Is it possible to adjust boost & alda on 300D 2.5 (602.962) - PeachParts Mercedes-Benz Forum

CJ · #1 05-12-2002, 08:17 PM

I want to adjust the boost on my 1991 300D 2.5, but it does not apear that you can adjust it in the same fashion as the other TD Benz's. Any suggestions??

#2 05-12-2002, 11:05 PM

This is all speculation because I do not know exactly how the electronic boost control works on your engine, but here are some ideas that might be worth experimenting or researching.

Does the system control boost pressure based on feedback? If so, you can attain higher boost pressure by fooling the ECU.

If the system uses a manifold/boost pressure sensor, you must somehow decrease the pressure it sees. One way is to install a calibrated pressure leak in the hose that feeds the sensor--making the ECU see less pressure than there really is. The ECU should compensate by increasing boost pressure.

If the system uses an air flow measurement before the turbocharger to calculate boost pressure, you can install a calibrated leak between the metering device and the turbocharger--making the ECU see less airflow than there really is. The ECU should compensate by increasing boost pressure.

Hopefully fuel enrichment is independent of this boost control function, making it possible to obtain more fuel to accompany this increase in boost pressure.

-Joe

CJ · #3 05-13-2002, 07:11 AM

Thank you, I think we are on to something. Has anyone out there ever done this?

CJ · #4 05-13-2002, 09:13 PM

Any news?

Billybob · #5 05-14-2002, 12:22 AM

Boost Control Install!!

This might help!

http://www.dawesdevices.com/

CJ · #6 05-15-2002, 07:45 PM

Thanks!

CJ · #7 05-15-2002, 09:33 PM

I checked out the links as well as utilized the search function, but I can not find anythng for my car.

#8 05-15-2002, 11:30 PM

Since your engine has ECU-controlled boost pressure, you will not be able to successfully utilize simple external boost controllers like the 617 guys... You must either be creative OR find something specifically for the late 2.5 Turbo.

There might be a performance chip available for your engine. I did some misc searches in google and found references to chips for both 2.5 TDs and 602.xxx engines. Since the ECU controls boost pressure, a performance chip would likely just contain instructions for higher pressure.

You can always try the "cheating" route I recommended above. hehehe

-Joe

CJ · #9 05-16-2002, 08:21 PM

I was thinking abot it, but I am looking for something more "factory"

#10 05-16-2002, 09:03 PM

Heh heh, I'm not sure what you mean... "factory" implies stock or unmodified... Changing boost pressure is definitely a modification

Unless you experiment with one of the "rigs" I suggested originally, your only other choices would be to install a chip OR find a device that connects in series with the air flow meter or manifold pressure sensor and modifies the signals reaching the ECU.

D-chip sells an OM602 chip that boosts power from 122bhp to 149 bhp, and torque from 208 lbs/ft to 262 lbs/ft. This is a HUGE increase in performance for a diesel engine. I don't know if it will work with your '91, but I'm sure they would know... shoot them an email if you're at all interested.

I have searched for ECU-fooling devices and found nothing. I suppose you could adapt an air/fuel ratio controller for a gasoline engined car to your diesel engine, and use it to change the values coming from the air flow meter, etc. But that of course would take some time and money to work out.

-Joe

CJ · #11 05-16-2002, 11:03 PM

Who is D CHIP??

#12 05-17-2002, 12:33 AM

They're just one of the many automotive performance software companies...

-Joe

CJ · #13 05-17-2002, 06:56 AM

Do you have any information on them or any companies that make chips for the 300D 2.5?

#14 05-17-2002, 07:09 AM

I don't have any specific or first-hand experience. I just did a quick search in google and found a pdf datasheet. The site in in German, but the google-supplied translation was fairly decent.

Other manufacturers are Superchips, Powerchips, etc. AMG or Brabus could possibly have something too.

-Joe

AMGmercedes · #15 06-19-2002, 08:33 PM

I tried finding d-chip(couldnt) and other diesel tuning companies but they only offer chips for late 90's-current cars. Joe, do you have the web site for d-chip or what search you entered into google? Ive tried everything but cant find them. I am interested in their 300D 2.5 chip. Thanks!