Which Air Filters are best for a C43 AMG

[Justin1600]

Like this Guy...

They should fire this in Afganistan from a large tank, what is the point of that

 

[Justin1600]

I have doubted if "performance" filters do anything to BHP. I have the Renntech airbox supplied by Renntech with standard MB filters fitted by Renntech.

Do you think the Renntech airbox makes any BHP gains ? or does it just look nice ( which it does )
I heard the you still have to use some of the original airbox

 

[Dieselman]

They should fire this in Afganistan from a large tank, what is the point of that

You're the one into modifying..Guess..??

It was your RS made me think of this car, they have a part in common to do with the idea behind this car.
Can you guess what it is?

 

[Justin1600]

You're the one into modifying..Guess..??

I am, but what i modify can be put back to standard if required. That Civic is fit for the bin

I have taken on board what you say about the airflow. But as my bonnet is higher at the back, don't you think the air will deflect a quarter of the way up the windscreen and over ?
I am completely confused now

 

[Dieselman]

The raised bonnet will possibly help the air clear the wipers, but there will be the positive pressure issue.

You are right about the Civic being a beater which is why he felt that spending $400 and a few hours time wouldn't be a problem for it's resale value...

The mods are aerodynamic mods as he has a long commute. That car has over 500,000 miles and is still going. He now achieves 102mpg at constant 70mph and doesn't feel any wind pressure until over 90mph with a calculated top speed of 140mph due to the low Cd of 0.17

Modifying cars isn't about bolting bits on, it's about thinking what's happening and testing, testing testing.

 

[Justin1600]

Alot of thought and design was put into the Turbo, Radiator and Intercooler.
I made cardboard templates etc and had it all made custom, using a company who only normally deals with the racing teams and not the public. Using thicker high quality cores, i got the running coolant temps down from 103 degrees to 75 degress and similar with the air intake temps

 

[Bobby Dazzler]

I am, but what i modify can be put back to standard if required. That Civic is fit for the bin

I have taken on board what you say about the airflow. But as my bonnet is higher at the back, don't you think the air will deflect a quarter of the way up the windscreen and over ?
I am completely confused now

It's that deflection that causes the high pressure. The void beneath the deflected air is effectively stagnant air. If you didn't raise the bonnet it would still be there, just physically smaller.

The fast moving 'deflected' air is low pressure. The stagnant air is high pressure. That's why windscreen wipers lift at speed - they're physically sucked by the vacum created above them.

 

[Dieselman]

I've no doubt the mechanical side is thought out to produce power. Have a think about airflow both into the engine, the engine bay and around the car.
The engine bay and radiator make up something like 30% of total drag.

What I said about the air filter causing diddly squat of the pressure drop in the intake system is correct, nearly all the losses will be elsewhere.
Get a very low pressure gauge and perform some testing of intake pressure/vacuum and you will find the pressure drops.
The intercooler will be one..that's always going to be the case, but by how much is variable, the throttle body will be another restriction, the airbox may well be as may the internal trumpet.
It looks like you've moved the air pickup to the light, which is good. You might find an even higher pressure further central and a bit lower if you test. The intake doesn't need to face forwards and will pick up more dirt if it does.

Next go for phenolic inlet manifold gaskets and ensure there is no heatsoak into the intake ducting due to being metal pipe or routed near hot components.

After that go for aerodynamic mods for absolute performance. For a car to go 25% faster it needs 100% more power, 200% faster needs 800% power.

Look on the Civic just in front of the front wheel. See the little deflector, your RS has those for the same reason. Front wheels in particular create a lot of turbulence and drag, so deflect the air round them.

if your air filter isn't on the absolute limits of it's ability to allow air through and isn't causing pressure drop don't waste your money on a performance filter, it will do nothing but make someone else rich.

 

[Dieselman]

Nearly forgot.

Before you modify a car and after every mod...get the stopwatch out...!!!

This applies for both power testing derived from acceleration and aerodynamic mods tested with coast-down testing.

If you have a trip computer or data logging, use that to calculate efficiency by fuel used.

 

[Dieselman]

This will draw air into the engine bay due to the pressure differential. Unfortunately it's unlikely (but not impossible) to pass the intercooler, and so will be of limited benefit.

I once read an article where the inter-cooler temp was always high and didn't appear to work unless the fan was on.
After pressure testing it was found the hot engine bay air was indeed exiting via the inter-warmer.

Probably not quite what was intended..

 

[Number_Cruncher]

Broadly, I agree with most of the points made by DM in this thread. However, one sentence in particular stands out for its clarity and wisdom, and deserves some thought.

%%%%%%%%%%

>>Modifying cars isn't about bolting bits on, it's about thinking what's happening and testing, testing testing.

%%%%%%%%%%

This tallys with my experience. By far the majority of aftermarket and DIY vehicle modifications I have seen are poorly thought out, and degrade the vehicle and its performance.

50 years ago, yes!, cars were designed by empirical methods, and tweaks from the last design rather than by the more scientific methods used today. It was quite easy to make a meaningful gain when inlet manifolds were the size of peashooters and heated by contact with the exhaust. Manufacturers employ lots of their own "number crunchers" to optimise designs, and the scope for bolt on goodies is now rather meagre.

Most automotive engineers who work in manufacturers are also petrol heads and performance nuts - the idea that the manufacturers would spend millions CFD modelling, airflow and engine testing all aimed at optimising the airflow through the engine to then ruin it by fitting a needlessly restrictive air filter is quite a crazy conspiracy theory.

 

[Dieselman]

I have taken on board what you say about the airflow. But as my bonnet is higher at the back, don't you think the air will deflect a quarter of the way up the windscreen and over ?

I've just done some checking on some figures, I haven't got any for an Escort but these are for Nissan Maxima turbo.

At 50mph the under bonnet pressure was 0.4" H2O, which is quite high.

the pressures on the outside of the bonnet ranged from -0.5" H20 just back from the lead edge, to +0.6" H20 at the trail edge.

If your bonnet is propped at the rear and leaking air, will it flow into the engine bay or out given those pressure differentials?

It costs nothing to test and a RR is the worst place to do it.

http://us1.webpublications.com.au/static/images/articles/i21/2162_7mg.jpg

The large forward facing air scoop was actually acting in reverse and the intercooler was being heated by engine heat.

I hope that makes sense.

 

[BlackC55]

Do you think the Renntech airbox makes any BHP gains ? or does it just look nice ( which it does )
I heard the you still have to use some of the original airbox

Yes I do.

It feels much faster and it is not far off a C55 in driving comparison.

The lower section is part of the original airbox where it mounts ontop of the engine. The upper section is much different inside.

 

[Justin1600]

Yes I do.

It feels much faster and it is not far off a C55 in driving comparison.

The lower section is part of the original airbox where it mounts ontop of the engine. The upper section is much different inside.

Ahh ok Olly, thanks for the info

 

[Justin1600]

I've just done some checking on some figures, I haven't got any for an Escort but these are for Nissan Maxima turbo.

At 50mph the under bonnet pressure was 0.4" H2O, which is quite high.

the pressures on the outside of the bonnet ranged from -0.5" H20 just back from the lead edge, to +0.6" H20 at the trail edge.

If your bonnet is propped at the rear and leaking air, will it flow into the engine bay or out given those pressure differentials?

It costs nothing to test and a RR is the worst place to do it.

http://us1.webpublications.com.au/static/images/articles/i21/2162_7mg.jpg

The large forward facing air scoop was actually acting in reverse and the intercooler was being heated by engine heat.

I hope that makes sense.

Ok, i may drop the back of the bonnet down again and see the difference

 

[travelininstyle]

I am an expert on Air Filter !

You mean dirt, not induction noise.

As the previous member states - buy MB original - I work for the world's largest manufacturer of air filters,we have people from K & N working with us - unless you want to screw up your engine performance and MAF - stick with original MB parts.

 

[Justin1600]

As the previous member states - buy MB original - I work for the world's largest manufacturer of air filters,we have people from K & N working with us - unless you want to screw up your engine performance and MAF - stick with original MB parts.

If i was going to put paper filters in, i would not put MB ones in at £90 i would get some Fram one's at a third of the price

 

[moonloops]

As the previous member states - buy MB original - I work for the world's largest manufacturer of air filters,we have people from K & N working with us - unless you want to screw up your engine performance and MAF - stick with original MB parts.

Have you got independent verifiable evidence that shows maf failure caused by these filters?

 

[Justin1600]

I went out in someone elses C43 yesterday that had K&N's fitted sometime ago. He has had no problems with them, and the car sounds much better under acceleration

I think i will get some of these this week

 

[andy27168]

I went out in someone elses C43 yesterday that had K&N's fitted sometime ago. He has had no problems with them, and the car sounds much better under acceleration

I think i will get some of these this week

What problems has he had with them? did you think there was an increase in induction noise?