Economy related to max torque? GKN OVERDRIVE

Hi there,

Ok, you can see my modifications to my TD5 below. This post is a bit about the overdrive and the link between peak torque and economy.

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I normally get 280-300 with my chipped intercooled td5. With some recent long runs with the overdrive activated I achieved around 380 on a full tank which was great!

Now then:

Q1) Do you have the best economy at peak torque?

A thorough GKN overdrive review was undertaken by someone, they stated:

"The O/D puts less stress on engine, drops revs I reckon by 800rpm at 70mph which was calculated and is proved by the fitted rev counter. Which now means 70mph is closer to peak torque for the engine at 2100rpm."

Q2) If peak torque is near 70mph will I do more mpg at 70mph with overdrive on than say 55-60 with overdrive on?

Q3) This is one for overdrive owners I guess. When I do 70mph, the noise I hear, to say the engine is doing around 2100 rpm is the noise from the transmission? The engine cant be humming and buzzing away that much right? Its relaxing with the overdrive surely!

Lots to talk about. But I appreciate your time.

Thanks everyone, look forward to replies.

James

ah think fool economy was covered not so long back on most of the forums. and i'm sure that the general consensesusss was that, the more you drive it, the more fuel you will use. i'm pretty sure it was yella dog that gave us this piece of vital info of course it may have been grunt .BUT.......
i don't care

L90 TD5 said:

Q1) Do you have the best economy at peak torque?

A thorough GKN overdrive review was undertaken by someone, they stated:

"The O/D puts less stress on engine, drops revs I reckon by 800rpm at 70mph which was calculated and is proved by the fitted rev counter. Which now means 70mph is closer to peak torque for the engine at 2100rpm."

Q2) If peak torque is near 70mph will I do more mpg at 70mph with overdrive on than say 55-60 with overdrive on?

Q3) This is one for overdrive owners I guess. When I do 70mph, the noise I hear, to say the engine is doing around 2100 rpm is the noise from the transmission? The engine cant be humming and buzzing away that much right? Its relaxing with the overdrive surely!

Lots to talk about. But I appreciate your time.

Thanks everyone, look forward to replies.

James

Click to expand...

1) peak torque is the point at which your engine is at its most powerful as regards performance. which basically means any acceleration past this point is just wasting fuel

2)peak torque is set by the engine speed as opposed to the road speed (revs)

3)if an engine is revving less then obviously its under less strain, therefore the engine is more relaxed

you should always drive a car and change gear by use of your ears not your speedo(no sarcasm about using your hands please). the sayings"i can get 40mph in second gear" should be left to the little boy racers with their 1.0 litre saxo's

i hope you find this informative