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997.1 GT3 Air Filter Change

Thank. you again for that informative view , nice to read info from someone who business is the subject in question. rather than a speculate reply based on an assumption . Certainly given me food for thought and also will I am sure help others reading this thread and allow them to make a decision what they want do.
My personal feeling is the fab speed induction kit appears to draw more air in than the car can compensate for, meaning you really need a remap this would then give you the BHP gains that they claim , although as said clever marketing wording avoids explaining this in detail allowing them to take the full credit for the gains :grin: I have got a full 200cell cargraphic performance exhaust to hopefully increase the speed of exit gas while still allowing enough back pressure to not be detrimental to the science behind induction and exhaust :thumb:
 
One thing to remember is that the engine as standard is probably operating at very high volumetric efficiencies - the standard system is not acting as a ceiling to the limit the volume of air the engine can ingest.
Once 100% volumetric efficiency is reached for example, the only way further air can be ingested (Excluding pulse tuning) is with forced induction.

Yes, whilst not operating at 100% volumetric efficiency there are gains to be had, however lowering intake losses will not create a surplus of air as such that can be exploited with a remap (Volume flow rate would still be the same as this is determined by Swept volume / RPM * Engine RPM), but will marginally increase the pressure of the air charge (And therefore the mass flow rate of the air / volumetric efficiency)
The only way of remapping a naturally aspirated car for more power / torque without adjusting cam timing is to increase spark advance, usually limited by pre-ignition / detonation, this goes back to charge temperature as increased charge temperature increases the likelihood of pre-ignition.


Take a look at the 997.2 GT3 RS intake, very similar to the standard set up of a 997.2 Carrera.
The main difference looks to be the larger opening cross sectional area of the air cleaner inlets vs base carrera due to the higher mass flow rate of the engine.
If the fabspeed set up was better the RS set up would have followed suit.

Again, if you can keep air charge temperature the same and reduce intake losses there are marginal gains to be had, but looking at the differences between standard and fabspeed, i would expect them to be marginal as the base system looks very nice indeed and in all likelyhood the engine is already operating at very high volumetric efficiencies :thumb:

Your reduced exhaust back pressure will probably help though :bandit:
 
Interesting read, thanks for taking the time :?:


Can I say I was right then :floor:
 
That really was an interesting read , I feel considerably more knowledgable about induction now , kind of killed the theory a bit that Porsche amongst other things, use the induction and exhaust as simple ways to restrict the Carreras from getting too close to the flagship models thus killing the sales of the flagship cars.
 
This is a really interesting thread!

Making me think about the problems I had with the twin cone filter I fitted when I had the turbo wing on. Different to the Fabspeed setup in that the filters were fully enclosed in a carbon box that mated with the seals on the deck lid! The engine just couldn't cope with this set up at all, rough idling and a huge flatspot around 2500 rpm, however it did seem to fly like a scalded cat over 5000 rpm! In the end it had to come off as I was getting CELs and all sorts of fault codes. I came to the conclusion that it was potentially turbulent air over the MAF that could have been the source of the poor running! From the excellent explanations above it would seem that it couldn't have been down to any major increase in airflow/pressure reduction that the ECU couldn't cope with :?:
 
DucatiRob said:
This is a really interesting thread!

Making me think about the problems I had with the twin cone filter I fitted when I had the turbo wing on. Different to the Fabspeed setup in that the filters were fully enclosed in a carbon box that mated with the seals on the deck lid! The engine just couldn't cope with this set up at all, rough idling and a huge flatspot around 2500 rpm, however it did seem to fly like a scalded cat over 5000 rpm! In the end it had to come off as I was getting CELs and all sorts of fault codes. I came to the conclusion that it was potentially turbulent air over the MAF that could have been the source of the poor running! From the excellent explanations above it would seem that it couldn't have been down to any major increase in airflow/pressure reduction that the ECU couldn't cope with :?:

Good shout, very much could be to do with altering the MAFS signal, changing the diameter of the duct that the sensor sits in alone can cause problems, presenting turblent air to the sensor will also definitely cause problems! :cop:
 
Thanks for sharing your knowledge RL.

:thumb:
 
Interesting thread.
 
Phil 997 said:
That really was an interesting read , I feel considerably more knowledgable about induction now , kind of killed the theory a bit that Porsche amongst other things, use the induction and exhaust as simple ways to restrict the Carreras from getting too close to the flagship models thus killing the sales of the flagship cars.

Not really Phil, as our expert says its all about the efficiency of the big air-pump which is the engine. If all things are equal then the intake doesn't make much difference, but if things aren't equal then differences can be noticed.

Take the 986s boxster. Same engine as the 3.4 Carrera minus 200cc across the cylinders, but nearly 70hp difference. 200cc does not equate to that much power. The intakes are very different and the boxster is choked to prevent it competing with the 911 of that model range.

The boxster has a postage stamp sized filter, a very narrow intake tract to a microscopic throttle body and then into different inlet manifolds. By changing the filter to a 987 filter (and airbox) coupled with a larger diameter intake path, mated to a 996 throttle body and plenum, you increase the power of the boxster.

The differences between the Carrera and the GT cars will be much less, but if they have bigger TB's then the intake will play some part in choking the power, albeit minor as the % increase in cross sectional area of the TB will be less between those two variants than it was between the 986s and 996.
 
ah so as I have also got a bigger ipd plenum and the gen2 comes with the bigger gt3 tb from stock then ,I should expect some increases albeit maybe marginal but add that to the twin cone fabspeed and the cargraphic exhaust there should be some improvements which is what I was hoping for.
The remap was really to move the power curve to suit a fast road car as the low mid range gains are what I was looking for.
It will be interesting to see what the read out numbers are when the cars been remapped with all the other bits on it.
But I can see the logic from RLs original post that JUST changing the panel filter alone to a sports filter wouldn't make hardly any more power and TBH I didn't notice much if anything when I did it , what I noticed was what seemed to be a much more freely breathing engine that didn't have the restricted wheezy note that it had with the stock filter ,and it sounded quite nice aswell.
 
Phil 997 said:
ah so as I have also got a bigger ipd plenum and the gen2 comes with the bigger gt3 tb from stock then ,I should expect some increases albeit maybe marginal but add that to the twin cone fabspeed and the cargraphic exhaust there should be some improvements which is what I was hoping for.
The remap was really to move the power curve to suit a fast road car as the low mid range gains are what I was looking for.
It will be interesting to see what the read out numbers are when the cars been remapped with all the other bits on it.
But I can see the logic from RLs original post that JUST changing the panel filter alone to a sports filter wouldn't make hardly any more power and TBH I didn't notice much if anything when I did it , what I noticed was what seemed to be a much more freely breathing engine that didn't have the restricted wheezy note that it had with the stock filter ,and it sounded quite nice aswell.

The noise alone is almost worth it Phil :thumb: The induction roar when I had the Agency Power twin cone kit fitted was addictive, really howled above 5000, rpm, just wished I could have made it work! :damn:
 
DucatiRob said:
Phil 997 said:
ah so as I have also got a bigger ipd plenum and the gen2 comes with the bigger gt3 tb from stock then ,I should expect some increases albeit maybe marginal but add that to the twin cone fabspeed and the cargraphic exhaust there should be some improvements which is what I was hoping for.
The remap was really to move the power curve to suit a fast road car as the low mid range gains are what I was looking for.
It will be interesting to see what the read out numbers are when the cars been remapped with all the other bits on it.
But I can see the logic from RLs original post that JUST changing the panel filter alone to a sports filter wouldn't make hardly any more power and TBH I didn't notice much if anything when I did it , what I noticed was what seemed to be a much more freely breathing engine that didn't have the restricted wheezy note that it had with the stock filter ,and it sounded quite nice aswell.

The noise alone is almost worth it Phil :thumb: The induction roar when I had the Agency Power twin cone kit fitted was addictive, really howled above 5000, rpm, just wished I could have made it work! :damn:

:grin: :grin: gates of hell opening as the default sound works for me Rob :thumb:
 
Excellent insight RL1989

So back to the OEM Panel Air Filter, so does anyone want a 993 K&N air filter ?
 
Some great knowledge there. Wish I had some engineering skills
 
Could anybody explain why then that the current GT3 RS has a BMC air filter installed from new? :dont know:
p.s. Cracking read by the way RL :thumb:
 

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