Can we get a verdict on those stacked exhausts yet?
02-27-08, 08:07 AM
#46
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Ok, going off your Wiki page, #1, those tail pipes cannot be be considered diffussers. #2 Adding a set of crome tail pipes does jack for a cars performance.#3 here is a quote from that page.
So the muffler and exhausts has nothing to do with the diffusser.
I would love to know the physics behind how a set of tail pipes reduce back pressure? And just for the record a normally aspirated car needs a certain amount of back pressure to perform (remember this car is not a turbo).
I think you are confussing what diffussers are???
So the muffler and exhausts has nothing to do with the diffusser.
I would love to know the physics behind how a set of tail pipes reduce back pressure? And just for the record a normally aspirated car needs a certain amount of back pressure to perform (remember this car is not a turbo).
I think you are confussing what diffussers are???
I think that the Stacked Quad Tips on the IS-F double as a rear diffuser at those higher speeds...
The back side of those tips are shaped into a collector design and I am certain that they are catching air from underneath the car which helps exit it through the tips and through the mesh that is incorporated into that very same area...
At the SAME TIME those same collectors also assist in making sure the exhaust waste properly exits that area and doesn't get caught up in the rear bumper ..
In other words routing / diffusing the air flow out of that area..
This is what I came up with..
I will see if our good friend "flipside909" can get us the exact Lexus Tech / Spec info behind this design to confirm what I am explaining or it might just come out that this is purely cosmetic (which I Highly doubt)
Joe Z
Last edited by Joe Z; 02-27-08 at 08:22 AM. Reason: typo
02-27-08, 11:13 AM
#48
"diffusers" work by channeling airflows. In order to generate any meaningful benefit you need to cover and close up the underside of the car and make it smooth. These fake tips are not going to have enough airflow to be function as "diffusers". It's a pure cosmetic and a not a good looking one at that.
Nope.. I am not confusing anything...
I think that the Stacked Quad Tips on the IS-F double as a rear diffuser at those higher speeds...
The back side of those tips are shaped into a collector design and I am certain that they are catching air from underneath the car which helps exit it through the tips and through the mesh that is incorporated into that very same area...
At the SAME TIME those same collectors also assist in making sure the exhaust waste properly exits that area and doesn't get caught up in the rear bumper ..
In other words routing / diffusing the air flow out of that area..
This is what I came up with..
I will see if our good friend "flipside909" can get us the exact Lexus Tech / Spec info behind this design to confirm what I am explaining or it might just come out that this is purely cosmetic (which I Highly doubt)
Joe Z
I think that the Stacked Quad Tips on the IS-F double as a rear diffuser at those higher speeds...
The back side of those tips are shaped into a collector design and I am certain that they are catching air from underneath the car which helps exit it through the tips and through the mesh that is incorporated into that very same area...
At the SAME TIME those same collectors also assist in making sure the exhaust waste properly exits that area and doesn't get caught up in the rear bumper ..
In other words routing / diffusing the air flow out of that area..
This is what I came up with..
I will see if our good friend "flipside909" can get us the exact Lexus Tech / Spec info behind this design to confirm what I am explaining or it might just come out that this is purely cosmetic (which I Highly doubt)
Joe Z
02-27-08, 12:38 PM
#49
I have no problem with the disconnected pipes. If Lexus says the reason is to help with downforce who am I to doubt that. I seriously doubt they'd screw around with their reputation on something like that....
02-27-08, 02:25 PM
#50
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Be careful with that assumption. Those engineers could be the same ones who claimed the wing on the Supra was good for 66 lbs of downforce - it's well known to be zero downforce at any speed now.
02-27-08, 03:17 PM
#51
Lexus Champion
The back side of those tips are shaped into a collector design and I am certain that they are catching air from underneath the car which helps exit it through the tips and through the mesh that is incorporated into that very same area...
At the SAME TIME those same collectors also assist in making sure the exhaust waste properly exits that area and doesn't get caught up in the rear bumper ..
In other words routing / diffusing the air flow out of that area..
This is what I came up with..
I will see if our good friend "flipside909" can get us the exact Lexus Tech / Spec info behind this design to confirm what I am explaining or it might just come out that this is purely cosmetic (which I Highly doubt)
Joe Z
At the SAME TIME those same collectors also assist in making sure the exhaust waste properly exits that area and doesn't get caught up in the rear bumper ..
In other words routing / diffusing the air flow out of that area..
This is what I came up with..
I will see if our good friend "flipside909" can get us the exact Lexus Tech / Spec info behind this design to confirm what I am explaining or it might just come out that this is purely cosmetic (which I Highly doubt)
Joe Z
02-27-08, 03:37 PM
#52
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If you are saying those tips are doubling as diffussers, I really have to question that, look at the pic below. If there is any air passing through those gaps it would be so minimal that you would have a hard time detecting it. The design of this bumber/diffusser is to have the air go around the tail pipes so the exhaust can flow freely, it is not the tips that are the diffussers.
02-27-08, 04:29 PM
#53
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02-27-08, 05:44 PM
#54
02-27-08, 06:39 PM
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02-28-08, 08:05 AM
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I am sorry if I wasn't clear in my earlier posts.
The Exhaust diffusers have nothing to do with air flow under the car, and they produce no downforce. They do however smooth the exhaust flow, to eliminate lift from the exhaust as it exists the vehicle at high speeds. Lexus found that in high speed testing, that the billowing effect from the exhaust caused rear end lift, and skittishness in the handling. The diffusers eliminate this effect.
I work for Lexus, and am trained by Lexus. I hope that this clears things up.
The Exhaust diffusers have nothing to do with air flow under the car, and they produce no downforce. They do however smooth the exhaust flow, to eliminate lift from the exhaust as it exists the vehicle at high speeds. Lexus found that in high speed testing, that the billowing effect from the exhaust caused rear end lift, and skittishness in the handling. The diffusers eliminate this effect.
I work for Lexus, and am trained by Lexus. I hope that this clears things up.
02-28-08, 09:20 PM
#58
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02-28-08, 09:42 PM
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02-29-08, 07:22 PM
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I am sorry if I wasn't clear in my earlier posts.
The Exhaust diffusers have nothing to do with air flow under the car, and they produce no downforce. They do however smooth the exhaust flow, to eliminate lift from the exhaust as it exists the vehicle at high speeds. Lexus found that in high speed testing, that the billowing effect from the exhaust caused rear end lift, and skittishness in the handling. The diffusers eliminate this effect.
I work for Lexus, and am trained by Lexus. I hope that this clears things up.
The Exhaust diffusers have nothing to do with air flow under the car, and they produce no downforce. They do however smooth the exhaust flow, to eliminate lift from the exhaust as it exists the vehicle at high speeds. Lexus found that in high speed testing, that the billowing effect from the exhaust caused rear end lift, and skittishness in the handling. The diffusers eliminate this effect.
I work for Lexus, and am trained by Lexus. I hope that this clears things up.
You work for Lexus? Doing what, if I may ask?