Intake: Cold air... Pressurized airbox
09-18-2002, 12:30 PM
#1
Drifting
Thread Starter
Intake: Cold air... Pressurized airbox
I was reading about GURU's new idea for a cold air intake. Danno, have you thought about using a scoop and pressurizing that space around the filter? I have no idea how much or even if this would improve power. Maybe use a similar scoop to the 924 GTR.
Just a thought.
87 944
951 in the near future
Just a thought.
87 944
951 in the near future
09-18-2002, 04:12 PM
#2
Race Director
Yes we've considered the ram-air possibility. Despite the Pontiac Firebird WS6 marketing hype, there are very few examples of true ram-air induction benefits with before & after comparisons. What I've seen that has been proven, has been on various motorcycles out there. Have you seen the size of the scoop on the Honda CBR600F4i? Or the CBR1100XX. But they do work at the top-speed ranges.
Some preliminary calculations to model ram-air on our air-box experiment shows we would need a 0.5 x 1.5m scoop. At 100mph, that would yield 1psi of pressure in a closed airbox assuming zero flow (full backpressure). This was assuming we also had a perfect parabolic funnel to ram the scoop down to a neck the size of a turbo-inlet (not to mention the 90-degree bend needed to get through the hood).
As mentioned in the <a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=18&t=002400" target="_blank">previous post</a>, our primary goal was to reduce the distance between the air-filter and turbo-inlet since the length and volume of that area is under vacuum; the less the better. Having shortened that down to about 3", that's the best we can do at the moment I think. Air outside of the filter doesn't seem to matter much (aside from temperature) since there's so much surface-area on the filter. We're looking at some custom MSDS filters next since we've had such a hard time getting shipments of K&N filters reliably to ship with our kits. The MSDS filters also uses the internal surface of cone to flow air as well, thus should be even more free-flowing than a K&N for the same size.
Some preliminary calculations to model ram-air on our air-box experiment shows we would need a 0.5 x 1.5m scoop. At 100mph, that would yield 1psi of pressure in a closed airbox assuming zero flow (full backpressure). This was assuming we also had a perfect parabolic funnel to ram the scoop down to a neck the size of a turbo-inlet (not to mention the 90-degree bend needed to get through the hood).
As mentioned in the <a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=18&t=002400" target="_blank">previous post</a>, our primary goal was to reduce the distance between the air-filter and turbo-inlet since the length and volume of that area is under vacuum; the less the better. Having shortened that down to about 3", that's the best we can do at the moment I think. Air outside of the filter doesn't seem to matter much (aside from temperature) since there's so much surface-area on the filter. We're looking at some custom MSDS filters next since we've had such a hard time getting shipments of K&N filters reliably to ship with our kits. The MSDS filters also uses the internal surface of cone to flow air as well, thus should be even more free-flowing than a K&N for the same size.
09-18-2002, 05:04 PM
#3
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Hey Danno - I like the way you think on things (having seen lots of posts).. heh.
Since I don't have a car yet, and don't know where everything's located yet, I just wanted to bounch this off you. Thinking along the lines of a pressurized air intake setup, if you provide an inlet on the hood (where ever the Shortest distance to where the air is needed) with the inlet going through a flat filter (as found in most motorcycle air-boxes) Right Away, then feeding the engine. You could (fairly easily) fabricate an 'air-box' that would affix/seal to the underside of the hood (again, or whatever is closest). Granted, another can of worms is opened with the design of the airbox so the flow is proper (might not be that big of a deal)...
But you gain things like, fresh air intake that's NOT pulling from inside the engine compartment (250+ deg) and Theoretical 'ram-air' at speed.
Just thoughts.... <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
Since I don't have a car yet, and don't know where everything's located yet, I just wanted to bounch this off you. Thinking along the lines of a pressurized air intake setup, if you provide an inlet on the hood (where ever the Shortest distance to where the air is needed) with the inlet going through a flat filter (as found in most motorcycle air-boxes) Right Away, then feeding the engine. You could (fairly easily) fabricate an 'air-box' that would affix/seal to the underside of the hood (again, or whatever is closest). Granted, another can of worms is opened with the design of the airbox so the flow is proper (might not be that big of a deal)...
But you gain things like, fresh air intake that's NOT pulling from inside the engine compartment (250+ deg) and Theoretical 'ram-air' at speed.
Just thoughts.... <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
09-18-2002, 05:30 PM
#4
Race Director
"I like the way you think on things "
Why thank you!
<img border="0" alt="[bigbye]" title="" src="graemlins/xyxwave.gif" />
"Thinking along the lines of a pressurized air intake setup, if you provide an inlet on the hood (where ever the Shortest distance to where the air is needed) with the inlet going through a flat filter (as found in most motorcycle air-boxes) Right Away, then feeding the engine. You could (fairly easily) fabricate an 'air-box' that would affix/seal to the underside of the hood (again, or whatever is closest). Granted, another can of worms is opened with the design of the airbox so the flow is proper (might not be that big of a deal)..."
Yup, that's the idea behind this:
<img src="http://www.gururacing.net/ImagesMisc/GURU-CAI.jpg" alt=" - " />
Notice that the big K&N filter is only about 3" way from the turbo's inlet (directly underneath the blue hose going to throttle-body). We're not sure if this is getting down to the point of diminishing returns going to this extreme vs. our 4" J-pipe. Only objective testing with dyno-results will provide some numbers to analize.
I just happen to think that nothing looks more sexy than having a big K&N filter stuck directly on your turbo's inlet like you see with the SupraTTs or Skylines...
<img border="0" title="" alt="[Wink]" src="wink.gif" />
Why thank you!
<img border="0" alt="[bigbye]" title="" src="graemlins/xyxwave.gif" /> "Thinking along the lines of a pressurized air intake setup, if you provide an inlet on the hood (where ever the Shortest distance to where the air is needed) with the inlet going through a flat filter (as found in most motorcycle air-boxes) Right Away, then feeding the engine. You could (fairly easily) fabricate an 'air-box' that would affix/seal to the underside of the hood (again, or whatever is closest). Granted, another can of worms is opened with the design of the airbox so the flow is proper (might not be that big of a deal)..."
Yup, that's the idea behind this:
<img src="http://www.gururacing.net/ImagesMisc/GURU-CAI.jpg" alt=" - " />
Notice that the big K&N filter is only about 3" way from the turbo's inlet (directly underneath the blue hose going to throttle-body). We're not sure if this is getting down to the point of diminishing returns going to this extreme vs. our 4" J-pipe. Only objective testing with dyno-results will provide some numbers to analize.
I just happen to think that nothing looks more sexy than having a big K&N filter stuck directly on your turbo's inlet like you see with the SupraTTs or Skylines...
<img border="0" title="" alt="[Wink]" src="wink.gif" />
09-18-2002, 05:45 PM
#5
Hey Danno,
Has anyone looked at the flow over the 951's nose? Your location may provide a viable location for the NACA style duct, but with it being a low pressure area, not a good location for a scoop. An extreme example of this would be the useless hood scoops on 60's musclecars. Most were not open because the air flow never even touched the hood on that location... This is a good time to not talk about computational fluid mechanics, laminar flow and boundary layer analysis.
I think it's a cool idea, though.
Has anyone looked at the flow over the 951's nose? Your location may provide a viable location for the NACA style duct, but with it being a low pressure area, not a good location for a scoop. An extreme example of this would be the useless hood scoops on 60's musclecars. Most were not open because the air flow never even touched the hood on that location... This is a good time to not talk about computational fluid mechanics, laminar flow and boundary layer analysis.
I think it's a cool idea, though.
09-18-2002, 07:18 PM
#6
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LOL, ok - damn, guess you've been working on this a little bit already. *chuckles*
Like c5driver951 mentioned, have you had opportunity to look at what the air is doing around the car? There might be a better high-pressure area to 'suck' from. I mean, motorcycles route their air through a few bends and around a meter of tubing. Pull the driving lights and split half of the left side to the airbox and the other half to the brakes with the right side going half to brakes and other half to general under-hood circulation. It's almost certainly a higher-pressure than the NACA duct on the hood. Maybe widen the sloot for the intercooler a few inches and run the ducting straight back (offset the intercooler). It'd certainly be a straight shot from there and people would likely be more willing to modify that little plate/body panel than the hood.
Damnit, I'm not supposed to think like this about cages - that's just plain wrong. Big ole heavy tanks that can't hardly get out of their own way (no, I've never been in a 951 or any other Porsche for that matter). Tomorrow I do the PPI on mine though - I expect to be driving it by noon. I'll probably change my tune then. Heh....
Like c5driver951 mentioned, have you had opportunity to look at what the air is doing around the car? There might be a better high-pressure area to 'suck' from. I mean, motorcycles route their air through a few bends and around a meter of tubing. Pull the driving lights and split half of the left side to the airbox and the other half to the brakes with the right side going half to brakes and other half to general under-hood circulation. It's almost certainly a higher-pressure than the NACA duct on the hood. Maybe widen the sloot for the intercooler a few inches and run the ducting straight back (offset the intercooler). It'd certainly be a straight shot from there and people would likely be more willing to modify that little plate/body panel than the hood.
Damnit, I'm not supposed to think like this about cages - that's just plain wrong. Big ole heavy tanks that can't hardly get out of their own way (no, I've never been in a 951 or any other Porsche for that matter). Tomorrow I do the PPI on mine though - I expect to be driving it by noon. I'll probably change my tune then. Heh....
09-18-2002, 08:55 PM
#7
I think more importantly, given that this is something being proposed for turbo applications, you would have to be pushing SO much air in there for it to be the least bit effective as a pressurized system...you'd pretty much have to make a nice Pro-Stock style induction hood. Realistically what Danno's kit provides is an endless source of cold air! I think I still prefer the 'behind the headlight' effect, as a simple headlight scoop could potentially provide the cold air as well with a modest wall to hold out the cold air, but keeping the system pressurized in a turbo car seems to be overkill
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09-18-2002, 10:35 PM
#8
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Danno, that's some nice looking metal work! Whose car is that, if you don't mind my asking?
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I just happen to think that nothing looks more sexy than having a big K&N filter stuck directly on your turbo's inlet like you see with the SupraTTs or Skylines...
~~~~
I'll have to agree with ya on that one!
~~~~
I just happen to think that nothing looks more sexy than having a big K&N filter stuck directly on your turbo's inlet like you see with the SupraTTs or Skylines...
~~~~
I'll have to agree with ya on that one!
09-18-2002, 10:49 PM
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[quote]Originally posted by C5Driver951:
<strong>Has anyone looked at the flow over the 951's nose? Your location may provide a viable location for the NACA style duct, but with it being a low pressure area, not a good location for a scoop. An extreme example of this would be the useless hood scoops on 60's musclecars. Most were not open because the air flow never even touched the hood on that location... This is a good time to not talk about computational fluid mechanics, laminar flow and boundary layer analysis.</strong><hr></blockquote>
That is a very good point! It could be possible that the air would be at an even lower pressure than in the fender. Thus, the turbo *might* actually have to work harder to make more boost, possibly negating some positive effects of the cool air source.
Further, the factory 968 Turbo S has the naca ducts turned around the other way. This would work very well to vent the hot engine compartment because the low pressure area near the hood would literally suck the hot air out from under the hood.
I can't quantify any of these ideas. The real way to test the effectiveness of this mod is to drive the car at speed with a vaccum gauge in the air filter/airbox and a temperature gauge either between the turbo and the intercooler or the intercooler and the intake ports.
<strong>Has anyone looked at the flow over the 951's nose? Your location may provide a viable location for the NACA style duct, but with it being a low pressure area, not a good location for a scoop. An extreme example of this would be the useless hood scoops on 60's musclecars. Most were not open because the air flow never even touched the hood on that location... This is a good time to not talk about computational fluid mechanics, laminar flow and boundary layer analysis.</strong><hr></blockquote>
That is a very good point! It could be possible that the air would be at an even lower pressure than in the fender. Thus, the turbo *might* actually have to work harder to make more boost, possibly negating some positive effects of the cool air source.
Further, the factory 968 Turbo S has the naca ducts turned around the other way. This would work very well to vent the hot engine compartment because the low pressure area near the hood would literally suck the hot air out from under the hood.
I can't quantify any of these ideas. The real way to test the effectiveness of this mod is to drive the car at speed with a vaccum gauge in the air filter/airbox and a temperature gauge either between the turbo and the intercooler or the intercooler and the intake ports.
09-18-2002, 11:04 PM
#10
Here is what i think could work good on a 951 with the filter behind the head light.
Make a custom insulated box for the filter and get the cold air from a tube a the bottom.That tube could be plugged up to the brake air ducts and share the air comming into the brake duct tube.
kinda like this.
I think making something like this will work good.
A ram-air type systems work good on n/a engine but on a turbo car you just want cold air.
Make a custom insulated box for the filter and get the cold air from a tube a the bottom.That tube could be plugged up to the brake air ducts and share the air comming into the brake duct tube.
kinda like this.
I think making something like this will work good.
A ram-air type systems work good on n/a engine but on a turbo car you just want cold air.
09-18-2002, 11:14 PM
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I have that same intake set-up on my 2001 Ford Powerstroke diesel. It really works great and sounds nice too.(is that what you wanted to hear?)
345 horsepower
832 foot pounds of torque(930 what?)
Word to your mother
345 horsepower
832 foot pounds of torque(930 what?)
Word to your mother
09-19-2002, 12:03 AM
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[quote]Originally posted by Edman951:
<strong>
Are all your other 2 post this good.
Word up
</strong><hr></blockquote>
That they are.
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<strong>
Are all your other 2 post this good.
Word up
</strong><hr></blockquote>That they are.
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09-20-2002, 01:24 AM
#15
I'm particularly impressed with the Queen's high English! Apparently he-who-gets-taken-to-school must address the masses in the third person
"Sorry to offend you with our humor"
Apparently this is post-by-committee
"Sorry to offend you with our humor"
Apparently this is post-by-committee