Max boost?

[DPKetchum]

Well i guess I'll ask this question. The injectors i used were the 40 to 42 h. p. marine injector. Truck pulls 21 psi of boost almost immediately from a stop and a max of 950 egt unloaded. The max boost i assume is governed by waste gate?High rpm screw is 3 turns from stock. Only tweak on pump is 1/2 to 3/4 a turn on fuel screw. I thought i read somewhere that the Banks waste gate was preset at 21. 5 psi. Truck pulls strong and at 21 or so psi from a stop to 90mph. Smoke is slight except at intermittent engine temp then its noticeable at idle. Pump timing has been advanced. Any thoughts?

 

[formula]

Boost and EGT seem to be about right



Max boost will, to a point, be determined on the setting of the wastegate and the spring rate of the actuator.

I've got the same turbine housing. The wastegate is set to open at 22psi. On mine the actuator was cranked up so darn tight that the wastegate was only opening about 1mm. This was good for about a 0. 5 to 1 psi regulation of boost. I've also heard that most of these banks housings come with the wastegate cranked way tight like that. Just hook up some compressed air with a regulator and pressure gauge to the actuator. Watch the actuator rod, turn the pressure up to 30psi and watch to see how far it travels. About 10mm or so is full travel. If you decide to adjust it, make sure that you don't back it off too far or the wastegate will remain open all the time.



90 mph with 4. 10s..... what is your engine rpm at this speed?



Sean

 

[BushWakr - RIP]

Just an FWIW addition here...



My brother took his 92 out to PDR to have the wastegate tweaked on his truck (Banks orig. 14cm WG)

In the process he discovered that he had so many holes in his intercooler that it was a miracle the turbo produced 15psi let alone the 'gate' dumping at 21psi. (seems a common setting for the Banks system).

Might be worthwhile checking your charge air systems too... .

Be sure, if you decide to do this, that you connect your air supply at the inlet of the turbo and tighten your fitting good and do not exceed 20 psi since the coupling can often pop off and damage the connector on the back of the alternator.



Bob.

 

[DPKetchum]

Don't have a tach so don't know rpm's. Before turning high rpm screw it would run 85 or so. Before 4:10 gears it would run 100 plus. That was before injectors also. It pulls to 90 with what seems to be no effort. I just kept seeing all the post with max boost at 25 and 28 etc. Before new injectors it GUTTED to pull 19psi at WOT high speed and would drop off on large inclines when towing to 12/13/14 or so. Now it pulls 20 or so easily and whenever foot stuck partialy into it with no problem and no matter the incline. Towed short distance(7600lbs)and mostly same results so far its never hit a 1000 egt. Does 90 mph seem high?

 

[J DeMaio]

Right now with my mods, It'll hit about 28 pounds of boost at 90-95MPH on flat ground. The highest I've seen my ehhaust temps were 1000*. I have the Full power screw in 1. 5 turns and the AFC screw (top scew on diaphram) in 3 turns. It's amazing at the power of it now compared to before. I have noticed that I'm only getting about 15MPG, BUT I'm into the winter fuel which seems to significantly effect it and I have the throlltle matted all the time. Just taking off I govern it out anymore. I can't help to see that smoke and listen to her bellar I think it's runnin pretty good for a 1992. But I haven't ridden in one with POD's and an HX 40 either



Hope this helps.



John

 

[J DeMaio]

By the way DP, have you called Central Motive Power about your pump rebuild yet?



I forgot all about asking you that.



John

 

[formula]

DPKetchum,



I was just curious of your rpms with your gears. I did some rough calculations (based on my rpms with the 3. 54 gears) and you should be running around 2900rpm at 90mph. If you want to go faster, you should probably change your gearing.



The high idle setting won't have any effect on maximum boost.



When I installed my PODs, my full load fuel screw was turned in about 1/2 turn. I would make about 22psi boost max with that setting.



If you want your boost to be higher, then you will have to add more fuel



Sean

 

[CAROLINA CUMMINS]

I'm getting 22-23#(empty) with the pump settings: fuel rate pin= max

starwheel= +1 1/2 turns, smoke screw= +2 turns. I haven't messed the the full load fuel screw because I have no way to check idle.

I can just barely hit 1075-1100 deg(pre-turbo)WOT up hill,empty. This is all on a EARLY 91. I was confused with the 900-1000 deg on some trucks with the pump cranked more than mine but their intercooled,right?

That does make a difference, doesn't it? All in all I am pretty happy with the pump adjustments.





Steve

 

[Old Smoky]

Anybody have an Autometer Z-Series boost gauge that goes over 35psi? I thought that would be plenty when I bought it. Maybe I could just make a few more equally spaced marks .



Mike

 

[DPKetchum]

No dont want to go faster. Mine came with 3. 55 gears. Swaped them for 4. 10 several years back. Wanted it to PULL. Towing I never exceed 70 and normaly cruise 65/68 mph. I pull 9600lbs loaded with horses. Wanted more stout on takeoff and inclines. Wasnt happy with 3. 55. Not sure what was meant about pump rebuild??Tows ok now. Was just curious about the higher boost figures and mine seems to hit its max quick and maintains it now with new injectors. It just seems like it would go a lot more but i assume waste gate bleeding off more then 21. 5 psi?My pump is still a virgin!Havent made up my mind to playing with it or leave well enough alone. At i time i had a D. C. tech rep tell me not to higher then 20 psi or so on 1st generation. He said they would suck in intake gaskets?I wonder if thats why Banks presets waste gate to 21. 5?

 

[nascar mark]

Originally posted by DPKetchum

. At i time i had a D. C. tech rep tell me not to higher then 20 psi or so on 1st generation. He said they would suck in intake gaskets?I wonder if thats why Banks presets waste gate to 21. 5?

???????????????????

How could you suck in a intake gasket when our engines are turbo charged, which means they are possitive pressurized and can only blow out a intake gasket. There is 3 gaskets on the intake side, 1 between the head/air horn base, and 2 on both sides of the heater grid. I haven't ever heard of anyone blowing out one of these even with 90psi. The head gasket will go but not a intake gasket. The stock boost hoses will explode or blow off the easiest.

 

[DPKetchum]

Dont know. I just remember his comment about that. I did'nt ask in more detail. Then whats with the 21. 5 setting?