Outer Limits 4x4 Board

Okay some here may think I am on the wacky tabacky but here goes. I looked at me air filter the other day GU 3.0TDI and found a few critters in there so I decided to rotate the head of the snorkel.

I have found that this has improved the performance of the donk

The only reason I can think of is that when it was the other way the air ram effect was meesing with the sensor in the boom box and somehow changing the way the turbo spooled up.

Before hand I had a flat spot between 1800rpm and 2400rpm and you can hear the turbo unspool during this. With the head back to front it spools all the way from 1100rpm on. Being a varible vane turbo (which I don't undestand how it works) does this sound right.

It may be my imagination but I feel it is pulling away in third and fourth roll ons from round a bouts etc much better now. Roll on accelaration over taking is better too.

I have heard of someone else here doing this (can't remember who) with simular results. I am not saying that I get more power what I am saying is that now the engine is performing how it should've been in the first place and would be only relevant to TD's and maybe the later model everything electric doova's.

Anyone who is more mechanically competant than have any idea's or is this just me imagining things.

i wonder if you lose power at high speed with it that way.
was it a safari snorkel?

big red wrote:i wonder if you lose power at high speed with it that way.
was it a safari snorkel?

From what I can tell it is in every gear and was still pulling well up to 130kph before I eased out of it. But that day was a good ambient day so the conditions might've had something to do with.

Now thinking about it. Its not that there is necessarily more power (expcept for the changing in spooling up) than before but it responds to throttle input faster and there is little lag or should I say time between the throttle input and feeling the vehicle come on full spool which gives you the impression of more torque. Or in laymans terms more toey on the throttle.

I have heard of a few guys with these donks who have changed several air sensors because of a problem with the things making power at times I just wonder how much testing was done with a snorkel. (my guess is zip but nissan do stock em aftermarket)

Sorry yes Safari (old type head)

I might give it a go on my NA 4.2 Diesel Qee.

She ain't running to smoothly at the moment.

drafty is running his turbo petrol backwards intentionally

i'm running mine backwards on my n/a 1.3 4cyl but just cos i wanna fit in with this cool clique

In my days of v8 street cars I was told by an expert that those hornet scoops that a lot of cars use can actually do the opposite of what the people fitting them think or want them to do. Instead of air pushing though the smallish hole it creates a vacume within the engine bay. (if this makes sense) I am thinking it may be a similar situation with the snorkle.
I was also told that the most effective scoops are the torana a9x reverse ones. They actually suck more air into the engine compartment. Therefore maybe this all relates to airodynamics of the snorkle and the vehicle in general.
Or maybe your truck just needs more fuel in that rev range you speak of because it is getting too much air with the snorkle??????
Very interesting anyho

Article in Toyota Mthly on Adam Birds car, stated that he gained 17kw with no snorkel head, so it must have something to do with air pressure or the air is not flowing cleanly thru the snorkel.

Maybe the ram effect could cause issues on some cars:?:

Which snorkel and head type is it?

Some people who run LPG turn there snorkels backwards to stop stalling when decell.
This can be fixed by plumbing vent on gas reg to intake before aircleaner instead of having open to atmos.

Bazzle

You know too much..

bazzle wrote:Some people who run LPG turn there snorkels backwards to stop stalling when decell.
This can be fixed by plumbing vent on gas reg to intake before aircleaner instead of having open to atmos.

Bazzle

fatass75 wrote:In my days of v8 street cars I was told by an expert that those hornet scoops that a lot of cars use can actually do the opposite of what the people fitting them think or want them to do. Instead of air pushing though the smallish hole it creates a vacume within the engine bay. (if this makes sense) I am thinking it may be a similar situation with the snorkle.
I was also told that the most effective scoops are the torana a9x reverse ones. They actually suck more air into the engine compartment. Therefore maybe this all relates to airodynamics of the snorkle and the vehicle in general.
Or maybe your truck just needs more fuel in that rev range you speak of because it is getting too much air with the snorkle??????
Very interesting anyho

Air pressure that hits the windscreen is forced in 2 directions... over the roof ....and down the screen and into the vent grill, thats why tha A9X scoop worked so well.
The air flow over a windsceern/roofline is much the same, there's a eddie of aircurrent right at the edge of the roof/screen line, while a majority goes over the roof, a percentage actually returns down the w/screen.
In relation to the snorkel its actually facing 90 degrees to the airflow when in the std position and by facing it backwards you pickup the returning air that comes down the screen!
Truck ones work because they are somuch higher than the disrupted airflow around the truck, in order to achive a similar effect as trucks do then you would place the snorkel on the bullbar and it would have to be about 2 foot above the bonnet to get the same effect , or about 4 foot above the roof line in the std 4x4 position !!!! and that would look like and be as practical as tits on a bull !

bogged wrote:Article in Toyota Mthly on Adam Birds car, stated that he gained 17kw with no snorkel head, so it must have something to do with air pressure or the air is not flowing cleanly thru the snorkel.

Maybe the ram effect could cause issues on some cars:?:

Which snorkel and head type is it?

17kw sounds awfully strange. Considering most dynos are not moving up the higway at 100kph. But then again.... maybe they did some other sort of test..... ??? I doubt it would make that much difference, but I may try it!!

bj on roids wrote:17kw sounds awfully strange.

yea was mentinoed in another thread, but sounds a little 'much' to gain...

then as you say, that was stationary without the air turbulance of driving.

17kw sounds awfully strange. Considering most dynos are not moving up the higway at 100kph. But then again.... maybe they did some other sort of test..... ??? I doubt it would make that much difference, but I may try it!!


possiable.... no negitive airflow or vacum in a dyno setup whereas onroad there is . Now if we put a dyno in a wind tunnel.........

On my non-turbo 4.2 Patrol with the ram head reversed once above 60kph the fuel usage doubles and the power drops conserderably.

bundyrum4x4 wrote:On my non-turbo 4.2 Patrol with the ram head reversed once above 60kph the fuel usage doubles and the power drops conserderably.

Quite soon I am moving to perth so what I will do is run a tank through it with it forward and then with it backwards. I have got around 6500k's to do so at around 6 tanks I should be able to get a good average the best conditions will the run outta Port agutta to Norseman.

If you were to take the snorkel off would you get twice the fuel use. Like did you get twice as good fuel economy when you put it on. On my hilux I prolly got about another 50k per tank which I lost when I stuck muddies on it. (don't own it now aspirated 3.0d)

Another one I might try is turning the head a little more inboard.

I am not entirely convinced it is airflow pure I am thinking it might have more to do with engine management getting confused with the added ram effect thinkin the engine is doing something it isn't.

Variable vane tech works on the exhaust side of the turbine right? restricting exhaust flow for faster spool up low rpm and the allows more flow for higher rpm I am wondering is there a transition period where moving from restricted flow to less restricted where having positive pressure inlet side could actually reduce the effective progression from one state to the other and being felt as a flat spot in the rev range?

V8Patrol wrote:17kw sounds awfully strange. Considering most dynos are not moving up the higway at 100kph. But then again.... maybe they did some other sort of test..... ??? I doubt it would make that much difference, but I may try it!!


possiable.... no negitive airflow or vacum in a dyno setup whereas onroad there is . Now if we put a dyno in a wind tunnel.........

I dunno when I had mine dynoed they had the big arse blower at the front of the vehicle to provide airflow over the radiator, loud as and about 2ft in diameter in a cowling. I assume this is for cooling purposes so you would need something to simulate road type airflow rates. Mine was with the bonnet up but I could'nt see why you couldn't move it to a position to blow on to the snorkel.

turning it to the side gives you 100kw

its all crap

forwards for street, and backwards off road!

bj on roids wrote:turning it to the side gives you 100kw

its all crap

forwards for street, and backwards off road!

Crap you say Outerlimits sticker gave me 200Kw

Nope there is a difinative difference between forward and backwards and even if power figures can't be quoted I can hear the Turbine distinctly spool up and down through the snorkel head front or back. Front has a flat spot (not always but more often than not) backwards have no drama's. I would just like to know WHY?

Some people who run LPG turn there snorkels backwards to stop stalling when decell.
This can be fixed by plumbing vent on gas reg to intake before aircleaner instead of having open to atmos.

yeh i got told that by 4b pro sed u actually cant run a snorkel with lpg withour doin this mod
its Fuggs up the tuning of ur car coz gas flow and air flow

with the ram head foward, there is positive pressuregoing into the motor.
in a lpg setup there has to be an even pressure at the convertor and the gas mixer. There has to be a balance pipe placed between the vent on the convertor and just before the nmixer so pressure is even.
this is the same setup as used on lpg turbo motors, cylinders and rotories.
OR TURN THE HEAD BACKWARDS!!!!!!!!

This may sound stupid but if you can 'hear' the difference with the snorkel pointing backwards is it possible you are actually hearing the noise back through the ram that is now pointing towards a window (ie louder)
Just my 2 cents worth but the noise from my snorkel is much louder when pointing back! I can hear a vacuum that I normally can't hear!

hey all

if you run the snorkel head backwards then you are creating a vacume and so you engine will run rich due to a lack of air (for a carby motor) now for a new fangled fuel injection and turbo model it should know how much air is going in and put in the right amount of fuel.

as for the positive air presure for raming the air in it should not make any difrence to a fuel injection motor (na or other wise) unless you have a huge amount of boost + the 1 bar atmosphere (about 14 psi from memory) because the air flow meter is on the engine side of the turbo/blower and still knows how much air is going by.

now this is my understanding of the situation if i'm wrong some one please tell me.

Matt

Tony78rr wrote:This may sound stupid but if you can 'hear' the difference with the snorkel pointing backwards is it possible you are actually hearing the noise back through the ram that is now pointing towards a window (ie louder)
Just my 2 cents worth but the noise from my snorkel is much louder when pointing back! I can hear a vacuum that I normally can't hear!

Yeah a little louder but I haven't assumed that the loudenss is the difference.


It is turbo operation that is different. I can hear the same operation forward or rearward.