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It's hard to see the numbers , your picture is very small . I'll be adding BMC or K&N filters shortly too
 

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Discussion Starter #5
Sorry about that ive noticed screen shots come out like crap. [email protected] The 60 ft was 1.70. Slope -0.41. DA was 2204. First and only try it pulled like a misile
 

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Discussion Starter #7
I disconnected the exhaust valve vacuum lines in the R engine bay. Described in the valve disconnect thread
 

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interesting I would think the more free flow of the exhaust from like 4k to redline would be a benefit. I know I feel the need for some back pressure in the lower rpm range. Might just be what I've seen with a aftermarket exhaust.
 

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Discussion Starter #9
There is NO power loss. It rips. Same on a gt3. You unplug the valves and get more smooth and instant power delivery. See below dyno on a gt3 from obsessed garage, top curve is disconnected valves. The gains arent this big on the R8 but the stock muffler provides enough restriction to get gains. It sounds glorious too. Valves are for VWs
251AD0D3-4CC7-4196-B663-EA030EB81130.jpg
 

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Discussion Starter #11 (Edited)
No gen 1 gt3. Just to illustrate the back pressure myth with a stock muffler. More power with slightly less restriction.
 

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No gen 1 gt3. Just to illustrate the back pressure myth with a stick muffler. More power with slightly less restriction.

I get it the stock muffler probably creates enough back pressure. With Capristo I found that open valves at the lower range just doesn't take off as fast. In all actuality all it probably does is get the B**** down the street to come out and yell at me :)

Still waiting on her to call the cops like she says she's going to do every time.
 

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Discussion Starter #13
I get it the stock muffler probably creates enough back pressure. With Capristo I found that open valves at the lower range just doesn't take off as fast. In all actuality all it probably does is get the B**** down the street to come out and yell at me :)

Still waiting on her to call the cops like she says she's going to do every time.
Lmao. Yes with a full exhaust on an NA engine it might end up less sharp down low unless it has an x pipe. Actually with the stocker and valves open all the time plus the intake it feels like I put an exhaust on the car already... tho it doesnt scream alot more at the top end. Good enough for me... for now. Lets see if some intake tubes add some more juice and sound. I still think there is enough room in the stock exhaust system to cram in some more air in the motor through a better plenum
 

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What was the point of removing the vacuum lines ? valves can be opened anytime with the switch on the steering wheel
 

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They still close from low rpm to like 4k.
No , they don't . if you hit the exhaust switch it puts the exhaust in sport mode ,valves stay open all the time even at idle
 

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Discussion Starter #17
I would hope youre right but at least on porsche theyre open at idle and close at around 1800 and open again around 4k. When they were connected on the R8 i was getting a tonal change around 1800-4200 even in sport mode that went away after the disconnect (just like my 911). It also feels like the throttle sharpened. Maybe its placebo. I should have mounted a gopro back there but I figured empirically it would be equally labor intensive just to cap the vacuum line and I believe it made a noticeable difference in sound and response during regular driving.
 

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Lmao. Yes with a full exhaust on an NA engine it might end up less sharp down low unless it has an x pipe. Actually with the stocker and valves open all the time plus the intake it feels like I put an exhaust on the car already... tho it doesnt scream alot more at the top end. Good enough for me... for now. Lets see if some intake tubes add some more juice and sound. I still think there is enough room in the stock exhaust system to cram in some more air in the motor through a better plenum
I have a x pipe on mine still needs that initial back pressure. When I went supercharged I did notice that initial loss of response. The smooth tubes do give you a bump and they make a different sound kinda like hearing the air get sucked in the lower ranges. BMC filters brand new and clean give you a good bump in the power. Get some prefilters it was the only way to keep it that responsive.
 

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Discussion Starter #19
Good to know. What year and model do you have?
Also what type of pre filter and where is it installed?
 
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