Surprise return of some power & torque

**MickG** · 18th December 2008, 08:12 AM

I have been meaning for a long time now to look at my top turbo hose which I have always thought might be delaminated or flexing under load thus restricting my manual '99 TD5's performance - bottom one replaced with silicone a couple of years ago due to delam. Over the weekend I replaced this hose with an OME hose (which apparently are now made much stiffer and as good as the silicone ones (may have some silicone in them I'm not sure). While at it, I CRC'd the MAF sensor which looked fine and was new a few months go and also changed the air filter which had obviously gotten slightly wet during all the rain we have had up here (questions about that in a minute)
Anyway, since doing all this work my car has so much more torque and the power is delivered very smoothly so I am very happy. Pulls away from a standing start with no fuss now.

Questions;

1. Could my top turbo hose have been collapsing under load thus restricting air flow? Hose was very flexible and easy to squeeze together but no sign of delam.
2. Should I be worried by the fact that my air filter gets some water on it even though I have a snorkel? Very small amounts appear to make their way past the filter and the MAF but only very small dirty water spots.

Aye, Mick

**PhilipA** · 18th December 2008, 08:31 AM

My V8 RRC also gets water in during heavy rain. I used to worry about it.
The solution is to turn the snorkel top around if it looks like rain, but I couldn't be bothered as it reduces the ram effect and seems to reduce throttle response a little.
The filter gets a bit wavy but there are no holes.
Regards Philip A

**waynep** · 18th December 2008, 08:37 AM

I think the ram effect theory is a bit of a furphy - my TDi seems to be performing better with a Donaldson pre-cleaner then the standard ARB head. Way less bugs in the main filter too, and no chance of any water going down the tube.

**barrangey** · 18th December 2008, 08:39 AM

What hose do you mean, if it's a boost hose then it would expand under load as there is pressure in the pipe. In my experience with TD5's the MAF is the root of most problems......

**MickG** · 18th December 2008, 08:55 AM

Originally Posted by barrangey

What hose do you mean, if it's a boost hose then it would expand under load as there is pressure in the pipe. In my experience with TD5's the MAF is the root of most problems......

I'm not too technically minded but it's the hose that goes into the radiator or intercooler past the side of the air box. I suppose if it expanded, then this would have some effect on performance too, am I right?

**barrangey** · 18th December 2008, 08:59 AM

It would have to expand a HUGE amount to notice any difference to be honest, so much so that it would blow to pieces

**MickG** · 18th December 2008, 09:03 AM

Originally Posted by barrangey

It would have to expand a HUGE amount to notice any difference to be honest, so much so that it would blow to pieces

Interesting....must be the combination of MAF an air filter then making the diference......very noticable difference mind you.

Thanks barrangey

**PhilipA** · 18th December 2008, 09:12 AM

I think the ram effect theory is a bit of a furphy - my TDi seems to be performing better with a Donaldson pre-cleaner then the standard ARB head. Way less bugs in the main filter too, and no chance of any water going down the tube.

Maybe on a diesel but on a petrol the throttle blade is closed, so pressure can build in the inlet.
I measured about 0.5 inches of water at 80Kmh ( with a Minihelic pressure gauge connected between the MAF and throttle), which is small but enough to put positve pressure on the throttle blade.
Remember turning the top around will create an area of low pressure at the inlet probably larger than 0.5 inches of water ( so the difference could be maybe 2 inches of water or even more ) but I haven't measured it..
It is quite noticeable on a V8.
Regard sPhilip A

**locorr** · 18th December 2008, 10:15 AM

Easy to check if you still have the old air cleaner just put it back in and test.

**discowhite** · 18th December 2008, 02:33 PM

Originally Posted by locorr

Easy to check if you still have the old air cleaner just put it back in and test.

or the old hose.

cheers phil

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