cell foam tape, 6mm thick and 9mm wide, following the outline of the rubber on the door where it contacts the car body. Could have got better results if the tape was a rubber hollow tube like Moroday MWS11, like a small version of what is on the door. But the foam tape was $3.20 for 5m and I couldn't find rubber tape of the right size.
The front doors use just under 4m and the rear doors about 3m of tape, so a 15m roll should suffice.
I used a off-cut to seal the gap flush the bonnet (hood) and wing (fender). It might be possible to seal the door gaps flush Unlike doors, I applied this seal flush in the gap.
A didn't seal the hatch... the gaps are huge but I just thought that the rain has to go somewhere.

The inspiration was from a Japanese magazine Prius Style RV 2 and at amon.co.jp The process is should translate fairly well in your favourite browser. And there's plenty more DIY stuff on the same site.

I didn't do a before and after with a sound pressure meter, so don't expect proof. I spend $13 and I'll be damned if anyone suggests that I wasted my money.

 

The steps are fairly clear on the 3 pages. The key step is to run a water-based marker around the door rubber and then shut it. The line is where the tape should go. It might seems obvious from the contour of the door frame, but you want the door rubber to sit on the tape as the door closes, not shear across it.
Oh, and start from the door strap as that's the only cut you should need. Don't be tempted to cut to get around a corner as the ends will never stay together.
I was having trouble sharing my photos from picasa, but here's a lovely collage to make up for it.

No photoshop. The steering wheel is on the right 'because that's how we roll.

 

It won't reduce the sound like laying sound deadening material throughout. However, it should take the edge off road noise and vibration and give a slightly more satisfying thud when closing the door.

I've since purchased Moroday Special-seal MWS 11 (as hinted at in the original post). The specs are 9mm wide, 6mm high for gaps of 3-5mm (0.35in, 0.24in, 0.12-0.2in) Compared to the foam, the EPDM rubber is waterproof and because it is closed loop it should absorb sound and reduce vibration in the door better. The rubber is stiffer than the door rubber.

Retail Packs
http://www.moroday.com.au/files/MWS%2011(4).pdf
Moroday might not be available outside Australia, but any company that makes weather seals should have a similar product.

 

My previous car was a Citroën C5 that was so quiet, soft, squidgy and comfortable that any car short of a Rolls would sound and feel like a Mazda RX-7 on 22" wheels by comparison.

I haven't added soundproofing to the car; just the tape. There are several good good threads devoted (and I mean devoted) to soundproofing on this forum, so check those for details.
Australia generally has coarse-chip roads, so every car sounds loud no matter what tyres you have on. Sealing the doors helps keep dust out too.