Longevity, RPM, and fuel efficency.

F

Finisterre

Senior member
 Buxton Narnia
I wore out my Passat engine by trundling around in too high a gear.
It was a mistake, I gained a couple of pence a mile and it cost me ten grand to replace.
I have been trying to keep the Z4 engine (N46) between 1800 and 2500rpm when cruising in traffic.

Is this too low?
Is it profligate?
Am I being too cautious about engine wear or fuel consumption?
 
:? too high a gear? As in, keeping the rev's too low for a given speed?

I have not heard if this before. As long as you're not labouring an engine you should be fine....

I regularly trundle around town with the zed in 6th gear at 1,100rpm. Usually at this speed i'm doing 35mph ish....
 
On the e89 with the econo guide thingy running it has me changing up at 1500 rpm and tbh the six has bags of low down torque so I can't seeing it doing that much harm.

What's isnt good for an engine is too much load, i.e. low torque and high vehicle mass, I presume that the Passat wasn't a diesel then
 
Adamski said:
:? too high a gear? As in, keeping the rev's too low for a given speed?

I have not heard if this before. As long as you're not labouring an engine you should be fine....

I regularly trundle around town with the zed in 6th gear at 1,100rpm. Usually at this speed i'm doing 35mph ish....
Click to expand...

Dito! No labouring no problem!
 
cheers sars - I will just play that back to check I have the right end of the stick.

pootling along, in third 1450rpm
slight increase in speed to 1500 rpm
the dash indicates fourth would be good.
you change up.

Exactly the sort of info I wanted - when does it suggest dropping a gear?


And yes -the passat was the 18 petrol turbo and I wore out the main bearings but managed 42mpg. 5 better than they claimed was standard. It was false economy. :)
 
Running any engine at too low revs will knacker it far more that thrashing it. I've always been a bit heavy footed, but I've never had a big engine repair bill.Spent plenty on brakes and tyres over the years, but no major mechanicals. Sounds like the cash you saved on fuel was spent on a new engine.Let the motor spin a bit, i's better for it.
 
To be fair the 1.8T and 2.0T engines have a reputation for weak main bearings but problems are usually caused by hard use or tuning, rather than labouring. There are lots of aftermarket uprating kits to for the bottom ends on these motors but the oil pumps were none too clever either which doesn't help.
In the old days before knock sensors you could certainly bash a set of big ends by flogging in too low a gear due to pre-ignition (knocking), but on a modern engine I doubt that flogging in a low gear would be the ruination of it - If it makes you feel better Fin' I had two engines in a Golf before I gave up on VW/Audi :cry:
 
Should I stop pottering about in 6th at 30mph then?

The engine isn't struggling, and I never ask for max torque pulling away at that speed in 6th.

You guys have me worried :cry:


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Adamski said:
Should I stop pottering about in 6th at 30mph then?

The engine isn't struggling, and I never ask for max torque pulling away at that speed in 6th.

You guys have me worried :cry:


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Click to expand...

not at all, I potter about all the time 6th at 30. what theyre all saying is when the car is kangarooing you should change down!
 
Adamski said:
Should I stop pottering about in 6th at 30mph then?

The engine isn't struggling, and I never ask for max torque pulling away at that speed in 6th.

You guys have me worried :cry:
Click to expand...

That's what I like about the 3.0l six, it's so lazy with lots of grunt low down, so at 30 I'm in 5th and it will still pull smoothly, try that in the old 1.8T engine and it will labour.
 
Yeah was driving my dad's diesel passat the other day. Anything below 1,300rpm is labouring the engine. Means constant gear changes, despite it being diesel with ample torque. It's the 1.9 tdi 130 I think....


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Ive always shifted up in my scirocco around 1500 - 2000 never anymore unless im really gunning it. No problems in 4 years and this is on an engine 20+ years old which has an unknown mileage history!
 
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