Fastcar Clio 172 Air Filter Test

[Bob the Frog]

Can anyone put their finger on what it is about the stock airbox that is so good? Is it simply the heat shielding effect it has and the cool air source?

Also... has anyone bothered relocated the battery to make way for a really short/direct filter run-in and a boxed off cold air area? Would it have an effect, or would we not know until it gets tested?

 

[SReeves]

​Pipercross panel filter

After reading this and all the other helpful advice on the Forum I decided to fit a Pipercross panel filter to my 172 Ph2 to compliment the Milltek sports exhaust. I ordered the filter from Pipercross online for about 40 quid and it arrived next day. Fitting took a leisurely 45 minutes and was easy. Simply unscrew the airbox cover screws (taking care not to drop any into the engine bay) and loosen the jubilee clip that fixes the airbox cover to the air inlet pipe. Then carefully prise the cover off and lift out the paper panel filter. What struck me immediately is that the Pipercross filter is half the thickess of the OEM Fram paper filter. Its made of three types of foam impregnated in oil that Pipercross claim is less restricive that paper or cotton gauze (e.g K&N). Simply pop it into place then refit the filter cover.

I chose a simple panel filter rather than an induction kit as I like the stock look, and as others have said the OEM airbox is well designed, so I was intrigued to see what difference the new filter would make, if any. An hour drive consisting of country lanes and a dual carriageway revealed smoother driveability and throttle response, especially on a slightly open throttle. Pick up when entering a roundabout felt better for example. My feeling based on the way the engine revs to the redline is that the filter works well with the exhaust and the engine is breathing more efficiently. I can't say it feels more powerful but it is a slightly better drive.

All in all given the long life of this filter and I feel it's worth it. Time will tell.

 

[Feates172]

Took you 45 minutes?

 

[DaveDreads]

Must mean 4-5 minutes, the only way it could take 45 minutes is if you had a little sleep half way through.

 

[SReeves]

The fettling continues. Ran some RedEx through the car after the remarkable results Plato (Jason not the philosopher) got on Fifth Gear with a VW Corrado. After a couple of long runs and a dose of Tesco 99 RON the car feels more lively across the full throttle range and mpg has improved on long runs from 38 to 42. Over a 10% improvement. But most importantly the car is even more fun to drive It makes sense, get more air in, clean the fuel system and the engine will be more efficient. I've run the car on both normal and super unleaded and results seem consistent.

One last note. The shock to the system of the RedEx tripped the engine management light (rh bottom corner of dash). I simply analysed the fault using my ODB II Bluetooth reader and the Torque app then reset the ems light. FYI to do this ignition needs to be fully on- all dash lights on- but engine not running. Fault has not reoccurred. A mate in the industry who writes engine mgt software explained that the ems is sensitive and not particularly intelligent so is easily triggered. Worth bearing in mind if you get an EMS orange light and your garage advises the MAF /Cat /lamda sensors need replacing. As long as the engine is running fine it's worth clearing the fault to see if it returns before replacing parts.

Now I'm wondering whether it's worth trying a 182 inlet manifold when I get the plugs changed at the next major service. My understanding is that Renault fitted a polished intake manifold and tweaked the EMS software to go from 172 to 182PS. Anyone tried this?

 

[Deejuk]

I bought my car with a RAM foam induction fitted and have driven it like that for the last 8 months. The previous owner also provided the stock airbox which has been sat there the whole time. The car has always given that '4-5K kick' and I thought that was normal... Until now!
Gave the car a service yesterday and thought I'd switch back to stock as the foam had perished, fitted it all up and then took it for a spin. The difference is astounding, power delivery is smooth and clearly present throughout the range, whereas before there was a bit of and induction lag (more deep noise than power).

As much as I loved the noisy induction note from the RAM, the stock airbox provides a smooth output and a huge drive ability difference! Therefore I agree with those that say, stick with the OEM Airbox!

 

[chipchip2010]

Took the simota induction kit off mine last week and replaced with standard airbox and pipercross filter find it loads better now

 

[matt911]

the new KTR induction kit for 172/182 has fantastic reviews and it looks fantastic aswell

Im really thinking of buying this and im in a hurry to decide. Miss induction noise and this seems to be the one to go for

Anyone else tried this kit??

Has anybody tested this apart from K Tec?

 

[Luigi172]

What's the best set up to use when battery had been re-located?

 

[ripp]

I really don't understand why the std setup is said to deliver the best output. Ok if compared to a cheap open cone setup behind the rad it' obvious that the std setup is getting colder air into the engine.
But take the K-tec setup for example. It has a good quality foam filter positioned in the coldest area of the engine bay (there is an article about this). The air route is shorter and smoother than the std setup which has 2 smaller air feeds and a acoustic valve.
So maybe someone will put this setup against the std one to the test and I'll be amazed if it will come worse tbh

 

[matt911]

I really don't understand why the std setup is said to deliver the best output. Ok if compared to a cheap open cone setup behind the rad it' obvious that the std setup is getting colder air into the engine.
But take the K-tec setup for example. It has a good quality foam filter positioned in the coldest area of the engine bay (there is an article about this). The air route is shorter and smoother than the std setup which has 2 smaller air feeds and a acoustic valve.
So maybe someone will put this setup against the std one to the test and I'll be amazed if it will come worse tbh

This is why im asking if there is any OTHER test been done other than K Tec. As they claim with proven results that its has gains from 5bhp. But thats just 1 car.....

 

[reedy107]

Interesting little read there.

 

[matt911]

So maybe someone will put this setup against the std one to the test and I'll be amazed if it will come worse tbh

I'm getting remapped soon il try test them both

 

[ripp]

looking forward to hear the result!

 

[matt911]

looking forward to hear the result!

Me too. Hope it gives better gains cus I miss having a roar

 

[matt911]

Remap had to be delayed, but it's still happening

 

[joshsta]

Remap had to be delayed, but it's still happening

Looking forward to your results with the k-tec setup, itching to buy one!

 

[matt911]

Looking forward to your results with the k-tec setup, itching to buy one!

Yeah sorry for taking the pi** but I'm waiting for k tec to get stock of my cams. Hopefully get the result end of next week

 

[juniorx88]

Me too. Hope it gives better gains cus I miss having a roar 

Take a look at this thread. I own the silver Clio and i've put the K-Tec style intake. It'a awesome and it give 6hp more than the open cone setup: http://www.cliosport.net/forum/show...uction-setups-tested-pics-and-videos-included

 

[matt911]

Confirmed k tec induction gives better results than the std box. I don't have any figures for mine though

 

[ripp]

any details? owner of the car a member here?

 

[Vaughan]

Can anyone put their finger on what it is about the stock airbox that is so good? Is it simply the heat shielding effect it has and the cool air source?

It's not just about volume of air, or air temperature. It's about weird, wonderful fluid-dynamic type things happening to the moving mass of air as it travels through the intake tract, where resonances and other n-th order stuff increases the amount of air actually getting into the cylinders. This is usually experienced as an increase in mid-range torque.

The effects are subtle and difficult to obtain, which is why Renault would have spent millions of Euros getting the air box designed just right to make them happen.

Sure, the after-market induction kit might add a couple of extra hp at the top end, but it will be at the expense of the increase of low- and mid-range torque that the well designed air box creates.

If replacing the standard air-box with a naked or bigger filter would instantly release extra hp and make the car more drivable, then Renault would be selling them that way.

 

[matt911]

It's not just about volume of air, or air temperature. It's about weird, wonderful fluid-dynamic type things happening to the moving mass of air as it travels through the intake tract, where resonances and other n-th order stuff increases the amount of air actually getting into the cylinders. This is usually experienced as an increase in mid-range torque.

The effects are subtle and difficult to obtain, which is why Renault would have spent millions of Euros getting the air box designed just right to make them happen.

Sure, the after-market induction kit might add a couple of extra hp at the top end, but it will be at the expense of the increase of low- and mid-range torque that the well designed air box creates.

If replacing the standard air-box with a naked or bigger filter would instantly release extra hp and make the car more drivable, then Renault would be selling them that way.

But ITB's would eliminate this all together surely, so why ain't Renault selling it with those? 4 trumpets apposed to a massive intake manifold and the airbox itself.

 

[Vaughan]

But ITB's would eliminate this all together surely, so why ain't Renault selling it with those? 4 trumpets apposed to a massive intake manifold and the airbox itself.

Take a look at this thread where somebody put ITBs (and a whole lot more) onto a 172:

http://www.cliosport.net/forum/showthread.php?650026-Road-Track-172&p=9080652&viewfull=1#post9080652

Post #144 is a dyno chart; post #145 is a response saying "Good power figure... but you have lost torque throughout the rev range". It appears that the intake mods have increased max power, but have reduced the torque at lower revs because the mod only focusses on getting the most amount of air into the engine. The OP of that thread then talks about putting on longer trumpets to try to get some torque back, but he's already had to cut off half the front of the car already to fit the shorter ones in. They later go on to high compression pistons etc which is an impressive project worthy of admiration.

You know water hammer: the banging that happens when a running tap is turned off suddenly. It's caused by the mass of the moving body of water in the pipe suddenly not having any where to go, so it squishes up against the tap which significantly increases the water pressure in that area. That pressure region then bounces backwards through the pipes. The longer and narrower the pipe is, the worse the hammer.

The idea of the intake tract is to get the same thing happening with the moving column of air: a cylinder intake value opens and sucks the air down the intake pipe, the air in the pipe starts moving and gains momentum. The intake valve then closes: the moving air stops suddenly and pressure builds up quickly. The smart thing would be for another intake value to open RIGHT NOW and benefit from that increased pressure in the intake air. Rinse and repeat. You end up with higher pressure in the intake = forced induction! If the intake is shortened or widened then the pressure does not build up as much, this is why even small changes like opening out the intake ports can often reduce the low-end and mid-range torque because the air changes velocity as it expands. (ITBs won't enjoy this effect because each cylinder has its own pipe: they are all about maximum air intake.)

To get the air charging effect we have to get that body of air moving. That means a narrow, long pipe. Unfortunately, the narrow pipe means the intake volume will be restricted at higher revs. At wide open throttle you just want to get the most amount of air into the engine as possible. For this a short, fat pipe would probably be ideal.

So for maximum torque at low revs a long narrow pipe is needed to get the column of air moving fast, but at WOT a short fat pipe is needed that restricts air flow as little as possible. It's easy to create an intake that is optimal for one but not the other.

For optimal performance across the rev range an intake is needed that can morph itself from a long narrow pipe into a short fat one as rev change, fits into the very limited space inside the engine bay, meets the strict noise and emissions requirements for road registration, and is cheap to manufacture, and install and reliable for the service life of the car.

 

[Knuckles]

For optimal performance across the rev range an intake is needed that can morph itself from a long narrow pipe into a short fat one as rev change, fits into the very limited space inside the engine bay, meets the strict noise and emissions requirements for road registration, and is cheap to manufacture, and install and reliable for the service life of the car.

Is that like a plenum such as the rs2 manifold?

individual, short fat trumpets being fed by one long intake.

im aware it doesn't morph and isn't all that cheap, but does adding the longer intake to feed the shorter ones provide any theoretical gains over individual, short, fat trumpets?

 

[Marcos999]

Sports bike manufactures do this by (on a 4 cylinder engine) using one size trumpet on a couple of cylinders then another size on the other two and each cylinder has its own fuel and ignition map. Suzuki were also using two inlet butterflies, one for the throttle, the other controlled by the ECU purely for controlling intake air pressure. Yamaha also have been using butterflies in the exhaust to control exhaust back pressure.

 

[stokie4ker]

Is that like a plenum such as the rs2 manifold?

individual, short fat trumpets being fed by one long intake.

im aware it doesn't morph and isn't all that cheap, but does adding the longer intake to feed the shorter ones provide any theoretical gains over individual, short, fat trumpets?

He's talking about Ram Theory which doesn't really apply to the RS2 or throttle bodies.

When the intake valve slams shut it produces a shock wave which travels up the pipe to the plenum chamber at the speed of sound, rebounds off the wall of the chamber and travels back down the pipe.
Get the length right and the rebounded shock wave arrives just as the valve opens giving a boost in power and torque at that engine speed.
If you look at some of the fancy plastic inlet manifolds used on the likes of Honda and Toyota engines you will see how they have a two, or sometimes 3, stage induction length with a valve mechanism that switches between them to improve torque and power.



Create an intake that instead of the stepped increase like the above image, can go seamlessly from wide and short all the way to long and thin depending on the needs of the engine and you'll have the best of both worlds.

 

[Vaughan]

Thanks for adding to the conversation Marcos999 and sotkie4ker.

To summarise the answer to "Can anyone put their finger on what it is about the stock airbox that is so good?" it's because the stock air box takes into account resonances and fluid dynamics of the intake air to optimise torque at low- and mid-range engine speeds, while trying to remain as optimal (or be the least sub-optimal) as possible for red-line engine speeds, because it's the low- and mid-range torque that makes the car feel responsive, and is the range where the vast amount of everyday usage occurs.

Replacing the stock intake with something else might change the induction sound, but unless you're paying a lot of money (and the manufacturer has more resources than Renault) it will not be providing any gains in the low- to mid-range torque, and is likely reducing it. It might be improving the maximum power figure by improving air flow at WOT but to be honest, that's and EASY thing to do: any piece of short fat pipe will do it. Getting that low- and mid-range torque is REALLY HARD.

The calculation for engine power = torque x revs so one way to increase the max power of the engine is to get it to rev more. But you'll notice that most torque charts have a peak somewhere in the middle and then drop off as revs increase, so you reach a point where revving the engine further only makes more noise. This top end max-power situation when more air can help: more, and colder. But designing an intake optimised for "more and colder" will be at the expense of the mid and lower rev ranges. Probably a most reasonable compromise for a track car, but not one I'd like to drive around public roads at legal speeds: it'd feel pretty gutless.

 

[jackaleks]

For optimal performance across the rev range an intake is needed that can morph itself from a long narrow pipe into a short fat one as rev change, [/COLOR]fits into the very limited space inside the engine bay, meets the strict noise and emissions requirements for road registration, and is cheap to manufacture, and install and reliable for the service life of the car.

Mazda did just this on the 787b Le Mans car. The intake trumpets were sleeved in two pieces and actuated by solenoid so they could shorten as the revs went up. Freaking amazing.

Also anyone that finds this stuff interesting should read up on Helmholtz resonance and the Lenoir cycle. Both really applicable to intake design.

 

[nd-photo.nl]

Any video material for that? I would love to see that in action

 

[bozothenutter]

F1 cars (used to ) have this aswell, i remember seeing video if an old Honda F1 engine wher the intakes moved( got shorter) through the fev range.

 

[nd-photo.nl]

I just remember Porsche had a system as well, shown on Wheeler Dealers (check from 16 minute mark):

 

[Andy93]

Yamaha R6 had this as well. The trumpets were on a stepper motor. Impressive s**t

 

[Whitebomber]

What I don't understand is if the standard airbox is the way to go then why do so many members of this forum run with an alternative setup?

 

[gambit]

What I don't understand is if the standard airbox is the way to go then why do so many members of this forum run with an alternative setup?

For the noise

 

[bozothenutter]

Truly epic....

 

[MRBILLYUK]

As we all know. The space in the engine bay on is extremely limited . So Renault designed an airbox to fit that space rather than design an airbox for better performance. I'm sure if there was more space it would have been a different shape / design entirely.
There's always been lots of talk over the years that the ph1 cylindrical airbox is better than the ph2 airbox. That's why they seem to get snapped up quickly when one comes up for sale.

 

[Radugns]

I've just put the ph1 airbox in my Clio. The noise is great, I will keep it In terms of performance, I don't think is anything better.

 

[PP200t]

I remember switching from an itg maxogen to a ph1 box in my 172 and thought it was actually better. Definately felt like it pulled better and certainly sounded just as good with a piperx filter!

 

[R3k1355]

View attachment 1442585View attachment 1442586View attachment 1442587View attachment 1442588View attachment 1442589View attachment 1442590

I've just put the ph1 airbox in my Clio. The noise is great, I will keep it In terms of performance, I don't think is anything better.

You don't have the two cold air intake pipes connected?