Si Need to ask a theory question about a purposely higher idle...technical

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How do the gurus think this would effect things like higher vacuum assist through the crank case ventilation and its detriments to the system or positive effects increasing vacuum on the piston rings etc. Also seems to assist with a faster speed to operating temperature. Helps with vibration from the aftermarket engine mounts. Generally better driveability with less throttle apply needed for initial take off. Would also in theory and application prevent lower oil pressure conditions in hot idle. I have my car idling now around 1050 up from factory 720-750. My thinking is that the OE reduces idle speed to bare minimum to increase mpg ratings at the cost of whats mentioned above (strain during compressor turn on for a/c etc). My car seems to be MUCH happier overall with a bump in idle speed. The threshold for the dash vibration using the hasport mount is 1k rpm like religion. So I bumped to just above and the car drives butter smooth now along with quicker warm up and quieter idle (ie: less valvetrain noise possibly due to more oil flow etc)

Thoughts? Opinions? Any possible angles I havent considered?

Really aside from insane city driving the car will hardly be at idle anyway so..........

Also completely got rid of the feeling of very very slight missing at idle when only at 700 rpm or so....

Looking to review technical results of increasing idle speed.
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Toolz

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I have been thinking about this also!, you explained it perfectly..thanks!
 

IronFusion

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if you look at the idle plots the ECU has stored, you will learn something There are at least, or generally, two RPM vs temp idle targets. Warm/cold, same for restarts; they are temp vs rpm and the temp is ECT.

Only thing you are doing is increasing wear. If the prescribed 0w-20 is used, there is no need to cycle oil. You are elevating the energy of the exhaust by idling at higher rpms. When the state of the engine changes to acceleration, you will be much closer to the threshold of the ECUs Boost Table for more boost. You have a modification, so you have a different circumstance for wanting to idle faster. Sure, you will not have vibrations. But should you have them? Does the manufacturer of the mount advise of the vibrations at factory idle? You might consider concern for losing nearly 5% of the rpm band (ego-centric CVT here; 6500rpm is red) that your vehicle is intended to operate in, that you no longer have use in or intact diagnostic integrity. If you need warranty service or something else for a commingling issue that begins to present at factory idle, you now have static that will complicate things. I would contact the mfg and ask for assistance. You may need to reinstall. I have a mildly modded OTS tune and have purposely found the min idle my car can do, and downset the ECU to below the 750 you mentioned.
 
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I'm not cvt and can reflash the idle tables at will. The target idle still puts the car in "idle" condition no matter the number. Within reason of course.
 

caspar21

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wear difference would be minimal effectively over a couple hundred k miles unless you let it idle for a high %of the lifetime usage of the car.

i brought my idle up a bit too to avoid the missing sound at 700ish rpm.
 


IronFusion

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Just tweaked mine down to 630-640 at higher, but attainable ECT. I experience a lot of heat soak, so I have been tuning to counter with a streak of efficiency and reduced thermals. My preferred fuel is rock steady; it's consistent in my vehicle. I don't have an unstable high temp idle. Plus... CVT. Not lighting the world on fire from a dead stop. For the torque limits of the powertrain, CVT shines with unbroken applied load. Staying in the power.
 

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IMO the absurdly low factory idle on these cars is absolutely for fuel efficiency. I bumped mine up to 900 a/c off 1000a/c on. There was a slight dip in economy (I idle alot more than average though) by maybe .5mpg over 8 hrs of city driving. I raised mine up because it was vibrating even on factory mounts. The engine sounds and feels terrible at 650rpm, I cant see why they'd run it so slow unless shooting for max efficiency. Especially in the CVT cars where the vibration is so bad the passenger seat shakes when stopped/brake applied.
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