Right now I'm at a standstill with someone on another message board.

The original poster says while driving a manual trans car, that shifting at lower RPMs contributes to more wear on the engine than shifting at a higher RPM.

He’s saying that his sister drives a stick and she shifts around 2000 RPM repeatedly. He swears this is going to ruin the engine because it presents more wear on the engine than if she was to shift at ~3000 RPM or more. I’m trying to explain that the load on the engine is only relative to how much she’s trying to accelerate.

He’s under the impression that anytime you accelerate, you should hold the RPMs until the car won’t accelerate anymore while keeping the same throttle position. I told him that regardless of RPMs increasing the load is what causes the engine to wear. It doesn’t matter if you’re at 2000 RPM or 5000 RPM, the load is what causes the wear. If anything, higher RPMs can cause increased wear time.

I understand that the engine won’t have as easy of a time accelerating at lower RPMs because it may not be near peak TQ, but as long as the car is accelerating (I.E. not taxed enough so it won’t) then there should be no increase in wear, correct?

I guess the main question is...... does shifting to sooner cause more wear than shifting later? I understand that if you cause the engine to jerk by dropping the RPMs so the engine doesn’t even have the power to accelerate is bad, and that’s what I’m trying to tell him. But just accelerating at low RPMs is OK, right?

What I did was... well here’s more of a description. My wife and I also have a 1993 Mazda MX-6 (the other message board is based on the MX6). It has a 160HP, 2.5L V6, with a 5 spd transmission and a 7000 RPM redline and the car weighs ~#2700. Normally I shift into 5th going ~35 mph if I don’t need to accelerate quickly. The other day I did that, and just out of curiosity (due to his claims) I floored it. The engine was spinning ~ 1500 RPMs when I did. Granted the car didn’t exactly pin me against the seat, but it accelerated fine until I was up to ~50 mph, where I let off the throttle and continued to cruise. Does this cause more wear on the bearings and rings than if I was to downshift to 3rd and bring the RPMs up to say 4000 RPM? I know the car will accelerate quicker, but is keeping it spinning slower making it wear faster?

I would think not, since the engine is made to always be presented with a load regardless of RPM, correct?

I sure hope I’m explaining this right so someone can understand what I’m trying to find out. I’m not asking if causing the engine to jerk or stall is bad. IMHO, that’s obvious because you’re obviously presenting a greater load on the engine than what it’s made to handle.

Thanks in advance, and if I’m wrong please say so. Nothing’s ever stopped any of you before.

 

My advice is to never argue with a fool...innocent bystanders cannot tell who is who

Unless you're lugging the engine, no wear will occur any faster at a lower RPM.

Wear will accelerate with higher engine speeds.

Plain and simple.

Ask your foe what will last longer..

An engine running 3000 RPM's until it dies...

Or an engine running 5000 RPM's until it dies...

 

OK. Thanks.

I just want to make sure. There's a difference in what you think you know, and what you DO know, ya know?

And if anyone else would like to comment, feel free. I guess I'd also like to know "why" to further my knowledge. I've got my own reasons, but that doesn't make them right.

 

My Dad had a 1980 datsun 200sx......that car never saw over 2000rpm.....I mean he was in 4th in about 100ft 200,000 miles later it uses 1 quart between oil changes...:hail:

Higher RPM's create more friction...more heat....more wear. Look at what it takes to build a motor that will rev 10,000 rpm More than 10 passes......
I think this guy you are talking about has been talking to his grandfather...the old sbc needed rpm's to make power.....today we know that isnt so........."Hey Dad why ya driving so fast?" "Just burning out some carbon son"..

 

Well, obviously high-revs will put a strain on the engine.. but... I would imagine that low-RPM shifting would put quite a strain on the engine.

Think of riding a bike. You keep it in a certain gear until you can move comfortably into another one. If you tried to go from 1st to 21st gear, you could do it, but your legs would be a LOT more sore by the time you got up to speed.

A lot of people also say you should keep an auto car in drive until you reach highway speeds, because in OD the tranny's making up for the power lost at lower RPM's and it puts a strain on the tranny and shorten's it's life, but I've mostly heard this from the guys without OD, like th350 owners.