Engine/Transmission (1998.5 - 2002) Uderstanding Wastegate and boost adjustments??

[SnoKing]

I am on a RV trip in the Western States and I am trying to understand the workings of the wastegate and boost adjustments. I had my PDR35-12W set to 30-32 lbs at sea level at home and now I am in the Colorado high country and seeing only 26 lbs of boost. Alt 6000-9000. I have turned the setscrew in all the way on the boost elbow, thus blocking almost all the boost pressure to the wastegate. Note, if I turn the screw out, the boost goes down!



The way I understand it, is the the spring in the actuator holds the wastegate shut and boost moves the actuator over coming the spring and opening the wastegate to regulate boost level. I tried to shorten the rod on the wastegate, but it is frozen up, so I put a couple washers between the actuator and bracket, which moved the actuator away from the wastegate arm (same as shortening rod). No Change. When I had the actuator off the wastegate arm, the arm moved freely.



I cleaned the IAT last night and this morning I checked and tightened all the boot clamps and check all the hoses. Near the fender wells also. No holes that I can see. I have more throttle in 3rd pulling hard at 19K with the 5er in tow, then I can cool at 26 lbs, so I do not think it is a fueling issue.



I want to clean the map sensor. I read 1 1/16 inch deep socket? Or is it really 27 mm?



When I get setup again in Taos, NM later today, I may pull the boost elbow and install a plug and test with wastegate out of the picture.



SNOKING

 

[SnoKing]

Well I was getting 28 of boost today and crossed a pass at 10,500 feet going east on 64 to Taos, NM. Was able to use a bit more power and stay at or below 1200 pre turbo. Will disable the wastegate and see where I am at while at Taos.



SNOKING

 

[Forrest Nearing]

less oxygen/density at altitue = less boost

 

[SnoKing]

Well still had only 28 lbs of boost with line removed from wastegate actuator and blocked off. Will have to pressure test the system when I get home in Nov.



If I had a gasket issue at the grid heaters, I would see it sticking out, right?



SNOKING

 

[PC12Driver]

What setting do you have your Comp on? What RPMs are you at?



Regardless, I wouldn't sweat it too much. You should expect to lose a few pounds of boost at high altitudes (especially if the Comp is off).

 

[SnoKing]

My comp is not tapped. I run sublevel III. RPM do not seem to make much difference. I think I see 28 lbs at around 2500. Busy towing/driving. SNOKING

 

[SnoKing]

Well this trip has been a study in EGT's, Boost and AIR. We left Washington on Sept 10 and headed East to Devils Tower, Mount Rushmore, Crazy Horse, Pikes Peak, Mesa Verde, Albuquerque Balloon Fista, Phoenix, La Vegas, South Tahoe, Northern California Coast and now the Oregon Coast.



So we have seen our share for driving conditions, including Hills, Mountains, Hot and Cool weather.



I have found that the air the engine breaths does make a large difference in boost and EGT's. I will be checking for boost leaks when I get home, but can not see any at this point.



My conclusion at this point is that my PDR35W12 set to low 30's at sea level in nice damp air, is at or near it's limit with my small Jammer 1's and non tapped Comp. As I went higher I could only make 28 lbs of boost and had to watch my EGT's while pulling mountains. Pulled over a 10500 foot pass going into Taos, NM from the West.



Now that I am am back in the low lands with nice damp coastal air, I can put my foot deep into on 7 percent grades and get only to around 1100 degrees. So now I can look at the views rather than the EGT gauge.



I am kinda hoping to find a boost leak, that I can fix and move the turbo into a different range on the waste gate, allowing more air when in thinner and warmer air.



Another thing, the noise of the BHAF after weeks on the road is going to go. I think I will get the stock air box out of the garage attic, drill some more holes in the fender side, and try an Amsoil Nano filter. For that matter, I am also going to add a resonator back into the Magnaflow SS exhaust system(stepson says he stocks a 4" SS unit) and do some sound deading in the cab. It's that or the Volvo 660 that my wife will not let me have.



Its been a great trip. I have a Geno's/Valcun kit with a stock LP on the frame rail, and see 15 lbs at idle and 12 at WOT pulling mountain passes. Truck and trailer have performed great. Worst mileage was heading West out of Custer, SD at 10. 25, best was from South Lake Tahoe to Bedega Bay, Ca at just under 14. Average is around 12 to 12. 5. Fuel prices have been going up and Diesel in North Ca and Oregon has been 3. 55 for so. We are in South Beach SP at Newport, Or.



SNOKING

 

[NoSeeUm]

What setting do you have your Comp on? What RPMs are you at?



Regardless, I wouldn't sweat it too much. You should expect to lose a few pounds of boost at high altitudes (especially if the Comp is off).

Yeah...



At 26 psi of boost the PDR35 is likely in the top right corner of its efficientcy map. At elevation you are probably running at about the same PR as at sea level. I would guess that to be about 2. 2 or so. I noticed about the same thing for my HX35 at higher elevations. You might, as well, only check for boost leaks once you get back to the flatlands.



If you have no EGT concerns?



Be happy, enjoy your trip... Oo.



Jim

 

[jeepit]

Snoking, I too am thinking about putting the stock airbox back in with the Amsoil Nano filter. The sound is the worst when I just take foot off the pedal and motor starts to decelerate. It is annoying to say the least. My wife hates it. Let me know how yours sound going back to semi stock. I may be the next to follow.

 

[SnoKing]

Well I can tell you the truck is a lot quieter with the air box back on it. I have a stock paper filter in it right now. In thinking about it, the BHAF was not that bad with the HY35, then I switched to the PDR35W12 and it got very airy sounding. I also change the exhaust tip to a turned down unit and installed a small SS resonator. Next is to sound proof the cab. SNOKING

 

[SnoKing]

Well, this morning I did a pressure test on the truck. Bought "things" at Lowes yesterday, and removed hose from air box to turbo, and mounted a 4" rubber coupler with a plug and valve stem on the turbo inlet. Removed the air horn and put a 3 inch rubber cap on the pipe coming up from the intercooler. Set regulator on the compressor way down and played around getting the caps to seal. When everything was sealed up, it holds pressure just fine, no leaks. Re-installed the air horn with the new gaskets I had, but did not use while doing the VP44 swap. SNOKING

 

[Gary - K7GLD]

I want to clean the map sensor. I read 1 1/16 inch deep socket? Or is it really 27 mm?

It's 1 1/16 deep socket... That and a 4-6 inch extension between socket and handle gits-er-done - good luck!