vented air box
01-31-2006, 02:04 AM
#47
Addict
Rennlist Member
Rennlist Member
If you increase exhaust output (Ott Xpipe, RMB),why wouldn't it make sense to allow for more air to be sucked in? Makes sense it seems. Sounds like a puzzle for Doctor Ott to me. At speed can't see air temp being an issue. Am I wrong?
Harvey
Harvey
01-31-2006, 11:59 AM
#48
928 Collector
Rennlist Member
Rennlist Member
Well Harvey there's the elixir of life ..... the point ... the eternal secret .... The air intake is NOT MORE with holes in the 928 box. It is LESS. And it is HOTTER. The intake is designed in a way that allows enough flow at any revs, open pipes or not. There is SUPPOSED to be some vacuum there. And there is supposed to be a very particular air FLOW onto and through the filter. The enemy of FLOW is TURBULENCE. That is the secret. I've spent years talking with Louie and Z and other incredibly knowledgeable people about this, and Louie and I tested my car repeatedly on a dyno. More turbulence == less flow == less air into the engine. Simply put, without the intake tubes as they were designed you WILL DEFINITELY LOSE torque.
01-31-2006, 12:35 PM
#49
Originally Posted by FlyingDog
I think it was Steve Pappas that determined that if the car is moving, the air temp in the tubes and air box is the same as ambient. As somebody else mentioned, I think Louis Ott determined that there is no pressure drop through the tubes and airbox.
01-31-2006, 01:52 PM
#50
Racer
Join Date: Oct 2005
Location: middle of nowhere, USA
Posts: 309
Likes: 0
Received 0 Likes
on
0 Posts
If we were suffering an air starvation issue or a restriction in the air box system, simply porting the box could solve this problem, however ingesting hot air will create a loss in air density thus having an impact on power. Since we really don't suffer a great restriction in this area, especially on stock motors, porting the box and ingesting the warm air is most likely a break even situation, or a minor loss since you are getting more air, but if that air is thinner, is it really more air? The ports will allow more induction noise out and sound cooler so if that's what your after, go for it.
Drawing hot air from the engine compartment is not impossible or cause for earth shattering decrease in performance, many cars over the years drew all of their air from inside the engine bay, but drawing fresh cooler outside air is an improvement. The base of the windshield is a high pressure area at speed which can be taken advantage of to both bring in cooler thus denser outside air and at speed there will be some ram air effect from the higher air pressure there. This is why late 60's and early 70's Camaro and Chevelle cars got the cowl induction hoods to pressure feed cooler outside air to the engine. These systems were designed with vacuum actuated doors to only open in situations where the engine was at speed, and did include air cleaners with drain ports to deal with ingesting rain water though Im not sure how effective they were at this, but I have had the cold outside air freeze the carburetor in a 70 Oldsmobile 442 Ram air car in the winter which was quite fun to put it mildly. Ended up driving the rest of the way home with a towel crammed in the openings on the hood, now that was a classy looking mod!
Prior to the ram air and cowl induction hoods these cars had dual inlet air cleaners with hoses running to holes in the front bumper or ducts under them which is just like our setup.
Now even the non performance oriented factory cars draw their air from outside the engine bay to eliminate the reduction on performance and efficiency when the hot air is ingested. If engineers from all walks of automotive life have decided that everything from a V12 Ferrari to a 4cyl Yugo were better off getting the cooler air from outside the hot engine bay it is definitely worth the effort.
Just my $0.02
Drawing hot air from the engine compartment is not impossible or cause for earth shattering decrease in performance, many cars over the years drew all of their air from inside the engine bay, but drawing fresh cooler outside air is an improvement. The base of the windshield is a high pressure area at speed which can be taken advantage of to both bring in cooler thus denser outside air and at speed there will be some ram air effect from the higher air pressure there. This is why late 60's and early 70's Camaro and Chevelle cars got the cowl induction hoods to pressure feed cooler outside air to the engine. These systems were designed with vacuum actuated doors to only open in situations where the engine was at speed, and did include air cleaners with drain ports to deal with ingesting rain water though Im not sure how effective they were at this, but I have had the cold outside air freeze the carburetor in a 70 Oldsmobile 442 Ram air car in the winter which was quite fun to put it mildly. Ended up driving the rest of the way home with a towel crammed in the openings on the hood, now that was a classy looking mod!
Prior to the ram air and cowl induction hoods these cars had dual inlet air cleaners with hoses running to holes in the front bumper or ducts under them which is just like our setup. Now even the non performance oriented factory cars draw their air from outside the engine bay to eliminate the reduction on performance and efficiency when the hot air is ingested. If engineers from all walks of automotive life have decided that everything from a V12 Ferrari to a 4cyl Yugo were better off getting the cooler air from outside the hot engine bay it is definitely worth the effort.
Just my $0.02
Last edited by EB338; 01-31-2006 at 10:33 PM.
