02-23-2007, 03:14 PM
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#1
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Porscheectomy
Join Date: Mar 2006
Location: Seattle Area
Posts: 3,011
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I'm having trouble understanding how anyone who proclaims to be knowledgable in fluid dynamics can look at the snorkel and look at the intake without the shorkel and decide there isn't a flow benefit to removing it.
The intake is just as smooth and radiused into the intake without the snorkle as it is with so the vena contracta won't be an issue without the snorkel. The inlet area of the snorkel is smaller than that of the outlet, causing a pressure loss and the cup at the end of the snorkel will further restrict inlet flow.
I wouldn't guess what power difference removing the snorkel would make, but I can look at it from an engineer's perspective and know it's a restriction without a doubt.
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02-23-2007, 03:29 PM
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#2
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Registered User
Join Date: Sep 2005
Location: Minneapolis/St. Paul, Minnesota, USA
Posts: 3,308
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Quote:
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Originally Posted by blue2000s
I'm having trouble understanding how anyone who proclaims to be knowledgable in fluid dynamics can look at the snorkel and look at the intake without the shorkel and decide there isn't a flow benefit to removing it.
The intake is just as smooth and radiused into the intake without the snorkle as it is with so the vena contracta won't be an issue without the snorkel. The inlet area of the snorkel is smaller than that of the outlet, causing a pressure loss and the cup at the end of the snorkel will further restrict inlet flow.
I wouldn't guess what power difference removing the snorkel would make, but I can look at it from an engineer's perspective and know it's a restriction without a doubt.
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Hi,
It's only a restriction if the engine can gulp more CFM than the Snorkel can provide. If the Snorkel meets this demand (which I suspect is the case), then it's merely a smaller hole, but with no consequence. You'd need a Flow Bench to say for certain. Excellent observation though...
Happy Motoring!... Jim'99
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02-23-2007, 03:35 PM
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#3
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Porscheectomy
Join Date: Mar 2006
Location: Seattle Area
Posts: 3,011
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Quote:
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Originally Posted by MNBoxster
Hi,
It's only a restriction if the engine can gulp more CFM than the Snorkel can provide. If the Snorkel meets this demand (which I suspect is the case), then it's merely a smaller hole, but with no consequence. You'd need a Flow Bench to say for certain. Excellent observation though...
Happy Motoring!... Jim'99
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That's totally incorrect. It's always a restriction and there will always be some pressure drop, no matter how much or little the engine is pulling in as long as some air is moving. A flow bench would show a pressure drop as soon as any air started flowing through the snorkel.
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02-23-2007, 04:37 PM
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#4
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Registered User
Join Date: Feb 2005
Location: Chicago
Posts: 283
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@ Everyone-- Lets just all de-snorkel and be happy for the great sounds we have just unleashed and the possibility of 1-2% more HP ±2% of that HP. 
@ All the engineers-- These debates make the common man (myself) just smile. I have no idea what is being debated, yet love the fact that it is! Keep it up everyone! 
__________________
2000 Porsche Boxster S 
2007 Lexus RX350
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02-23-2007, 04:44 PM
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#5
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Registered User
Join Date: Sep 2005
Location: Minneapolis/St. Paul, Minnesota, USA
Posts: 3,308
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Quote:
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Originally Posted by blue2000s
That's totally incorrect. It's always a restriction and there will always be some pressure drop, no matter how much or little the engine is pulling in as long as some air is moving. A flow bench would show a pressure drop as soon as any air started flowing through the snorkel.
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Hi,
Of course you are correct. I just meant to express that I just think this differential in pressure has little to no effect on overall Volumetric Efficiency which of course is a major determinant in how much power the engine can produce.
I'm not convinced that the Snorkel makes a significant difference, but that aside, I don't think the lister has proven otherwise.
Mrs. MNBoxster is away doing the Accenture Match Play Tourney in Tucson, and I'm having some guys over tonight for a little Boozer. But, I have a neat little engine where I can model AVF, TAF rates and VE, for given engine volumes and parameters. I'll plug in the Boxster data to see what we're looking at. With that, and some measurements of the Snorkel (which I have on a shelf in my garage), we should be able to have something more concrete. But, It will be a day or two.
I'll come back to this in a separate thread. Hope to have your input there...
Happy Motoring!... Jim'99
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02-23-2007, 05:10 PM
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#6
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Registered User
Join Date: May 2006
Location: Toronto
Posts: 277
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self-levelling annoyance
Jim, while we're on the topic of factoring in variables, do remember to take into account the "self-levelling annoyance" caused by the vodka you mentioned in a previous thread.
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02-23-2007, 08:08 PM
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#7
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Registered User
Join Date: Jan 2007
Location: Hacienda Heights, Ca
Posts: 75
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Wow..this is so sad...so much happened on the board while I spent more time beating my poor S on the dyno today. I have repeated the results on 17...yes 17 passes with and without the "snork". The data remains the same. For what it is worth, this mod produces 4.6~5.5whp at high rpms. Whew!
__________________
Bisimoto Engineering
2001 modified Boxster S, slate grey, red interior
Last edited by Bisimoto; 02-23-2007 at 08:09 PM.
Reason: more info
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02-23-2007, 10:10 PM
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#8
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Registered User
Join Date: Sep 2005
Location: Minneapolis/St. Paul, Minnesota, USA
Posts: 3,308
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Quote:
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Originally Posted by Bisimoto
Wow..this is so sad...so much happened on the board while I spent more time beating my poor S on the dyno today. I have repeated the results on 17...yes 17 passes with and without the "snork". The data remains the same. For what it is worth, this mod produces 4.6~5.5whp at high rpms. Whew!
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Hi,
Well you're certainly getting consistent results. I may be starting to come around.
This is for the 3.2L, I doubt the 2.5L w/o egas, Motronic ME 7.2 and variable intake will achieve anywhere near the same result.
I called a friend who owns a shop w/ 2 inertial dynos, and just for ********************s and giggles, I'm gonna run over there this spring and see what it tells me, even with the tire dynamisicm, I should also get consistent positive results based on your findings. A good engineer is also intuitive and still I have this nagging sense that something's amiss.
But, at least for now - You Da Man! Congrats!
Happy Motoring!... Jim'99
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02-23-2007, 09:52 PM
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#9
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Registered User
Join Date: Sep 2005
Location: Minneapolis/St. Paul, Minnesota, USA
Posts: 3,308
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Quote:
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Originally Posted by wanna986
Jim, while we're on the topic of factoring in variables, do remember to take into account the "self-levelling annoyance" caused by the vodka you mentioned in a previous thread. |
Hi,
What's that all about? You're just being NASTY! No call for that - shame, shame... That's very Clintonesque - attack the detractors - congratulations! Anyway you cut it, thats a cheap shot - Thanks for your valuable contribution to this thread. Feel Good now?...
Last edited by MNBoxster; 02-23-2007 at 10:36 PM.
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02-24-2007, 06:33 AM
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#10
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Registered User
Join Date: Nov 2006
Location: NYC area
Posts: 681
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Quote:
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Originally Posted by MNBoxster
Hi,
What's that all about? You're just being NASTY! No call for that - shame, shame... That's very Clintonesque - attack the detractors - congratulations! Anyway you cut it, thats a cheap shot - Thanks for your valuable contribution to this thread. Feel Good now?...
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Jim,
I may be wrong, but judging by the "tone" and context of his post, I am sure he was only joking.
__________________
Miss my Boxster
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