Finally: Dyno charts of de-snorked 986S!!!

[RandallNeighbour]

Now where are all the critical comments from forum members who have said emphatically that desnorkeling will not increase HP at all and it's all about making the intake a little louder?

Lurking now, aren't you?

[porsche986spyder]

Originally Posted by RandallNeighbour

Now where are all the critical comments from forum members who have said emphatically that desnorkeling will not increase HP at all and it's all about making the intake a little louder?

Lurking now, aren't you?

When people always referred to "de-snorkle" I thought they were talking about the intake tube that contains the little extra noise/silencer box that sticks out from the tube just before the throtle body. I had no idea there was another "snorkle" shaped device in front of the air box, that one could remove fronm the outside. I think many others were thinking of the C.A.I. tubbing also. I'm deffinately going to remove this "snorkle" part now.

[Bavarian Motorist]

If you are referring to that guide I posted, the author said that Porsche added it for the 987 because of the cigarette incident...

[porsche986spyder]

Originally Posted by Bavarian Motorist

If you are referring to that guide I posted, the author said that Porsche added it for the 987 because of the cigarette incident...

That's funny, because I heard that was the reason for the CUP shaped part.

[porsche986spyder]

I wonder if the shape of the snorkle tube being a long smooth part leading up to the intake had some type of airflow/aerodynamics pupose. Therefore it would have been better to test it on the dyno with a fan blowing on the intake vent to simulate the car moving forward, since it was sitting still when you did the before and after test. Just a thought to consider for future testing.

[Bavarian Motorist]

http://www.ppbb.com/boards/ppbbphp/showflat.php?Cat=&Board=ARCHIVES&Number=820409&Forum=ARCHIVES&Words=10min&Match=Entire



Here is a good guide on how to remove the snorkel.



So removing this little thing will really make that much of a difference. Nice.



EDIT: For you, porsche986spyder

[porsche986spyder]

Originally Posted by Bavarian Motorist

http://www.ppbb.com/boards/ppbbphp/showflat.php?Cat=&Board=ARCHIVES&Number=820409&Forum=ARCHIVES&Words=10min&Match=Entire



Here is a good guide on how to remove the snorkel.



So removing this little thing will really make that much of a difference. Nice.



EDIT: For you, porsche986spyder

Thanks man!

[Bisimoto]

Originally Posted by porsche986spyder

I wonder if the shape of the snorkle tube being a long smooth part leading up to the intake had some type of airflow/aerodynamics pupose. Therefore it would have been better to test it on the dyno with a fan blowing on the intake vent to simulate the car moving forward, since it was sitting still when you did the before and after test. Just a thought to consider for future testing.

I did use a fan in 2 areas: the front for the heat exhanger/radiator, and the rear driver's side vent, but only to provide cool air. A single cylinder in our P-car engines demands air at 2000RPMs that none of my industrial grade fans can generate. As a matter of fact, a NACA duct (superior to our Porsche side vents) is only efficient as a ram at above 200mph.

2 weeks ago i performed a test using a fully radiused intake pipe on single cylinder induction tubes, and gained 12whp on a 320whp engine. Infusing such technology in our induction may prove benefitial, but the factory ram tube, incorporated with the "deflection cup" is a restriction, and hence, the power gains seen in the upper RPM range.

Thanks for the suggestion...great minds think alike!

[porsche986spyder]

Originally Posted by Bisimoto

I did use a fan in 2 areas: the front for the heat exhanger/radiator, and the rear driver's side vent, but only to provide cool air. A single cylinder in our P-car engines demands air at 2000RPMs that none of my industrial grade fans can generate. As a matter of fact, a NACA duct (superior to our Porsche side vents) is only efficient as a ram at above 200mph.

2 weeks ago i performed a test using a fully radiused intake pipe on single cylinder induction tubes, and gained 12whp on a 320whp engine. Infusing such technology in our induction may prove benefitial, but the factory ram tube, incorporated with the "deflection cup" is a restriction, and hence, the power gains seen in the upper RPM range.

Thanks for the suggestion...great minds think alike!

Wow! Thant's amazing. Thanks for all the info. Sounds like you know what your doing for sure. Please keep us posted with any more dyno test you do with other mods.

[MNBoxster]

Originally Posted by Bisimoto

I did use a fan in 2 areas: the front for the heat exhanger/radiator, and the rear driver's side vent, but only to provide cool air. A single cylinder in our P-car engines demands air at 2000RPMs that none of my industrial grade fans can generate. As a matter of fact, a NACA duct (superior to our Porsche side vents) is only efficient as a ram at above 200mph.

2 weeks ago i performed a test using a fully radiused intake pipe on single cylinder induction tubes, and gained 12whp on a 320whp engine. Infusing such technology in our induction may prove benefitial, but the factory ram tube, incorporated with the "deflection cup" is a restriction, and hence, the power gains seen in the upper RPM range.

Thanks for the suggestion...great minds think alike!

Hi,

As someone who did their thesis on NACA duct research, I can tell you that you are somewhat correct so far as Ram Effect is concerned. In fact, a Ram Effect is not achieved within a NACA Duct until transonic speeds are reached (about 0.8 mach, or approx. 609 MPH).

But, this isn't why NACA ducts came into widspread use in motorsports. It was because of a reduction in drag over previously used protruding intakes. This reduction in drag, not achieving a Ram effect, is what made them desireable...

Happy Motoring!... Jim'99

[MNBoxster]

Originally Posted by RandallNeighbour

Now where are all the critical comments from forum members who have said emphatically that desnorkeling will not increase HP at all and it's all about making the intake a little louder?

Lurking now, aren't you?

Hi,

Just caught this thread - see: http://www.pca.org/tech/tech_qa_question.asp?id={5628EC8F-3626-40D2-8AE0-E9F524E0718F} . I'm still not totally convinced, I think there's an error in the methodology. That's an approx. 6 CHP gain, and I'm just not convinced this part robs 6 HP. I can hold a thermometer in my hand and watch the Mercury rise, that doesn't mean I've made the room any warmer, or conversely, that I have cooled the room when I release the thermometer. There's no reason for Porsche to do it...

Happy Motoring!... Jim'99

[Bavarian Motorist]

I'm not sure if the thermometer analogy conceptually applies here.

[pecivil]

Bisimoto!!

Welcome to the board! You are definitely the kind of Boxster guy we need on here.

I would love to drop by your place and test my engine. There are some great roads through the hills in Hacienda hts. I have transplanted a 3.4l 996 carrera engine in my car. I have revo software, the K&N intake and a somewhat screwed up set of headers, 200 cell cats and muffler from a shop in Maryland that was supposed to be designed for the swap. Alas, the exhaust system sounds really great, but there are fitment issues with suspension. I would love to see what you come up with for the 3.2 engine exhaust wise. The 3.4 and 3.2 are (almost) the same engine.

If you need/want a guinea pig for exhaust system work, I would be happy to volunteer!!

BTW nice work on the desnorkleing. I did this a long time ago, and decided it was worth it just for the sound. Glad to see it does add a bit of torque.

Monte

[Bisimoto]

Originally Posted by pecivil

Bisimoto!!

Welcome to the board! You are definitely the kind of Boxster guy we need on here.

I would love to drop by your place and test my engine. There are some great roads through the hills in Hacienda hts. I have transplanted a 3.4l 996 carrera engine in my car. I have revo software, the K&N intake and a somewhat screwed up set of headers, 200 cell cats and muffler from a shop in Maryland that was supposed to be designed for the swap. Alas, the exhaust system sounds really great, but there are fitment issues with suspension. I would love to see what you come up with for the 3.2 engine exhaust wise. The 3.4 and 3.2 are (almost) the same engine.

If you need/want a guinea pig for exhaust system work, I would be happy to volunteer!!

BTW nice work on the desnorkleing. I did this a long time ago, and decided it was worth it just for the sound. Glad to see it does add a bit of torque.

Monte

Greetings Monte,
Feel free to call my facility, and we can set up a good time to baseline your powerplant. I love the porsche 6-cyl, and look forward to applying some concepts to extract power. I may even take you up on the exhaust testing. I also appreciate your kind words.

Jim, I fail to understand why you feel this test is not factual. I duplicated both results, twice, as stated on page 1. As an engineer, who takes pride in being meticulous, I understand the value of repeating experiments to ensure validity. Such attention to detail has allowed me success in my present field of racing. In addition, I even invested in the most accurate and repeatable chassis dynamometer...no skimping there either.

I am here to share my experience, not to blow hot smoke. Feel free to perform the same tests...I am confident that you will perceive similar results.

In regard to the NACA ducts..at least we agree on that:



I use it to supply cool air to my induction throats!

[MNBoxster]

Originally Posted by Bisimoto

...Jim, I fail to understand why you feel this test is not factual. I duplicated both results, twice, as stated on page 1. As an engineer, who takes pride in being meticulous, I understand the value of repeating experiments to ensure validity. Such attention to detail has allowed me success in my present field of racing. In addition, I even invested in the most accurate and repeatable chassis dynamometer...no skimping there either.

I am here to share my experience, not to blow hot smoke. Feel free to perform the same tests...I am confident that you will perceive similar results.

In regard to the NACA ducts..at least we agree on that...

Hi,

Sorry, but we do not share the same confidence. In my years at the Naval Flight Test Center at Pax River MD, we spent about 5 times the effort on defining the methodology than we did in actual testing, to insure the results we got were valid, and even then, with virtually unlimited time and expenditures, we sometimes got it wrong. I was trained at MIT and Pax River to distrust all testing results until no other plausible explanation could be found to invalidate them.

Your results, IMHO, lie within the degree of error of the testing methodology as you describe it (or even within the HP variation between individual cars and engines), which automatically makes them suspect, if not altogether invalid.

You insinuate that this is the definitive test, but I remain skeptical for the reasons already stated. Did you even monitor Alternator Output? This variable alone could make your runs Doo-Doo.

I'm glad you shared your experience, but I'm concerned that many less-knowledgeable people will take it as Gospel, which I don't believe is the case. Judging from some of the Pied Piper responses already, of people believing what they want to hear without question, this seems to be the case.

A $61k Chassis Dyno, isn't any better than a $25k Inertial Dyno if the methodology is flawed. I'm not impressed by the cost of the gauges. An inertial Dyno can be just as good a tool, if used properly.

I spoke personally with a Porsche Engineer (an invited Guest Speaker at a Tech Session) in 2005 and asked him specifically about the Snorkel. His response was that it was solely a Noise Abatement device, aimed specifically at the Swiss Market (but with an eye toward increasing Noise Abatement regulations in other countries as well). He said that several prototypes were rejected for various reasons, including a power reduction, and Porsche, rather than mute the exhaust note - a Marketing Decision, chose to meet the overall madated Noise Levels, by reducing the Intake noise instead, so long as it didn't interfere with creating power. He said that this gen of Snorkel showed no change to the power/torque curves at all, which is why it was approved for production.

While I'm inclined to support his arguments, I am nonetheless prepared to change my mind in the face of definitive testing. I just don't think you have done any. You may in fact be on to something, but I don't believe you've proved it - yet. Improve your methodology, and you may just win me over.

It isn't a matter of Snorkel vs De-snorkel to me, I removed my snorkel well over a year ago - but for the sound enhancement, not to try and eek another 1-2% from the motor. Good Luck...

Happy Motoring!... Jim'99

[Bisimoto]

Greetings Jim,
I do not want to turn this into a debate, but honestly, feel free to perform the results yourself. Voltage will not skew results even within 8to 14.4volts since modern day EMS/ECU units have compensation values integrated into their programs. The $25K, or more, intertia dynos CANNOT replicate the sensitivity or repeatability of the hub chassis dyno simply because of the varibles introduced by the tyre, and the tyre interface...both of these in addition to how those dynos measure power. Even very slight changes in room temperation can affect the tyre growth and skew results. Straps introduce even more questionable readings the aformentioned units.

Bottom line, everyone is entitled to their opinion, but opinions can further become validated with data. Have a pleasant balance of the week.

[porsche986spyder]

Originally Posted by Bavarian Motorist

I'm not sure if the thermometer analogy conceptually applies here.

I agree. I look at the dyno results. I think it speaks for itself. By the way the link the other guy posted by PCA says he thinks by doing this we are removing the cooler air from the outside!?! Makes no sence, all we are doing is removing something that is restricting the air flow, not REMOVING the air flow all together, nor are we re-directing it from some place else, like from the inside of the engine. It will still pull the air from the outside! Look how close the opening is to the vents.

[MNBoxster]

Originally Posted by porsche986spyder

I agree. I look at the dyno results. I think it speaks for itself. By the way the link the other guy posted by PCA says he thinks by doing this we are removing the cooler air from the outside!?! Makes no sence, all we are doing is removing something that is restricting the air flow, not REMOVING the air flow all together, nor are we re-directing it from some place else, like from the inside of the engine. It will still pull the air from the outside! Look how close the opening is the the vents.

Hi,

Dyno results can be funny and not always verifiable or repeatable. The Lister must admit this if he's the kind of engineer, he seems to be.

So many variables must be exactly the same on each run for any results to be meaningful, especially since you're claiming a very small % gain of overall power (1.9%). Some, but not all include: Ambient Temp, Barometric pressure, Fuel flow, Octane, Alternator Output, each line of code in the DME operating w/o fault on each run, Engine Temp, Tranny Temp, Bearing Temp, and on and on.

For example, an Alternator (whose power draw is variable and not constant) alone can draw as much as 4-30 crank HP because of the inefficiencies in a Belt & Pulley system, so if it was filling demand on the 1st run, but not the 2nd, this alone could account for the variance seen.

The best method is to do multiple runs exactly duplicating the conditions of all previous runs and then averaging the results. Then, you reverse it, put the snorkel back on and see if you consistently achieve the previous Baseline numbers over an average of multiple runs. If these results aren't duplicated to within a pretty narrow degree, there is some variable not being accounted for.

Just because you get a graph from a single run which supports your theory, isn't in, and of, itself proof of anything...

Happy Motoring!... Jim'99

[pecivil]

I must admit that I too did not really "buy" what it suggests on the thread from the PCA website. I had seen that before, and it does not make sense how the snorkle would actually cool air as it flows inward. Why would the restriction cool airflow?

[Bavarian Motorist]

I can't figure out how to remove the blinds w/out breaking it. I see it has little snaps.


I have no clue what to do. Neither of the guides really explain how to do it.