I’d like to see a lot of different studies done... wish it were as easy as starting a thread, opening my mouth wide and waiting for the spoon to come in. Super-millennials these days...
I don’t have a study to show you. I have years of ‘anecdotal’ evidence based on driving with and without snorkels around the globe. I’ve driven brand new Tacoma’s/4Runners with and without the OE raised air intake (not water tight, literally just for dust) day after day on super dusty trails, we were cleaning filters each night. The snorkeled ones absolutely stayed cleaner and frankly didn’t need cleaning. We ran snorkels on the Hilux’s in Greenland, the engine bays would get packed tight with snow kicked up by the tires and ground. The snorkel intakes were quick/easy to keep clear.
Doubt the ambient air at roof level is cooler than air sourced under the hood? Are we really going to argue that? The hottest recorded air temp on earth is 134*, under-hood temps can easily beat that by 50% particularly on engine top mounted air cleaners. We can easily see 10-15* cooler IAT temps at pre and post snorkel install on a newer Cruiser. With some quick googling, I’m seeing plenty of ‘anecdotal’ results others have shared showing this exact phenomenon, some reporting 50% lower intake air temps. I’m a but shocked that this is surprising to anyone? Your bombing down a dusty dirt road, would you rather breath air taken from the wheel well or in the engine bay or at the roof line? It may be helpful to spend a few minutes watching vehicles bombing down dusty roads, you’ll see this over and over. If your vehicle pulls it’s air thru the front grill, this likely won’t apply to you so much, many Toyota’s pull via the wheel well.
Fender air vs roofline air.
”Safe follow distance”? Why not say ”safe speed” too?
Many risks and vehicle needs would be mitigated if we all slowed down or spaced out miles, why do that when OE’s and aftermarkets have provided us workable solutions? Just because you have clean air in front of you doesn’t mean you’re pulling clean air through the wheel well, see my photo above, I’m not sure how much clearer I could illustrate it?
Do prefilters and cyclonic tops help? Absolutely, hence why OE’s (Toyota for example) and aftermarkets (SafarI Snorkel for example) have them. If you need ultimate dust protection, run em, I have.
We absolutely wish we could easily (and within rules) mount a snorkel on the Canguro 200 we desert race. We suffer from immense air filter issues (running a large in cab dry filter, anything fit under the hood wouldn’t make it pit to pit). This is the exact reason you’ll see so many Dakar Rally vehicles sporting them, they expect zero water for fordings in Saudi Arabia.
As for the experience
@Tonkaman had, it’s a common occurrence. Some with far worse outcomes. Many OE’s including most modern Toyota‘s pull their air from the fender mounted air box. With most popular Toyota models its right behind the headlight, it’s not high, it’s not safe from water and it’s definitely choked with dust churning in the wheel well and/or engine bay.
This YouTube gent was on a Toyota media drive and wanted to compare filters each night as we cleaned them. Tacomas with raised air intakes had consistently cleaner filters each evening. Anecdotal, sure. But this dude doesn’t give two shits about snorkels... perhaps his findings are less anecdotal than mine.
At the end of the day, if you don’t think you’ll have a need for a snorkel or raised air intake, simple, don’t get one. The same logic goes for lift kits, bypass shocks, winches, lockers, ham radios, USB outlets, air compressors, spare tires, etc. It may be a ‘must have’ for one person and a waste of time/money for the next. If you don’t spend days in dust/water, a snorkel is a waste of money imo, if you don’t outdrive your Rancho’s, bypass shocks are a waste of money imo.
