MBC's and air filters

[Kelly&Ben]

why does everyone on this forum use mbc's and not ebc's? just seems weird to me. is it cus the majority are auto's so adjusting the spool up rates etc is kinda pointless?

and why are air filters so bad? basics of tuning are airflow... more are in more air out. so why is restricting the in with an airbox seem like it needs to be done? is it because of the air flow sensor would need uprating or does it just cause boost creep cus the internal wastegates on the turbo's just cant vent fast enough?

[scott.mohekey]

As far as I'm aware, it's due to cost. In all my searching, MBCs seem to be roughly a fifth the price of an EBC.

[Kieran]

Not everyone uses an MBC. It's just a cheap and easy way to wang up the boost.

Regarding airbox... The standard item actually isn't that restrictive; Rally205 did some pressure-drop testing and the airbox isn't the problem. And you can always drop in a high-flow filter. It also has a sealed cold air feed as standard - Important in the VR-4's somewhat volcanic engine bay.

On top of that, many induction kits muck up the MAF readings and this tends to make the car run rich - This hurts power and screws up the MPG.

[peter thomson]

I run and EBC and an ARC box which so far have worked well for me and intake temps looked fine when I logged them on evoscan but the arc box does point away from the engine whereas most of the pod filters are closer to it. The arc box will allow me to make up a cold air box at a later stage if I need to and if I move the battery to the boot.

[Nick Mann]

I can't answer your question about MBCs. Years ago almost all used EBCs. Maybe as the cars have got cheaper, so have the tuning ideas? The EBC will give you much better spool, which doesn't worry the auto, and therefore a much bigger area under the power curve. Your top end power doesn't increase that much, but your 0-60 time will decrease drastically.

I agree with the airflow bit. However, what you really need is air volume. The engine bay of the VR4 is so hot, that the air heats excessively in the engine bay. This reduces the air volume even if you have managed to slightly increase the air flow. So you often get a power loss with a mushroom/pod filter rather than sticking with your standard air feed.

Hope that helps explain it.

[bradc]

Most pod filters just mess up the readings as Kieran said, and they will of course be sucking in VERY hot air from the engine bay. Not a good idea!

[Kelly&Ben]

thanks for replies. yea i know with the auto a mbc wouldnt matter. we have an auto starlet turbo and run one just on the fact i had one laying about, it has nothing to go wrong with etc and is perfect for a full auto. but with the triptronic an electronic would def benefit. just thought i'd ask as a lot seem to use em from what i've read on here. i guess its cus theyre cheap then and perhaps people dont realise the massive difference an ebc will make from not experiencing one before

[CANDEE]

When we did a filter test on the dyno with Wynn(VR4MAD)'s car he lost 7.1kw atw with a pod vs the std airbox and Ralliart filter...

[Kenneth]

The short answer to both MBCs and Air Fliters is that Cost vs Benefit is greatly in favour of MBC + Panel filter.

I haven't seen a significant enough difference between EBC and MBC results (I will restrict this to the NZ dyno results) to warrant the extra cost.
At the last NZ dyno day, 1st and 3rd places (peak power) were taken by cars running MBC.
The 2nd place car had been setup by the dyno operator a year or so previous and still had the same fuel general characteristics as the MBCs (problems with fuel cut ~3000RPM - 3500RPM)

I suspect that a top of the line EBC which is able to vary the duty cycle based on RPM would out-perform the MBC and the cheaper EBCs (which compared to MBCs are not really cheap). However for the cost, you could get some down pipes made and install a MBC at the same time, which would give better results than the top of the line EBC anyway.
Of course you could go with a full exhaust and a top of the line EBC as well, however those who have been up for spending that sort of money tend to be willing to spend a little more on a more sophisticated ECU solution (piggy back or full ECU) which generally sorts out the boost control anyway.

As for the pod filter issue, again it is a cost vs benefit. I am yet to see a car with the MAF still connected (and no piggy back correction of the air flow signal) which performs better with a pod filter than those which run off the standard system + panel filter. What I have seen, is cars fitted with a pod filter which run horribly.
To get any benefit out of a pod filter, you have to buy the correct filter and the correct adaptor so that the air flow into the MAF (which must be attached directly to the filter) is un disturbed. You also need a custom air box with cold air feed built around the filter (usually requires MAF cable extension) so that it doesn't then suffer from increased air temps under the bonnet.


Of course everyone has a different opinion, I have just given the opinion I have formed through my experience with the VR-4.


thanks for replies. yea i know with the auto a mbc wouldnt matter. we have an auto starlet turbo and run one just on the fact i had one laying about, it has nothing to go wrong with etc and is perfect for a full auto. but with the triptronic an electronic would def benefit. just thought i'd ask as a lot seem to use em from what i've read on here. i guess its cus theyre cheap then and perhaps people dont realise the massive difference an ebc will make from not experiencing one before

[Turbo_Steve]

Ken,

Why does the filter have to be next to the MAF...sure this is the cause of errors? I've always used a short (10-15cm) length of pipe between the filter and the MAF to stabilise the airflow.

Admittedly, I haven't on our legnum at the moment, but then it arrived with the filter already on it.

[Nick Mann]

I think a straight smooth pipe should be okay. But introduce bends or roughness and the air flow is no longer smooth and linear.

[bradc]

Someone on ozvr4 is a <something or other> mechanic and said that you need a straight length of pipe 12 times the diameter for the flow to become steady again after a 90 degree bend. Not sure how it changes for say a 45 degree bend if it is exactly half or some silly logarithmic thing, but I just thought I'd put that up there as food for thought.

[scott.mohekey]

you need a straight length of pipe 12 times the diameter

Do you mean a straight pipe of length 12 times the diameter?

[bradc]

Yes.

[Kenneth]

Depends on the diameter of the Pipe. The mouth of the MAF is designed to minimise turbulence from the air drawn in from the sides(like a bell mouth), if you introduce a pipe, this will no longer be the case and you may actually hurt the air flow. The best way is to have the MAF opening directly into a much larger chamber, such as the air box.

Any introduced turbulence in the air flow stream will cause the MAF to miss read, this is the cause of the errors. (Not the hot air temp, which may cause the ECU to run different maps, but wouldn't cause it to fuel so poorly)



Ken,

Why does the filter have to be next to the MAF...sure this is the cause of errors? I've always used a short (10-15cm) length of pipe between the filter and the MAF to stabilise the airflow.

Admittedly, I haven't on our legnum at the moment, but then it arrived with the filter already on it.

[Nicky123]

My Legnum has a POD filter in the left front guard, with a polished alloy pipe all the way to the intake. All statndard piping from there. I will try and get some photos up. If all I have read is the case then I should not be getting the performance I am. As it is, it goes like stink, the mechanic said I would get a performance gain from a cold air box, but did add, 'it goes alright, better than standard', only other mod as far as I know is a big cat back exhaust.
How will I know if there is an ECU mod (piggy back etc)?
What does the acronym MAF stand for?

[amsoil]

I would question why anyone would want to go for anything other than a panel filter? After all it fits as standard, allows cold air to be ducted is cheap enough and lets the car run smoothly.
No filter can increase flow, and in general the less the restriction the less the filtering. oiled filters (like K& N ) only work if nearly dripping with oil which means re oiling them weekly or the filtering falls away rapidly. Not good.

[Kenneth]

MAF stands for Mass Air Flow

Have you had your car on a dyno? You could say that all VR-4s "go like stink" and just because it feels fast, doesn't mean that you are getting the power figures you should be.

As I said, I have yet to see dyno results where a pod filter has resulted in a power gain over standard. Usually the result is air fuel ratios that dive below the ability of the measuring apparatus to measure.

Apparently the special K&N filter designed for the mitsubishi air flow meter does work, however I haven't seen one in use in NZ. This air filter still requires the MAF to be bolted directly to the filter.


I am happy to be proven wrong, though you will need some more proof than a mechanic who says "it goes better than standard" to convince me.
I am also more than happy to do an acceleration test along side to see if your car does go better than one which is 99% standard. (has a Ralliart panel filter)

[Turbo_Steve]

Worth noting also that the standard setup has a "ram scoop" effect from the high pressure area at the front of the car, which should actually stabilise airflow and allow the airbox to sit at positive pressure.


Pod filters sound nicer...but I can't hear it on the legnum.