Basically I’ve never driven a manual before. I know, I know, I’m a total loser. Anyway, sometimes I’d slow down and downshift from 4th to 3rd in my 5 speed automatic 2003 touring 350z because it feels like it accelerates a lot faster in 3rd. Note that I’m keeping way within the RPM limits but is driving in 3rd gear consistently on a highway bad for the engine? Don’t care about gas consumption, just the car that the engine is constantly around like 5k RPM could wear out the engine faster?

I know it’s a question so basic so some you may be inclined to ignore it as if a child were to ask you what’s 2+2 but I’m a part of the Z community and I’m trying to keep the Z number from decreasing on account of another blown engine lol

btw its only 43k miles well maintained all around NA with some bolt-ons.

 

wHY

 

Well, running an engine consistently at 5k RPM does increase the wear factor but you're still well within limits. As was asked though, why? For acceleration (or downhill compression braking), it's fine but for the most part, makes sense to keep it in Auto mode or for spirited driving, using the gearbox as needed; but to consistently run at that engine speed is not necessary nor recommended for longevity. If you do like to run at that speed consistently, would recommend paying very careful attention to gauges and oil changes.

 

accelerates much faster in 3rd than in auto that’s pretty much why, like the feel, but I hear ya. Probably won’t do it too often or even consistent anymore

 

I think what you mean to say is the acceleration in speed is more immediate in manual mode, which is true. Not that the car is any faster in Auto vs Manual because obviously the engine and gearing are identical.
The main advantages of manual mode are faster shifts, clearly faster than a manual 6 speed (the reason new cars are going to paddles) and engine braking for hair-pin turns. The torque curve goes flat at 6K hence the 6.5K redline.

Keeping the engine close to the redline for extended periods of time is like cheating death- you can get away with it but one day it will catch up with you. If that's your style, go for it and have fun!