MrSpace

I went to the dyno with my 2000C230k (W202) automatic trans.

I got really bad numbers, and I need to fix those. 138hp at the wheels, it's supposed to be around 150 (because I have the older W202 engine).

There are the issues/questions:

I dynoed in 3rd gear by selecting 3rd on the touch shift. Now when flooring it, we did 3 tries, from 400, 3500 and 3000rpm. all 3 did not downshift, but I don't know if the guy pressed the "WOT button", I think yes because he said he floored it.

How did you manage not to downshift? By flooring it from a minimal RPM (like 3000)?

Second.. heat. After the second dyno pull, I had 120 degrees on the cluster. This is way too high ans I'm SURE that the timing was retarted = less hp. I'm sure the first pull was also with a very high temp. The temps probably wnet high when he "matched speed" whatever that means.. he tried at 200rpm foirst, then at 4000 (means holding the car at 400rpm for long and setting the dyno program to match the rpm I think. This part probably heated.

What do you suggest to cool the engine down? spray some fire extinguisher "ice"?

Then, there is a setting I don'T understand on the dyno chart. It states "ratio" and it'S setted at 5.137. That'S what the guy setted before the pulls at 4000rpm, he pressed the up and down keys top change that number on the screen. What does it mean?

Any help appreciated, I want a better dyno after my pulley install!

Etienne

MrSpace

http://www.dynapackusa.com/gear.htm

I think that's the gear ratio...

I'm pretty sure it's not 5.137, I'll try to find out what it is on my car so next time he can set it up. DO you think this can make the huge difference in hp?

Etienne

Buellwinkle

You're not supposed to floor it off the bat, let the engine build up some speed on the dyno and then floor it. An auto trans W202 should get 150Hp but every car is different, every dyno is different, every day is different. Check the condition of your air filter, plugs, tire pressure. Also run an obd2 scanner at the same time and log all the events, it may have something marginally wrong like a worn O2 sensor that's not bad enough to trigger the CEL but still bad, also the MAF sensor could getting old and the wire gets coated in dirt and the ECU compensates for it but there's still loss of power. Also, you'll easily get a 13HP difference between a cold run and a hot run. Check the IAT to make sure it's not much above ambient temps before doing the run and your IC is not heat soaked.

MrSpace

thanks, next run I'll ask more about that 5.137 ratio, I think this should be more the actual gear ratio of my car (which is around 3 I think).

Also, which odb3 scanner tool you recommend? I read that MB have slow refresh on odb2, is that true? I will get a laptop scan tool for the odb2. Does it state timing so I can see if it's retared because of heat?

air filter is a new K&N, spark plugs changed 5000 miles ago, tire pressure not an issue since on a dynapack the wheels are removed and the dyno is right on the hibs (maybe I should get even more than 150 whp since I don't have wheels on)

I really think the heat and ratio thing made the difference. Next time I'm pulling when colder, and putting the right ratio if I need to.

Etienne

MrSpace

too bad you changed my post of forum

this was not related at all to the W202 more than another model..

And there's nobody in the W202 compared to the W203.. I should have posted in the R170 since it'S the same engine, but anyways even the W203 have supercharge so probably same heating problems.

this move was really not necessary.

thanks for nothing.

Etienne

budgood

did you supply air for the intercooler?