Anybody install a K&N cone filter?
02-10-2005, 08:18 PM
#31
Originally Posted by M758
Lead foot,
Nice fab work To bad it does not give you any gains over the stock air box and snorkle.
Nice fab work To bad it does not give you any gains over the stock air box and snorkle.
From my experiments last summer, airbox versus cone filter on cold engines, the stock airbox beat the cone hands down. It has nothing to do with hot air in the engine compartment and I wish folks would stock claim that it does. The stock airbox is just a fairly good design and that is all there is to it.
02-10-2005, 11:51 PM
#32
Three Wheelin'
Originally Posted by testarossa_td
You guys are just making too much of this.
Just get a filter for your filter...then wrap your car in tac cloth and drive happy
Something to note here of course is that rare is it that we are the original owners of these cars and who knows(regardless of previous paperwork) what conditions our cars have been run on. You can run a K&N or stock all you want, that does not mean that the previous owner kept up on filter maintenance. So unless you did a full rebuild-Goodluck...and even then
-have you checked your whole induction sytem for being sealed?
(There are plenty of areas that wear or don't seal 100% behind the filter to suck in un-filtered air/debris.)
Plus(for the owners with MAF or the likes) I would be more worried about junk getting down in my timing belt cover(even with rubber cap), and FUBARing the works!
Or just drive and be deligent about maintenance and enjoy owning one of the most amazing car lines out there.
Just get a filter for your filter...then wrap your car in tac cloth and drive happy
Something to note here of course is that rare is it that we are the original owners of these cars and who knows(regardless of previous paperwork) what conditions our cars have been run on. You can run a K&N or stock all you want, that does not mean that the previous owner kept up on filter maintenance. So unless you did a full rebuild-Goodluck...and even then
-have you checked your whole induction sytem for being sealed?
(There are plenty of areas that wear or don't seal 100% behind the filter to suck in un-filtered air/debris.)
Plus(for the owners with MAF or the likes) I would be more worried about junk getting down in my timing belt cover(even with rubber cap), and FUBARing the works!
Or just drive and be deligent about maintenance and enjoy owning one of the most amazing car lines out there.
If your intake system behind the filter leaks any considerable amount, then you've got more problems than any you'd get from running a K&N.
02-11-2005, 12:32 AM
#33
Race Director
The stock air box may be a fairly good design, but its in a stupid place with having to route the IC pipes around it so much. You gain a lot by straightening them up. People dont seem to be counting that in this thread.
02-11-2005, 01:02 AM
#34
Sorry Andrew, I guess I should have pointed out that I was referring specifically to NA applications. you're much less likely to see improvements and more likely to see degradation if you kludge together an NA intake. Or I guess maybe it is harder to mask bad NA intake design since you aren't forcing air into it.
02-11-2005, 02:20 AM
#35
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All true. A K&N filter is not going to singlehandedly blow up your engine. But it will give you much dirtier oil, which will give you greatly increased wear.
If your intake system behind the filter leaks any considerable amount, then you've got more problems than any you'd get from running a K&N.
If your intake system behind the filter leaks any considerable amount, then you've got more problems than any you'd get from running a K&N.
Most common leaks behind the filter for turbo.
The biggest one I have seen is a hole worn in the bottom of the air box corner(pretty common), And I can't tell you how many badly placed K&N filters in stock boxes let air through under it, at the turbo intake, anywhere on that ancient J-boot rubber, intercooler connections, and at the throttle body and venturi tube.
Then most people go to a Aftermarket filter for a few horsepower(regardless of whether it works, and expect gains or for it to fix problems...fix what you got! you would be amazed at the difference. Sure there are some funky Porsche engineering things that we scratch our heads about, but how much time, money, road testing, and general effort did any of us put into engineering these marvels?? They did the hard work we are just grains of sand on the beach compared to what has been laid before us. No desrespect to the amazing talent on this board everyday...but I have not seen anybody here build the 952.
And as far as dirt in the oil...that is what a oil filter is for not an air filter
REGULAR MAINTENANCE. Don't buy a pcar if you can't maintain it...or afford to pay someone
02-11-2005, 05:57 AM
#37
Race Director
It's not just the air-box, but the thin snorkel going into the airbox. Then the tiny rubber J-boot coming out of the airbox. However, the most restrictive part of the entire intake is the AFM itself. Just put all these parts we've been discussing on a flow-bench and you can see for yourself that EVERY part easily flows 10x more than the AFM.
For NA applications, the intake, exhaust, valves, cams,e tc. are all optimised to work together. By changing any one component, you're really just moving your torque & HP peaks around, with a matching counteracting drop somewhere else. You gain 2-5hp in the upper RPMs from 5500-7500rpm and lose just as much from 2500-5000rpm. Peak-HP figures are nothing more than bragging rights. Does you no good unless you have a CVT. For a street car, you want a wide and useable powerband, not a peaky-revvy one that's fine for a race-car. So look at mods that gives you more torque and HP across the entire RPM range. Things like larger displacement, higher-compression, 4-1 headers, cams, dyno-tuning for custom-chips are the best bang-for-the-buck values, or HP-gained per dollar spent (in roughly that order). Everything else is just icing on top of the cake.
For NA applications, the intake, exhaust, valves, cams,e tc. are all optimised to work together. By changing any one component, you're really just moving your torque & HP peaks around, with a matching counteracting drop somewhere else. You gain 2-5hp in the upper RPMs from 5500-7500rpm and lose just as much from 2500-5000rpm. Peak-HP figures are nothing more than bragging rights. Does you no good unless you have a CVT. For a street car, you want a wide and useable powerband, not a peaky-revvy one that's fine for a race-car. So look at mods that gives you more torque and HP across the entire RPM range. Things like larger displacement, higher-compression, 4-1 headers, cams, dyno-tuning for custom-chips are the best bang-for-the-buck values, or HP-gained per dollar spent (in roughly that order). Everything else is just icing on top of the cake.
02-11-2005, 10:15 AM
#38
Race Director
Originally Posted by testarossa_td
-have you checked your whole induction sytem for being sealed?
(There are plenty of areas that wear or don't seal 100% behind the filter to suck in un-filtered air/debris.)
(There are plenty of areas that wear or don't seal 100% behind the filter to suck in un-filtered air/debris.)
Dude,
What you are describing is called a vacuum leak. The engine will find it quickly and tell you with idle problems. So I can say quite honestly ... My engine is 100% sealed from the filter back.
02-11-2005, 10:30 AM
#39
Race Director
Guys,
The impact and usefullness of a cone filter is different on NA vs Turbo cars.
On the NA car the reall restriction is not in the air box, or even AFM as danno states. It is in the head itself and I believe the intake port. So this is reason why cone filters and even MAF systems don't do sqat for 8v NA cars. They are not addressing the real restriction. I also believe the stock NA air box and snorlke is very well designed for the 8v NA motor.
Now the turbo is different story. The head issues are the same, but because of the turbo you can force your way through the head and still make power. The impact is simply less efficiency from turbo pressure as compared to better intake port. What this means is that with the turbo cars the air box and AFM can become restrictions. Look at it this way. How much bigger is the Turbo AFM vs the NA? Hmm not much if any. Yet how much more air needs to flow through? Well Assume a turbo S at 250 hp vs the NA at 150 HP and clearly it is 100 more HP worht of air.
So the AFM in turbo could be restriction. However I still don't know to what degree if you are running stock boost. Also look at the air box. The intake snorkle is the same size as well as the hole in the fender. The filter element is no much bigger (may be even smaller) also it must snake around the IC pipes. So while Porsche may have been able to optimize the NA intake path It seems they would have had to compromise the Turbo intake for packaging reasons. Again I still don't know if this really a restriction vs the AFM or not given stock boost levels.
Once however you increse the boost you need to flow more air. Therefore you tax the system even further and therefore freeing the intake with MAF and cone may prove useful.
On an 8v NA however you will never convice me that freeing the intake does anything. I have been around enough NA cars and dyno of these to lead me to keeping the stock box and paper filter even on a Race car when 2-3 hp is valuable gain.
The impact and usefullness of a cone filter is different on NA vs Turbo cars.
On the NA car the reall restriction is not in the air box, or even AFM as danno states. It is in the head itself and I believe the intake port. So this is reason why cone filters and even MAF systems don't do sqat for 8v NA cars. They are not addressing the real restriction. I also believe the stock NA air box and snorlke is very well designed for the 8v NA motor.
Now the turbo is different story. The head issues are the same, but because of the turbo you can force your way through the head and still make power. The impact is simply less efficiency from turbo pressure as compared to better intake port. What this means is that with the turbo cars the air box and AFM can become restrictions. Look at it this way. How much bigger is the Turbo AFM vs the NA? Hmm not much if any. Yet how much more air needs to flow through? Well Assume a turbo S at 250 hp vs the NA at 150 HP and clearly it is 100 more HP worht of air.
So the AFM in turbo could be restriction. However I still don't know to what degree if you are running stock boost. Also look at the air box. The intake snorkle is the same size as well as the hole in the fender. The filter element is no much bigger (may be even smaller) also it must snake around the IC pipes. So while Porsche may have been able to optimize the NA intake path It seems they would have had to compromise the Turbo intake for packaging reasons. Again I still don't know if this really a restriction vs the AFM or not given stock boost levels.
Once however you increse the boost you need to flow more air. Therefore you tax the system even further and therefore freeing the intake with MAF and cone may prove useful.
On an 8v NA however you will never convice me that freeing the intake does anything. I have been around enough NA cars and dyno of these to lead me to keeping the stock box and paper filter even on a Race car when 2-3 hp is valuable gain.
02-11-2005, 11:08 AM
#40
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Dude,
What you are describing is called a vacuum leak. The engine will find it quickly and tell you with idle problems. So I can say quite honestly ... My engine is 100% sealed from the filter back.
What you are describing is called a vacuum leak. The engine will find it quickly and tell you with idle problems. So I can say quite honestly ... My engine is 100% sealed from the filter back.
Turned out to be o2 sensor and TPS combined(thought the AFM had some hand in it but it was not) Car was running "perfect" plenty of boost, idle fine, AF good(have the AF/Duty meter) Then I decided to go MAF
All kinds of hoses were trashed some ripped apart in my hand, J-Boot was so dry and had cracks around just about every neck and at the turbo. The j boot was so hardened it only took a couple of turns to loosen and slide out the AFM. The airbox back end tabs were gone so the K&N did not seat properly(no clamp force) and then at the bottom of the box was a big hole! The boot to the Throttle was letting light oil blowby back down the neck. The same for the intercooler connection to the intake. And the venturi tube was not even hooked up-it was sucking air! This thing was a mess!
But it ran "perfectly fine" I kept up with a VW R32 in this condition!
All this was a case of the previous owner not maintaining it properly(ignorance and insufficient funds)...and that was just the air related stuff.
I think it is safe to say Porsche builds a solid motor with plenty of room for error!..and improvement
