Does Size Matter? - Oil Filter comparison
 

While buying the filter to change my oil in my '04 Infiniti G35, I was amazed at how small the oil filter is - I kept thinking it was a mistake.

The Infiniti engine is a 3.5-liter V6, larger than my 3.3-liter Flat-6 in my Porsche - yet the filter is about 25% the size of the Porsche oil filter. The G35 holds 5 quarts (compared to more than double that in the Porsche), but that shouldn't determine the size of the filter...

What determines filter size? Is it flow rate? Production tolerance (a tighter engine runs cleaner)? Filter material? Packaging?

An overhead view shows that the opening and holes are about the same - yet the filter material is much, much less in the G35 unit.

What do you think the reason is?

http://forums.pelicanparts.com/uploa...1082137996.jpg

http://forums.pelicanparts.com/uploa...1082138026.jpg

there's so much crap under the hood that there wasn't room for a larger filter. Well maybe not, just a guess. Probably the real reason is below.

lot's of different size engines cars use small or large filters. Much of it probably has to do with making some parts interchangeable with other models.

Who is it that makes the G35, Toyota, Honda, bet that filter fits tons of the other cars that come with tiny little 4 cylinders. Remember, these other companies aren't Porsche, they are probably engineered not to last, but to last until the warranty runs out.

I was thinking that, until I crawled down and changed it. There was tons of room - maybe the easiest access I have ever had to a screw-off filter.

The engine on the G35 is shared with the 350Z, Nissan Altima, I35, Maxima, Quest, G35 Coupe, FX35... so Nissan does get some use of that filter!

There you go, maybe there's very little room in the 350.

Sad to say, but it seems that it is packaging and cost that drives filtration these days. Pressure drop is another concern, and the Porsche probably has a much higher oil flow rate.
I'm not sure about the Infiniti filter, but the spec's I've seen of some Japanese oil filters are very inefficient compared to american ones. They are rock catchers. In general the German filters are loose as well.

I'll bet part of it is volume of oil that it flows. A porsche flat six flows ALOT of oil and has lots of oil to fiilter. It takes 3 times the amount of oil that any other engine I've owned.

maybe it is because this filter was deisnged in the late 90s and they are able to get adequate filtering out of a smaller package?

the last time I bought oilfilters the guy at the counter took it out of the box and said...

"Kenworth?"

I think size must matter in this iunstance.

My '89 Honda uses a small filter, about 1/3 the size of the Porsche filter. I recenlty went to purchase more filters from Honda and found out that Honda has gone to an even smaller filter for the whole model range except the S2000. The current S2000 filter is the same one I've been using for years. The parts guy said that the larger S2000 filter has better flow and that is what he puts on his own Acura versus the smaller one. The fit is the same so I bought several of the S2000 filters. I can only guess that they are trying to simplify the inventory?

A small filter like that will push a lot of oil through the bypass. It isn't a full flow filter. As long as it makes it past the warrenty the engineers don't care.
God forbid that they accidently build a car with an average life over 150K miles. It could kill their future sales!

(if I was more jaded I would change colors!)

Wayne

I frequent a G35 board, and the guys are noticing quite a bit of muck in their oil with 3500 mile "low interval" changes (they send their oil out to a lab for diagnostics). Seems to support your theory. I am glad this car is a lease... :D

There may also be differences in the filtering media. My guess is also along the lines of "sized to volume".

Older designs typically have larger filters - dunno which of the resaons above is "the" reason, but there is something else to muddy the waters.

ANybody want ot call up Piech and ask him?

Ahh...son.... put that FR%M filter down and walk away from the car....

Seriously...that looks like a FRAM filter you have there and just throw it away. If you want cheap and good, look to Purolator or Ford, or....

but not FRAM....maybe they were good at one time, but not in today's market...

---Wil Ferch

Funny thing about Fram......

When I spoke to an engineer at Mann, USA he said Fram had one of the best long term filtration rates. Then I caught the engine builder from Edelbrock, who built an engine from scratch for the father and two daughters, using a Fram filter.

BTW, I typically use Napa Gold, Mahle or Purolator.

Ahh...son.... put that FR%M filter down and walk away from the car....

Yes, that is a FRAM "Tough Guard" filter. According to the packaging, it is 99% efficient (SAE Test J858) - much better than their normal line. I "settled" for FRAM as it was the only filter in stock that fit! :mad:

My G35 is leased, and this is the first oil change with dino (3500 miles) before synthetic goes in at 7000 miles (when I extend the changes to 7500 miles). I don't want to say I don't care about the car after 45,000 miles.... but...

:D

Go here:

http://forums.pelicanparts.com/showthread.php?s=&threadid=143288&highlight=oil+fi lter

--Wil