BHP test problem

[markg14]

Guys,

Does anyone have any idea how I can get an accurate report on BHP being produced by my 2007 W204 C220 CDI Sport (auto)?

Normal Dyno test will give me a figure at the wheels, but they can only guess at bhp at the flywheel.

I need to get this figure as I suspect that MB have detuned the engine as a result of 2 expensive warranty claims on the torque converter.

Thanks.

Mark

 

[bigasotonuk]

Hi,
The only way you can get a true and accurate BHP figure from the flywheel is to remove the engine from the car and do it on an engine test bed.
What makes you think they have de-tuned the car? What was MB's response to this?
I believe there is an excepted formula to workout flywheel BHP that allows for losses through transmission, axle, drive shafts etc, but this still won,t be 100% accurate, and can only be considered best guess really.

 

[markg14]

I suspect the engine mapping has been "updated" to reduce performance for two reasons:-

1. Car does not seem as responsive since the 2nd torque converter was fitted. Does not pull as strongly as pre-repair, and at low revs seems slightly "flat"

2. Fuel economy has improved by 10-15 percent since 2nd torque converter fitted

 

[bigasotonuk]

Hi,
Can i ask what you hope to gain, if you prove your power has been lowered?

 

[markg14]

What I hope to gain?
I hope to gain nothing, but I hope to have the engine software restored and RE-gain the performance that has been removed without my prior knowledge or consent.

 

[blassberg]

is it possible the gearbox has been reset and it needs you to drive 'enthusiastically' to return it's responsiveness?

 

[bigasotonuk]

I would image if you managed to persuade them to restore your software to a previous version, that the warranty (If the car is still in warranty) then would be voided.
Have you asked them yet? what was their response, I have read somewhere about 200CDI gearboxes/torque convertors were used in the 220 CDI for a while, and there was an issue of them failling as the 220 CDI produced more torque than the 200 CDI gearbox could take, and MB allegedly de-tuned the effected engines to remedy this.
I,m sure it was mentioned in a thread regarding performance chip tuning, if you do a search on the forum i,m sure you will find it.

 

[blassberg]

so they effectively created a 200CDI for people who had bought a 220CDI....?

 

[bigasotonuk]

I,m only repeating what I have read, but I have read the same thing were than once and on different forums, so draw your own conclusions, I believe it was resolved, as they then started fitting different/uprated gearboxes at the factory and their "alleged" solution to the effected cars was to de-tune them as markg14 has stated.
This all could be hearsay though, it would be interesting if someone was to have a look on the EPC comparing the gearbox/torque convertor combination on the allegedly effected models.
One of the threads I read was mentioning specific pt. no.'s and max. torque figures of the gearbox/torque convertor combination and the peak torque figure of the engine was in excess of 30lb ft more than the gearbox.

 

[LYNALL]

I think that thread was titled 722 gearbox torque figures or similiar and was on here.



Lynall