Can we get a verdict on those stacked exhausts yet?
02-25-08 | 05:32 PM
#31
Lexus Connoisseur
Joined: Mar 2001
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From: USA
It's sad because I sat next to some of them at the 2nd IS-F Carmel Valley Press Event back in October. I was there sitting next to the guys from Super Street, Sport Compact Car, Luxury Modified & Exotics and ahem Autospies. My cohort from my.IS, Jruhi4 was with me throughout that event.
02-25-08 | 06:31 PM
#32
The point is,
the exhaust would have been better if it wasn't integrated into the bumper. It would have been better if it was free-flowing, resting underneath the bumper, and had chrome tips on the ends. It just seems more seamless, more mechanical that way. The bottom line is that the tips are fake, regardless of other more expensive cars having the same thing. And really? Most if not all of those higher end cars have exhasts integrated into the bumper, which is why, obviously, they have fake tips. And I think that's lame.
the exhaust would have been better if it wasn't integrated into the bumper. It would have been better if it was free-flowing, resting underneath the bumper, and had chrome tips on the ends. It just seems more seamless, more mechanical that way. The bottom line is that the tips are fake, regardless of other more expensive cars having the same thing. And really? Most if not all of those higher end cars have exhasts integrated into the bumper, which is why, obviously, they have fake tips. And I think that's lame.
02-25-08 | 07:51 PM
#33
Lead Lap
Joined: May 2006
Posts: 639
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From: WA
Why would you have to lower the mufflers? Look at the exhaust as it is now. If you cut the bottom off that goes beneath the exhaust tips and connect the tips to the actual muffler, it'd be inegrated underneat the bumper, nestled in the crevices of the exhaust cut-outs. I think that would look pretty damn nice, actually. Sort of like the regular 250 and 350 exhaust, but it'd be DTM.
02-26-08 | 08:43 AM
#37
Driver School Candidate
Joined: Feb 2008
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From: Arizona
The quad diffusers help to reduce billowing from the exhaust, that could cause lift above 140mph. Lexus found that connected exhaust tips caused exhaust billowing, and that by giving a small gap between the actual tips and the diffusers actually smoothed exhaust flow and eliminated lift. Your engine at that speed is producing a ton of exhaust, which needs to be managed.
Connected? No. Funtional? Yes.
Connected? No. Funtional? Yes.
02-26-08 | 10:53 AM
#38
Lead Lap
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From: WA
The quad diffusers help to reduce billowing from the exhaust, that could cause lift above 140mph. Lexus found that connected exhaust tips caused exhaust billowing, and that by giving a small gap between the actual tips and the diffusers actually smoothed exhaust flow and eliminated lift. Your engine at that speed is producing a ton of exhaust, which needs to be managed.
Connected? No. Funtional? Yes.
Connected? No. Funtional? Yes.
Link? I didn't know this.
02-26-08 | 11:52 AM
#39
Lexus Fanatic
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From: Under an IS F since 2008
*************
For what its worth.. I dug up some more helpful info...
A true high-performance engine relies on outstanding support systems and thoughtful engineering that touches every detail. The Lexus IS F's unique stacked quad diffusers, for example, make more than a visual statement. They play an important role in a high-performance exhaust system by reducing backpressure. The stainless steel exhaust system starts with tubular exhaust manifolds and integrated catalysts. Next come dual 2.4-inch diameter front pipes that are joined before a pre-muffler and 2.7-inch single center pipe, after which the system splits into two 2.1-inch pipes and enters dual 16.8-liter mufflers.
Enjoy
Joe Z
Originally Posted by Lexus Tech Info
A true high-performance engine relies on outstanding support systems and thoughtful engineering that touches every detail. The Lexus IS F's unique stacked quad diffusers, for example, make more than a visual statement. They play an important role in a high-performance exhaust system by reducing backpressure. The stainless steel exhaust system starts with tubular exhaust manifolds and integrated catalysts. Next come dual 2.4-inch diameter front pipes that are joined before a pre-muffler and 2.7-inch single center pipe, after which the system splits into two 2.1-inch pipes and enters dual 16.8-liter mufflers.
Enjoy
Joe Z
02-26-08 | 01:42 PM
#40
Driver School Candidate
Joined: Feb 2008
Posts: 11
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From: Arizona
I learned about the stacked diffusers at the Lexus IS-F Champion training in Las Vegas, a few weeks ago. No link, but I had a chance to pick the brains of the tech guys, and drive the snot out of this car. I learned lots of good stuff about this beast.
Last edited by IS-Freak; 02-26-08 at 01:48 PM.
02-26-08 | 06:50 PM
#41
Lexus Champion
Joined: Feb 2008
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From: Japan
A true high-performance engine relies on outstanding support systems and thoughtful engineering that touches every detail. The Lexus IS F's unique stacked quad diffusers, for example, make more than a visual statement. They play an important role in a high-performance exhaust system by reducing backpressure. The stainless steel exhaust system starts with tubular exhaust manifolds and integrated catalysts. Next come dual 2.4-inch diameter front pipes that are joined before a pre-muffler and 2.7-inch single center pipe, after which the system splits into two 2.1-inch pipes and enters dual 16.8-liter mufflers.
02-26-08 | 07:54 PM
#42
Lead Lap
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From: WA
I hate to say it, but it says nothing in this quote about the disconeced exhaust tips reducing back preasure? It says that the unique stacked design of the the exhaust reduces back preasure, but nothing about the tips not being connected playing a part. I think more proof is needed on this topic.
Exactly.
02-27-08 | 01:07 AM
#44
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The 2 sentences say... and I re-quote
The Stacked Tips back side are shapped into a funnel type design which I would say is another term for "diffusers"...
See here for more detailed diffuser definition..
http://en.wikipedia.org/wiki/Diffuser_%28automotive%29
Bottom: Bottom-view. Top: Side-cut-view, the red circles mark the front and rear diffuser respectively
Now for the same pics we have seen over and over again...
Pay close attention to the Diffusers / Tips attached with two bolts to the bottom of the bumper..
(If he had a pic from the mufflers looking out of the tips, it would better show how this works.. I'll see if i can get some.. )
The Lexus IS F's unique stacked quad diffusers, for example, make more than a visual statement.
They play an important role in a high-performance exhaust system by reducing backpressure.
They play an important role in a high-performance exhaust system by reducing backpressure.
See here for more detailed diffuser definition..
http://en.wikipedia.org/wiki/Diffuser_%28automotive%29
Bottom: Bottom-view. Top: Side-cut-view, the red circles mark the front and rear diffuser respectively
Now for the same pics we have seen over and over again...
Pay close attention to the Diffusers / Tips attached with two bolts to the bottom of the bumper..
(If he had a pic from the mufflers looking out of the tips, it would better show how this works.. I'll see if i can get some.. )
02-27-08 | 06:05 AM
#45
Lexus Champion
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From: Japan
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.
The muffler and exhausts make way for the diffuser
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???
The muffler and exhausts make way for the diffuser
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???