WG 2.7 CRD rev limit when locked in gear

[octanepwr]

Hi all

I have noticed if I lock the transmission in 1 it seems to rev out to like 5000 revs (or maybe more) i.e. past redline.

Does it not have a limit when you lock in 1 (or other gears)? Seems odd that it will let itself go that far past redline.

Keen to hear other's experience.

Thanks

Lewis

[Deezelweazel]

It is not very smart to rev a Diesel- the redline is there for a reason.
You got 4 valves per combustion chamber. At high rpm your valve springs can start to oscillate and break.
The rpm is limited electronically to 4700 up 4900 per manual. We do also have a so called pre-runing needle. That means if the gauge shows 5000 rpm it is as an example only 4800 in real enginr speed ....

Rule:
Don't run a Diesel in the RED Line! It's not built for that.

That does not answer your question- which is a stupid one.

[octanepwr]

You seem to have missed the point lol, or perhaps I wasn't obvious enough...

I don't want it to rev out, but it does... When you are planting your foot on a hill offroad and don't want it to shift up - that is the purpose of locking it in gears. It should auto govern at a safe RPM for obvious reasons. I would expect the redline which is of course after peak power rpm.

If the manual limits it to 4700-4900 then something is wrong with mine as i have recorded 5000 rpm in historical data from scanner... however if that is 200 rpm off through to the scanner (not just the gauge off by 200) then I suppose that aligns with what you are saying...

[JeanLuke]

On hillclimbs, just leave it in drive and the problem doesn't exist. The gearbox logic is very good, and will hold gears on hills in low range. About the only time I shift manually is holding low gears going down hills.

Seriously, if you are hitting over 4000rpm on a hillclimb either pick the next gear or slow down. Otherwise you will be taking your engine home in a bucket very soon.

Sent from my moto g( plus using Tapatalk

[Deezelweazel]

Don't get it wrong

The manual is not the stick shifter. There is no stick shifted WG. The manual is the Factory Service Manual.

But I wasn't kidding when you rev it. Diesel components are made way heavier than gas components. Therefore the valve springs do not like high revolutions, they are simply stiffer.
If you need to rev the engine offroad, than something is wrong anyway. Spinning tires to get rid of mud? Okay. But anything else with a high reving diesel engine? Could leave you stranded with a serious engine fail. If the valve spring breaks the valve will hit the piston- and changing a cylinder head on a diesel... If you can bite the price, then go for it.

With a Diesel engine you can almost perform everything with moderate engine speed. You do have a torque monster. No need for high engine speeds in the redline area. You got full torque of 400NM at 1750 rpm!! So why the excess engine speed?

[Deezelweazel]

"octane Power"- huh, those ricerkids...
cetane is the way to go

hehehehe

[octanepwr]

You guys can't help yourselves hahaa... I never said I wanted to do 5000rpm, I don't know why it has been assumed I WANT to do this lol

I have 4wd for years in other diesel trucks and found holding gears useful for certain terrain in ups and downs/undulating/technical when you don't want it to go up a gear when you let off for a corner in a hill climb or something. Manufacturer should limit revs to safe speed - all other autos I have had do that...

I agree >4000rpm is bad. With this truck I won't lock it in gear, but I am still not sure my question was really answered haha. At as you say this truck has more torque/power than older diesels I have had before

p.s. yep sig name is from generation ago, and I did have a 400hp RX7 once... before kids haha