87GT Posted June 1, 2010 Report Share Posted June 1, 2010 Help me end an argument. Is shifting gears in low rpms 2-3k regularly in a manual car bad for the transmission? Yes or no and why do you say so? What is a good range for best fuel economy without damaging anything? For the record this is a normal car with no modifications to it. Quote Link to comment Share on other sites More sharing options...
FyrhzrdGT Posted June 1, 2010 Report Share Posted June 1, 2010 If its bad for your car my car is fucked. What is the argument for that being bad for the trans? The Mercedes diesel guys shoot to keep their rpms under 3k all the time for mpg. Its kind of hard to tell you where the optimal shift point is not knowing the car. Different cars are efficient at different points and you have different gears to help the motor at times. Keeping your car in top gear at no revs isn't necessarily what you want. My car will move up a hill at 700 rpms in 5th at WOT lugging the shit out of it. Is that better for mpg than using a lower gear? Doubtful. Net effect, shifting bad for the trans? In my opinion no. Where to shift for mpg, what was the SAT answer - "not enough information" Quote Link to comment Share on other sites More sharing options...
Alex L. Posted June 1, 2010 Report Share Posted June 1, 2010 Powershift all the time. Quote Link to comment Share on other sites More sharing options...
Clifford Automotive Posted June 1, 2010 Report Share Posted June 1, 2010 Well to answer your vague question. It will not damage anything. Quote Link to comment Share on other sites More sharing options...
TTQ B4U Posted June 1, 2010 Report Share Posted June 1, 2010 Help me end an argument. Is shifting gears in low rpms 2-3k regularly in a manual car bad for the transmission? Yes or no and why do you say so? What is a good range for best fuel economy without damaging anything? For the record this is a normal car with no modifications to it. Not sure how it would damage the tranny. The only harm I can think of in terms of shifting is if you were to "lug" and engine at low RPM. I know in the MS3 it's easy to be lazy and not downshift since the engine has plenty of torque, but it's not good to got WOT at under 3k rpms as that puts a lot of stress on the internals. Common case is if I'm cruising around at 35mph in 5th, it's best to pass in 3rd vs flooring it in 5th. You'll feel the engine lug prior to rpms climbin/boost coming on if you don't downshift. Quote Link to comment Share on other sites More sharing options...
Richard Cranium Posted June 1, 2010 Report Share Posted June 1, 2010 I'm also unsure about the trans. I can't think of anything that would be damaged. However, I did hear a story a while back the the Nascar crew chiefs were pissed when their driver would lug the engine by driving slow in too high a gear. Since the oil pump is run by the RPM of the motor you are stressing the motor while providing less oil pressure than normal. Quote Link to comment Share on other sites More sharing options...
Tripleskate Posted June 1, 2010 Report Share Posted June 1, 2010 I idle around town all the time. As long as you're not putting much load on the engine, it's fine. If I'm trying to get good MPG, 2k shifts are where I'm at. Quote Link to comment Share on other sites More sharing options...
Benner Posted June 1, 2010 Report Share Posted June 1, 2010 I'm also unsure about the trans. I can't think of anything that would be damaged. However, I did hear a story a while back the the Nascar crew chiefs were pissed when their driver would lug the engine by driving slow in too high a gear. Since the oil pump is run by the RPM of the motor you are stressing the motor while providing less oil pressure than normal. Most pumps are have variable pressure rates. They use a spring to adjust pressure so even if your at idle you can still have the same oil pressure as redline. Hell I watched a 06 GTP blow the Oring out from the filter multiple times at idle. The oil pump got lodged at wide open so it was pushing full pressure. Quote Link to comment Share on other sites More sharing options...
RyM3rC Posted June 1, 2010 Report Share Posted June 1, 2010 well, a race car designed to run between 7k-9.5k rpm isn't going to make good oil pressure at 2k, duh. Horrible comparison. No, shifting at 2000rpm isn't going to hurt anything. Street cars are designed to have plenty of oil pressure at low RPM, because that is where they're designed to spend their time. I've had a few SBC's apart that I know I "lugged" the hell out of (4th gear off-idle acceleration, etc.) and there was no damage or abnormal wear to the bearings like all internet nimrods like to think there would be. Shift early, and enjoy your car lasting longer. Less rpm = longer life. Oops, got a little off-topic. No, it isn't going to hurt your stock, production-car transmission. Unless you stick a Big-block behind a 901 trans, no harm done. Quote Link to comment Share on other sites More sharing options...
ImUrOBGYN Posted June 1, 2010 Report Share Posted June 1, 2010 I'd say it depends on the car. As long as youre not causing it to chug, I don't see it being a problem. Quote Link to comment Share on other sites More sharing options...
Littleguy Posted June 1, 2010 Report Share Posted June 1, 2010 I'd be more worried about not putting the clutch pedal all the way down between shifts for regular/long-term damage. Quote Link to comment Share on other sites More sharing options...
Mr. Jones Posted June 1, 2010 Report Share Posted June 1, 2010 Seriously, what kind of retarded question is this ? Quote Link to comment Share on other sites More sharing options...
87GT Posted June 1, 2010 Author Report Share Posted June 1, 2010 Seriously, what kind of retarded question is this ? Eat me Jones. For the rest of the posters if I am driving around where the speed limit is 35-45 I will stay in 4th gear. I will shift in low RPMs like 2k at most until I get to 4th. That is how I was taught to drive a stick from my dad and I haven't damaged any transmission or clutches to date and neither has he. If I need to go faster then I will downshift as needed. Someone I know says that damages the transmission because it is such a low RPM. They really couldn't tell me why other then "because it is low RPMs". He normally will drive in 2th or 3th gear and says your car should always be at least 3K RPMs. I told him that doesn't make sense in a car that has 6 gears. At 65mph in 6th gear you are not at 3K RPMs. Even an automatic transmission car won't act in this manner if driving conservatively. Are we correct or incorrect? For example purposes pick any generic 4 cylinder manual car and go off that. Quote Link to comment Share on other sites More sharing options...
RyM3rC Posted June 1, 2010 Report Share Posted June 1, 2010 Your friend doesn't know what he's talking about. Don't worry about it. Quote Link to comment Share on other sites More sharing options...
FyrhzrdGT Posted June 1, 2010 Report Share Posted June 1, 2010 Your friend is wrong. Open your owners manual, it will tell where they think the optimal shifts are. Even my automatic mercedes has a chart that plots shift speeds based on throttle position. Quote Link to comment Share on other sites More sharing options...
Avenger1647545502 Posted June 1, 2010 Report Share Posted June 1, 2010 Ideally, the optimum shift point for acceleration will take you from your HP peak to the torque peak (or close to it)...IDEALLY. Real world is a little different, of course. My old Duster loved being in 5th at 35. But that motor makes its peak torque at 1700rpm. Quote Link to comment Share on other sites More sharing options...
Draco-REX Posted June 1, 2010 Report Share Posted June 1, 2010 Bad for the transmission? No. No reason why it should be. If anything, it'll be easier on the synchros since the difference in revs between one gear and the next will be less. I don't know what your friend seems to think goes on inside a transmission, but there's nothing that has trouble operating at low speeds. Bad for the engine? Maybe, in a small way, if you are lugging the engine all the time. But I don't think it really matters.. The Colorados at work like to tool around at 1.5K rpms. Quote Link to comment Share on other sites More sharing options...
Mensan Posted June 1, 2010 Report Share Posted June 1, 2010 Punch your friend in the mouth and tell him to shut the fuck up. Also, tell him to have a spare engine on hand for when his blows up. Quote Link to comment Share on other sites More sharing options...
Cordell Posted June 1, 2010 Report Share Posted June 1, 2010 Your friends car will wear out parts much faster then yours. Tell him that parts spinning faster wear out faster, does he think that an automatic car would hold the RPMs up like that? Quote Link to comment Share on other sites More sharing options...
87GT Posted June 1, 2010 Author Report Share Posted June 1, 2010 Punch your friend in the mouth and tell him to shut the fuck up. Also, tell him to have a spare engine on hand for when his blows up. LOL you are crazy. Quote Link to comment Share on other sites More sharing options...
Farkas Posted June 1, 2010 Report Share Posted June 1, 2010 Your friend is clueless. Quote Link to comment Share on other sites More sharing options...
Avenger1647545502 Posted June 2, 2010 Report Share Posted June 2, 2010 Betcha he downshifts because "compression braking extends brake pad life"... Quote Link to comment Share on other sites More sharing options...
Ringo Posted June 2, 2010 Report Share Posted June 2, 2010 Depends what you are driving... i would have to say not at all. However, I would just redline it all day long Quote Link to comment Share on other sites More sharing options...
87GT Posted June 4, 2010 Author Report Share Posted June 4, 2010 Betcha he downshifts because "compression braking extends brake pad life"... If I told him I skip gears in the jeep when getting onto highway he would divorce me. Quote Link to comment Share on other sites More sharing options...
AWW$HEEET Posted June 4, 2010 Report Share Posted June 4, 2010 Tell him to get an auto and stfu. PS tell him to never join CR. Quote Link to comment Share on other sites More sharing options...
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