944 Wind Tunnel Testing
10-04-2012, 09:35 PM
#46
Drifting
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ill bet the 944 fenders make the car drag more than the narrow body 924, howeverthey allow yout fit wider wheels/tires(which create more drag) granted more grip too
wonder how the turbo rear under panel does, or the 968 rs spoiler, or even 968 vs 944 spoiler
wonder how the turbo rear under panel does, or the 968 rs spoiler, or even 968 vs 944 spoiler
10-04-2012, 09:50 PM
#47
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i'll be back right here (post #47) to give my 0.02 on why the front of the 944 suffers from the front end floating (getting light at high speed).... first, a thought: look at the front lip in the avatar on the second to last post of the previous page..... 944s built to go very fast have, since the beginning of time (and we can cite scores of examples) been running some of the most jurassic front lip spoilers ever seen on the planet.... those huge Nascar spoilers on the Sprint cup cars are just about right for a 944 going maybe 60% as fast. (or did they first appear on the 944) ? and, has anyone seen the latest edition of Tony G's spoiler?—that thing's as big as your house.....
are your cars at 130 (indicated) really going 130 ? no. this goes for all our cars.
more on the way.
.
Last edited by odurandina; 10-05-2012 at 09:24 AM.
10-05-2012, 01:31 AM
#48
Rainman
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1. Most cars only require approx 4x12 inches of radiator opening to maintain cooling and maximize the efficency of the radiator without greatly affecting aero. Street cars are unfortunately subjected to stop and go traffic, and varying climates, so 4x12 may not be appropriate for all cars in all conditions.
5 vortex generators (mounted near the rear of the hatch where the air normally begins to delaminate do work.
5 vortex generators (mounted near the rear of the hatch where the air normally begins to delaminate do work.
would be interesting to see vortex generators on the hatch about halfway up...they arent very expensive taken off an evo...
10-05-2012, 08:38 AM
#49
Three Wheelin'
for the intercooler you only need 1/4 of its frontal surface exposed to keep it above 90% of its own efficiency. Not to mistake what i said for 90% intercooler efficiency...i'm talking about the performance drop is more than 10% of its maximum efficiency after you decrease the exposed area to less than 1/4 of its frontal core surface.
10-05-2012, 11:49 AM
#50
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My car is maybe 5 mph slower than the speedo shows (GPS says) at 120. Speedo 125=GPS 120. Havent checked beyond that, nowhere safe or legal to do that until I get on a track with it.
Morghen, are the Carerra GT / 931 vented nose panels worth installing? I have considered adding my own vents (similar to the "Boss" 944 GTR car) or just buying one.
Odurandina, how many inches out front would you say would be "Jurrasic" enough? I am building one currently for my car, parking bumps will something I will have to avoid, as all the reading I have done seems to point at a minimum of 3" forward to be more than cosmetic. I want it to actually produce noticable improvement at speed.
Jeff
Morghen, are the Carerra GT / 931 vented nose panels worth installing? I have considered adding my own vents (similar to the "Boss" 944 GTR car) or just buying one.
Odurandina, how many inches out front would you say would be "Jurrasic" enough? I am building one currently for my car, parking bumps will something I will have to avoid, as all the reading I have done seems to point at a minimum of 3" forward to be more than cosmetic. I want it to actually produce noticable improvement at speed.
Jeff
10-05-2012, 12:06 PM
#51
Three Wheelin'
You've considered buying a 944 GTR? :P
if you have a 951 then the 931/GT nose panel wont fit...you have to combine it to the 951 panel.
if you have a 944 NA then its not worth installing..unless you want to confuse people weather you drive a 924 with a 944 body kit or a 931 with a 944 body kit, or just a 944 with a 931/gt vented nose panel :P
There are fiberglass parts for the 951 that have the vents...i've seen some for sale at about 150 euros.
the boss nostrels are quite sexy indeed.
if you have a 951 then the 931/GT nose panel wont fit...you have to combine it to the 951 panel.
if you have a 944 NA then its not worth installing..unless you want to confuse people weather you drive a 924 with a 944 body kit or a 931 with a 944 body kit, or just a 944 with a 931/gt vented nose panel :P
There are fiberglass parts for the 951 that have the vents...i've seen some for sale at about 150 euros.
the boss nostrels are quite sexy indeed.
10-05-2012, 12:24 PM
#52
Rainman
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i'll be back right here (post #47) to give my 0.02 on why the front of the 944 suffers from the front end floating (getting light at high speed).... first, a thought: look at the front lip in the avatar on the second to last post of the previous page..... 944s built to go very fast have, since the beginning of time (and we can cite scores of examples) been running some of the most jurassic front lip spoilers ever seen on the planet.... those huge Nascar spoilers on the Sprint cup cars are just about right for a 944 going maybe 60% as fast. (or did they first appear on the 944) ? and, has anyone seen the latest edition of Tony G's spoiler?—that thing's as big as your house.....
10-05-2012, 12:46 PM
#53
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You've considered buying a 944 GTR? :P
if you have a 951 then the 931/GT nose panel wont fit...you have to combine it to the 951 panel.
if you have a 944 NA then its not worth installing..unless you want to confuse people weather you drive a 924 with a 944 body kit or a 931 with a 944 body kit, or just a 944 with a 931/gt vented nose panel :P
There are fiberglass parts for the 951 that have the vents...i've seen some for sale at about 150 euros.
the boss nostrels are quite sexy indeed.
if you have a 951 then the 931/GT nose panel wont fit...you have to combine it to the 951 panel.
if you have a 944 NA then its not worth installing..unless you want to confuse people weather you drive a 924 with a 944 body kit or a 931 with a 944 body kit, or just a 944 with a 931/gt vented nose panel :P
There are fiberglass parts for the 951 that have the vents...i've seen some for sale at about 150 euros.
the boss nostrels are quite sexy indeed.
I have a 951, so they would be functional. Just wondering if it would be worthwhile to help the intercooler or just a waste of time. I have seen the ones available for sale. I can do it myself if it is worth the effort. And on topic, I wonder how those 931 vents affect aerodynamics if at all?
I know the GTR intercooler and aero is of course completely different.
Jeff
10-05-2012, 02:01 PM
#54
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I have a 951, so they would be functional. Just wondering if it would be worthwhile to help the intercooler or just a waste of time. I have seen the ones available for sale. I can do it myself if it is worth the effort. And on topic, I wonder how those 931 vents affect aerodynamics if at all?
I know the GTR intercooler and aero is of course completely different.
Jeff
I know the GTR intercooler and aero is of course completely different.
Jeff
10-06-2012, 12:05 AM
#55
Rennlist Member
I'm as guilty as others by putting on a vented nose panel in the past as I liked the look of it. However without somewhere for the air to go (ala 968 rs hood vent) you are actually hurting your car's performance. It will likely build up a high pressure area and also possibly effect the cooling system's efficiency. So I included some hood vents which I know helped evacuate underhood heat but am still not sure if they actually helped with the flow through effect of the front nose vent. The next hood will have both side vents and a central one that is similar to the 968rs version. Plus include some dedicated ducting as described already. There has also been some speculation over opening up the front bumper for those with larger front mount intercoolers. Interestingly as the factory did, they only had a quite small opening with the stock setup. Some say that you don't need the whole face of the intercooler exposed but I think without quantitative testing I am going to opt for a larger opening with the different bumper panel. Not my car in last pic but just to show what I mean.
10-06-2012, 03:20 AM
#56
Three Wheelin'
for the intercooler you only need 1/4 of its frontal surface exposed to keep it above 90% of its own efficiency. Not to mistake what i said for 90% intercooler efficiency...i'm talking about the performance drop is more than 10% of its maximum efficiency after you decrease the exposed area to less than 1/4 of its frontal core surface.
10-06-2012, 04:07 AM
#57
Race Car
Thanks! It was a huge and risky undertaking, as it took considerable $$ and time to set up, and obviously not everyone that helped with $$ was able to attend/help with the work. People donated cars, specific aero parts, and their time. It took a long time to decide what would be tested, as there are hundreds of body/aero kits built/designed over the years for the 1st gen 240-280z (1970-1978).
As for some key information that we gleamed from the results transfers to almost any car. The rest is very specific to the car.
1. Most cars only require approx 4x12 inches of radiator opening to maintain cooling and maximize the efficency of the radiator without greatly affecting aero. Street cars are unfortunately subjected to stop and go traffic, and varying climates, so 4x12 may not be appropriate for all cars in all conditions.
2 Air dams and wings etc had limited effects on their own, and in somecases hurt the aero (by aero, I'm generalizing the term to include drag, and front/rear downforce/lift) It was proven that these enhancements need to be used as a matched "system" in order to maximize the benefits. In other words, not all air dams worked well with all spoilers/wings.
3 Tires had a larger impact on drag than thought. Wide tires, or tires that stuck out past the fenders (exposed to oncoming air) Keeping them covered as much as possible (not talking about wheel well covers like old limos) many times the wheels stick out slightly when viewing the car from the front (normally down low on the fender where it curves in slightly)
4 Windows down causes significant drag (not an option for some racecars)
5 vortex generators (mounted near the rear of the hatch where the air normally begins to delaminate do work.
6 In the case of the Datsun's sugar scoop headlight buckets, installing covers is a huge improvement, so I expect switching to non flip ups for the 944 to have a similar effect.
7 Belly pans. even stock ones are important and effective. Home made rear diffusers much less so (only because of the r&d required to design them correctly.)
8 Filling in seams/holes/ducts that are not needed showed lots of potential, though again the front of a Datsun has terrible aero, that has huge potential gains when modifying it with air dams, belly pans, radiator ducting etc.
9 Getting air OUT of the engine bay either out the sides or under the car helps air pass through the rad, and reduces the amount of air that can "pile up" in front of the rad.
There was a ton more learned, and I used most of the info when designing/modding my 280z.
Disclaimer. I am not an aeronautical engineer. I am just a nutso car enthusiast that had way too much fun playing with cars for 25yrs and counting. I am just generalizing what I learned from the wind tunnel, and my personal racing experience.
As for some key information that we gleamed from the results transfers to almost any car. The rest is very specific to the car.
1. Most cars only require approx 4x12 inches of radiator opening to maintain cooling and maximize the efficency of the radiator without greatly affecting aero. Street cars are unfortunately subjected to stop and go traffic, and varying climates, so 4x12 may not be appropriate for all cars in all conditions.
2 Air dams and wings etc had limited effects on their own, and in somecases hurt the aero (by aero, I'm generalizing the term to include drag, and front/rear downforce/lift) It was proven that these enhancements need to be used as a matched "system" in order to maximize the benefits. In other words, not all air dams worked well with all spoilers/wings.
3 Tires had a larger impact on drag than thought. Wide tires, or tires that stuck out past the fenders (exposed to oncoming air) Keeping them covered as much as possible (not talking about wheel well covers like old limos) many times the wheels stick out slightly when viewing the car from the front (normally down low on the fender where it curves in slightly)
4 Windows down causes significant drag (not an option for some racecars)
5 vortex generators (mounted near the rear of the hatch where the air normally begins to delaminate do work.
6 In the case of the Datsun's sugar scoop headlight buckets, installing covers is a huge improvement, so I expect switching to non flip ups for the 944 to have a similar effect.
7 Belly pans. even stock ones are important and effective. Home made rear diffusers much less so (only because of the r&d required to design them correctly.)
8 Filling in seams/holes/ducts that are not needed showed lots of potential, though again the front of a Datsun has terrible aero, that has huge potential gains when modifying it with air dams, belly pans, radiator ducting etc.
9 Getting air OUT of the engine bay either out the sides or under the car helps air pass through the rad, and reduces the amount of air that can "pile up" in front of the rad.
There was a ton more learned, and I used most of the info when designing/modding my 280z.
Disclaimer. I am not an aeronautical engineer. I am just a nutso car enthusiast that had way too much fun playing with cars for 25yrs and counting. I am just generalizing what I learned from the wind tunnel, and my personal racing experience.
10-06-2012, 06:24 PM
#58
Rennlist Member
Quote:
Originally Posted by 333pg333
Some say that you don't need the whole face of the intercooler exposed but I think without quantitative testing I am going to opt for a larger opening with the different bumper panel.
here
Quote:
Originally Posted by morghen
for the intercooler you only need 1/4 of its frontal surface exposed to keep it above 90% of its own efficiency. Not to mistake what i said for 90% intercooler efficiency...i'm talking about the performance drop is more than 10% of its maximum efficiency after you decrease the exposed area to less than 1/4 of its frontal core surface.
Yes, and others have said this. But this was also what the factory did with the stock intercooler. Not with a much larger front mounted version. From what you're saying, it would seem that you're discussing the differences of making the opening smaller, not larger ?
Originally Posted by 333pg333
Some say that you don't need the whole face of the intercooler exposed but I think without quantitative testing I am going to opt for a larger opening with the different bumper panel.
here
Quote:
Originally Posted by morghen
for the intercooler you only need 1/4 of its frontal surface exposed to keep it above 90% of its own efficiency. Not to mistake what i said for 90% intercooler efficiency...i'm talking about the performance drop is more than 10% of its maximum efficiency after you decrease the exposed area to less than 1/4 of its frontal core surface.
Yes, and others have said this. But this was also what the factory did with the stock intercooler. Not with a much larger front mounted version. From what you're saying, it would seem that you're discussing the differences of making the opening smaller, not larger ?
10-06-2012, 07:23 PM
#59
Three Wheelin'
i've read this in a book about turbocharging written by corky bell...i believe we can take this man's word
in order to keep the front mounted intercooler efficiency at the maximum that it can perform, the exposed surface(yes the opening for it) must not be smaller than 1/4 of the frontal area of the intercooler.
i've designed my intercooler setup based on that book...it works very well
in order to keep the front mounted intercooler efficiency at the maximum that it can perform, the exposed surface(yes the opening for it) must not be smaller than 1/4 of the frontal area of the intercooler.
i've designed my intercooler setup based on that book...it works very well
10-06-2012, 11:10 PM
#60
Rennlist Member
So you're not talking about limiting the opening, you're saying not to limit the opening. My point was that the factory saw fit to only have the smallish opening for the factory setup. When people want to add a vented nose panel it will probably hurt, not help. However once you start to modify the car and put in a large fmic as on the Red car in post #55 you can see that there is a lot less restriction for this setup. What is your take on this?