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Engine, Exhaust, Transmission Discuss the FR-S | 86 | BRZ engine, exhaust and drivetrain. |
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03-08-2021, 01:44 PM | #29 |
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Gotcha, I did know that but forgot about it. I assume the effect of this to the secondary cat is lessened and not to worry about?
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03-08-2021, 08:24 PM | #31 | |
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Quote:
For purpose, as others already wrote, to heat up cats sooner, as cats need to be heated up to working temps to do their job efficiently, and such design and tune specifics is what's needed for car to meet more modern emissions standarts that take measure emissions from cold start. Those specific timings are much bigger contributor of extra loudness/noise of cold start then rpms alone, which probably you can easily check by yourself with comparing cold start noise level vs that of warmed up engine at same higher rpms. And tuning out cold-start in ecu tune means also adjusting those cold start timings, not just rpms. |
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03-09-2021, 12:42 AM | #32 |
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No change in valve timing actually, i know everybody read in steve' posts that there is overlap during cold start
there is no overlap, the cold start noise is just retarded ignition timing, a slightly higher set rpm and a slightly more open throttle body EDIT: oh, and very very retarded Direct inection angle , that creates stratified combustion together with the earlier spray of the port injectors Last edited by tomm.brz; 03-09-2021 at 11:29 AM. |
The Following User Says Thank You to tomm.brz For This Useful Post: | Dzmitry (03-09-2021) |
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