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Old 12-27-2012, 10:51 PM
LalaRay's Avatar
LalaRay LalaRay is offline
Location: Maryland
Join Date: Dec 2011
Posts: 899
Mein Auto: 03 ///M5
Originally Posted by geargrinder View Post
Yeah. Sounds like just the kind of thing a ricetard would say.

On an old school motor the issue would be that you could tune hotter for winter air density and temps but would have to be more careful about detonation and exhaust temps in summer when the air is hot and thin.

Anything from 90's on will have IAT (intake air temp) and engine operating temp and MAF (mass air flow) sensor and ambient atmospheric and/or manifold air pressure (MAP) and then compensation constants and tables that ensure the car runs in all conditions as those things go up and down. A good tune and ECU/DME can totally handle all that for you.

Shizzy tuners only know the main fueling / timing tables and don't know the more sophisticated and nuanced stuff which is where you'll hear about guys getting great peak dyno numbers but then when the weather changed or he started driving it on the street the car wouldn't idle right or wouldn't make power or threw CEL's etc.

Only reasons I can think you might "need a seasonal" tune would be:
  • If the tuner didn't KNOW how to or didn't bother to tune the temp or barometric compensation properly for either a speed-density or mass-air type system
  • Running speed-density but the ECU doesn't HAVE an atmospheric pressure sensor or MAP to tell it if barometric is up/down.
  • If the car is running speed-density or alpha-N system pushed to limit so that seasonal barometric changes knock it out of range of trim

Assuming your tune would still be on OEM DME then it will be totally fine. It's a MAF based system with IAT sensor. If the tuner really does crazy stuff and sets you up speed-density with the OEM DME then you might have an issue since it doesn't seem to have an ambient or MAP pressure sensor but that's highly unlikely.

Oh and BTW even if the ric3rs tune did need seasonal changes, he's chosen poorly if he doesn't have a setup these days where he can reflash the tune back and forth himself a la shark injector / etc. etc. style - SO many tuners now use tools where you can flip yourself back and forth from stock to tune and more and more allow you to buy a second tune so you can have street-tune and track-tune for instance and this would be just the same... shouldn't be a big deal even if you have to do it...

ok thanks youve been great help Anyone happen to know how many hours a Headers install for a 540 is ?
2003 ///M5. ~ Jet Black/ Le Mans Blue

RK Supercharged @ 501wheel horsepower
Supersprint Headers,
Evolve Alpha N Tune,
CNS lightweight dm flywheel/Spec clutch,
ST coilovers,
Eibach Rear Sway bar/Beast Power Brackets,
Drilled slotted Rotors/Akebono Euro pads,
Magnaflow 14816 Mufflers

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