Wow!

@Martin who the hell has two thousand litres of engine oil lying around?

@motosubatsu a: Fell off a truck. b: Somebody sold him toxic waste as barely expired engine oil c: Inherited a farm and found it in the last corner of the barn, hidden under decade old junk

Morning

@RoryAlsop Good morning

Joy of old cars, again: my son's old Honda Jazz had a clutch failure. Diagnosed as master cylinder fail. Replacement sourced. It was faulty. Second replacement sourced and installed. Still didn't work. Next problem found in pipework. Finally sorted. Total cost > current value of car :-(

@RoryAlsop on the positive side: He now has a working car and knows the entire history. I personally dread used cars: I never know what happened before and what faults got covered up.

@Martin d: the OPEC equivalent of stealing office supplies?

@RoryAlsop I thought the whole point of the Honda Jazz was that it never ever ever went wrong?

@motosubatsu managed 14 years before anything went wrong, other than a bit of rust and some wear and tear on CV joints/suspension etc

@RoryAlsop that's a pretty good run!

@Martin last new car I bought was last century. I don't like the entire new car industry, based on marketing and fashion (I don't like fashion or trends in anything...) So I refuse to do the whole thing

I'd rather buy a car between 1 and 5 years old and then keep it for quite a few years

@RoryAlsop amen to that... buying used has it's downsides but personally I like the bang-for-buck

if I took the purchase price for my current vehicle de jour and shopped around I'd have been able to get something that would be charitably described as "boring"

Hi guys

How is that called the term identifying the amount of rev that's making the higher acceleration with the lowest fuel consumption?

I don't know if you understand what I mean, if not please ask, I would be glad to explain better.

@Syncro dunno. It's not something I know of. Either I look at highest power or greatest fuel economy. And they are often diametrically opposed

Oh okay.. Btw I mean that amount of rev you get before upshifting.

I don't understand what you mean then

An upshift requires a drop in revs to make the gears mesh

Why you upshift? Because increasing revs does not produce the needed power, right?

Oh are you talking about short-shifting? That is better for fuel economy, but not power

So I upshift at the point that the drop in revs on gear change will still be in the power band on my car - as I don't want the turbo to spool down

By driving at lower revs you consume more fuel and you get less power, same happens when you drive at very high revs, you consume very high amount of fuel while you're no more getting the needed acceleration

I want to know the exact amount of revs per minute for the highest amount of power.

Maybe that's me asking a dumb question, if so please let me know xD

So you'll need to look at your car's torque curve. You will typically find it won't be quite as simple. Many cars have a couple of peaks/wiggles

The highest power and highest torque will be at different revs as well. The more revs you can get, the more power you can get, but that doesn't translate to torque exactly

When I search for "maximum torque" on Google I get an amount expressed in N*m

Newton * meters

And cars don't have a simple fuel consumption relationship with revs - these days fuel injection is very variable, you'll have to look at drag coefficients etc

@Pᴀᴜʟsᴛᴇʀ2 is there a useful translation between fuel consumption and torque curves that you know of?

I'm not looking for fuel consumption, I don't really care about fuel, I said fuel consumption but I would mean another thing

I wanted to mean: which is the maximum amount of rev that I have to reach before upshifting?

For that you look at how fast the torque curve drops off

Yes

But I think I will not find the torque curve for my Fiat Punto 188 xD

Like I said before, for me fastest acceleration is more about not letting the revs drop below about 3500rpm, and in fact usually I change up at 6200rpm in my current car, which means the revs drop to about 4200rpm so still full on turbo pressure

Sure you will. Hang on, I'll try and find one

Ok thank you very much Rory Alsop :)

Yep, put fiat Punto 188 torque curve into Google and it comes up

First result

My first result is this one: 2016 Fiat Punto 1.2 Pop (man. 5) engine Horsepower / Torque Curve

My fiat punto belongs to 1999 xD

So just pop that in the search - the internet has torque curves for everything

@RoryAlsop - Don't both of them somehow factor into brake specific fuel consumption?

I found it, thank you veyr much!

Now I know that I need to upshift when I reach ~2200rev/min <3

Well, remember that might not be the best revs to upshift

Ate you wanting fastest acceleration?

Because you'll want to change up write a bit later for that

Sorry for spelling

Yes I didn't understand xD

What do you mean Rory Alsop?

From that graph, I reckon 4200rpm would be your best upshift point if you want high acceleration

2200 will be more relaxed, slower acceleration, but lower fuel consumption

Wait wait wait, which graph are you watching? xD

automobile-catalog.com/curve/1999/723785/…

If it was me I'd go up to around 5000, but I really do like to push acceleration to the max

You see the torque curve drops off after 2200 and the power curve after 5000

Yes but I'm looking for torque, not for horse power

I mean.. by going up to 5000 rev/min, you reach very high power but your engine is not "trasmitting" that power to the wheels so it's kinda useful

useless*

Well, it's not as simple as that

It is transmitting that to the wheels

I'm kinda dumb, to understand that I need to check out what Netwon is. I feel embarassed xD

The power drop off after 5000 is significant, but generally you want to balance the two curves

And the exact point will vary depending on which gear you are in

As an example, my last car I would go to 7500rpm on first but by the time I was in 5th I would probably change up at 7000rpm, and I have to admit I never got to 7000 in 6th... The straight at Knockhill track was too short...

It's so kinda difficult to understand. I always thought that the exact point is always the same for every gear

:(

No, because of things like aerodynamic drag and other mechanical challenges, and the wonders of fuel injection systems

@RoryAlsop - Was it a six speed car?

Lol - yes

This was the Litchfield

I did get it to 187mph once

I'd never get anywhere close to that in my 94 Z28 ... I'd drive 70mph in sixth @ 1600rpm ... lol ... 7k in 6th gear probably would have been somewhere close to 200mph (if I had the hp to push it that fast, lol)

First would get me to 60mph when I ragged it

I mean... why you look to HP? Nm is all you should care about because it's actually the acceleration on wheels provided by the engine

No?

Not that simple :-)