Air filters???

[adelaide navara]

Hi everyone,

I understand I will get the best airflow and performance with a snorkle but I am not willing to fork out for it yet. For now, which type of airfilter will give me the best performance? Does anyone run a pod filter? What is best for a 3L TD?

Cheers

 

[will]

there is a trade off when it comes to air filters. Airflow Vs Filtration. you cant really have both criteria simultaneously satisfied. K&N filters & BMC are essentially the same (and were used in the Apache helicopters in the Gulf War) but they let a lot of crap through, but they flow well. Foam type filters like ram flo filter well, but dont flow as well. you need to consider the environment you are going to use it in.

for on-road use i'd use K&N type for sure, but going off-road in dry, dusty and dirty environments, id just use a standard ryco type due to the ease and cost of replacing it regularly.

just my opinion.

 

[Brock200]

http://www.mkiv.com/techarticles/filters_test/2/

here is a test performed on air filters where they used a vacuum to determine the efficiency of the filter (air flow/bhp gained) and the filter capability (piece of cloth to collect what got sucked through) The brands that were looked at were HKS, Apexi, k&n, blitz stainless mesh, and a few others. Results showed that the HKS element which was a foam was the worst filtration followed by the stainless mesh. K&N surprisingly enough came 2nd best to apexi for filtration. The apexi had best filtration. Overall the k&n was good overall. I think its highly dependent on the amount of oil applied, you have to be careful not to go overboard as ive heard the oil hitting the turbine wheel isnt the best thing for it. Id still use it off road, but just make sure i service it before and after the trip.

 

[Krankin]

"Lifetime zero maintenance" on a 4WD air filter!
I'd like to see that,

though my wife would love an extra 14 HP on her vacuum cleaner.

Personally, I'll stick with the standard type paper filter for the dirt, and with a snorkle they stay cleaner longer.

i know the KN type flow better, but they dont have the filtration for everyday use,
great for the dragstrip, not for the bush tracks or motorway construction sites.

Oiled foam type filters, great for the dirt bikes as essentially I would clean them after several hours/days ride.

 

[Leprechaun]

Hi everyone,

I understand I will get the best airflow and performance with a snorkle but I am not willing to fork out for it yet. For now, which type of airfilter will give me the best performance? Does anyone run a pod filter? What is best for a 3L TD?

Cheers

You've bought the wrong vehicle if your looking for performance.

The snorkles main job is to stop water getting into the engine and snapping the crank. It also allows cooler air into the engine, which is probably worth .05% more horsepower and maybe the same by going to a fancy expensive air cleaner.

I don't believe any air cleaner thats oil impregnated and washable should be on a offroad 4WD, leave those for the fluro orange painted rice burners.

 

[big orse]

I've got a K&N pod on my ute. It definitely helps it breathe better and gives you slightly better low down. I just put a snorkel on and the response difference is quite noticeable It has also improved my fuel consumption.

I have tried it inside and outside the airbox and the best combo by far is inside the airbox with the snorkel. Before the snorkel and intercooler, I made a modified intake that went in front of the radiator and removed the cyclone prefilter. The snorkel is still more effective.

Yesterday I cleaned the pod for the first time since installing it just before Christmas. I have travelled down a lot of dusty roads but always hang back to try and keep out of the dust. My intake was spotless and the filter wasn't overly dirty.

 

[Jason]

I'd say stick with the standard filter.

On a side note, with the scangauge fitted I can now monitor air intake temps. From stationary to moving the air temp has dropped up to 5 degrees. I put it down to the snorkel. Getting the air temp down will give better performance than slightly increasing air flow.

 

[adelaide navara]

Thanks everone,

A mixed response but hopefully something here I can use for my Nav.

Cheers

 

[simonk8]

If you want to get a snorkle and are worried about the cost, get a genuine one from nizzbits, about $250, then (I assume you are in adelaide) join the TJM club on main north road (just sign a form) and get them to fit it for about $170. So total installed cost around $400, this was the best option I found. If you have a 100mm holesaw, you could do it yourself, but if you don't, they will cost you about $100 (including the arbour). Don't expect any significant gains from the snorkle, except in the noise department!

 

[Krankin]

If you want to get a snorkle and are worried about the cost, get a genuine one from nizzbits, about $250, then (I assume you are in adelaide) join the TJM club on main north road (just sign a form) and get them to fit it for about $170. So total installed cost around $400, this was the best option I found. If you have a 100mm holesaw, you could do it yourself, but if you don't, they will cost you about $100 (including the arbour). Don't expect any significant gains from the snorkle, except in the noise department!

I would call a cleaner element for longer periods and cooler/cleaner intake air a "significant gain" &
just from a snorkel installation.

 

[nav04]

i'm running a UNIFILTER in my Nav and its working well....

 

[barna]

Snorkle much noisier???

Hay guys just wondering with the snorkle is the noise level much higher?.I have a nissan one on order mainly for cleaner and cooler air ,"also to be away from water".$375.00 just suplied,going to fit it my self.

 

[Krankin]

Nothing to worry about,
I actually like the sound produced.

 

[tweak'e]

http://www.mkiv.com/techarticles/filters_test/2/

here is a test performed on air filters where they used a vacuum to determine the efficiency of the filter (air flow/bhp gained) and the filter capability (piece of cloth to collect what got sucked through) The brands that were looked at were HKS, Apexi, k&n, blitz stainless mesh, and a few others. Results showed that the HKS element which was a foam was the worst filtration followed by the stainless mesh. K&N surprisingly enough came 2nd best to apexi for filtration. The apexi had best filtration. Overall the k&n was good overall. I think its highly dependent on the amount of oil applied, you have to be careful not to go overboard as ive heard the oil hitting the turbine wheel isnt the best thing for it. Id still use it off road, but just make sure i service it before and after the trip.

thats not compared to a stock paper filter tho. also they are looking at it from a petrol motor point of view. the problem with diesels is on average they consume far larger amounts of air hence will suck in far more dust than a petrol so air filtration has to be very good.

 

[Old.Tony]

Don't forget that I'm a relative newcomer to the world of diesel engines, so please correct me if I'm wrong on a technical point here - I'm trying to understand this air issue and plain ordinary math is getting in my way.

I assume that air volume consumed is going to be directly related to engine capacity and rpm. Remove the turbo from the equation, because you can compress the incoming air on a petrol engine as well.

So, if the engine capacity of the diesel is less (let's pick the 2.5L diesel vs the 4L petrol) then its going to naturally want only 62.5% of the displacement that the petrol engine is going to want (or, the petrol engine uses 1.6 times the displacement that the diesel does). The engine capacity itself is the limiting factor here.

Also, the petrol engine is happy to sing its way up to 6,000rpm where the diesel is breaking its balls at 4,000rpm - that petrol engine is doing a whole 50% extra, so it's now 2.4 times the displacement - which should, in my understanding of things, mean that the petrol engine uses 2.4 times the air volume of the diesel engine.

Have I made a mistake on that - like, is there some part of the diesel combustion process that I'm missing out on understanding? I assume both are 4-stroke motors, meaning the piston has to rise twice - once for the combustion stroke and once for the exhaust stroke.

(This should also help out any curious readers who want to understand this better but may feel it difficult to ask).

 

[tweak'e]

your missing the basics here.

take your atmo diesel and petrol motor. the diesel runs unthrottled so it consumes it capaisty all the time. now a petrol is heavly throttled at cruise (part throttle accounts for 90% of driving). so the petrol may only be getting 10% of its capasity in air flow.
(purly as an axample, this is not accurate) assuming they cruise at similar rpm your 2.5 diesel users 2.5 litres of air to the 4 litre petols 0.4 litres of air.

now a bit more real world....most diesels are turbo and typically sit at quite high boost at cruise, 10psi would be roughly right for a lot of motors. now 15psi is basically double the airflow. so the turbo 2.5 is now using 3-3.5l of air to the 4 litre petrols 0.4 litres.

this is all very rough but i think you get he idea.
the AVERAGE airflow depends a lot on how much flow the motor gets at cruise, which is the largest amount of driving. you have to factor in that the throttle on a petrol reduces air flow a lot and turbo on a diesel increases airflow a lot.

with modern motors the amount of EGR used complicates things somewhat also.

 

[Old.Tony]

That explains it marvelously, thanks very much!

 

[Krankin]

Don't forget that I'm a relative newcomer to the world of diesel engines, so please correct me if I'm wrong on a technical point here - I'm trying to understand this air issue and plain ordinary math is getting in my way.

I assume that air volume consumed is going to be directly related to engine capacity and rpm. Remove the turbo from the equation, because you can compress the incoming air on a petrol engine as well.

So, if the engine capacity of the diesel is less (let's pick the 2.5L diesel vs the 4L petrol) then its going to naturally want only 62.5% of the displacement that the petrol engine is going to want (or, the petrol engine uses 1.6 times the displacement that the diesel does). The engine capacity itself is the limiting factor here.

Also, the petrol engine is happy to sing its way up to 6,000rpm where the diesel is breaking its balls at 4,000rpm - that petrol engine is doing a whole 50% extra, so it's now 2.4 times the displacement - which should, in my understanding of things, mean that the petrol engine uses 2.4 times the air volume of the diesel engine.

Have I made a mistake on that - like, is there some part of the diesel combustion process that I'm missing out on understanding? I assume both are 4-stroke motors, meaning the piston has to rise twice - once for the combustion stroke and once for the exhaust stroke.

(This should also help out any curious readers who want to understand this better but may feel it difficult to ask).

Without entering into this thread you may find this formula usefull.

CFM = rpm x displacement (cu in)
divided by 3456.


convert litres to Cu inches.......multiply by 61.023744.




And Tweake,
having difficulty with your last post above.
If the diesel is consuming all its airflow/capacity all the time, why is it that its airflow intake increases as rpm increases?

 

[brockbaker]

I am also running a direst replacement Unifilter in my D22 and have been for about 2+ years now.

Its a great airfilter because of its 2 stage foam filter preventing all that fine dust and dirt from finding its way into your motor. I also ran a Unifilter on my Yamaha YZ250F and it was a fantastic airfilter; mates of mine that were running other aftermarket airfilter still got small traces of dirt on the otherside of the airfilter but because of Unifilters 2stage foam filter its a really great filter.

When I installed the filter I didnt notice any performance, but I dont think that is really the idea with the diesel replacement filters. Unifilter sell a really great pack that also includes some cleaner solution and more oil too spray back on the filter too assist it keeping the fine dirt from getting in the motor; Plus it all comes in a bucket which you can use to clean the airfilter at regular intervals.

I cant remember what I payed for the pack but when you weight up having too purchase a new paper type airfilter and the different service times, it pays for itselfs pretty fast, especially if you are doing alot of driving in those dusty 4B parks on the wkend, you would have to replace the paper type filter even more; when its just as easy to wash your Unifilter and save money at the same time.

 

[tweak'e]

And Tweake,
having difficulty with your last post above.
If the diesel is consuming all its airflow/capacity all the time, why is it that its airflow intake increases as rpm increases?

its full capacity per rpm.
6000rpm will roughly flow 6x more than 1000rpm. (obviously pipes and ports sizes generally mean flow drops a bit due to restriction etc etc, this is only a rough idea)

diesel no inlet restriction = max flow
petrol high inlet restriction due to butterfly= low flow.