TD42T Driving style advice Up hill

With an aftermarket gauge for coolant I can see the temp rise slowly on slight hills on highways. (which I know is normal as its under constant load)
From what I also read its not the fact it climbs but how soon the cooling system gets the temps back down to a good place is an indication of a good cooling system as any car under load (hills,towing sand etc) will rise.



This got me thinking .

Even steeper hills


What is the best way to get coolant temps controlled? Keep revving high in a lower gear when going up hill?
Or drive in a normal manner in the torque range of the gear.


I live in Sydney NSW and out Wollongong way There is MT Ousley road.
I can just imagine going up there with a TD42T :D

Last few times I drove up mount ously in the ute I just drove it in third.

Quote:

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Originally Posted by Ben-e-boy

Last few times I drove up mount ously in the ute I just drove it in third.

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Cheers Ben

What did temps sit at?

Quote:

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Originally Posted by drgtr

snip...

What is the best way to get coolant temps controlled? Keep revving high in a lower gear when going up hill?
Or drive in a normal manner in the torque range of the gear.

I live in Sydney NSW and out Wollongong way There is MT Ousley road.
I can just imagine going up there with a TD42T :D

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First thing is to understand what is happening when the engine is under load.
Heat is the unwanted byproduct of any internal combustion engine when we want it to produce torque.
The faster you want to go or the steeper the hill you want to climb the more torque you need.
The more torque needed the more heat produced.

Gears are a torque multiplier IE the lower the gear the more torque is available at the wheels (RW) for the same torque (heat) at the flywheel
The work required (getting a 3T vehicle up a particular hill) doesn't vary the way to reduce heat is use less engine torque to accomplish the work
Which means go slower in a lower gear.
Unfortunately humans are very averse to that concept.

Sooo... the way to get up a hill producing the least heat (before we introduce other factors such as cooling efficiency etc) is to go up in first gear at approx 2,200 ish RPM which is max RW torque at minimum engine torque.

In practical terms, if you want to go up the hill faster you need more RW torque.
More RW torque means more heat.
How efficiently you accomplish dumping the heat determines if you can produce sustained higher RW torque to get up the hill in subsequently higher gears.
Higher gear gets you up faster but produces more heat so it only works if you produce less heat than you can efficiently dissipate

Therefore to minimse heat produced, in whatever gear, operate the engine near but faster than peak torque which is approx 2,000 RPM in a TD42Ti (factory)
The reason why you want to be over peak torque RPM (known as being ahead of the torque curve) is so that any slight decrease in RPM still keeps you in the curve and not falling off.
If your temps start to rise to an unacceptable level, change down (the earlier the better)

I always have to/want to gear down going up hills. Even long slight hills the temps go up... On highways that are 100km/h, I'll drop it to 4th, and on proper hills, down to third, the less the motor is laboring the lower the temps...
I just drive it like a truck and not a Suzuki Escudo up Pikes peak...
I have a standard radiator with a high flow water pump. And onces im over the peak, on level ground, the temps recover very fast to normality.
My temps are usually 77-80 pending ambient temps and whetehr the AC is on or not... But up a hill, I've seen them as high as 90C. Thats the highest ive ever had on my car I reckon. If I didnt gear down and lugged it up a hill in 4th or even 5th on highway, they wold go much higher I imagine.

I dont know whats safe MAX. But I just go with the "less is better" attitude.

Quote:

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Originally Posted by the evil twin

First thing is to understand what is happening when the engine is under load.
Heat is the unwanted byproduct of any internal combustion engine when we want it to produce torque.
The faster you want to go or the steeper the hill you want to climb the more torque you need.
The more torque needed the more heat produced.

Gears are a torque multiplier IE the lower the gear the more torque is available at the wheels (RW) for the same torque (heat) at the flywheel
The work required (getting a 3T vehicle up a particular hill) doesn't vary the way to reduce heat is use less engine torque to accomplish the work
Which means go slower in a lower gear.
Unfortunately humans are very averse to that concept.

Sooo... the way to get up a hill producing the least heat (before we introduce other factors such as cooling efficiency etc) is to go up in first gear at approx 2,200 ish RPM which is max RW torque at minimum engine torque.

In practical terms, if you want to go up the hill faster you need more RW torque.
More RW torque means more heat.
How efficiently you accomplish dumping the heat determines if you can produce sustained higher RW torque to get up the hill in subsequently higher gears.
Higher gear gets you up faster but produces more heat so it only works if you produce less heat than you can efficiently dissipate

Therefore to minimse heat produced, in whatever gear, operate the engine near but faster than peak torque which is approx 2,000 RPM in a TD42Ti (factory)
The reason why you want to be over peak torque RPM (known as being ahead of the torque curve) is so that any slight decrease in RPM still keeps you in the curve and not falling off.
If your temps start to rise to an unacceptable level, change down (the earlier the better)

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Thankyou. What an answer!

Quote:

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Originally Posted by Hodge

I always have to/want to gear down going up hills. Even long slight hills the temps go up... On highways that are 100km/h, I'll drop it to 4th, and on proper hills, down to third, the less the motor is laboring the lower the temps...
I just drive it like a truck and not a Suzuki Escudo up Pikes peak...
I have a standard radiator with a high flow water pump. And onces im over the peak, on level ground, the temps recover very fast to normality.
My temps are usually 77-80 pending ambient temps and whetehr the AC is on or not... But up a hill, I've seen them as high as 90C. Thats the highest ive ever had on my car I reckon. If I didnt gear down and lugged it up a hill in 4th or even 5th on highway, they wold go much higher I imagine.

I dont know whats safe MAX. But I just go with the "less is better" attitude.

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lol I remember the twin motor suzuki in the 90s up pikes peak. 1000hp or something. Massive Spoiler Wing on the rear.

Thanks for the answer.

On a normal day on highway depending on ambient im seeing around 69 to 77 degrees at 110kmh depend if there is a slight gradient.

Makes sense. Lower gear better for up hill .

Thank you

Quote:

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Originally Posted by drgtr

Cheers Ben

What did temps sit at?

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Only had a factory gauge, I've always had a big radiator and a well serviced cooling system. Never had an overheating issue
Wouldn't have got yo half way up that hill