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RL1989
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Joined: 20 Mar 2016
Posts: 49



PostPosted: Sun Jan 06, 2019 8:35 am    Post subject: Reply with quote

DucatiRob wrote:
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 Question


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
 
  
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James M-S
Suzuka


Joined: 11 Apr 2017
Posts: 1076
Location: Derbyshire

2009 Porsche 997 Carrera 2

PostPosted: Sun Jan 06, 2019 9:33 am    Post subject: Reply with quote

Thanks for sharing your knowledge RL.

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MaxA
Albert Park


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PostPosted: Mon Jan 07, 2019 10:40 am    Post subject: Reply with quote

Interesting thread.
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ragpicker
Reims


Joined: 14 Apr 2013
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Location: North East England


PostPosted: Mon Jan 07, 2019 11:12 am    Post subject: Reply with quote

Phil 997 wrote:
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.
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Phil 997
Le Mans
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Joined: 05 Dec 2015
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2009 Porsche 997 Carrera 4S

PostPosted: Mon Jan 07, 2019 12:14 pm    Post subject: Reply with quote

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.
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DucatiRob
Kyalami


Joined: 22 Jul 2015
Posts: 1778
Location: Milton Keynes

2006 Porsche 997 Carrera 2S

PostPosted: Mon Jan 07, 2019 8:28 pm    Post subject: Reply with quote

Phil 997 wrote:
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
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Phil 997
Le Mans
Le Mans


Joined: 05 Dec 2015
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Location: Bournemouth,Dorset

2009 Porsche 997 Carrera 4S

PostPosted: Mon Jan 07, 2019 8:31 pm    Post subject: Reply with quote

DucatiRob wrote:
Phil 997 wrote:
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
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1997 Porsche 993 Carrera 2

PostPosted: Mon Jan 07, 2019 8:55 pm    Post subject: Reply with quote

Excellent insight RL1989

So back to the OEM Panel Air Filter, so does anyone want a 993 K&N air filter ?
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FRP
Albert Park


Joined: 30 Apr 2014
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Location: Middlesex


PostPosted: Tue Jan 08, 2019 5:56 am    Post subject: Reply with quote

Some great knowledge there. Wish I had some engineering skills
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michelin
Indianapolis


Joined: 28 Oct 2010
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2006 Porsche 997 Carrera 2

PostPosted: Tue Jan 15, 2019 7:24 pm    Post subject: Reply with quote

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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Phil 997
Le Mans
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2009 Porsche 997 Carrera 4S

PostPosted: Tue Jan 15, 2019 8:21 pm    Post subject: Reply with quote

michelin wrote:
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


thats an interesting curveball Grin I will wait here and see what those in the know have to say Question
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RL1989
Newbie


Joined: 20 Mar 2016
Posts: 49



PostPosted: Fri Jan 18, 2019 8:16 am    Post subject: Reply with quote

michelin wrote:
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


That's an interesting one!

It looks like the 991 GT3 has paper filters but the RS has BMC filters in what appears to be a very similar if not identical layout.

The RS has an extra 20PS from a NA engine and the systems appear otherwise identical.
Perhaps in the quest for ultimate power it could be that the standard GT3 system had no further opportunity for improvement given the packaging space and compromises are now being made (Law of diminishing returns...). One of the reasons Porsche probably allowed this compromise would be that GT3 RS's are probably expected to be used sparingly compared with the 'run of the mill' 911.

However i will reiterate my original points, the flow velocity through the element is probably very high which is why the BMC filters were chosen for the RS model only, there was probably no further opportunities to reduce flow restriction, also note that the air box layout was retained rather than moving to exposed cone filters.

Clearly the best comprise for the job on every other 911 variant is the paper element + an air cleaner.
Swapping to a BMC filter in a lower power 911 variant will not yield the same results as the GT3 RS as the flow velocities will be much lower.


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