air filters

nJm

nJm

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This is more of an academic question, but I am curious. I am getting delivery of a '83 Pug505 GR (so XN1 2L carb engine) in a week and was wondering if there was something like a K&N filter for them?

Just curious to know if it would be worth while installing one in the pug, or if its standard setup (that huge cylinder shaped one) is adequate?

I'll be interested to see what you guys think,

thanks,
 
:) If your interested i have added a k&n filter to my Renault 19. It originally had some kind of huge barrel type air filter on it and when I took it to 'Northshore rallysport' in sydney they looked at it and added a filter from the (manifold is it) back. It makes a bit of noise and makes the angine go a bit better now. You wont get huge power surges on cars like ours but it will not strangle the engine from air.. :)
 
The original filter does the job excellently, and mostly a K&N or foam filter only offers benefits through being washable and reusable. Considering the low cost of an original filter, I don't think there's much benefit.

The only way to test if the engine is strangling for air is with a manometer - it takes all the guesswork out and for less than $2 you can build one yourself and save your $90 or whatever on an aftermarket job.

External pod filters suck hot air which usually negates the free flowing benefit (which is guess work anyway - there's no testing of tuned length induction pipes with aftermarket kits, normally). Better of sticking to the manufacturer's R&D budget on engine development IMHO.
 
Yes, I'd stick with the original too.

But hey, ntrx, where do we find the instructions for creating a manometer and how do we use it!

Cheers

Rod
 
Nick,

If you keep the stock carby then the stock aircleaner is OK. An oilbath would probably be a bit better, although I'm not sure if a 504 oilbath would fit under the 505 bonnet.

Apparently it makes a bit of a difference if you remove the flap thingy from the front of the aircleaner barrel and then run a large cold air pipe from the inlet to the front of the car. Make sure you change the paper element often, and it should flow OK. A K&N element fitted to the stock aicleaner would probably be better, but you probably wouldn't notice the difference performance wise, so don't bother unless you're feeling extravagant.

The 505 motor also goes better with a 160 (i.e 1.6mm) main jet in the second throat of the carby. The 1980 505s had these but on later versions they went to a much leaner jet and were more prone to pinging and piston failure if the engine was laboured, particularly with the latest fuels. I'd put a 160 jet in just to be safe. If you can't get one from a wrecker, just get the normal jet drilled out by someone who has a 1.5-1.6mm drill (like a Dyno tuner or a Jeweller). Interestingly a 1/16" drill bit is 1.5875mm, so you can probably do the job yourself with one of those.

Also for reliabilty's sake, I'd change all the hoses in your engine bay as a matter of course.

Dave
 
Rod - easy!

The $2 manometer I speak of is built out of clear plastic tube (cheap at hardware stores), a length of dowel (say 1 metre), an empty 1.25L softdrink bottle, and some coloured water. You need enough flexible tube to go from your bonnet to the cabin, about 4 metres will be more than enough so you can move the piping around without getting it caught on objects etc. The diameter to choose is whatever is convenient (read on).

You make a small hole in the cap of the softdrink bottle just big enough to push the tube through. Put some water in the bottle - about a 1/3 full will do, and add in food colouring so you can easily see the water in the tube.

Get your dowel, line it up vertically against the bottle of water, and gaffa tape it to the bottle (wrap it around the bottom, and around the top of the bottle).

Run the tubing up along the dowel so its nice and straight, and gaffa tape the tubing to the dowel at the very top. Gaffa tape it at the bottom the dowel, near the bottle lid, so it's taught against the dowel. Suck the water from the other end of the hose, just to make sure that the water level in the tube is equal to the water level in the bottle (smaller hoses seem to resist an equal water level at first) or just above it. Mark the water level in the tube on the dowel.

At the intake, you need to find a good point to tap in the tube, just before the throttle body (so the reading you'll get will be the total intake restriction.) You might find a convenient tap in point like a crankcase breather tube connection... so you can temporarily disconnect the breather tube, and connect your own appropriately sized tube to it.

Else, you can disconnect part of the intake, and drill a small hole for the purpose, and seal it up with black silastic later on (no one will notice). Make a good, sealed connection.

Run the tubing out of the bonnet, and into the passenger window, where your passenger will be sitting to hold the bottle and length of dowel upright, on the floor.

You should now have a good connection to the intake, the tubing running kink-free into the passenger window, running into the bottle, with the water level marked on the dowel.

You need to arm your passenger with a permanent marker.

Take the car for a slow drive in 1st, and you'll notice little blips in the throttle will move the water up and down slightly.

Try max acceleration in first and you'll probably notice it moves quite a lot. I found max water level movement was in 2nd gear, on a level road, at wide open throttle close to the rev limiter (on my last car).

Take the car for a real workout in 1st, 2nd, and give 3rd a go (just in case), and get your passenger to mark out the highest water level that occured.

Now I don't have the exact formula on me, however I do remember that my last car had a spot on 6" reading, which worked out to be 0.25 psi. I will double check on this. So, according to that, every 1" increment in the water level equates to 0.04psi negative pressure in your intake.

I spoke to Julian Edgar about this, and he said a 6" reading is quite acceptable, and that the intake should be left alone. You could reduce the restriction by putting on big intake pipes and ram pods etc, however you'd lose all that beautiful tuning and smoothness that the manufacturer spent big dollars on.

If you would like to move towards zero restriction, you can plumb the tubing into various points, the relevant one here being before and after the original filter. You will find a very small percentage of the restriction lies in an original filter.

Cheers,
Adrian
 
Aussiefrogs resident Professor Sumner-Miller, aka ntrx, aka Adrian.... :D :D :D
 
Great stuff, Adrian. I love it.

Hey Yelo20. I thought I was the only one here old enough to remember Julius! Its all Karl, Karl, Karl these days!

Cheers

Rod

<small>[ 29 April 2002, 04:48 PM: Message edited by: Rod Hagen ]</small>
 
It would've been Karl, except no one can spell his surname!

Nick, I (literally) have just ordered K&N's for the E-Type at $142 a pop. A bit exxy. This is only because the correct air filter plenum can't be found in metal (only fibreglass replicas). Luckily it's only got the twin Strombergs and not the triple SU's...$$$$$$$$

Stuey
 
When i got my BxGT the whole air cleaner assembly was missing and it was easier and cheaper by far to do a custom jobbie. I used a k&n pod filter ducted from the carby to behind the right hand headlight. And to keep away the hot air i made a heat shield out of sheet metal. When i tested the temperature the part of the engine bay isolated by the shield was 25 degrees cooler than the rest of the bay. I have been very happy with this setup. Sounds nice too :D
anyway i threw a piccy on a website so you know what i'm on about, anyway good luck with whateva you end up doing!!
cheers,
Dave
<a href="http://davebxgt.tripod.com/" target="_blank">http://davebxgt.tripod.com/</a>
 
Thanks guys, I recommend doing it just as an experiment one weekend, I've been trying to allocate time for ages. :)

Dave that intake setup looks good to me, I had one very similar on my last car only using a Uni Filter pod which has a nice alloy bellmouth shape.

I'm guessing there's a cold air pickup tube ducted from the front into the heatshielded area?

BTW - not sure if it's of interest to you, but I read a very interesting article about changing the pipe length before the filter and associated power curve differences. I can tell you about it if you like.... on a 1.3L Charade, they managed an 8hp hike through most of the rev range just by changing the length of the pipe 30cm! Amazing huh?
 
Heheh and there's another way to check for low pressure areas in the intake, but it involves a boiled egg... :D
 
ntrx: the filter picks up cold air from holes in the front bumper and from the inside of the wheel arch.
I read an article ages ago i think it was in HOT4s where they were mucking round with sizes of inlet resonators using crazy things like milk cartons etc. And it was actually making a couple of KW difference. All interesting stuff.
:)
if i can dig up the article i'll throw it on my site for you
cheers,
dave
 
Dave - if you're after tech articles, I know I might sound like a stuck record but <a href="http://www.autospeed.com" target="_blank">www.autospeed.com</a> is simply amazing when it comes to DIY articles. Membership fee is pretty small, and you get access to ALL articles. :)
 
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