I used a rubber 3" to 3" pipe connector found at the hardware store to connect a Donaldson pre filter to my Safari snorkel. Worked perfectly. I just don't use the Donaldson any longer because I couldn't get over 40-45 mph on my 80 series when installed. Going from low speed to high speed and back and changing the thing out started to be a PITA. It did work well however. It caught the powder-like dust in the bowl.
Copied from my thread in the Land Cruiser section.
Let's be honest... I'm sure that less than 5% of the my LC's mileage is gained while out on the trail and less than 5% of that time it's seeing some serious dust clouds. For all the times that I have driven in those windy, sandy, dusty, brown out trails though... the OEM Toyota air filter was working overtime in trying to provide clean air for the engine. Installing a Donaldson Pre Filter to the Safari Snorkel seemed only natural in an on going effort to help maximize engine reliability, performance, and engine lifespan. I opted for the 10" model to allow for maximum air intake. The use of the 10" model also required use of a 4" to 3" reducer to connect to the snorkel and also acts as a vibration dampener. The Donaldson pre filter works by creating a cyclonic effect on incoming air while capturing and preventing up to 75% of dust from reaching your vehicles air filter.
Here's a video on Donaldson Air Cleaner Accessories.
Installation was straight forward. I did fab up an aluminum brace connecting the pre filter to roof rack and replaced the nylon wing nut that secured the pre filter cover with a nyloc stainless steel nut for added support at high speeds/vibrations and theft prevention. Personally, I wouldn't suggest installing the pre filter to a snorkel that wasn't installed with the use of rivnuts at the pillar due to the increase in wind resistance and load placed on the snorkel. I feel that the supplied nylon attachments would be insufficient in keeping the snorkel body secure and may lead to an unwanted failure.
During installation of the support brace, I removed the cover and bowl for cleaning and was surprised to find at least a full thimbles amount of fine sand and dirt accumulated in the bowl after a couple thousand miles and months of on road use. I can only speculate on it's effectiveness while out on the trail... I'll bet the OEM Toyota air filter will be breathing a bit easier.
So I ordered one of these for my Safari Snorkel (3.5) to use here in Israel. Often, dust will blow in from the Negev, and everything will have a fine coat of dust and dirt on it. My air filters are really taking a beating, especially being 3rd or 4th in line when off road. Let's see what this thing scoops up in 30 days, as we are at about the end of the "winter".
Since this thread's been given the Lazarus treatment (not by me) I'm going to throw this question out there:
I've got the Jeep 4.0L engine which, by all accounts and through the use of handily provided formulae, I've figured that the MAX intake cfm is around 370. This is if I've got it wrung out to redline which, unless I mess up drastically, should not often be the case. So, realistically, I'd be looking at a max RPM of 3000 which works out to approx 160 cfm.
That said, if I understand the prior discussion re: Donaldson pre-cleaners, I'd be better off to go with the smaller 7" pre-cleaner which has a max effective CFM of 170 vs. the larger 10" which has a max CFM of 320 for a couple of reasons:
1) since I will not be pushing the intake cfm to the max, the smaller pre-cleaner should suffice for probably 90-95% of the driving that I will be doing,
2) the larger pre-cleaner would actually be beyond the point of diminishing returns both in terms of dollar value and efficacy because: a) I would not be using all of the flow capacity of the larger pre-cleaner. so why spend the extra $$$ for the unused capacity; and b) the higher flow rating actually HAMPERS the pre-cleaner from doing its thing because the demanded flow rate is significantly lower than the MAX.
3) the 7" pre-cleaner will, obviously, have somewhat less aerodynamic drag and therefore would not stress the snorkel body and the mounting points as much as the 10" would.
I did order the 7in. It's great and in the first month, collected several mm's of dust out of the air, as well as pieces of road debris (small pieces of tire rubber, etc.). I have cleaned it our twice now, and Have noticed no performance issues or fuel guzzling as a result. I have the 3.4L 5VZ-FE.
Just a suggestion, I went through this when I had my JK and was looking for an alternative to the ram air head. I ended up with a sy-klone head which separates the heavy particles and automatically ejects them, no need to empty the tray. I liked it, worked very well. Still have the head, although the jeep is gone...