This is an exert from a thread over on M3 Cutters. It is very interesting and implies there are some big gains to have with very little modification. Obviously its referring to the M3 but I'm wondering if we can do something similar?
"No pictures to hand at the moment but I will try and explain.
Looking at the front of the car go to the right hand side foglight and look the opening next to it.
You will see that there is a hole.
This hole leads directly into the lower part of the airbox.
If you extend the hole/tube so that it comes down and faces forwards (like the foglight) you will see very low intake temperatures very quickly inside the airbox.
You can prove this to yourself by simply datalogging the temperatures at the MAF.
On a std car temperatures take a very long time to come down.
If you have a forward facing tube you will see intaker temperatures come down as soon as you start moving. It's incredibly quick.
This proves one thing - the lower air feed is the one that's most important. It has the largest diameter and is the one that feeds the air most directly into the airbox.
Personally, I would recommend losing the foglight altogether and fabricating a piece which fits in and feed air directly into the airbox opening.
The factory airbox is infact very very good and optimising it will give you much more consistent performance from your engine.
Now, let us look at what happens on a standard car with respect to intake temperatures and why intake temps are so important:
I think it's generally understood that lower intake temperatures = better power.
This is just the physical side of things.
When the ECU detects high intake temperatures (through intake sensor in MAF) it will retard the ignition timing which loses you power.
On a standard car intake temperatures rise very quickly if the car is standing for a very short space of time.
Best example - SantaPod.
Your engine is started and everything is at operating temperature. Your intake temperature by the time you get to the line will be around 60 degC even if outside temperature is 10 DegC (pretty cold).
So you launch the car with very high temps and I can guarantee that by the time you reach 1/4 mile your intake temps are still over 35degC.
What what Baris has done, the intake temps drop seriously fast as the car accelerates and the engine pulls in air. The oncoming air is pushed directly into the airbox and you have lower temps.
On the road with this method you will always have the best possible scenario which is intake temperatures = ambient temperatures.
Further more, even if you are doing 100+mph on a stock car (crusing) your intake temperatures are much higher than ambient because there is no direct feed into the airbox.
Again, with a direct feed you could be doing just 60mph with no load on the engine and your intake temperatures are ambient.
Your engine will always feel more responsive and be producing more power.
Modifying the intake with RPI scoops or anything else is just not going to do much because this area is firstly a low pressure area and secondly it is not a direct feed into the airbox.
The foglight area is high pressure and extended the tube has a much shorter direct passage with a larger cross sectional area.
Hope this helps.
__________________
Evolve Automotive
T: 01582 573 801
E: [email protected]
W: http://www.evo-s.co.uk
"
"No pictures to hand at the moment but I will try and explain.
Looking at the front of the car go to the right hand side foglight and look the opening next to it.
You will see that there is a hole.
This hole leads directly into the lower part of the airbox.
If you extend the hole/tube so that it comes down and faces forwards (like the foglight) you will see very low intake temperatures very quickly inside the airbox.
You can prove this to yourself by simply datalogging the temperatures at the MAF.
On a std car temperatures take a very long time to come down.
If you have a forward facing tube you will see intaker temperatures come down as soon as you start moving. It's incredibly quick.
This proves one thing - the lower air feed is the one that's most important. It has the largest diameter and is the one that feeds the air most directly into the airbox.
Personally, I would recommend losing the foglight altogether and fabricating a piece which fits in and feed air directly into the airbox opening.
The factory airbox is infact very very good and optimising it will give you much more consistent performance from your engine.
Now, let us look at what happens on a standard car with respect to intake temperatures and why intake temps are so important:
I think it's generally understood that lower intake temperatures = better power.
This is just the physical side of things.
When the ECU detects high intake temperatures (through intake sensor in MAF) it will retard the ignition timing which loses you power.
On a standard car intake temperatures rise very quickly if the car is standing for a very short space of time.
Best example - SantaPod.
Your engine is started and everything is at operating temperature. Your intake temperature by the time you get to the line will be around 60 degC even if outside temperature is 10 DegC (pretty cold).
So you launch the car with very high temps and I can guarantee that by the time you reach 1/4 mile your intake temps are still over 35degC.
What what Baris has done, the intake temps drop seriously fast as the car accelerates and the engine pulls in air. The oncoming air is pushed directly into the airbox and you have lower temps.
On the road with this method you will always have the best possible scenario which is intake temperatures = ambient temperatures.
Further more, even if you are doing 100+mph on a stock car (crusing) your intake temperatures are much higher than ambient because there is no direct feed into the airbox.
Again, with a direct feed you could be doing just 60mph with no load on the engine and your intake temperatures are ambient.
Your engine will always feel more responsive and be producing more power.
Modifying the intake with RPI scoops or anything else is just not going to do much because this area is firstly a low pressure area and secondly it is not a direct feed into the airbox.
The foglight area is high pressure and extended the tube has a much shorter direct passage with a larger cross sectional area.
Hope this helps.
__________________
Evolve Automotive
T: 01582 573 801
E: [email protected]
W: http://www.evo-s.co.uk
"