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2000 K3500 Gone Mechanical Build

I don't believe so. I had to advance it some when I put the stock lift pump back on, but I messed with it a bit and seems to be in a decent spot. I do think performance wise that it could be advanced more, but it's right on the edge of getting the clanking noise at idle of the "extreme" advancing.

The pump just puts out a lot of fuel. Way more than a tuned ds4 or turned up mechanical pump is capable of. Almost double the amount of a stock mechanical pump at 3500 rpm and I would guess quite a bit more than double at lower rpms. It needs a lot of air and it needs it early.

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It might be capable of more fuel but it is determined by your right foot. Late injection causes higher EGTs.

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True, but hauling a load it isn't quite as simple as giving it less throttle to keep egts down and same as stock fueling. Keeping it at a constant speed with a load on flat ground it could easily put out more fuel than what the turbo could move air for. Add in hills and hot, humid air and there is no timing in the world that will keep egts down.

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Maybe you might need to do what I did at first... turn the fuel down and the heat will come down, and with time you can get the cac in and tune the fuel later when you can help the heat more..

Also, with you wanting/needing to stay in the 2000rpm range, a little different turbo may be needed, around a 12-14cm turbine hsg would give you more low rpm boost & faster response to the fuel.. I also have one of John's pumps so I know some of what you are seeing, ( but not quite the same mods to the motor ), things are a LOT different than a normal pump, it took me a while to get my motor tuned so that I NEVER need to mash the petal to the floor when heavy.. and my pump is now all the way back up like John built it...

There is one person on here that drove it a few weeks ago ( dieselnut )with my load on it, he also couldn't believe what he was seeing ..... it can be done in 100* heat with the right mods AND watching gauges..
 
The term "throttle" is misleading. The foot pedal is actually a RPM request on the governor. More pedal when you are below the RPM is more fuel to get there. However, this is hard to control as you can easily go full fuel due to high load, low RPM, and not being at WOT. Trying to keep smoke down for snap emissions tests is one way to show this. The other is a fixed throttle setting, manual gear selection and engine stops speeding up at a set RPM - at any 'throttle' setting below the governed RPM. The entire point of this is the fuel screw in the DB2 is more of a fuel limit unless you are extremely careful on the throttle. Very hard to tune the transmission shift points to this as well.

Timing: Going advanced increases time to wind up the turbo as EGT's are lower. It also can cause black smoke. Retarded will dump more heat seen as EGT's in the manifolds to drive the turbo. It is possible that you are bringing on too much timing in the upper RPM. The light load retard lever on the side of the pump may need to be brought on sooner. It is possible you need more timing down around 2000 RPM or less to overcome where the boost isn't so high. 5-7 PSI at the IP inlet as anything over that will mess up (advance) timing. Oddly my DB2 likes lots of advance. Black smoke when the cold advance is on and clears when it kicks off with the GM3 was perfect. To me the mechanical pumps rattle more at idle than the DS4 pumps.
Timing explained with results:
http://www.oliverdiesel.com/tech/timing.htm

I have worked on the theory that high EGT's can be from fuel still burning when the exhaust valve opens. More air may improve this. A BD spool valve is one way to do this. Adding a boost valve with the ATT got me the best MPG ever with the 1995 2500 4x4 Suburban of 16 MPG at 75MPH+ Freeway. For me breaking 14 MPG was rough esp with high speed and constant grades everywhere out here. It may hold more heat in the engine than a smaller turbo. You trade off pulling hard all the way to redline with a smaller turbo and then have to mess with getting the WG adjusted.

Humidity has some effects, but after turbo, at 200 degrees and 15 PSI the humidity is way different. Regardless I need less timing with hot dry air vs. high humidity as the humidity slows down ignition and the fuel burn. It was 2% RH yesterday and like 110. It gets more miserable with the Monsoon season - 110 and some humidity. :eek:

What ECT temperature does your engine fan start sounding like a jet on takeoff? On flat level ground steady 65 MPH is would cycle on me a few times, but, usually not full blast. The only times I would go slightly over 210 was a sneaky grade for a freeway interchange that did not require a downshift, but, heated it up before the low temp fan clutch locked up. Again the low temp clutch overcomes the delays in getting the slow to respond spring thermal fan to lockup under load. The longer it takes to get the fan on the higher the ECT goes before the temp rise stops. This engine doesn't have much high temp room to play with so I err on the side of cold - T-stats and clutch lockup.

At this point from your past DS4 and my experience with both DS4 and 6.5/6.2 DB2's I suspect the area to look is the pump setup/build/timing. Otherwise you may need to build the rest of the engine around the pump.
 
WarWagon said:
The term "throttle" is misleading. The foot pedal is actually a RPM request on the governor. More pedal when you are below the RPM is more fuel to get there. However, this is hard to control as you can easily go full fuel due to high load, low RPM, and not being at WOT. Trying to keep smoke down for snap emissions tests is one way to show this. The other is a fixed throttle setting, manual gear selection and engine stops speeding up at a set RPM - at any 'throttle' setting below the governed RPM. The entire point of this is the fuel screw in the DB2 is more of a fuel limit unless you are extremely careful on the throttle. Very hard to tune the transmission shift points to this as well.

Timing: Going advanced increases time to wind up the turbo as EGT's are lower. It also can cause black smoke. Retarded will dump more heat seen as EGT's in the manifolds to drive the turbo. It is possible that you are bringing on too much timing in the upper RPM. The light load retard lever on the side of the pump may need to be brought on sooner. It is possible you need more timing down around 2000 RPM or less to overcome where the boost isn't so high. 5-7 PSI at the IP inlet as anything over that will mess up (advance) timing. Oddly my DB2 likes lots of advance. Black smoke when the cold advance is on and clears when it kicks off with the GM3 was perfect. To me the mechanical pumps rattle more at idle than the DS4 pumps.
Timing explained with results:
http://www.oliverdiesel.com/tech/timing.htm

I have worked on the theory that high EGT's can be from fuel still burning when the exhaust valve opens. More air may improve this. A BD spool valve is one way to do this. Adding a boost valve with the ATT got me the best MPG ever with the 1995 2500 4x4 Suburban of 16 MPG at 75MPH+ Freeway. For me breaking 14 MPG was rough esp with high speed and constant grades everywhere out here. It may hold more heat in the engine than a smaller turbo. You trade off pulling hard all the way to redline with a smaller turbo and then have to mess with getting the WG adjusted.

Humidity has some effects, but after turbo, at 200 degrees and 15 PSI the humidity is way different. Regardless I need less timing with hot dry air vs. high humidity as the humidity slows down ignition and the fuel burn. It was 2% RH yesterday and like 110. It gets more miserable with the Monsoon season - 110 and some humidity. :eek:

What ECT temperature does your engine fan start sounding like a jet on takeoff? On flat level ground steady 65 MPH is would cycle on me a few times, but, usually not full blast. The only times I would go slightly over 210 was a sneaky grade for a freeway interchange that did not require a downshift, but, heated it up before the low temp fan clutch locked up. Again the low temp clutch overcomes the delays in getting the slow to respond spring thermal fan to lockup under load. The longer it takes to get the fan on the higher the ECT goes before the temp rise stops. This engine doesn't have much high temp room to play with so I err on the side of cold - T-stats and clutch lockup.

At this point from your past DS4 and my experience with both DS4 and 6.5/6.2 DB2's I suspect the area to look is the pump setup/build/timing. Otherwise you may need to build the rest of the engine around the pump.
Click to expand...

Will be building around the pump. Most wouldn't agree with that, but my goal since I decided to ditch my Duramax and go back to a 6.5 was to attempt to build a 400 hp engine. Figured I would need a pump putting out in the neighborhood of 120cc. This is about as close as I am going to get to that for now. Won't reach the 400 mark, but good enough. So I have the fuel I've been after, just need to support it.

I'm not a huge believer in the updated fan hype. In school we were taught that, generally speaking, at speeds above 35 mph, there is more airflow from those speeds than a fan is capable of pulling. So technically speaking, a fan wouldn't be needed at any speed above 35. Now this was 10 years ago and I'm sure fan designs are improved and the numbers given were just a generalization, but I still have a hard time believing any fan can pull more air through the radiator than a 55mph wind can.

For example, I had a Duramax that I was pulling 10000+ lbs with in the middle of summer, maybe low 90 degree temps. Ended up on a road that was constant 90 degree turns and steep hills. As soon as you were down one hill, you were going up the next. I was hauling without being in tow/haul mode and temps got warm enough that it put itself in tow/haul mode. The fan clutch was engaged the whole time and was screaming. However, whenever I would climb to around 40+ mph, it would instantly disengage. This tells me that at around that point, air flow became greater than the fan could pull. Oddly enough, it would also do this on cold mornings too. Only it would disengage at around 30 mph.

I also had a 91 Corvette at one point. It had an electric fan on it. These Corvettes weren't exactly known for staying cool. The design of them put the radiator at a very bad angle and there is no airflow through the front of the car. It had little "wings" under the car to help direct airflow up to the radiator while driving. As bad as airflow was on the car, the only times the fan ever kicked on was when I was stuck in traffic. And if it was warm at all out and I was stuck in traffic for long, it would start to heat up bc the fan couldn't pull enough air. Cruising at any speed and it would never come on and would stay perfectly cool. Now that was a very light, 6 speed car so conditions are obviously different, but still makes a point.

Maybe some day I'll test it and pull my fan off and put electric fans on on a switch to turn on only at low speeds and see how it does.

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sctrailrider said:
Kinda figured that, I know what you will be getting and I am sure you will like the difference..
Click to expand...

Yeah, I figure that he has a lot of time invested in testing and running his pumps so he would know best as far as what will work best with it. Along the same lines as my att and the ds4 with Dennis. He has a ton of time getting the programming down to work flawlessly with that set up. And it did with mine. Just wasn't quite the fueling I wanted. Figure might as well get the turbo built to work with the pump, same as what I had when it was electronic.

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I have to disagree with the fan clutch idea. My lbz fan clutch kicks on at 60mph if I get it hot enough. Same w/ all my 6.5's.

Yes you have more flow at highway speed but w/ enough load you can still get hot.

source unknown
 
I'm not saying it won't get hot, my truck proved that they will. All I'm am suggesting is that @55 mph or faster, that is a lot of air. I don't see a fan pulling more air than what naturally runs across the radiator at those speeds. That would mean that a fully engaged fan would be pulling enough air in excess of 55 mph. I've never felt a fan pull my arm back as hard as what the wind does when I stick it out the window at 55. Could have been a teacher's opinion and was just blowing smoke, but seems viable to me, at least when you're talking about speeds of 55 and above.

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I think our pickups need help getting the air through the grill w/ our aerodynamic design and small grill for air to flow through. If we pushed enough air through at 55mph then the fan should never kick in but it does.

source unknown
 
Thanks for the transmission temp numbers. For the first time since I owned my 1993 I have finally seen 180 operating temps vs. 210. The air also froze me out in 108 degree weather for the first time.

I trusted the transmission shop to hook up the cooler when they rebuilt the transmission. Never questioned it. I flushed the cooler lines and coolers to make sure the rebuilt radiator didn't have any nasty stuff in the trans cooler. Oil was flowing the wrong way making an unexpected mess. The hottest oil from the transmission was going in front of the condenser and then going through the radiator. This kept the trans at at 210 and hotter under load. I wound up swapping the cooler lines on the transmission. The correct oil flow cooled down the trans temps. My last experiment of removing the air to oil cooler shows that even 'backwards' the extra cooler helps the transmission temperatures. Some people think the radiator is needed last in oil flow to warm up a cold transmission. Yeah, it's the last thing I need out here.

I will suggest you bring your clutch fan along if you experiment with electrics because I'd hate to see you have to turn back towing to go get it. Electrics are not recommended on IDI diesel due to airflow requirements. In 1/2 ton daily driver 'show trucks' you might get away with them.

As far as fans go at speed:
1) The hood being closed, engine in the way, restrictions of the radiators, dynamic air pressures from the vehicle in motion, and fan 'windmilling' all reduce air speed through the radiator stack. It is a significant reduction of air speed through the radiator when you add it all up.
2) As you go faster the airflow through the radiator 'helps' your fan move more air in some vehicles.
3) Electric fans are "Game Over" vs. clutch fans at just 1200 engine RPM.

If you mount a radiator on top of the cab at 60 MPH it will have more than 60 MPH of airflow hitting it from the air trying to go over the cab. It is restrictive so it won't let the full 60 MPH of air through it. This assumes the air isn't being deflected higher than the cab from the windshield angle resulting in little or no airflow. It is also a sail cutting down MPG.

Measuring a fan off a Trailblazer SS in garage I found 10,500 CFM was 35.5 MPH average airflow speed through the radiator at 3K engine RPM with the fan at full lockup. This same fan when used on the 6.5 caused me to run hot. So it isn't as good as the 9 blade steel or Duramax fan as far as pitch - CFM per RPM. Conclusion: our IDI diesel needs more than 10,500 CFM or has a more restrictive stack requiring more fan blade pitch.

Electric fans get ~5000 CFM "freestanding": without the restrictive radiator, etc. in the way. At 1200 engine RPM with a fully locked up fan clutch I found this number with the restrictions in place. So electrics only have an advantage, maybe, at idle.

So your professor was right by saying 35 MPH airflow through the radiator is enough for a gas engine. This left off a few important details. IDI diesels need more airflow and our truck's aerodynamic body style has low airflow through the radiator while being known for good MPG but reduced MPG loaded. Others are known for the same MPG loaded or not the trade off being MPG used for 'ram air' cooling. So radiator airflow MPH is not equal to vehicle MPH due to several reasons the major ones being outlined above. This is why HD trucks have a big power sucking clutch fan.
 
Makes sense, as it was a non diesel auto class... And yes, the experiment would come with precautions. The hope would be that it would not need the electric fan except for at low speeds anyway, where I would not be spending much time at for the test as that is not where my questioning comes into play. But your explanation makes sense and would give reason as to why a fan could flow more than what a 55 mph vehicle speed could flow on its own.

The idea of quicker warm up time seems logical, but only a minor issue if anything for me. I always figured it was more for space saving and quick heat up times was an added bonus. Even here where it is normal to have lows in the single digits below zero during the winter, it doesn't cause a huge difference in the warm up time of the tranny though. Enough to notice the converter not locking as quickly, but not something I cant live with.

Both my Duramax's (01&02) ran virtually the same temp as the engine, usually 200-210 at any air temps of above maybe 60 degrees. When it was hot and I pulled a heavy load, the tranny would consistently run slightly hotter than the engine did, maybe 215-220 at the hottest. Some people say they are designed to run that hot, but seeing all the Allison's that were needing rebuilt, even on stock trucks, I can't help but question if it has to do with the temps they run. I know that the crappy design is definitely an issue with these trucks and short 4l80e life so I couldn't imagine it being any different on those trucks.

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You have to be careful working on auto transmissions. The transmission can be scalding hot with a cold engine. A brake stand will heat the converter up fast. So it is possible to have a cold to the touch engine and burning hot transmission cooler lines. Same for malfunctioning/slipping transmission and IMO possibly just normal operation - you can heat the trans faster than the engine. Certainly faster than any 'hot' coolant getting across the radiator to the cold side to heat anything up esp. when the fan is locked up with 'morning sickness'.

Cold mornings doing a brake stand without a burnout is a quick way to defrost the windshield. Say if it is a company truck...
 
Haha very true. They gave us numbers on how quickly a torque converter can heat up back in school, but I couldn't tell you without going through all my books and notes. I know it was only seconds, not minutes, of holding the brakes and forcing the converter to max stall speed before you can overheat it and run the risk of ballooning and frying the converter. Another bad reason for running the cooling systems together. A failing tranny can overheat the engine and vise versa. At least with an external cooler only, you have a less chance of cooking both parts bc of one overheating. And not to mention what can happen when the internal cooler decides to start leaking....

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Here are some pictures of the teardown of the engine that will be going in the truck....someday....
va3uha7e.jpg

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agava6y4.jpg
a5esehyv.jpg
u4a8abu8.jpg
asy6emy7.jpg


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