Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 07-27-2003, 01:30 PM
Registered User
 
Join Date: Jul 2003
Location: HELENA,MT
Posts: 179
Question turbo boost preasure adjustment

i have an83 300tdt. Has 11 lbs of boost max. Reading old posts it said to pinch hose from turbo to wastegate &test again. did that with maybe a 1/2 lb change in boost presure. i understood from the old post that i should have seen an increase to max boost . did I do it wrong or did I not understand the post ? I would like to get it to 15lbs. whats wrong with my car or testing or thinking?

help thanks JOHN

Reply With Quote
  #2  
Old 07-27-2003, 01:38 PM
Registered User
 
Join Date: Aug 2001
Location: Evansville, Indiana
Posts: 8,150
Wastegate may be worn, so it doesn't seal properly when closed. Or the turbo is going, and wont' come up to speed. Note that you must have full load to get full boost, and that means driving it with a boost gauge installed, you cannot measure it properly with the car stationary unless you have a proper dyno (not one of those silly little "10 second" ones).

The other other adjustment is to change the spring on the wastegate controller -- it is probably weak by now, and not allowing enough boost.

11 psi is within factory spec, and is the usual pressure in a good system.

Do not exceed 13.1 psi unless you don't care if the engine blows in a year or so.

Most preformance complaints can be "fixed" by increasing the ALDA responce a bit, they lose effectiveness with age.


Peter
__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!
Reply With Quote
  #3  
Old 07-27-2003, 02:05 PM
Registered User
 
Join Date: Jul 2003
Location: HELENA,MT
Posts: 179
I did check with boost guage under full load, 4000rpms 3rd gear full throttle. Have previously adjusted the alda per recomendations from this board . I may infact have gone too far with that adjustment as i have seen a drop in MPG.
I am not unhappy with the performance as it will do 80 mph over a 5 mile long hill that i drive to / from work daily total mileage is 30 1 way & i get 24 mpg at 75 to 80( yes it is nice to drive in Montana)
JOHN
Reply With Quote
  #4  
Old 07-27-2003, 11:20 PM
ForcedInduction
Guest
 
Posts: n/a
Quote:
Originally posted by psfred
Do not exceed 13.1 psi unless you don't care if the engine blows in a year or so.[/B]
Isn't the factory spec 13.5PSI, Or is that just the overboost sensor opening pressure?

I run mine at a good 13-14 PSI (inaccurate gauge [cheapo gauge]) and I don't seem to have any bad affects besides slightly higher temp at highway speeds.
Reply With Quote
  #5  
Old 07-28-2003, 07:26 AM
engatwork's Avatar
busy
 
Join Date: May 2000
Location: Soperton, Ga. USA
Posts: 13,635
I was under the impression that the max factory setting is 13.5 psi.
Referring to the good old "Electrical Troubleshooting Manual" for '83-'85, page 109/1 the intake manifold pressure switch closes when pressure is above 15.9 psi which will then pull in the overload relief valve.
__________________
Jim
Reply With Quote
  #6  
Old 07-28-2003, 05:04 PM
gsxr's Avatar
Unbanned...?
 
Join Date: Aug 2001
Location: USA
Posts: 8,101
Spec for the OM617.95x engine is 0.75-0.85 bar, which is 10.9-12.3psi. So you are right on spec. If you pinch the wastegate hose and get no more boost, then the problem isn't the wastegate. Might be low on fuel deliver, you could tweak the ALDA and see what happens (seach archives). Often there is NO power gain when turning up the boost, you just make more heat and possible reduce power! You need more fuel to make more power, stuffing extra air in does nothing without extra fuel...
__________________
Dave
Boise, ID

Check out my website photos, documents, and movies!
Reply With Quote
  #7  
Old 07-28-2003, 05:55 PM
Registered User
 
Join Date: Jul 2003
Location: HELENA,MT
Posts: 179
thank you GSXR I will leave it alone and turn down my alda to see if i can get my mileage back up
madsen
Reply With Quote
  #8  
Old 07-28-2003, 06:56 PM
Registered User
 
Join Date: Aug 2001
Location: Evansville, Indiana
Posts: 8,150
Hans said no more than 13 or 13.1, above that you risk engine failure. The 60x engines are designed for 13.9, one of the reasons they have more power.

Peter
__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!
Reply With Quote
  #9  
Old 07-29-2003, 11:33 PM
ForcedInduction
Guest
 
Posts: n/a
Would it be a good idea for me to turn my boost down to 12-12.5 PSI insted of 13.5 just in case I am really wrong about my specs? I use the highway alot and often reach max. boost, but never have any smoke except at cold starts on cool days.

I hope to have my car last me a good 5-6 years (Until I can buy an E270 CDI or E320 CDI in the USA) without having to dump a huge amount of cash into it.
Reply With Quote
  #10  
Old 07-30-2003, 01:06 AM
Registered User
 
Join Date: Aug 2001
Location: Evansville, Indiana
Posts: 8,150
I would. I would also adjust the ALDA for more fuel if you never get any smoke -- richen up til you just see some smoke over the deck lid at full throttle, third gear, 45 mph, no more.

Peter
__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!
Reply With Quote
  #11  
Old 07-30-2003, 10:20 AM
gsxr's Avatar
Unbanned...?
 
Join Date: Aug 2001
Location: USA
Posts: 8,101
Better yet, only turn the ALDA up to the point where you can't tell a power difference. Put another way, turn it down (CW) until you feel a power loss, then back out a hair. If you have the ALDA too rich (CCW) your MPG will suffer. It's not always possible to make the car smoke, since the ALDA is limited by the internal full-load stop. My '84 won't smoke visibly even with the ALDA backed waaaay out.


__________________
Dave
Boise, ID

Check out my website photos, documents, and movies!
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 12:29 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page