Do Not Sell My Personal Information Jump to content


Air filters - it seems Denso's are more efficient than others?


Recommended Posts

As part of my IS250's recent annual service I renewed the 1-year-old Lexus dealer-supplied, Denso-made air filter - part number: 17801-31110 - for a Bosch-made version supplied by AutoDoc.

First, the Bosch filter is a wee bit thicker / taller and, in turn, closing the airbox (OEM) required the finger-strength of Thanos  😖

Second, since fitting the Bosch my car's motorway MPG at a steady 80-ish has dropped from 40mpg to 35mpg, but with no detectable increase in oomph to compensate 🧐  

I've ordered another Denso 17801-31110 from lexuspartsdirect.co.uk to see if order can be restored.

Will report back.

Meanwhile, has anyone else ever experienced air-filter variances? (Excluding so-called 'performance' filters, many of which don't do a great job of actually, umm, filtering the engine-damaging crud.)

Link to comment
Share on other sites


There's been a misconceptions about air filters. The so called performance ones tho yes let more air in but also a lot more micro particles which knacker engines. I've always used OEM filters when I did my own servicing but I've not done one myself for at least 7 years. Been to either Lexus or Ford dealers. 

As for why you saw a huge 5mpg difference WOW that's one helluva weird filter and I'd personally send it back.

Link to comment
Share on other sites

4 hours ago, LexV84me said:

As part of my IS250's recent annual service I renewed the 1-year-old Lexus dealer-supplied, Denso-made air filter - part number: 17801-31110 - for a Bosch-made version supplied by AutoDoc.

First, the Bosch filter is a wee bit thicker / taller and, in turn, closing the airbox (OEM) required the finger-strength of Thanos  😖

Second, since fitting the Bosch my car's motorway MPG at a steady 80-ish has dropped from 40mpg to 35mpg, but with no detectable increase in oomph to compensate 🧐  

I've ordered another Denso 17801-31110 from lexuspartsdirect.co.uk to see if order can be restored.

Will report back.

Meanwhile, has anyone else ever experienced air-filter variances? (Excluding so-called 'performance' filters, many of which don't do a great job of actually, umm, filtering the engine-damaging crud.)

Are you sure it's not E10 unleaded giving you less efficiency?

Link to comment
Share on other sites


Also what else was changed as part of your ‘annual service’ ?

Question? How many miles has your 1 year old Lexus supplied Denso filter done? 

Link to comment
Share on other sites

14 hours ago, LexV84me said:

since fitting the Bosch my car's motorway MPG at a steady 80-ish has dropped from 40mpg to 35mpg, but with no detectable increase in oomph to compensate

Seems strange that a filter would make that much difference - did you leave the polythene bag around it LOL.

Any other changes at the time and could also account for the mpg difference? Started to use E10 rather than E5 fuel 😉

 

Personally I'd stick with the Denso filter, they aren't that expensive and don't need to be changed that often. Many of the cheaper replacements don't seal well in addition to questionable filtration properties.

Link to comment
Share on other sites


The engine air filter is a 36 month/30,000 mile item in the service schedule and unless you done anywhere near this mileage ( in a year!) or drive regular pass a quarry entrance then I guess your Denso was prob still quite serviceable, and I would be tempted to put it back it to check if it is indeed the culprit for your mpg readings.

Link to comment
Share on other sites

I change my filter (mann) every year - i ony do about 5k miles - is this overhill?

If the denso ones are really better I might be inclined to buy that on the next service and leave it for 2/3 years - not for the mpg but if it helps the engine run better then why not.

Link to comment
Share on other sites

Sort of overkill and a bit of expensive for no reason perhaps.

If the one year old Denso is not evidently dirty then a blast with an air line would give it a freshen up for another year!

Link to comment
Share on other sites

Ah, OK, I assumed the air filter is an annual service item. Anyway, mine was pretty choked with grey sooty dust.

The other service items were engine oil and filter; replaced brake fluid; drained / filled diff oil; MAF cleaned; checked spark plug health - all of which were done by a mechanic.

The air filter was changed a week later by me because of AutoDoc's tardy delivery. In the interim - ie, with the old Denso still in situ - all was normal re MPG. The change occured after the Bosch filter was installed. 

I always use either V-power or Momentum99, IME better low-speed throttle response, so E10 not an issue.

I'm guessing the problem is the Bosch filter being slightly too big means the air box isn't sealed correctly?

New Denso arrives tomorrow, so we'll see.

Link to comment
Share on other sites

Interesting thread.  I didn't previously know that individual brands of air filter could differ significantly in efficiency unless the size is wrong.

Like many or maybe most Lexus owners I take the quality of OEM replacement parts largely for granted, and get peace of mind in return for the prices asked.  It has, however, occasionally crossed my mind, without my ever having acted on it, that I might be able to switch from the Denso air filter to an equally good and cheaper equivalent, specifically Mann.  I base this  on my satisfaction with the latter's cabin air filters after having now used them for quite a few years, most recently in my RC and previously in both the IS250 and 300h.  AutoDoc and other online sellers list the active-charcoal type for my RC at about a quarter of the price Lexus asks for the Denso product, €11-12 v. €47 when last I checked.  I first came across Mann, which is a German specialist manufacturer of automotive filters, when a local garage replaced a clogged Denso filter identified as the cause of minor but irritating windscreen fogging in the IS250 I had at the time.  A side-by-side comparison showed no visible quality difference between the Mann and Denso products, and if there was any subsequent difference in cabin air quality I was frankly unable to detect it.  Since then I buy a couple of Mann filters at a time so that I always have one spare.  Would it be worth doing the same with the engine air filter?

I am aware that the saving in relation to overall running and maintenance costs is very small.  Inclusive of savings from other minor jobs that I am just about capable of doing myself such as replacing wipers and topping up sprinkler fluid, I doubt if my overall annual saving has ever added up to more than a free tankful of petrol.  Still, unless I end up with a piece of rubbish, I must admit that I love a bargain...

 

 

 

  • Like 1
Link to comment
Share on other sites

Speaking of pollen filters... In fairness to AutoDoc, my order also included a Denso aircon / pollen filter, which is absolutely fine.

And it cost £7.55 - although it's currently discounted further, £6.68 - which was a wee bit less than Lexus Battersea's quote of £25 for a Denso.

Link to comment
Share on other sites

Air Filters and their gains is a minefield.. every manufacturer will want to tell you it's better than others.. I've been using HKS air filters for years in all my cars and on the dyno (in my gt86) it make a whopping 2hp difference.. nothing you'd feel. However, I'll go for that over OE filters any day of the week. 

https://www.part-box.com/product/70017-at116-hks-super-drop-in-panel-air-filter-toyota-mark-x-lexus-is250-4gr-fse-05/

Link to comment
Share on other sites

I replaced my air filter recently, which i think was a denso which claims to have a 4 year life(?)! with a K&N panel filter i picked up cheap. I noticed the growling from it when using the cruise control on the motorway when came to a hill, which isn't really something i want. Doesn't seem appropriate for such a grandad car!

I've not done many miles and the filter certainly appeared very clean, but was uncertain as to it's age, and didn't realise it was an extended life filter until replaced it. Not noticed any change in MPG though.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...




Forums


News


Membership