snorkel top

Dunno.

Just thought I'd add a quick word of warning: don't use one of these if you're running LPG, use a 'tractor' type top instead.

Try Tuff Toys 4x4

email: snipped-for-privacy@tufftoys4x4.co.uk

cheers

- Paul -

sorry, forgot to add that Tuff toys 4x4 can be contacted on 01664 410666

ok thanks for that

Sam

Err- why?

Glad you asked. What took you so long? ;-)

OK, it's like this....LPG is drawn in by the vacuum created as the air whizzes by (remember those vacuum pumps in chemistry that attached to a tap - it's the same principle - the Bernoulli Effect). The idea of a forward-facing snorkel top is to get a ram-air effect, where air is forced in by the forward motion of the vehicle, which is great for overcoming the inherent losses when running on petrol. Unfortunately, it causes a build up of pressure just where the LPG is coming in. This prevents the gas being drawn into the mix and the system runs lean. If you turn the top sideways, or even backwards, you tend to get a negative pressure within the snorkel which inhibits airflow. To mix properly, you need a fairly 'neutral' air pressure around the mixer - just enough to satisfy the needs of the engine without preventing the LPG mixing. That's the theory.

In practice, I have a Southdown snorkel which, you may be aware, has a forward-facing inlet. I was getting really significant power loss at speed. I tried turning the top around in different directions - the effects change slightly, but basically it means drastically reduced power at speed. I've now changed the top for a Mantec 'tractor' type top and it's much, much, much better - only a small drop in power compared to not having the snorkel connected at all.

I hope that made sense.

Cheers - you learn something every day! Took so long: Have been away and then computer decided to get Alzheimer's disease, wouldn't work and had to be rebuilt. Not a virus - just old age.