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A military rebuilt 6.5

This is hard to explain......I don't have less power as RPM increases, I have less power directly related to throttle position. So I can be at 2500 RPM and 3/4 throttle position and have more power than I do at 2500 RPM and FULL throttle. The throttle pedal is acting correctly because when I had Car Code hooked up before I saw that it was displaying 100% throttle input and it also does control the RPM that the transmission shifts. So what I'm expecting to see with the data logging is what fuel and timing is commanded at 3/4 throttle and at full throttle and hope to find a clue there. So my problem shows up dependent upon throttle position, not RPM dependent, so there must be a parameter that is changing based on throttle position that my engine isn't liking. It did this with both IPs also, so it isn't an IP problem.

In addition, I did try swapping in the old tune and the problem isn't there....however, the new tune at 3/4 throttle is stronger than the old tune at full throttle. So the new tune in general is putting out more fuel, something is just off in the tables based on throttle position. I'm hoping the datalogging will show me something in the fuel and timing that I can relay back to Heath to get this figured out.

The more I read, the more I think I want to go to a mechanical pump. I like the price of the Peninsular pumps, but I feel like Unique Diesel might have a stronger pump for the GMs, but I don't know that for sure....I'm still reading. I will stay with the electronic setup for a while as I'm sure that once I have hard data showing what's going on with my tune I will be able to get it sorted, but for maximum power that this engine should make I think I will need the fuel that a mechanical pump can put out.

Yeah good points on the dyno inaccuracies, I would still hope to see a change to the shape of the overall curve between 2 cams and that at least would be a little informational.
 
You are on the right track there are 3 positions for the fly by wire throttle pedal "you problem appears to be in position 3" from what you stated, I'm very interested in your findings up top.

Look up the Bull Moose pump.
 
FellowTraveler said:
You are on the right track there are 3 positions for the fly by wire throttle pedal "you problem appears to be in position 3" from what you stated, I'm very interested in your findings up top.

Look up the Bull Moose pump.
Click to expand...
Oh crap, I'm sorry, I meant the Conestoga pumps, not Peninsular! I was thinking of them being in Pennsylvania and so Peninsular came out of my fingers. :facepalm:

Yes I've looked at the Bull Moose and then also what Unique Diesel offers. When I get serious I will speak with each company directly to see what they can actually offer fuel-wise. 6.5_3500 seems very happy with his UD pump.
 
n8in8or said:
Oh crap, I'm sorry, I meant the Conestoga pumps, not Peninsular! I was thinking of them being in Pennsylvania and so Peninsular came out of my fingers. :facepalm:

Yes I've looked at the Bull Moose and then also what Unique Diesel offers. When I get serious I will speak with each company directly to see what they can actually offer fuel-wise. 6.5_3500 seems very happy with his UD pump.
Click to expand...
I thought I was the only one on this board who suffers from brain f__ts, just kidding.
 
FellowTraveler, maybe I'm sleep deprived and not understanding, but can you explain post #660 about 2.0 pressure ratio/14/15 pounds of boost and actual boost pressure. Maybe explanation not necessary and I need sleep. Its the actual boost pressure thats throwing me off. I understand the fuel part I think. Thank you in advance.
 
hookedup50 said:
FellowTraveler, maybe I'm sleep deprived and not understanding, but can you explain post #660 about 2.0 pressure ratio/14/15 pounds of boost and actual boost pressure. Maybe explanation not necessary and I need sleep. Its the actual boost pressure thats throwing me off. I understand the fuel part I think. Thank you in advance.
Click to expand...

You're already at 14.7+-BP @ sea level w/o boost and your boost gauge reads zero however under boost you add whatever the atmospheric pressure is to whatever the max boost is on the gauge to get turbo actual boost pressure ratio of a given compressor. The compressor map has scales and boost efficiency plots that swing upwards to the right the left hand side scale of the map will give the pressure ratio at actual boost the bottom will give lbs of air pumped by the turbo at whatever the pressure ratio is........
 
Thank you, I'm definately sleep deprived as I didn't consider starting with atmospheric pressure when reading post. Maybe Saturday I can get some sleep and get some brain function.
 
Understand a diesel can need upwards of 60% more turbo than a same sized gasser because of broad spread of diesel compression/fuel ratios and other variables.
 
Holy crap that's a lot of reading for one night! I somehow missed this thread from the beginning and am playing catch up. Nice thread and very nice build! Sounds like you have a lot of time, money and energy in this thing. Looks amazing! I did all the reading in one night, so I skimmed over some of it, but from the sounds of things, I would agree that it is the tune. The problem with "tunes" for these trucks is that whether they want to admit it or not, they are all a generalized tune to accommodate a large amount of trucks. They are supposed to be vehicle specific, but the only way for that to be accurate is for it to be dyno tuned.

You are running a very unique build. Few people do that kind of work to their 6.5s. There is no way for Heath to build the correct tune for it without at least driving the truck and programming it in person. Plus, we have to remember that Heath now has it own turbo, cam, injectors and array of other performance parts so he is going to spend all of his times matching his tunes to his parts. So I could only imagine that tunes for out of the ordinary 6.5s that don't use his products get put on the back burner and get a much more generic version.

Another thing to consider is your compression. You dropped it to an unsure number. You dropped it with the thicker head gaskets, but you also dropped it with the larger precups. Since the size is unknown, then compression ratio is also unknown. This will affect power also. You can bump timing up more with a lower compression and gain power though. Another thing that will affect the timing is your marine injectors set to 2500 pop pressure. So if Heath's tune doesn't account for both of those, performance could easily be affected. For all we know, at wot, your tune may retard timing some to account for the added boost and that may be where your power drop off is coming from. Hard to say.

I, personally, don't think a ds4 can be programmed to put out enough fuel to justify dropping compression. But the way you have built this, I think the easiest way to get the power out of it that it was built for, would be to swap in a modified db2. I am not sure how I feel about the Moose pumps as they kind of give a false advertisement on fuel output. They give cc output, but they don't advertise that output for where it counts; at high rpms. They have one pump that they advertise as like 180 or 190cc I think, but that is just off idle and rapidly drops as rpms increase. 190cc does nothing for you at 1200 rpm except black out your rearview. Uniques gives output at 3000+ rpms. My pump puts out over 150cc but he didn't advertise it to me as a 150cc pump. He told me it is a 117cc pump bc that is where it is at 3500rpm. Just some food for thought if you decide to go mechanical and start shopping around. Make sure to find out at what rpm their advertised cc rating is at. Can make a huge difference on actual resulting hp.


Sent from my iPhone using Tapatalk
 
3500_6.5 said:
Holy crap that's a lot of reading for one night! I somehow missed this thread from the beginning and am playing catch up. Nice thread and very nice build! Sounds like you have a lot of time, money and energy in this thing. Looks amazing! I did all the reading in one night, so I skimmed over some of it, but from the sounds of things, I would agree that it is the tune. The problem with "tunes" for these trucks is that whether they want to admit it or not, they are all a generalized tune to accommodate a large amount of trucks. They are supposed to be vehicle specific, but the only way for that to be accurate is for it to be dyno tuned.

You are running a very unique build. Few people do that kind of work to their 6.5s. There is no way for Heath to build the correct tune for it without at least driving the truck and programming it in person. Plus, we have to remember that Heath now has it own turbo, cam, injectors and array of other performance parts so he is going to spend all of his times matching his tunes to his parts. So I could only imagine that tunes for out of the ordinary 6.5s that don't use his products get put on the back burner and get a much more generic version.

Another thing to consider is your compression. You dropped it to an unsure number. You dropped it with the thicker head gaskets, but you also dropped it with the larger precups. Since the size is unknown, then compression ratio is also unknown. This will affect power also. You can bump timing up more with a lower compression and gain power though. Another thing that will affect the timing is your marine injectors set to 2500 pop pressure. So if Heath's tune doesn't account for both of those, performance could easily be affected. For all we know, at wot, your tune may retard timing some to account for the added boost and that may be where your power drop off is coming from. Hard to say.

I, personally, don't think a ds4 can be programmed to put out enough fuel to justify dropping compression. But the way you have built this, I think the easiest way to get the power out of it that it was built for, would be to swap in a modified db2. I am not sure how I feel about the Moose pumps as they kind of give a false advertisement on fuel output. They give cc output, but they don't advertise that output for where it counts; at high rpms. They have one pump that they advertise as like 180 or 190cc I think, but that is just off idle and rapidly drops as rpms increase. 190cc does nothing for you at 1200 rpm except black out your rearview. Uniques gives output at 3000+ rpms. My pump puts out over 150cc but he didn't advertise it to me as a 150cc pump. He told me it is a 117cc pump bc that is where it is at 3500rpm. Just some food for thought if you decide to go mechanical and start shopping around. Make sure to find out at what rpm their advertised cc rating is at. Can make a huge difference on actual resulting hp.


Sent from my iPhone using Tapatalk
Click to expand...
Thanks for chiming in! I can't imagine reading all of that in one night, whew! I have really enjoyed following along with your build and you are definitely one of my inspirations for possibly going to a mechanical pump. I'm pretty sure that is ultimately where I will be going, but I need the bank account to build back up a little from the build.

I really need to do a little data logging with Car Code to see what the timing and fuel rate are doing relative to throttle position to see what changes from where I like the way it feels and where I don't to get an idea of what exact feedback to give Bill. Your comments make a lot of sense to me and confirm the hunches I had in my head, though I'm new to the diesel thing. I just need to carve out the time to do the data logging properly and gather the info. I've been busy with other projects in the meantime so it hasn't been a high priority. Plus I figure the longer I put it off, the longer the engine has to really break in before I really start hammering it.

If/when the time came to do a DB2 I was going to ask Conestoga about the fueling at the higher rpm specifically to see what they can really do. Their pumps are enticing because of the price, but I get the feeling that Unique will build a pump for what my engine would need because he understands the 6.5 since he's been there and done that.

Thanks for following along, if I go to the DB2 I hope you don't mind some questions if I have them.
 
3500_6.5 said:
Holy crap that's a lot of reading for one night! I somehow missed this thread from the beginning and am playing catch up. Nice thread and very nice build! Sounds like you have a lot of time, money and energy in this thing. Looks amazing! I did all the reading in one night, so I skimmed over some of it, but from the sounds of things, I would agree that it is the tune. The problem with "tunes" for these trucks is that whether they want to admit it or not, they are all a generalized tune to accommodate a large amount of trucks. They are supposed to be vehicle specific, but the only way for that to be accurate is for it to be dyno tuned.

You are running a very unique build. Few people do that kind of work to their 6.5s. There is no way for Heath to build the correct tune for it without at least driving the truck and programming it in person. Plus, we have to remember that Heath now has it own turbo, cam, injectors and array of other performance parts so he is going to spend all of his times matching his tunes to his parts. So I could only imagine that tunes for out of the ordinary 6.5s that don't use his products get put on the back burner and get a much more generic version.

Another thing to consider is your compression. You dropped it to an unsure number. You dropped it with the thicker head gaskets, but you also dropped it with the larger precups. Since the size is unknown, then compression ratio is also unknown. This will affect power also. You can bump timing up more with a lower compression and gain power though. Another thing that will affect the timing is your marine injectors set to 2500 pop pressure. So if Heath's tune doesn't account for both of those, performance could easily be affected. For all we know, at wot, your tune may retard timing some to account for the added boost and that may be where your power drop off is coming from. Hard to say.

I, personally, don't think a ds4 can be programmed to put out enough fuel to justify dropping compression. But the way you have built this, I think the easiest way to get the power out of it that it was built for, would be to swap in a modified db2. I am not sure how I feel about the Moose pumps as they kind of give a false advertisement on fuel output. They give cc output, but they don't advertise that output for where it counts; at high rpms. They have one pump that they advertise as like 180 or 190cc I think, but that is just off idle and rapidly drops as rpms increase. 190cc does nothing for you at 1200 rpm except black out your rearview. Uniques gives output at 3000+ rpms. My pump puts out over 150cc but he didn't advertise it to me as a 150cc pump. He told me it is a 117cc pump bc that is where it is at 3500rpm. Just some food for thought if you decide to go mechanical and start shopping around. Make sure to find out at what rpm their advertised cc rating is at. Can make a huge difference on actual resulting hp.


Sent from my iPhone using Tapatalk
Click to expand...
Excellent!
 
n8in8or said:
Thanks for chiming in! I can't imagine reading all of that in one night, whew! I have really enjoyed following along with your build and you are definitely one of my inspirations for possibly going to a mechanical pump. I'm pretty sure that is ultimately where I will be going, but I need the bank account to build back up a little from the build.

I really need to do a little data logging with Car Code to see what the timing and fuel rate are doing relative to throttle position to see what changes from where I like the way it feels and where I don't to get an idea of what exact feedback to give Bill. Your comments make a lot of sense to me and confirm the hunches I had in my head, though I'm new to the diesel thing. I just need to carve out the time to do the data logging properly and gather the info. I've been busy with other projects in the meantime so it hasn't been a high priority. Plus I figure the longer I put it off, the longer the engine has to really break in before I really start hammering it.

If/when the time came to do a DB2 I was going to ask Conestoga about the fueling at the higher rpm specifically to see what they can really do. Their pumps are enticing because of the price, but I get the feeling that Unique will build a pump for what my engine would need because he understands the 6.5 since he's been there and done that.

Thanks for following along, if I go to the DB2 I hope you don't mind some questions if I have them.
Click to expand...
Unless you run WOT most of the time I'd not worry about it now but plan for later.
 
With this much custom work it is past time to look at other tuners. After the hang up Heath Diesel has over large turbo's it should be clear that their tuning is for their products only with lackluster results on unique builds. If they don't think your build will work - good luck!

My 1995 build with the DS4 had a hell of a time getting the smoke under control with the NA precups, but, we had some success. Flip of a tune switch and passed emissions. The tuner took a ride with me while we tuned for least smoke and the best power. Again several tuners out there.

For example of what you can do thinking/tuning out of the box: Dennis retards the timing at a specific point in his tune to spool up the ATT. When I had the Spool Valve on it was one hell of a flat spot because the turbo was already spooled and the timing got cut. That build didn't need the timing trick, but, you can't do this with the DB2 pump. DB2's can only reduce fuel till the boost comes on with a smoke puff limiter.

Don't forget looking for "limits" that protect the engine. Like overboost, high IAT, etc. I learned the OEM MAP pegs out at 17 PSI. Perhaps something with more throttle heats up the IAT and then fuel gets cut?
 
I just wish there was a way to get more out of a ds4. I know Heath has his Merlin pump that is supposed to be good to 400hp, but I have not heard any experience with that pump. Plus I'm sure he is the only one who can do programming for it since it takes a special program to run. Hard to justify spending $2500 on a pump and tune with no flow numbers to back it up when for the same or less I can buy everything to swap to a db2 that I know the flow numbers of. But if a ds4 can be made to flow the same numbers as a modified db2, I would think it would have the upper hand. Hard to beat computer controlled.....as long as the PMD doesn't crap out....


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Yeah, any hp rating part without numbers to back it up reminds me of a late night infomercial.

When it comes to protective mapping, I think that belongs on a towing vehicle or dd. if your trying to go for serious power I believe the race car driver needs to be a driver and push the envelope of that ride for that race. Old school parts scattering on the line is the only way to go. :wacky:
 
FellowTraveler said:
Well, IMHO you are already at risk w/o CAC/IC, carcode data logger will give you all the info you need to determine what the loss of power can be attributed to up top.
Click to expand...
Oh yes absolutely, I was just being cute. ;)

WTA intercooler is happening this summer and in the meantime I keep a keen eye on my pyro gauge. Honestly though it is frustrating to have invested that much time, money and effort and have it not be everything I hoped for. I know I just need to keep going a little bit further and it will be what it can be for now.

This weekend the 14 bolt is hopefully going in so at least that base will be covered. After that then maybe I can start messing with Car Code once again.
 
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