Thread: Fitted Snokel drop in Performance

Originally Posted by discowhite

how do you get the ram air effect on a dyno?
cheers phil

good on ya phil,
it's a good question.
answer nup can't.

large axial fan &a big trumpet to get the air in the air box.set up variable speed drive on fan useing calibrated anamometer to get same airflow as already worked out at say 100k"s.make sure have same temperatures& humidity da da da




bloody easy.......i dont think so


more likely a genuine waste of time

cheers

From the time spent in Fluid mechanics some years ago now, I would have to add that in a motor vehicle application it wouldn't be the surface roughness inside the snorkel tube that would hurt the 'smooth' flow of air, as it is usually quite a lot larger diameter than is required. It would be the various compromises in the shape of the snorkel's plumbing that would dictate its effectiveness. For example, the Defender snorkel (300Tdi in this instance) is far more 'efficient' in my opinion than the early ABS fitment D1 Tdi application, where the plumbing from the snorkel body must squeeze through next to the ABS modulator and then travel around the airbox, entering it from the other side. Meanwhile, it changes diameters and shapes at least 3 times in about 400mm of pipe length.
THAT is a restrictive airflow system if ever I saw one.

Most snorkels will improve a diesel engines breathing though, as some have a intake labrinth from the manufacturer to reduce intake noise intrusion, and the Defender 300Tdi and Td5 have a ridiculous restrictive right angle bend from the side guard air intake to the air filter housing/ airbox.

I would however suggest that the ram air idea is not really applicable to the average turbo diesel 4x4, as the volume and velocity of the air being demanded by the turbocharger inlet is far more than can be 'rammed' in there at highway speeds.

JC

I recently fitted a Safari to my TD5 disco so I could make it back without drowning the engine up Cape York. River crossings included water going over the bonnet more than once.

First I would like to say that it is was fun to fit as it is really well made and fits beautifully.

I did not plug the air box drain ( forgot to do it) and had no problem with water getting in. It has a rubber one way drain valve/flap any way and in the end I figured that the intake was large enough up high compared to any leak down low. Splashes and rain that go straight down the ram intake need to go somewhere so was happy to leave it. I did take some bulldog clips thinking they would seal it for water but did not use them.

In the D2 the standard air intake in the inner guard makes for a lot of dust getting to the air filter from the front wheel arch on dirt roads and in the past I have spent a lot of time blowing out the filter on dirt roads each night. This time there was stuff all to blow out even with a couple of thousand Km of dirt so for the D2 I feel it has made a big difference in getting cleaner air to the filter box.

Fuel used was great on the trip and there was no increase in noise. Don't think there was any obvious increase in power either. Same goes for lower speed did not notice anything. At lower engine load the air flow is not that great so doubt it would be much of a restrictor.

Now to fix those door seals and clean and dry the carpet!

Originally Posted by scarry

now if a snorkle improves performance,wouldnt this bloke have one

note the bonnet scoop faces backwards

That's because there is a low pressure (or is it a high pressure?) area at the back of the bonnet, and more air got drawn in with the backwards scoop.

Originally Posted by spudboy

That's because there is a low pressure (or is it a high pressure?) area at the back of the bonnet, and more air got drawn in with the backwards scoop.

i recon the bonnet scoop is on the a9x for two reasons


it looks cool

to make room for carbys,air cleaners etc

i dont believe it would make any increase in performance

as for the polariser thingy.........we wont go there

a question still begs....why do most prime movers have snorkels?
asthetics?,and probably to pick up the coolest cleanest intake air possible,but whether this makes any increase in performance,who knows.it may extend the air cleaner life...

Originally Posted by one_iota

I'll be the sceptic. I'd like to see the science/engineering behind this.

So I'll throw this speculation into the mosh pit:

The thing that would reduce the rate and volume of air would be a reduction in the cross sectional area of the intake system and the friction caused by the additional length.

A snorkel will add say 1 metre of length and if it is designed properly should not reduce the minimum cross sectional area of the existing intake system. The friction should be negligable.

I'd bet that the existing filter is the greatest restriction not a metre of snorkel...the effect if any should be marginal at worst.

A Donaldson Filter on the end of a snorkel is another matter.

Well said Prof Mahn

Originally Posted by scarry

i recon the bonnet scoop is on the a9x for two reasons


it looks cool

to make room for carbys,air cleaners etc

i dont believe it would make any increase in performance

as for the polariser thingy.........we wont go there

a question still begs....why do most prime movers have snorkels?
asthetics?,and probably to pick up the coolest cleanest intake air possible,but whether this makes any increase in performance,who knows.it may extend the air cleaner life...

I fitted snorkels with pre-cleaners to all the non fitted machines at work in the first week not because of water or power but because I would have to change the filters every day if I didn't.In dusty area's you have to get the intake out of the dust and in Kal dust is one thing we aren't short of.Saying that alot of it could come from toyota's intake next to the headlight's on their vehicles that is garanteed to force water into the engine,the same goes for the amount of suspension kits on the market.Truth to it most people avoid water like the plague and rightly so but my motor is none the worst for having one so it will stay on. Pat