Alternative for the UNI Filter Mod to the Secondary Air Injection System

Following is my Alternative for the UNI Filter Mod to the Secondary Air Injection System.

I installed the "classic" UNI Filter Mod a few months ago. I did not have any issues with it but I did not like its possible water ingestion.


I do some wheeling and mud and water does get splashed into the engine bay.


The OEM filter is just a piece of filter foam.


I thought it would it great just to replace the foam every few years. However, finding the OEM foam filter has not been possible (for me).

I got an Arnold BAF-110 filter replacement for Briggs & Stratton 27987. This is a good substitute foam because as a lawn mower air filter it is oil and heat resistant.


This filter works because it is the proper thickness.


After some trimming:


Just replace the original:

 

This is brilliant, thank you for letting us know what you bought as a replacement.

I don't like the idea of the external filter and my first thought was "why not replace the foam after 40k miles?" - like you, I cannot find a part number for the foam but this is a great and effective solution.

Thanks again.

 

Looks like a winner idea. Thanks.

 

Forgot that I had sub-ed to this. This was definitely on my list, but waited because I was still under warranty. It is now time to do it. Brilliant idea @rnish !

 

A little late to this thread but how long do you think the lawnmower filter would last? I'm thinking just change it every time you change the engine air filter.

 

YMMV. It’s been close to 2 years since I did this. I’m going to let it go for awhile more before I swap it out.

 

Thanks for the info! looks like you can cut two out one of the filters as well?

 

I did this mod today and thinking I will replace every 15k with the air filter.

 

wow, great pics rnish. I have a 2007 4.0 Tacoma and don't remember seeing this secondary air injection system in the engine bay. Did all second gens have it?

 

Don’t quote me: started 2012-ish

 

Found this as an alternative to the Arnold filter for Canadian customers:

$10 Genuine Briggs & Stratton 27987S Air Filter Foam Element , Green

https://www.amazon.ca/Briggs-Stratton-27987S-Filter-Element/dp/B0038U3GB4

Also found this part at my local Toyota dealer for $27. I've heard it is the correct part for our trucks but can't confirm. Haven't decided which option to go with yet.

Part Number: 04008-3520c

 

Is that for the foam or the housing as well?

 

just make sure you change that foam out regularly, it'll break down over time if let go and then it'll be no better than the factory foam piece. I removed mine when I did the UNI mod and havent had any issues in almost 60k miles. It's my daily though & I don't wheel it. You can pick up the sheets of green UNI foam from Amazon in different colors/thickness/PPI rating for cheap.

 

One to two seasons depending on acerage. Less if you're mowing dry grass in dusty conditions.

 

Sorry to revive this post, but, I haven't done this mod and I’m debating which route to take whether the UNI/K&N filter or the Arnold BAF-110 filter. @rnish could you provide me with an update on how the Arnold filter has worked through the years and how many miles between changes?
(Anyone feel free to pitch in as well)

 

Still running the original replacement. Guess it’s something I lost track of during COVID.

 

I used the K/N filter and just put the cover back on the sais housing. The filter has very little exposure to the elements. Not perfect but I can just pull the filter and clean and oil it .

 

Whenever you have a chance, could you please take pictures on how it look now? This would be the real test on how it would look after years without changing the filter. It’s very interesting that this is not part of Toyota maintenance intervals.

 

Replace the stock foam with a different colored foam lol useless

Whole point is to delete the stupid foam so it doesn't get sucked in when it degrades.

This solves nothing

Also the SAIS only runs briefly on cold starts for about 60 seconds...not sure how it would suck in any water or dust etc while wheeling

 

I which the cover was enclosed on the bottom as well to prevent water intake if that ever happens.