HIGH FLOW AIR FILTERS.

[sundance kid]

I have a Swift Sundance 530L low profile two berth with a 2.0ltr JTD. We travel fairly light and well within the MPWL. I'm very pleased with the performance. She bowls along quite nicely and gives just over 30mpg. Thats with only 2500mls on the clock,so its barely loosened up yet. But!. there are odd occassions when on a long drag the power starts to drop off. I can live with that but would like to know if anyone has any experience of high flow air filters and was there any noticeable difference in performance.

Look forward to any replies.

Mike.

[davenewellhome]

Good point Mike, I too would be interested in any practical experiences of these. In theory its only going to make a difference at full throttle as the standard filter should easily flow sufficient air at lighter loads but I'd certainly be interested to hear of any experiences.

 

D.

[crinklystarfish]

I can see how you'd get more power and torque through the entire rev range assuming the ecu auto-compensated adequately and delivered a commensurate increase in fuel. It should also feel more responsive. As an experiment, how about removing whatever airbox restriction you can to let more air to the standard filter. It will have the same effect. It was a common dodge to drill socking great holes into the airbox lid on motorcross bikes, and then ponce about for days trying to rejet the carb! When you got it right though, it was worth it.

[Derek Uzzell]

Presumably we are talking about the K&N filters that are advertised in MMM magazine.

 

The claimed advantage of these is that not only do they provide a combination of high air-flow and good filtration, but that they are also washable and reusable. So, for motorhome owners intending to keep their vehicles for long periods and carry out the servicing themselves it might be considered financially worthwhile to purchase the K&N product.

 

Coincidentally, a few weeks ago, I discussed K&N filters with a motorhome dealer (who races cars as a hobby) who had an advert for them on the wall of his showroom. I asked how many of these filters he had sold and whether he would recommend that a motorcaravanner fit a K&N filter to his/her diesel-fuelled 'van. He replied "None" and "No", adding that, in his opinion, it was preferable to discard the relatively inexpensive standard disposable filter regularly and replace it with a brand new one than mess about trying to clean the much dearer K&N equivalent. He was also sceptical that claimed advantages for increased horsepower and improved mpg would translate to perceptible 'on the road' gains given the characteristics of motorhome power-plants and how motorcaravanners drive their 'vans.

 

In a quest for higher performance I fitted a K&N filter to one of my VW Golf GTIs back in the 1980s. Subsequently I could detect no improvement whatsoever either in performance or fuel consumption (not that the latter concerned me greatly!) I also recall that the K&N product fitted very poorly in the Golf's air-filter housing and, because of this, I rapidly returned to using the normal disposable filter. This experience discouraged me from repeating the exercise with any of my later vehicles.

 

Mike:

 

I believe your Sundance's motor has a maximum output of 84bhp at 4000rpm and 192Nm at 1900rpm - this is not much by current standards. My longer but not much heavier Hobby's 2-litre Ford motor produces nearly 50% more bhp and torque than that, but it still drags its top-gear heels when confronted with long uphill slopes. This is just the inevitable consequence of gravity acting on a 3 tonne vehicle with relatively low power plus a high top gear and, short of boosting the engine's performance radically, there's nothing that can be done to alter matters. In your case, even when your 'van's motor has more mileage under its belt (and I'm doubtful that this makes a vast difference nowadays) and even if you could get say a percent or so more oomph via a high-flow air-filter, I doubt you are going to notice much improvement in your Sundance's present slope-storming capability. For a significant increase in performance you'd need to have the Fiat motor 'chipped' pretty severely: however, even then, the result won't be a ball of fire. Might be worth trying a 'high flow' filter, but I'm pessimistic about you obtaining any positive benefits from doing so.

[Dave Newell]

I know they can improve performance across the range on a petrol engine where the air mass entering the engine is monitored and engine speed is effectively governed by the throttle valve but a diesel is a different matter. Air Mass is not so critical to a diesel as there is no throttle valve in the air intake. I agree you could simulate the air flow gain by removing the air filter assembly but how do you measure the difference without a rolling road?

 

D.

[crinklystarfish]

Dave, I agree air mass is not so critical, unless it's restrictive? More in = more out, hence forced induction etc.

A dyno would give the definitive answer, but a quick whiz up the nearest hill with the airbox tweaked would give a clue as to whether it was worth pursuing?

Don't be fooled by the induction roar though. It might sound quicker but actually go slower!

I'm open minded.

[Derek Uzzell]

If it's being argued that merely allowing Mike's motor the opportunity to breathe more easily may provide a noticeable upgrade in performance, why bother playing around with the air-box? Why not just try running the vehicle with the present filter removed and see what the effect is?

 

I'd be tempted to ask TB Turbo for advice (www.turboboost.co.uk) as they've got lots of experience getting best performance from motorcaravan engines and also market K&N filters.

 

[davenewellhome]

I think you're earlier response was spot on Derek. I doubt very much if a free flowing air filter will make any noticeable difference and quite possibly no measurable difference to a diesel motor. Even on a petrol motor it would have to be part of a group of upgrades to reap the best rewards.

 

D.

[sundance kid]

K&N advertise in most of the motorhome and caravan mags so I was half expecting a flood of positive responses but that is obviously not the case.

The 2.0ltr JTD does not have an intercooler so any means of increasing a cooler and higher air induction should in theory improve performance.

However, I am inclined to agree with Dave that a standard air filter should cope with any demands from normal driving and one is hardly likely to drive a motorhome with the rev pointer constantly on the red.

As I stated at the start of this thread I find that the engine performs very satisfactory under most driving conditions considering it is pulling up to 3000KLG. and the mpg is worth the sacrifice of a little extra power.

Thanks guys for your input.

Mike.