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For those U.S. Diablo owners out there - have you removed the factory installed restrictors from the air boxes and installed K&N's? If not, this mod is essential and very easy to do. All you need is a dremel and some fine sandpaper and about an hour or so. Made a big difference with my SV. I also just had the mufflers removed from my Burtoni exhaust and replaced with straight stainless pipes - huge sound! Maybe I should change my name to LOUDER V12...
 

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Are you speaking of the restrictors that are in the end of the air duct where it meets the air box? Don't have them in mine :)

You replaced your muffler with a test pipe? Or did you mean cats?
 

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Sounds interesting, but I must ask my names sake if this is the thing to do... Wiz"?

Also, is it over reacting to be concerned about the K&N's allowing more dirt in the engine, and just how much difference does it really make?
 

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From what I've heard from at 2 very informed resources, cutting of the restrictors actually lose 1-2 hp at high rpms. One of these sources even dyno-tested it. FWIW, both said it does sound "cooler" with it cut off. I thought of cutting mine just for the sound. I figured, I could spare a horse or two. However, once you cut the restrictor, there is no turning back. I guess you can alway buy a new airbox.
 

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I lost faith with K&N after having extensive problems with one of their air filters and my supercharged 85 Corvette. The oil from the K&N will collect on the mass airflow sensor during longer drives and eventually make the car run like $##@ - simulating a bad throttle position sensor.

The solution is to turn the car off for 3 minutes, wait for the MAF to go through it's cleaning process (heats the wire to burn off contaminants) and then you're good to go again. Not hard, a but a royal PITA on a long trip.

Many other people have had this problem, to the point where K&N has put a page on their website to disavow themselves of any responsibility. http://knfilters.com/faq.htm#6 (Question 7). They are technically correct in that their product doesn't DAMAGE the MAF, but it does make the car run like **** until it's cleaned.

I should note that the filter was coated with oil per their instructions. It was not over-coated or soaked as their tech kept trying to claim...
 

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I'm still not clear about the muffler.... You pulled the muffler and went straight pipes? No way?

BTW ... are you familar with the guy in MDR who has a Diablo kit car? There's a guy with a Murci who lives in the same complex and has made several posts about how loud that car is. Don't want you to be mistaken with that guy :)
 

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wiz357 said:
From what I've heard from at 2 very informed resources, cutting of the restrictors actually lose 1-2 hp at high rpms. One of these sources even dyno-tested it. FWIW, both said it does sound "cooler" with it cut off. I thought of cutting mine just for the sound. I figured, I could spare a horse or two. However, once you cut the restrictor, there is no turning back. I guess you can alway buy a new airbox.
As mentioned, mine were removed by previous owner. I have also been told by competent mechanics the same thing, you can lose power at top end. They are not restrictors, but difusers that stop wind turbulence. Same concept is used on jet engines. Rather than having the wind flying down the engine at 500mph the difusers guides the air into a proper angle for the fan blades to spin and get the correct bite. But on the other hand any loss of power would be minimal and I doubt anyone here would notice while driving.
 

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Not Restrictor

As Already Said They Are Not Restrictor (why Would Lambo Install
Restrictirs???) They Are To Help With Air Flow, Dont You Think That
Lambo Did More Then Just A Little R/d With The Air Box.
 

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Jeff,

Thanks for your input!!!

AllanLambos powergains BS has run rampant on the web for several yrs now and there were not enough "Professionals" helping owners to overtalk his constant yelling and static about his latest "magic formula"..

Let's face it....most people "want to believe" that "magic" exists. I for one however love hearing that refreshing song of reason.

:)
 

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jeffoc said:
As Already Said They Are Not Restrictor (why Would Lambo Install Restrictirs???) They Are To Help With Air Flow, Dont You Think That
Lambo Did More Then Just A Little R/d With The Air Box.
Perhaps it was made to insulate the roaring of the engine...
The car has to match the noise law which is really not that simple.

Does somebody have a picture of these so called restrictors?

I had some problems with the K&N installed in my QV (same as on the diablo), they broke since the support in the filterbox is not existing, now I have BMC-Filters installed. http://www.countach.ch/bmc.html
 
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