DECAT exhaust without a TUNE. Is it safe? - Page 3 - Rennlist - Porsche Discussion Forums


DECAT exhaust without a TUNE. Is it safe?


Old 03-17-2017, 11:48 PM
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Chris, the Bosch ECU doesn't "look" at the new aftermarket exhaust per se.. But with the flow improvement due to the reduction of backpressure the turbochargers spool up quicker and faster which yield BOOST.. Boost that is available earlier in the RPM curve.. The boost ramp rate will be linear and tied to the TIGHT A/R of the hot side/turbine. The Bosch ECU is measuring the airflow across both MAF's AND pressure measured by the MAP sensor. You will get "free" boost pressure/lag reduction = early RPM Torque. However, at around 3800 to 4000 RPM's the Bosch ECU will clamp down on load output... VNT nozzle ring/actuator output/duty can be logged to show us what the ECU is doing.
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Old 03-18-2017, 02:49 AM
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Very interesting info from posters in this thread regarding the ECU effectively capping power. I am loosing boost pressure post throttle after some recent mods. Could the ECU have a hand in that? I don't want to derail this thread with my situation, but if those of you with great knowledge of the ECU could take a look at my thread, I would appreciate it.
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Old 03-23-2017, 03:16 PM
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Originally Posted by [email protected] View Post
I can guarantee that is not true. Been beaten to death but I will 100% be there for those who claim to be experiencing it. It's a little too convenient of a claim in certain cases. #exhaustwars lol

But we will never take that stand. Just provide top notch service and guarantee the product. I have yet to have an actual unhappy client. Not to mention we have the fastest VTG cars in the states and some overseas running Kline! Lines are always open ; )
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Originally Posted by Ruskiy View Post
You're my go to guy, Sambo . As you can tell I am trying to kill two birds with one stone here.
A. Not messing with ECU
B. Power gain, nice sound and no drone

As soon as I'm ready, will be sending you a PM. I also seen some folks complaining about power loss on KLINE exhaust as oppose to Europipe/FVD etc... So I'll need to look into that. But I think that's only on versions with a CAT.
Don't believe the "exhaustwars" hype. When I am looking for big power builds for my clients, my first call is to Sam to review the game plan and get some of his turbos and intercoolers
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Old 03-24-2017, 09:06 AM
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Originally Posted by TT Surgeon View Post
That's only in 997.2 cars with the Siemens's ecu. 997,1 cars with the Bosch unit don't suffer this fate.
Makes no sense to me. I have the EP1 with an FVD tune. My friend with same identical car with the same exhaust and he claims the cars are different but not by much. Again, not to hijack and go off on a tangent but does an OTS tune make that much power? Maybe Sam can advise. By the way, no problems with my FVD tune and maybe a 50 hp gain as claimed is what my friend is describing. Actually his car seemed to be slower in response to mine, that I did notice immediately.
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Old 03-24-2017, 12:48 PM
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Cheers guys.

atcbi5 do you OTS Cobb or a factory map? All cars are a little different when you start adding hardware. Mileage, fuel, climate and several other things can create variances in how the car runs or simply it's consistency and how the car reacts to the tune and temperature. But tuners are even more different. Different tunes on the same unit can vary by quite a bit just depending on how aggressive one goes or the approach. Especially when taking advantage of specific hardware and it's quality/limitations.

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