Low rpm while cruising bad?

[tHe_sTiG]

Hi there mates,

I've got a VZ Executive 175 kw 4 speed auto, I do a mix of urban and highway driving on the way to and from school.
Highway speed limit is 80 km/h, urban is 60km/h . At both speeds, the rpm sits at about 1400 rpm (at 4th gear for 80km/h, 3rd gear for 60km/h). Would that be considered... well... not good? I haven't got much knowledge on this, but I think 1400 rpm would be considered labouring the engine... and therefore bad for fuel economy, engine and transmission? Should I shift down to 3rd and 2nd instead (2000 - 2500 rpm respectively)?

I don't know if anyone's considered this, but I've been told that a car runs at it's best when engine speed is near to maximum torque (2600 - 2800 rpm I think in my case).

Thanks in advance.

 

[impulsive]

Less revs less fuel. The engine iS not working. If the car was under enough load it would shift back.

 

[Verynice]

If you maintain a certain speed at that rpm, it should be ok. As long as you don't labour it.

 

[impulsive]

Auto gearbox, he won't labour anything...

 

[tHe_sTiG]

Alright, I'll drive it as I normally do I also noticed that if I bring it up to 80 myself. It'll shift into 4th at that speed, but if I allow the cruise control to automatically bring it up, it'll stay in 3rd. Any ideas there?

 

[impulsive]

Yeah the car likes to 'relax' so to speak.. It's almost like a cruising Gear to reduce engine noise and high revving, then when you want to go faster it shifts down for acceleration. in cruise control the car doesnt shift at all does it?? But if it does I'm guessing because if yo have cruise set @ 70 and it goes into 4 th then I dare say it would have to change up/down to maintain speed, thus changing constantly. 3rd gear probably is a low enough gear for good acceleration but 4th is too high

 

[tHe_sTiG]

Thanks for the info I'm mainly interested in fuel economy and developing any habits to keep the car in best condition, while enjoying driving it. I'm planning to keep it for a long time. I've heard a lot of people talking about the 2 hole mod. Will it give me extra power (if any) without:
1. Doing any long-term damage to the car
2. Increasing fuel consumption
3. Cause any problems when I take it to Holden for regular servicing

Just want to make sure it's a trouble-free mod

 

[Big Red VF-SII Go-kart]

It is imaginary to think the engine is labouring; the slightest inkling of any labour and the transmission will kick down. Ditto when it is at cruising speed — the gears will change as the engine/tranny interface sees fit. If you don't like what the engine is doing, apply short, firm pressure to the pedal and that is the cue for the tranny to move "now, not later".

A 2-hole mod may be (theoretically) "good for performance" but will not get you single-digit, long-term fuel economy of around 7.6-8L/100km (auto wagon, highway/freeway driving; some VZ utes commonly get 6.5L/100km, no mods). For that you need to refine driving habits namely avoiding city/urban low-speed driving when frequent up/downshifts occur. A tank of premium ULP now and then is beneficial but at foundation level it is driving habits that make in impact.

 

[Hangman]

Auto gearbox, he won't labour anything...

+1.

It's an auto, it knows what to do.

 

[richardpalinkas]

2 hole mod adds a bit of balls to the engine note, especially if you have a stock exhaust, really makes it deeper. i noticed in the sv6 when i did the 2 hole mod that fuel consumption dropped from 8 ish to 6.5 highway from gold coast to brisbane, but because i liked the extra induction noise, ended up using more fuel lol