With the ported head/bigger cam/bigger carb/bigger manifolds, my idle has a little of what you guys call rumpitty rump
How's your idle?
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My Mazda was probably typical old-school I4, in that it ideally idled at ~850 RPM, but its idle speed was rather inconsistent (because no feed-back idle-speed control in '81), and slight variations in speed could make a disproportionate difference in noise level, depending on various resonant frequencies. At its best, reasonably smooth, considering its size, weight, etc. Turning on headlights or stepping on the brake slowed the idle significantly, as did adverse temperatures. Pretty much all the same comments applied to my earlier Subaru with its 1267 cm³ horizontally opposed four.
Prius normally never idles much, except when cold. When it stops, it's quieter than any idling V8 or V-12. When it's cold, it idles at around 1200 RPM (not particularly constant, oddly), and makes considerably more noise than my niece's '13 Corolla (which has the non-hybrid version of the same engine) does when idling. I suspect that's because the Prius engine mounts and exhaust are tuned less for quiet idle than for unobtrusive cruising at its typical lowish engine speeds under moderately high load.
Coasting at speeds above ~45 mph, the Prius engine is rotated (as opposed to runs!) at 992 RPM, which is undetectable over road and wind noise.
Prius normally never idles much, except when cold. When it stops, it's quieter than any idling V8 or V-12. When it's cold, it idles at around 1200 RPM (not particularly constant, oddly), and makes considerably more noise than my niece's '13 Corolla (which has the non-hybrid version of the same engine) does when idling. I suspect that's because the Prius engine mounts and exhaust are tuned less for quiet idle than for unobtrusive cruising at its typical lowish engine speeds under moderately high load.
Coasting at speeds above ~45 mph, the Prius engine is rotated (as opposed to runs!) at 992 RPM, which is undetectable over road and wind noise.
The 3.6 Pentastar in both my vehicles is super smooth.
'05 Tahoe, 5.3. 144k mi. Idle is fairly smooth with the occasional stumble? Vibration? That trends with the oxygen sensor info. From what I understand it's due to some variance between injectors. Doesn't bother me enough to justify the cost of replacing injectors with a more closely matched set being that the vehicle otherwise runs great.
The G37, despite being a V6, is quite smooth at idle. It's not a quiet engine, generally speaking, but it does idle smooth enough compared to some of the things I've driven over the years.
02 Ford Ranger 3.0 auto...has always had stumbles/shakes, then at other times perfectly smooth.
94 Ranger 4.0 manual...has a bit of a shake, not terrible though. It may have worn mounts.
94 Explorer 4.0 auto... very smooth idle. Lifters tap when first started, but when it's warmed up it's the quietest and smoothest running of my trucks. Go figure. It has an EGR valve, which the other trucks don't, I've wondered if that might help somehow.
94 Ranger 4.0 manual...has a bit of a shake, not terrible though. It may have worn mounts.
94 Explorer 4.0 auto... very smooth idle. Lifters tap when first started, but when it's warmed up it's the quietest and smoothest running of my trucks. Go figure. It has an EGR valve, which the other trucks don't, I've wondered if that might help somehow.
1MZFE in a 2000 camry-- very nice
Various prii-- junk. Too high, and when warming up they sound like they're running out of gas when they shut off for hybrid reasons.
Ford 300-6-- good on paper but accessory noise ruins it.
BILs V6 2012 Ford fusion-- absolutely amazing
Various prii-- junk. Too high, and when warming up they sound like they're running out of gas when they shut off for hybrid reasons.
Ford 300-6-- good on paper but accessory noise ruins it.
BILs V6 2012 Ford fusion-- absolutely amazing
If your engine can do this, then yes it has a smooth idle. None of the cars I ever had could.
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Nick1994
$100 site donor 2024
The Sonata isn't real smooth. Decent though. HPFP on these are really loud.
The Camry has the 5SFE 2.2L, not a smooth motor.
The Jeep is pretty smooth, the occasional minor stumble though which I think is because it's a straight-six. But for a Jeep 4.0L it's really quiet and really smooth.
The Camry has the 5SFE 2.2L, not a smooth motor.
The Jeep is pretty smooth, the occasional minor stumble though which I think is because it's a straight-six. But for a Jeep 4.0L it's really quiet and really smooth.
Originally Posted by SnowDrifter
'05 Tahoe, 5.3. 144k mi. Idle is fairly smooth with the occasional stumble? Vibration? That trends with the oxygen sensor info. From what I understand it's due to some variance between injectors. Doesn't bother me enough to justify the cost of replacing injectors with a more closely matched set being that the vehicle otherwise runs great.
Seeing something similar on my 02 Silverado. Glad I'm not the only one feeling occasional stumble when sitting at a light.
01 Tundra V8 idle kicks up to ~800 RPM when A/C compressor kicks on and ~550 when off.
'05 Tahoe, 5.3. 144k mi. Idle is fairly smooth with the occasional stumble? Vibration? That trends with the oxygen sensor info. From what I understand it's due to some variance between injectors. Doesn't bother me enough to justify the cost of replacing injectors with a more closely matched set being that the vehicle otherwise runs great.
Seeing something similar on my 02 Silverado. Glad I'm not the only one feeling occasional stumble when sitting at a light.
01 Tundra V8 idle kicks up to ~800 RPM when A/C compressor kicks on and ~550 when off.
The 5 cyl Volvo is very smooth at idle, can't feel it, but exhaust and intake let me know it's running. The flat twin Airhead has a rocking couple that will shake the front wheel side to side.
Originally Posted by MCompact
All of my cars have a smooth idle; the 2er ha a throaty exhaust so you fee a bit of a rumble- but the idle itself is smooth.
The Clubman had a bit of a rough idle until I replaced the spark plugs, as the PO never changed them and they were 14k miles overdue.
That's a weird fact with my 6.1. It has the most interesting factory dual exhaust with 2.875 pipes and a huge single "suitcase muff with two little resonators. Nearly silent inside at all speeds, but with quite a bellow at full tilt. Strange bass resonance at idle that is quite loud yet you cannot hear it inside. My car came with a nifty set of matched Bosch injectors which Trav told me long ago cannot be beat.
All of my cars have a smooth idle; the 2er ha a throaty exhaust so you fee a bit of a rumble- but the idle itself is smooth.
The Clubman had a bit of a rough idle until I replaced the spark plugs, as the PO never changed them and they were 14k miles overdue.
That's a weird fact with my 6.1. It has the most interesting factory dual exhaust with 2.875 pipes and a huge single "suitcase muff with two little resonators. Nearly silent inside at all speeds, but with quite a bellow at full tilt. Strange bass resonance at idle that is quite loud yet you cannot hear it inside. My car came with a nifty set of matched Bosch injectors which Trav told me long ago cannot be beat.
Originally Posted by Miller88
My old Focus would vibrate pretty bad at idle. After I got the hydraulic engine mount replaced, I put a poly transmission mount in. Shift feel was great, though!
This is our Focus to a "T" .. Was ok but after the cylinder head change the catalytic converter guts I think came loose and it makes quite a racket now. It has a heavy duty transmission mount also.
The 6.0L I guess is smooth, defiantly not quiet but it's a big engine in a van so that's expected. The 3.0L Ford is smooth but the injectors are noisy. The 3.9L Dodge lol nothing smooth about that.
My old Focus would vibrate pretty bad at idle. After I got the hydraulic engine mount replaced, I put a poly transmission mount in. Shift feel was great, though!
This is our Focus to a "T" .. Was ok but after the cylinder head change the catalytic converter guts I think came loose and it makes quite a racket now. It has a heavy duty transmission mount also.
The 6.0L I guess is smooth, defiantly not quiet but it's a big engine in a van so that's expected. The 3.0L Ford is smooth but the injectors are noisy. The 3.9L Dodge lol nothing smooth about that.
Originally Posted by Pew
Freaking horrific, but it is a 3 cyl engine with an inherently unbalanced designed that is made tolerable with a dual mass flywheel and super soft mounts.
At some rpm it must smooth out a bit. I almost bought a triple tractor and triple snowmobiles always sound great, but they idle at 1+k or so and are 2 stroke.
Freaking horrific, but it is a 3 cyl engine with an inherently unbalanced designed that is made tolerable with a dual mass flywheel and super soft mounts.
At some rpm it must smooth out a bit. I almost bought a triple tractor and triple snowmobiles always sound great, but they idle at 1+k or so and are 2 stroke.
The 3.7L I5 in my Colorado has a rough idle for about 30 seconds. The seatbelt light starts to blink as the engine begins to run smoothly.
my 2016 frontier starts at 1200 -1300. but takes 3-4 min to droop to 700. so i just bang it into gear and it doesnt seam to hurt anything. my old Chrysler 727 and 904. if you go straight to R from P some will bang hard. of the servo is set wrong. so the thing to do is pull the lever all the way to L first. then to R.
Originally Posted by IndyIan
Originally Posted by Pew
Freaking horrific, but it is a 3 cyl engine with an inherently unbalanced designed that is made tolerable with a dual mass flywheel and super soft mounts.
At some rpm it must smooth out a bit. I almost bought a triple tractor and triple snowmobiles always sound great, but they idle at 1+k or so and are 2 stroke.
The shakiness is generally unnoticeable at the 750/800rpm idle unless you're specifically trying to feel for the vibrations, but pop the hood and the engine shakes worse than a Harley.
Originally Posted by Pew
Freaking horrific, but it is a 3 cyl engine with an inherently unbalanced designed that is made tolerable with a dual mass flywheel and super soft mounts.
At some rpm it must smooth out a bit. I almost bought a triple tractor and triple snowmobiles always sound great, but they idle at 1+k or so and are 2 stroke.
The shakiness is generally unnoticeable at the 750/800rpm idle unless you're specifically trying to feel for the vibrations, but pop the hood and the engine shakes worse than a Harley.
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