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Fourdoor 11-07-2005 09:37 PM

Quick Time Performance down pipe!
Holly mother of God is this thing loud with the electric butterfly valve open on the cutout!

I will be dyno tunning with it open in the morning, see if it gives me false knock with all the noise. If not, I expect to have as good of numbers as a car with a full turbo back exhaust. If that works out well for me at the end of the tunning sesion I will shut the valve and do one last run to see how much power difference there is with it closed and all of the exhaust flow going through the stock cat back exhaust.

Any bets on weather false knock makes me get better dyno results with the valve shut?

Any bets on power loss (or gain) with the valve shut?



Cosmo 11-08-2005 07:37 AM

You will see maybe 2-3 hp difference. That's what most people say.

Oh, and most people also report that the valve leaks after a few months...

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Fourdoor 11-09-2005 03:03 AM

[QUOTE=Cosmo]You will see maybe 2-3 hp difference. That's what most people say.

Oh, and most people also report that the valve leaks after a few months...[/QUOTE]

On 93 octane I made 218.4 with the cutout open, and then after shutting the cutout made 201.8 A difference of 16.6 WHP. Keep in mind this is with the stock cat back exhaust and stock muffler on the car. I can see that you would get very little gain with a cutout on a car that has a full 3 inch exhaust system.

On 100 octane unleaded (half and half mix of 93 octane pump gas, and MS-109) I made 233.3 with the cutout open, and 212.9 with it shut. A difference of 20.4 WHP.

Max boost on these runs was 15.4, and that is with the wastegate solenoid duty cycle maxed out.

Does the quick time down pipe make it harder to reach target boost?



DEMENTED 11-10-2005 11:59 AM

let us know how this works for you. maybe you can put the stock exhaust back on and test that too hehe

Fourdoor 11-10-2005 02:23 PM

Hey guys,

I found out what my boost control problem was!

On the dyno I was only getting a bit over 15 psi, found out this was due to the dyno ramping up too fast compared to actual speed ramp up on the street. Dyno was set up so that it took 12.5 seconds to run from 2000 RPM up to 6000 RPM in 4th gear. In reality on the street 2000 RPM to 6000 RPM takes 20.4 seconds.

The maps pretty much max out the stock boost solenoid and I am getting 16.5 psi in 3rd gear falling to 13.3 and 17 psi in the mid range in 4th gear falling to 14 psi by 6300 RPM.

Anyone wants my stage 2 with catless up-pipe 93 octane and 100 octane maps, PM or e-mail me :)


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