Too much torque!!

[R2D2]

That is definitely not a dyno chart of a petrol car, you only have to look at the torque to figure that one out.

Something not right, as previously posted OP given the wrong printout?

The full printout has my details on it and I was the only car "in" when it was done....

 

[camerafodder]

I'm not doubting your sincerity for a second R2. Its just that the figures make no sense when matched to the engine that's supposed to be in your car.

 

[camerafodder]

OK I'm a lemon and I think I'm reading the symbols incorrectly. At 3600 rpm you're developing about 215lbFt torque which is more like 150hp. Readout still looks queer though!

 

[flango]

but it would explain how I held off a Mondeo 220 diesel and also my fuel consumption and also my long held belief that my car is quicker than it should be. The C230 kompressor M271 is the same engine.....

Thats how I know it's wrong I'm quoting off the top of my head here but will look it up when I get home, when my car with Brabus upgrades was last dyno't it made 231 bhp @ around 5250 rpm and just short of 210 lb/ft torque kicking in at just over 2500 rpm. On the attached chart the maximum power is too low down the rev range as is the torque figure and has been said is indicative of a modern turbo diesel. Not doubting you but definitely think you are in possesion of someone elses dyno chart.

 

[RBYCC]

According to the MB literature my engine is supposed to develop 220nm of torque between 2500-4200 revs. Max power of 143bhp is supposed to be at 5200rpm. The same engine in a c200 produces 240nm between 3000-4000 and a c230 produces 245nm between 2900-5500rpm....

Something is seriously wrong with the graph and possibly the dyno operator.
The engine should be run to max rpm as you always want to see the HP/Torque cross at 5250RPM.
HP always equals torque at 5250RPM.
Most times the pulls on an automatic car are done in third gear with the dyno engaging around 3500 RPM.
To engage the dyno from a dead start can cause spikes during shift points.

 

[R2D2]

OK I'm a lemon and I think I'm reading the symbols incorrectly. At 3600 rpm you're developing about 215lbFt torque which is more like 150hp. Readout still looks queer though!

Where are you getting 215 lbft from , the graph shows 303.5 lft at 3625 revs.

BHP = Torque (lbft) x RPM
_ _ _ _ -------------------
_ _ _ _ _ _ _ _ 5252

303.5 lbft x 3625/ 5252= 209bhp ??

 

[camerafodder]

Where are you getting 215 lbft from

From the torque lines which on your fuzzy graph are the lower two lines on the readout at 3600rpm. Or are my dim eyes misreading it?

 

[Bellow]

According to the MB literature my engine is supposed to develop 220nm of torque between 2500-4200 revs. Max power of 143bhp is supposed to be at 5200rpm. The same engine in a c200 produces 240nm between 3000-4000 and a c230 produces 245nm between 2900-5500rpm....

And the plot shows none of the above - nowhere close.
The plot shows the power falling rapidly at 3700rpm.
So how can it possibly be expected that it goes on to produce its maximum power at 5200rpm when its all out by 3700rpm? And if it could have, why didn't they continue the run?

Yours might have been the only car there, but they will have dozens of plots stored on a computer.
At least 3 of us are saying you have been given the wrong one.
Get them to explain the anamolies.

 

[jonathanc]

I definitely read about 215 lbft at 3600 rpm.

If this peak at 1600 RPM the effect of a torque convertor, I dont know what the stall speed of a TC is on your car but I wonder if it is around 1800 RPM where the torque curve dips?

It can't be making 300+ lbft at any speed, let alone 1600 rpm so it must be related to the auto.

Why didn't they take the car to max RPM for each run? Is this a clue???

 

[R2D2]

From the torque lines which on your fuzzy graph are the lower two lines on the readout at 3600rpm. Or are my dim eyes misreading it?

Hmm I had been reading the red line at the top as torque and the blue line as bhp. If you read them the other way around then max bhp is 149bhp at 3625revs (which is what the text says) and ignoring the spike at the beginning max torque would be 298lbft at 3100 revs.

298 lbft x 3100/ 5252= 175bhp -that actually makes a bit more sense!

 

[Bellow]

Or simpler still. In driving, does your car stop pulling at 3700rpm - as the plot suggests? Or does it continue to pull vigorously to 5000-5500rpm?

 

[RBYCC]

Where are you getting 215 lbft from , the graph shows 303.5 lft at 3625 revs.

BHP = Torque (lbft) x RPM
_ _ _ _ -------------------
_ _ _ _ _ _ _ _ 5252

303.5 lbft x 3625/ 5252= 209bhp ??

Why did the operator disengage the dyno at 3600RPM?
Doesn't make sense !!!

Your calculation is correct, but your print out shows max RWP = 123.7 @ 3137RPM which would calculate to torque at 207 at that point.

T=HP x 5252 / RPM

 

[camerafodder]

Hmm I had been reading the red line at the top as torque and the blue line as bhp. If you read them the other way around then max bhp is 149bhp at 3625revs (which is what the text says) and ignoring the spike at the beginning max torque would be 298lbft at 3100 revs.

298 lbft x 3100/ 5252= 175bhp -that actually makes a bit more sense!

Nope, your torque on the graph at 3100rpm is around 245lbft which equates to about 144hp

 

[R2D2]

Hmm. well it doesn't run out of steam at 3700 revs, its does seem quite quick for a C180k, and Rapid Chariots aren't answering their phone.

 

[camerafodder]

Hmm. well it doesn't run out of steam at 3700 revs, its does seem quite quick for a C180k, and Rapid Chariots aren't answering their phone.

This is why we all think you have the wrong graph, badly set-up dyno or operator error. Or a blend of any/all of the above.

 

[tagnut]

No the colours are the run numbers. blue is run 1 and red is run 2. The lines climbing from left to right are BHP and lines descending are torque

 

[Bellow]

If this peak at 1600 RPM the effect of a torque convertor, I dont know what the stall speed of a TC is on your car but I wonder if it is around 1800 RPM where the torque curve dips?

Makes sense. Which puts the true torque peak at 2000-2200rpm.

But I think they have made a hash of the rpm and torque scales.
Could the torque be in N.ms, or is it wrong because the rpm scale is wrong?

 

[R2D2]

I'm very confused.

 

[Bellow]

I'm very confused.

You're not the only one!

You say the car keeps pulling beyond 3700rpm. The graph says it doesn't.
I believe you, not the graph.
I think they have made a hash of the graph calibrations. When you get them on the phone they should be able to explain and rectify it for you.

 

[tagnut]

Something else is very wrong with this graph.....Torque = HP at 5250rpm but on this graph it is at 2500