Driving Impressions

Panel filters/ Piper Cross Vecter Cone filter/ K&N 57i Cone filter

26 May 1998. MGF Technical BBS, thread entitled "1000 miles with a K&N panel filter":

A quick posting about my travels with the K&N panel filter fitted, as I promised earlier. I have now completed approximately 1000miles with it fitted, mostly over the b/h/weekend following a trip down to Cornwall.

Cautionary note, the panel filter is not the way forward in terms of out and out performance. However, it did make a surprising difference to the car’s responsiveness. More of this in a moment.

• Noise. Barely an increase. Any change in sound quality is quickly forgotten. Can hear a slightly increased hiss behind your left ear on acceleration with the roof down at low speed, and wide throttle openings. Your mother wouldn’t notice. My mother wanted more noise!
• Performance. Still no figures [they are now, click here]. Probably irrelevant anyway for this type of installation, as it could be regarded as a “soft option” in terms of installation ease, cost, and lack of modification from the original’s characteristics. But here comes the surprise; the basic panel filter really increases the “grin factor”. This related to the smoothness that the filter imparts upon the car’s manners. Throttle response is improved markedly, particularly from low speeds. The standard filter is not bad but it does impart some lethargy in town driving situations, which one naturally drives around. This has gone entirely. Whilst I mentioned that performance improvements are not dramatic, I found that I had to modify my driving style appreciably, necessitating change in braking.
• Refinement. Biggest surprise- as a result of the improved throttle characteristics, and I presume a change of the resonances within the airbox as a result of the filter change, the car has been running much more smoothly, and paradoxically subjectively QUIETER. Bizarre. But I doubt that this is something that you could pick up on a decibel meter, but it is a real subjective change.

If you get the impression that I liked the K&N panel filter, you’d be right. I think that all MG’s should come as standard with this filter. But now I have a 57i kit on order, and I feel encouraged by Tom’s experience that this should be straight forward to fit. But if I liked the panel filter so much, why do I want to change it? Well, you always want a little bit more don’t you? And besides, I actually wanted a rather “sportier” noise, and had been considering an exhaust system... The 57i is cheaper, and has the potential to release more BHP per pound sterling. This latter fact has led Kinnor to sell about 30 of these kits within a week, so many of you are equally convinced by this argument. Thanks to Spencer for his work on the rolling road!

Air filter summary:

Option 1:

panel filter
pros: cheap, easy to fit, no modifications to otherwise standard vehicle, surprising gains in drivability
cons: no significant improvement in performance over all, lack of MGF rolling road data to this effect.

Option 2:

cone filter
pros: reasonably cheap and available, quite easy to fit, some improvement in performance
cons: no “independent” rolling road data for this installation (?), foam filters have poor filtering characteristics (as previously discussed in older threads on the issue), tend to draw hot engine bay air into induction manifold (less dense air, reduced potential performance)- although you have the option to construct home made ducting, LOUD (apparently).

Option 3:

K&N 57i
pros: shown to give 8BHP in 1.8i guise, and 15BHP in VVC in tests on BBS contributor’s cars, good driving characteristics, nice sound. Straight forward fitting.
cons: more expensive, at 150% of panel filter cost.

I hope this is useful to anyone considering making changes to their cars

Happy motoring

The Pipercross Vector cone is fitted directly to the throttle body. It is constructed from oiled foam, and has a neat turned inverted ali conical end plate. Driving around with this filter fitted resulted in a big grin- mostly for the big gain in noise output, but also for the markedly improved throttle responsiveness- especially from around 3000 rpm. This combination really spured one on to use the throttle a whole lot more! Compared to the K&N 57i, paradoxically, I found this filter to be slightly quieter at high motorway speeds, resulting is a slight improvement in cruising refinement.

At wide throttle openings, and in particular at high rpm (circa 6000 rpm) I found the Vector to be less impressive than the K&N set up- there simply was not that eagerness to run all the way to the red line. Putting the Vector on the K&N spacer tube seems to confirm the hypothesis that this high rpm lethargy is largely down to the position that the filter is fixed at; bolting the filter directly to the throttle body is bad news for power delivery! Good for low end torque on a 1.8i though...

Over all, I was surprised at exactly how good this filter was- well worth the 30 quid or so that it costs, and it represents the most bhp per pound sterling you can buy- but only where filter cooling ducts are fitted (I was able to test the Vector with the K&N cooling ducts in place).

A confession. I was simply stunned by the roar the filter made when I first revved the engine after I had fitted the 57i for the first time. This was hysterical. And I am not alone in this view; the number of people who report the noise as being a positive feature of this instalation is very noteable. In fact, many consider this justification enough for fitting one!!!

Then there is the improved performance. Okay, so it doesn't turn your car into a rorty Cosworth eater, but the improvement in performance is noticeable, most usually indicated by the need to brake harder and modify your braking points to take into account the few extra mph you'll be going. The throttle response is excellent, and the engine's new found desire to discover the red line (not an area where the standard 1.8i engine necessarily likes to visit) is dramatic.

It has what all the other filters have, plus the additional benefit of even more high rev breathing. Put simply, this is the best filter set tested here, and one that is only matched by the Ramair- and there the price counts against it.

It's grreeeaaaaat!