Standard Airbox vs Open Air Filter
Discussion
I bought my car and it had a loud induction kit fitted, this one for reference: LINKY
It's obviously an expensive piece of kit but I have never been a fan of them, so a few weekends ago I fitted a standard airbox i had spare, but used the same cold air feed from the K+N
Here it is at them moment:
PC170060 by danny2107, on Flickr
From standard i have bypassed the resonator/anything else that was in the way and it is just an enclosed air box as it is.
This is what it used to be like:
Does anyone have any technical data on these? From what I've have read they are prone to heatsoak and "bogging" the car down, but since fitting the manifold you can see in the first pic it's as if the car is a bit starved of air, I'm going to refit the K+N kit when i get a spare hour or so and test it to see if it cures it, but i was wondering if PH had any theorys before hand?
Thanks
Danny
It's obviously an expensive piece of kit but I have never been a fan of them, so a few weekends ago I fitted a standard airbox i had spare, but used the same cold air feed from the K+N
Here it is at them moment:
PC170060 by danny2107, on Flickr
From standard i have bypassed the resonator/anything else that was in the way and it is just an enclosed air box as it is.
This is what it used to be like:
Does anyone have any technical data on these? From what I've have read they are prone to heatsoak and "bogging" the car down, but since fitting the manifold you can see in the first pic it's as if the car is a bit starved of air, I'm going to refit the K+N kit when i get a spare hour or so and test it to see if it cures it, but i was wondering if PH had any theorys before hand?
Thanks
Danny
You will likely not see an actual measurable power increase with the open air filter, most of them will increase throttle response (and possibly widen the power band) giving the feel of increased power. However, I am not familiar with your car, and i cannot tell you for sure weather you will see a power increase or not.
Your ECU should be fine with the aftermarket setup, the increased airflow will be minimal if any. You only need a new tune if you have made drastic changes to the motor (ie head porting), swapped to aftermarket fuel injectors, swapped to a significantly different cam, have made changes that cause sensors to read what would normally be out of range, or made modifications to an airflow sensor or the airflow path after it. Sometimes you still wont need a new tune after one or more of the listed modifications.
Many people believe that the manufacturers hide power away in the ECU. Ive even heard it said on car shows, this is a myth. Why would they do that, it would be bad for marketing. The manufacturer tunes the car to be reliable, economic, and powerful. The ECU controls 2 basic things, fuel and spark. The spark timing is set to the maximum advance the manufacturer feels is safe when running the recommended fuel. The timing is retarded whenever the ECU detects detonation, small advances in performance (throttle response) can be made by adjusting the attack rate and time for KR on the ECU, but the increase of performance will be more mental than real and will put your motor at increased risk (reduced reliability). Many cars will see an increase in throttle response when switching to higher octane fuel due to reduced KR, a slight performance increase (throttle response and larger power band) can be seen when adjusting timing after switching to higher octane fuel. Generally there is no noticeable power increase here. As for the fuel, the manufacturer will set the fuel to run as close as possible to stoichiometric (except in positive airflow and throttle changes) in order to increase reliability by reducing deposits on the inside of the combustion chamber.
Your ECU should be fine with the aftermarket setup, the increased airflow will be minimal if any. You only need a new tune if you have made drastic changes to the motor (ie head porting), swapped to aftermarket fuel injectors, swapped to a significantly different cam, have made changes that cause sensors to read what would normally be out of range, or made modifications to an airflow sensor or the airflow path after it. Sometimes you still wont need a new tune after one or more of the listed modifications.
Many people believe that the manufacturers hide power away in the ECU. Ive even heard it said on car shows, this is a myth. Why would they do that, it would be bad for marketing. The manufacturer tunes the car to be reliable, economic, and powerful. The ECU controls 2 basic things, fuel and spark. The spark timing is set to the maximum advance the manufacturer feels is safe when running the recommended fuel. The timing is retarded whenever the ECU detects detonation, small advances in performance (throttle response) can be made by adjusting the attack rate and time for KR on the ECU, but the increase of performance will be more mental than real and will put your motor at increased risk (reduced reliability). Many cars will see an increase in throttle response when switching to higher octane fuel due to reduced KR, a slight performance increase (throttle response and larger power band) can be seen when adjusting timing after switching to higher octane fuel. Generally there is no noticeable power increase here. As for the fuel, the manufacturer will set the fuel to run as close as possible to stoichiometric (except in positive airflow and throttle changes) in order to increase reliability by reducing deposits on the inside of the combustion chamber.
dblack1 said:
You will likely not see an actual measurable power increase with the open air filter, most of them will increase throttle response (and possibly widen the power band) giving the feel of increased power. However, I am not familiar with your car, and i cannot tell you for sure weather you will see a power increase or not.
Your ECU should be fine with the aftermarket setup, the increased airflow will be minimal if any. You only need a new tune if you have made drastic changes to the motor (ie head porting), swapped to aftermarket fuel injectors, swapped to a significantly different cam, have made changes that cause sensors to read what would normally be out of range, or made modifications to an airflow sensor or the airflow path after it. Sometimes you still wont need a new tune after one or more of the listed modifications.
Many people believe that the manufacturers hide power away in the ECU. Ive even heard it said on car shows, this is a myth. Why would they do that, it would be bad for marketing. The manufacturer tunes the car to be reliable, economic, and powerful. The ECU controls 2 basic things, fuel and spark. The spark timing is set to the maximum advance the manufacturer feels is safe when running the recommended fuel. The timing is retarded whenever the ECU detects detonation, small advances in performance (throttle response) can be made by adjusting the attack rate and time for KR on the ECU, but the increase of performance will be more mental than real and will put your motor at increased risk (reduced reliability). Many cars will see an increase in throttle response when switching to higher octane fuel due to reduced KR, a slight performance increase (throttle response and larger power band) can be seen when adjusting timing after switching to higher octane fuel. Generally there is no noticeable power increase here. As for the fuel, the manufacturer will set the fuel to run as close as possible to stoichiometric (except in positive airflow and throttle changes) in order to increase reliability by reducing deposits on the inside of the combustion chamber.
Wow, thankyou very much!Your ECU should be fine with the aftermarket setup, the increased airflow will be minimal if any. You only need a new tune if you have made drastic changes to the motor (ie head porting), swapped to aftermarket fuel injectors, swapped to a significantly different cam, have made changes that cause sensors to read what would normally be out of range, or made modifications to an airflow sensor or the airflow path after it. Sometimes you still wont need a new tune after one or more of the listed modifications.
Many people believe that the manufacturers hide power away in the ECU. Ive even heard it said on car shows, this is a myth. Why would they do that, it would be bad for marketing. The manufacturer tunes the car to be reliable, economic, and powerful. The ECU controls 2 basic things, fuel and spark. The spark timing is set to the maximum advance the manufacturer feels is safe when running the recommended fuel. The timing is retarded whenever the ECU detects detonation, small advances in performance (throttle response) can be made by adjusting the attack rate and time for KR on the ECU, but the increase of performance will be more mental than real and will put your motor at increased risk (reduced reliability). Many cars will see an increase in throttle response when switching to higher octane fuel due to reduced KR, a slight performance increase (throttle response and larger power band) can be seen when adjusting timing after switching to higher octane fuel. Generally there is no noticeable power increase here. As for the fuel, the manufacturer will set the fuel to run as close as possible to stoichiometric (except in positive airflow and throttle changes) in order to increase reliability by reducing deposits on the inside of the combustion chamber.
dblack1 said:
Many people believe that the manufacturers hide power away in the ECU. Ive even heard it said on car shows, this is a myth.
Is it not the case though that they put a cap on the outright power output in order to maintain reliability/longevity? Surely this is how tuners get more power out of a standard engine by a simple re-flash/chip; they are just accessing the "hidden" power albeit at the expense of long term reliability? I'm not actually saying the "extra" power is "hidden", just that manufacturers conduct long term relaibilty tests on their engines etc and have to strike a compromise between outright power and component life expectancy (as well as fuel efficiency, emissions and all the other crap).Toilet Duck said:
dblack1 said:
Many people believe that the manufacturers hide power away in the ECU. Ive even heard it said on car shows, this is a myth.
Is it not the case though that they put a cap on the outright power output in order to maintain reliability/longevity? Surely this is how tuners get more power out of a standard engine by a simple re-flash/chip; they are just accessing the "hidden" power albeit at the expense of long term reliability? I'm not actually saying the "extra" power is "hidden", just that manufacturers conduct long term relaibilty tests on their engines etc and have to strike a compromise between outright power and component life expectancy (as well as fuel efficiency, emissions and all the other crap).A remap for power is just choosing a different priority from all of those things, which will result in compromises in one or more of the other areas.
ringram said:
Usually the compromise is because of emissions. Also retards who chuck the wrong fuel in and load the engine in top gear off idle etc.
So yeah, plenty of things. Bypassing all that nanny stuff usually can release a lot more power.
wrong, emissions is almost all engine design, has very little to do with ECU tuning. (Edit: if your fuel maps are screwed up your car will have bad emissions, and if your timing is too retarded it could also cause you to fail emissions. Aftermarket ECUs do not have an OBD port and cannot pass emissions (in the US anyway). If your using a retuned/chipped factory ECU you can generally pass emmissions (but some retunes will turn off the rear O2 sensor among other things to make the ECU run a little faster))So yeah, plenty of things. Bypassing all that nanny stuff usually can release a lot more power.
There isnt really a "power cap", there isnt really a way to do that via ECU except limiting revs, and retarding timing. when a ECU is retuned/chipped, the timing is advanced and the KR is adjusted (as mentioned previously) which usually wont show a big power increase, but has a bigger effect on throttle response and will give the engine a slightly larger power band. To safely run a combination like this you will need higher octane fuel (have you noticed most of the cars that run premium already almost never get a retune). On some cars (equiped with an auto trans) the PCM will be adjusted to shift harder, giving slightly faster shifts (but the car is more likely to break loose when it shifts) at the cost of vastly increased wear on the trans.
Edited by dblack1 on Friday 24th December 03:16
Egg Chaser said:
OctyVrs said:
Was the ECU tinkered with to take advantage of the improved airflow of the open filter?
Surely that's why cars use a MAF sensor? Not 100% sure that the VTR will be fitted with one, but I'd expect that it is. If so, the ECU would be able to detect the improved airflow.My idea was that if the parameters in the ECU had been re-shuffled to leverage the increased airflow available, then you restrict the airflow back to factory levels, that would cause the symptoms above.
Reading off what the MAF (or MAP) thinks the current values are seems the most logical step forward to me.
OctyVrs said:
Egg Chaser said:
OctyVrs said:
Was the ECU tinkered with to take advantage of the improved airflow of the open filter?
Surely that's why cars use a MAF sensor? Not 100% sure that the VTR will be fitted with one, but I'd expect that it is. If so, the ECU would be able to detect the improved airflow.OctyVrs said:
My idea was that if the parameters in the ECU had been re-shuffled to leverage the increased airflow available, then you restrict the airflow back to factory levels, that would cause the symptoms above.
Surely if the ECU can handle the difference in air flow from fitting the new air filter, it can handle the difference from going back to the standard air filter.I'm sorry that I cannot join the debate as I simply don't know (hence asking the question) but I thank you for your detailed responses 
They have given me thought.
Had a little Xmas Day hoon today and the car went well but with the added bonus of that air filter roarrrrrrrrr, so I'll see how MPG pans out and go from there.
They have given me thought.davepoth said:
I doubt there would be an increase with that K&N. Where does all the air come from to get to it exactly?
In the bracket that holds the cone there is a circle hole in the base, a cold air pipe is fitted to this that scoops air from just above the radiator/behind the front grille.Had a little Xmas Day hoon today and the car went well but with the added bonus of that air filter roarrrrrrrrr, so I'll see how MPG pans out and go from there.
DannyVTS said:
I'm sorry that I cannot join the debate as I simply don't know (hence asking the question) but I thank you for your detailed responses They have given me thought.
Had a little Xmas Day hoon today and the car went well but with the added bonus of that air filter roarrrrrrrrr, so I'll see how MPG pans out and go from there.
Fair enough, but it'll be sucking a lot of air from off the exhaust manifold, which will be toasty. They have given me thought.davepoth said:
I doubt there would be an increase with that K&N. Where does all the air come from to get to it exactly?
In the bracket that holds the cone there is a circle hole in the base, a cold air pipe is fitted to this that scoops air from just above the radiator/behind the front grille.Had a little Xmas Day hoon today and the car went well but with the added bonus of that air filter roarrrrrrrrr, so I'll see how MPG pans out and go from there.
The under bonnet heat issue may or may not exist depending on airflow through your engine bay.
I was running a temporary cone filter on my car due to a non standard engine, I had no cold air ducting in a pretty crampt/hot engine bay (Porsche 944 with a 968 engine).
The intake temperatures did get pretty high in traffic but as soon as You stretched its legs a bit the intake temperature dropped to pretty much ambient.
I moved the filter location to a cooler area and it improved torque but it was more down to the fact that the intake was closer to the stock length, rather than nailed to the end of the manifold.
I was running a temporary cone filter on my car due to a non standard engine, I had no cold air ducting in a pretty crampt/hot engine bay (Porsche 944 with a 968 engine).
The intake temperatures did get pretty high in traffic but as soon as You stretched its legs a bit the intake temperature dropped to pretty much ambient.
I moved the filter location to a cooler area and it improved torque but it was more down to the fact that the intake was closer to the stock length, rather than nailed to the end of the manifold.
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