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#1
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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 |
#2
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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
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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! |
#3
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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 |
#4
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Quote:
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. |
#5
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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.
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Jim |
#6
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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...
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#7
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thank you GSXR I will leave it alone and turn down my alda to see if i can get my mileage back up
madsen |
#8
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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! |
#9
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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. |
#10
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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! |
#11
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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.
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