Thread: Fitted Snokel drop in Performance

Yes afraid so.

despite what people say about RAM air and stuff its basically nonsense on a LR. Some bikes use it but it only has an effect at high speed.

If you suddenly increase the length of the air intake it is going to make it more difficult to get air in, and less air = less fuel = less power.

My TD5 is notaiceably slower with a snorkle than without.

cheers
Pete.

I guess you've checked there is nothing blocking it ?
e.g. a piice of carboard or foam from shipment.

Must admit did cross my mind although had it fitted by TJM so presumed they would have checked before fitting??

Anyone else noticed a drop in off idle torque?

most snorkels cost some performance in my experience also.

you need to check for anything that maybe obstructing it and also check that it doesnt leak as it is too late when you hit water and it lets it in....

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.

Funny, I always thought a RAM type snorkel was supposed to actually improve engine performance. Not because of the RAM effect as much as the fact that air being drawn into the engine was that little bit cooler. I also support Mahn's theory that extending the pipe shouldn't do anything but reducing the cross-sectional area of the intake should.

Also, you need to be sure that TJM properly sealed the existing air intake duct-work all the way along inside the engine bay. There have been reports on the Defender2 forum that Land Rover, in their perplexing stupidity, have not actually sealed the pipe at all!

On some cars, where the air intake is under the bonnet, I can see the sense in the comment that the air 'may ' be cooler. It wouldn't be on a Defender, as the intake is on the outside of the car.

The friction wouldn't be neglible either in my opinion. It would definetley have more friction than the standard set up.

There are also 2 more 90 degree bends in the intake.

Its been so long since I studied fluid dynamics and I cant find my text books.... darn it!

Pete

Ha - found them

Right, looking through them there are quite a few comments, just in the general flow types that would have an impact on this.

Firstly is that it wouldnt be laminar flow, in my opinion it would be turbulent flow, ie the 'air particles' aren't everywhere in a straight line, they are in a intertwining disorderly manner, in effect I suppose richochetting about inside the snorkle. This means that (at least in a parallel tube) only the average motion of the fluid is parallel to the axis.

Theres the first issue

It would also be a non steady, non uniform flow, for example accelerating and decellarating through a pipe with a varied internal cross section.

I will read up a bit more tonight and see if I can come up with any simple examples..

Interestingly I am on a Cosmos Floworks (flow analysis software) course next week so could maybe do a working example......

cheers
Pete

ps feel free to tell me I am talking rubbish