stage 2+ cone filters and maf

[Toms306]

Is that all the maf is. Which makes it lifed! Can they be fixed then with a bigger gauge wire?

What your saying is tom with bad filters is erosion of the wire from the weather/shite

Will try and find out how much a new sensor is from pug today

You cant just replace the wire....and due to the way electricity works, that wouldn't fuction correctly anyway - bigger wire means more voltage (or is it current) can get through so the ECU wouldn't get the right reading.

Hope you're sitting down when you ask the price of an OEM MAF...I'm guessing £80ish lol....

OR the filtration oil coats the element and unnecessarily cools it, causing false readings?

---

Clicky

The above is a good read and actually a pretty bold statement by K&N. It doesn't rule out insufficient filtration as a cause of MAF failure but it categorically states that K&N filter oil does NOT contribute to failed MAF sensors. Not to say other brands or types of oil are different but they'd have to be 100% on their findings to make statements like this.

Ah, thats pretty interesting then.....theres only one way to test this though, get a good MAF from the scrap yard, coat it with KN oil and see what happens....

Ever thought it might be a coincidence and nothing to do with that air filter, just that they're 10 years old + now, if people replace them i would imagine most would try a 2nd hand unit first.. Again another already 10+ year old part, much higher chance of it breaking again...

I'm sure I said this above.

[Just Sean]

Then just use the same gauge wire?

[Toms306]

Then just use the same gauge wire?

Its not a replaceable wire though is what I meant.

[Jonny81191]

Ever thought it might be a coincidence and nothing to do with that air filter, just that they're 10 years old + now, if people replace them i would imagine most would try a 2nd hand unit first.. Again another already 10+ year old part, much higher chance of it breaking again...

My thoughts exactly. Just don't wanna fork out for a new one yet!

[Poodle]

Danny, we'll know soon enough. Ive fitted a new genuine maf and will be fitting an enclosed cone in the near future. Will see how long mine lasts and report back.

[Just Sean]

Brand spankers? Was it close to what toms306 said?

I've just picked one up from rik, I think he said it was of a 406...

[Poodle]

Don't know how much direct, i bought mine second-hand, still in the packaging. £30

[Just Sean]

bargain!

[DeeTurbo]

New MAF from dealers are £110.96 (1920 7S) and there £80.40 from ECP (434735120). I bought two for £100 and something when ECP had there 31% off sometime last year.

The hotwire on the MAF or the two "wires" are glass coated with a thin layer of copper.

My thoughts on failure are,
1) Open circuit failures are most likely broken wire or wires and most likely down to vibration or shock that have broken the fragile wire or wires.
2) Incorrect measurements are down to contamination. I think most contamination is most likely from the crankcase breather pipe on standard cars. Diesel engines have a lot higher crankcase pressures down to the higher compression ratio in the cylinders and have more blow by pressurising the crankcase so the oil mist in the system coats the MAF and builds up causing it to miss read. Yes the MAF runs a cleaning cycle but after some time the burnt oil starts forming carbon on the elements or "wires" and this build up is the reason of the miss reading.

I think MAF's usually read incorrectly more often then failing by broken wires.

Now these are just my thoughts on why MAF's fail and I have no proof of my theory just yet but it would be interested to see how long a MAF lasts on a car with an oil catch tank so there is no oil mist coming from the crankcase to cover the MAF?

You can manually clean a MAF but care must be taken in not damaging the element and if you do clean it yourself it's a good idea to check it's all ok with pp2000 after as if you damage any of the two elements it won't bring the ELM light up, it'll just log a silent code in the ECU. The cleaning solution mustn't leave any residue on the element as this will cause incorrect reading. Switch cleaner is good to get the carbon off but some leave a lubricant so best to give it a blast with IPA after but it is really easy to damage the element and not know until it's too late.

I've tried cleaning them with an ultra sonic cleaner but even that damages the elements.

[Jonny81191]

I'm sorry, but THIS is restrictive. No question of it IMO


IMG_2465 by Jonny_Moore91, on Flickr

[Ruan]

^^ This!

[cwspellowe]

Lol, looks like you stood on it first.

That's a terrible design!

[DeeTurbo]

I'm sorry, but THIS is restrictive. No question of it IMO


IMG_2465 by Jonny_Moore91, on Flickr

That pipe costs £270!! The 206 one looks a bit better though and it's a lot cheaper too £80.



Doesn't the 306 one go a lot wider at the kink?

[Toms306]

I was wondering if it was designed with that restriction to reduce lag at low speeds? I know you're bored of hearing about the golf but it has a similar restriction. The pancake pipe which runs behind.the wheel has to be thin so you can steer lol, however the diesel one is a lot smaller and restrictive than the petrol one. I upgraded to the petrol one (as others do) but it was noticably laggier bottom end with the bigger pipe, although top end was better. Just a thought anyway, as they wouldnt restrict it by accident surely? I think there's even a ram air effect from reducing pipe size (like covering the end of a garden hose gives more pressure) but obviously you get to a point where more volume is better than more pressure at top end.

Just thinking aloud really as its been occupying my brain today lol. What I don't understand though, is the long loop plastic pipe after the intake in the grill, seems pointless when a shorter direct pipe would've done the job...?

[DeeTurbo]

The long loop is better to aid the flow, I guess?

[Poodle]

Deeturbo, the crankcase breather is post maf, so that's option two out. Not sure vibration would kill the mafs, be a poor design if that were the case, what with being mounted to an engine, never know with peugeot though tbf... Also, think the pipe you're looking at on the second picture is the maf - turbo pipe, not the turbo - inlet elbow pipe.

I'm sorry, but THIS is restrictive. No question of it IMO

^^^ My point exactly.

Tom, you mean venturi effect bud, reduce cross-sectional area and you increase velocity. Looking at how much spare room (feck all lol) there is in the engine bay of these, i suspect most of the design is to meet packaging requirements.

[Toms306]

You're probably right tbh poodle, thought I was being clever there for a moment. Was one of the first things I noticed when we were fixing Sams HDi though....how tight and restrictive the bend was there!

[Ruan]

I fail to believe that Peugeot spent millions on designing an air intake system for a 90HP Turbo Diesel engine... They will have discovered that at low power, there's no need for a high performance air intake system... They were not worrying about whether the ram air effect is good enough at 70mph on a 90hp engine, when the same engine was producing 110hp on the same inlet, we know the inlet is good at 150hp, but I severely doubt it's good much past that...

Sure you can make more power than that, but you're going to be compromising turbocharger life, the amount of vacuum placed on the compressor will be silly..

They would have said make the air intake system as compact as possible as long as it does it's job at 110hp...

The 136HDi's inlet system is much better...

[DeeTurbo]

Ruan - you're right there, this is from the 406 138. The turbo inlet is facing the right way for starters.

[Ruan]

Image fail I'm afraid!

[DeeTurbo]

Oops and I meant 407.



Just looked at the 308 one and the filter look massive compared to this one.

[Mr Whippy]

I'm sorry, but THIS is restrictive. No question of it IMO


IMG_2465 by Jonny_Moore91, on Flickr

Is it?

Until you test it how do you know?

Lots of things on cars that don't need to be seen look crap... it doesn't mean that someone with a LOT of experience and test equipment hasn't spent their budget making it work right rather than look like it works right for people to then judge it on looks hehe.

The 206 one does look better but in practice on a flow bench they might be identical.
The 206 one might just have been cheaper to produce and increase profit margin and that is why they went with it, it's probably less robust than the more expensive metal one.


Until you test it to see why it's bad and how you can improve it you may as well just buy one of these and believe the hype!

http://www.ebay.co.uk/itm/RED-CAR-AIR-FI...1038526239


Dave

[cwspellowe]

Hang on, you're trying to justify a flattened piece of metal pipe in saying it's probably not restrictive because it was made by Peugeot?

Why the f*ck did I just spend £340 on a turbo then? Should have kept the T2. Silly me.

[Mr Whippy]

I fail to believe that Peugeot spent millions on designing an air intake system for a 90HP Turbo Diesel engine... They will have discovered that at low power, there's no need for a high performance air intake system... They were not worrying about whether the ram air effect is good enough at 70mph on a 90hp engine, when the same engine was producing 110hp on the same inlet, we know the inlet is good at 150hp, but I severely doubt it's good much past that...

Sure you can make more power than that, but you're going to be compromising turbocharger life, the amount of vacuum placed on the compressor will be silly..

They would have said make the air intake system as compact as possible as long as it does it's job at 110hp...

The 136HDi's inlet system is much better...

All this without a single experimental test.

You should go work for BMW making engines. You can just look at parts box diagram and decide how good it is


I appreciate what you are saying, but if you are not even willing to do a simple test to prove the concept then you may as well just burn your money.

No one has proved anything yet with regards to this poor pipe. They just look at it and give it a hard time for not looking flash.


Has anyone considered that the constantly reducing cross-section is probably the most important factor up to the compressor inlet?
That the cross-section although changing in shape does it smoothly?

Has anyone calculated the throat diameter change and determined the efficiency curve for flowing air at different speeds and mass?

Ie, will going too big cause it to be less efficient?

Will going big be good for peak power but cause poor response at low demand?


If engineering really were as simple as saying 2" and make it smooth for 200bhp, 3" and make it smooth for 300bhp, then life would be nice... but it's not that easy I don't think

Dave

[Midnightclub]

Difference is that mythbusters proved those fans do f*ck all

And tight bends will increase turbulence which is bad for air flow.. alot of things the manufacturers do are to do with spacing.. The hdi bay is tight enough as it is standard!

[Mr Whippy]

Hang on, you're trying to justify a flattened piece of metal pipe in saying it's probably not restrictive because it was made by Peugeot?

Why the f*ck did I just spend £340 on a turbo then? Should have kept the T2. Silly me.

It wasn't made by Peugeot, it was made by intelligent educated engineers being paid for their skills to make engines that will be produced in millions of units.

You spent £340 on a turbo because that was made by the same type of intelligent educated engineers too. It is probably known to be a worthwhile upgrade through testing too.


Just because a pipe looks simple and basic doesn't mean it is.

Just because it was designed without aesthetics in mind, unlike pipes which are visible on fancy sports cars in shiny metal, doesn't mean it isn't good.


All I'm saying is, until you know it's better, don't assume it is because it looks crap.

If someone proves it's crap then great, but no one has. So judging it on looks is pretty shallow hehe

Dave

[cwspellowe]

OR.. and this is more likely.. Peugeot threw an engine in and thought "aw crap, that's a bit awkward, someone smash a bit of pipe up until it fits. As long as it still works that's fine by us.

If you seriously think it was designed that way on purpose why do you think as many turbo applications as possible DON'T have an inlet like that? A sharp bend can be negated in terms of airflow by rifling the inside of the pipe but this to me just looks like it's been crushed to squeeze in the gap. The cross sectional area of the pipe clearly shrinks, then expands again after the bend to meet the mouth of the compressor.

The best design possible for an inlet is the longest, straightest bit of pipe you can find. Just because noone's done "extensive testing" on the HDi pipe doesn't mean it's not a poor design...

[Midnightclub]

But in the same way, how can you say its any good? Just because Peugeot spend a lot on r and d? It only needed to be good enough for 90bhp so i highly doubt they'd over engineer it costing them more money and reducing profits..

[Mr Whippy]

Difference is that mythbusters proved those fans do f*ck all

And tight bends will increase turbulence which is bad for air flow.. alot of things the manufacturers do are to do with spacing.. The hdi bay is tight enough as it is standard!

Yes but we are all arm chair engineers who just read a few books at best.

Anyone here have a fluid dynamics qualification and practices it daily who can comment?

The problem is we apply hard fast rules like 'bends are bad', but in practice everything is a compromise, and it's the sum of the compromises that engineers are BLOODY good at getting right... usually to the point that their compromise is often better than a half-arsed un-compromised solution!


Remember too that things don't just turn bad suddenly. There are a raft of efficiencies that fall off as you ask more and more from the engine and it's about dealing with the important ones first.

That pipe might be small fry vs other things even at 200bhp!


I'm not saying don't mod.

But until you incrementally modify and test to make sure mods improve things you may as well just wee in the wind!

Dave

[Poodle]

Tbf Dave, a vague grasp of basic fluid dynamics is enough to tell us the pipe is less capable than some alternatives. The most efficient conduit for a fluid is a dead-straight pipe with a circular cross-section, that OEM pipe is clearly far from either lol. Ok, so Peugeot's designers and engineers considered it the best solution and we can appreciate they know their stuff, but at the same time it's a fairly good bet there is an alternative solution more suited to our purpose, although that probably involves compromises that Peugeot weren't willing to make - cost, packaging, NVH, etc.

We get your point, but not everyone has the luxury of access to flow benches, data-logging equipment, simulators and dynos. Those who do generally aren't being very forthcoming with any information they find, so we're having to make educated guesses based on what we have got access to - what we can see, lessons learnt from similar situations and some basic theory.