Ok, I couldn't wait any longer and tried a very crude test over the weekend to see if there are benefits of cold air induction on Tobias (280se 3.5L W108).

Greg, Thank you for the advice of not doing anything drastic or irreversable cutting and drilling so I simply opted for a single 80mm flexitube (AUS$25.00) from the local auto parts store to run a test.

I haven't cut the snorkel but simply inserted it into the flexitube until the cold air sensor and found that the ouside circumferance of the snorkel is still way too small for a snug fit, so I used a strip of cork (about 4mm thick) around it to fill the difference prior to clamping.

Then I fed the flexitube down beside the alternator and then vertically down behind the sway bar then with a right angle bend straight to the front of the vehicle attaching the open end to right next to the towing point with cable ties. Yes, very crude indeed !!
I did put a fine wire mesh across the openning to stop large particles getting sucked in.

Anyway, with no changes really apart from a constant feed of cold air, I was really suprised at the results. I performed the test in city driving, freeway driving and up a very steep roads up Mt Keira - Wollongong.

I second Greg's findings in the above linked thread and did find that there's remarkable increase in power and quick accelleration, lots of power and pull all the way through to the high revs and no pinging or black smoke even under load up very steep roads. I was using 98 Octane fuel.

I just couldn't believe it !! So I took it all off and did the steep road test again and back to the old symptoms and performance. I tried it on the freeway going back home and got the same results. I reconnected the flexitube again at a road stop on the freeway and what do you know - back to better performance!

To experience such difference in performance with such a crude set up and simple testing, for me warrants the next stage.

So, I guess the next step for me is to address the snorkel and design a very inconspiquious airscoop.

I'm also hoping that the nearly two feet of vertical section of flexitube addresses the water issue as well as having drainage holes in the air filter housing - I'm not planning to drive in flooded areas and do any river crossings anyway...

Any thoughts on ramming the air in to an extent?

Tomguy, I'm looking forward to the results of your air pressure tests.

Best regards,

Ysmael