I was driving my uncles '03 M3 today and he was telling me to make sure i keep it above 2000RPM so the engine doesnt lug and put stress on the bearings...that made me wonder if i was actually doing more harm than good to my engine when i am 'pussying' it around like i normally do.

My car has the 2.73 gears and obviously the 700r4, so under normal driving conditions it rarely goes over 2000 RPM. If im cruising at like 40-50 MPH it stays under 1500RPM and i basically need to exceed 75 MPH to get over 2000RPM. basically my question is, am i hurting my engine by pussying it around and keeping the RPMs really low. I mean if i truely am hurting it, how else could it be driven to abide by the speed limit and be in the proper RPM range??

 

I dont know **** about cars but even i know the M3 makes all its power up top...the damn thing revs to like 7k. It makes sense to me that it might cause problems over time if you drive it under 2000 RPM. Now i wanted to see if that applied to my car..which it may not because my car doesnt rev as high, a completely different powerband, and has lower (numerically speaking) gears.

 

It wont hurt anything and it'll burn less gas. You don't have much of a choice in the matter since you've got an automatic trans.

 

when breaking in engines you want to keep the rpms up to get good lubrication but other than that you shouldnt "have" to keep the rpms up. Also if your car never ses anything over 2k rpm for a long time you can end up with some major carbon deposits but if you drive the **** out of it once in a while itll be fine.

BTW sb/bb chev engines arent r!cers they make power all around.

 

Your uncle is kinda right, you do not want to lug and engine at to low of an rpm in to high a gear.

In DOHC engines and higher rpm small engines you want to keep the rpms up so that the engine makes a decent amount of torque. With V8's, larger engines and pushrod motors this does not really apply unless your driving around in 6th gear or OD at 1200 or less rpm.

This is partially why big motors get just as good or better mpg than smaller engines. You can spin them slower and run higher gears.

 

amen! I hate driving my winter car, (DOHC 3.4L, 200HP, but nothing before 3500RPM!)....

very slick response nasty. This forum keeps me constantly amused.

If you keep the engine at low rpm, with a high load, on say, your old '76 ford truck, pulling your boat, up a hill, then yea, bad idea, for many reasons, auto trans is cooking, waterpump is spinning slowly, etc.... otherwise? nope, dumb idea.

Take your uncles advice, keep that M3 above 5000RPM all the time, bag the crap out of it, tell him it's 'cuz he told you to. Then wonder why the thing has it's "bearings stressed" before the warrantee is up....

 

With a 700-R4 I wouldnt worry much about it. The trans will shift/unlock the TCC long before it becomes a problem. With a manual it can be an issue, although Im sure driving it at 1500 rpms wouldnt be an issue. Its driving it at 800 rpms up a steep hill in 5th is what would really do some damage.

 

when the car is lugging (and you know it if it is) you are hard on bearing, also if I remember right it causes things to get a little warm inside the combustion chamber leading to possible detonation and stuff.

least if I remember right


but then again this is real lugging it where you know your lugging it

just giving it barely any load without any real lugging going on under low rpms and again LOW LOAD that is another story

 

Alrite thats all i needed to know.

 

You sure?

Bogging the motor causes increase bearing wear. Also causes the piston to scrape the cyl wals more as the rod deflects, and you end up with reduced oil pressure.

It's also prone to detonation, especially the mustangs. My buddies GT does the same thing if you cruise around under 2k and try to accel. You can hear it almost as bad as my vortec truck. (both standard transmissions).

-- Joe

 

The factory must really push these motors hard. My ford has the same problem. Does it constantly and its so loud I can hear it echoing off of walls and stuff. EGR and everything is working correctly.

Im surprised the vortec has detonation issues. Those heads are much less prone to detonation then my old smog heads where. There was almost no quench, compression, swirl, or anything with those heads, so they needed tons of timing just to run halfway decent. Ive yet to see (knock counts) or hear any detonation out of my 350 at high MAP, low rpm. I guess it all depends on how the tunes set up.

 

His car is an automatic, it's not going to bog bad enough unless there's something wrong with the trans or lockup. Under no load when he's cruising it wont hurt a thing.

 

In case some of you were wondering, I have taken some of my own valuable time to edit the non-tech personal attacks out of this thread. The offenders know who they are, and you all know better as well.

Stop wasting my time and stick to the Board rules.

 

Sorry, great one.

 

Yep. If I'm going up hill I need to maintani at least 2500+ rpm else it pings.

Both of my buddines mustangs do the same thing, and I've heard from others as well. Now adding you to the list, seems to be a common thing.

-- Joe

 

my brothers 4.6L ford does that too... spooky...