Military DB4

[vdb11]

6.2, I didn't realize there were different springs, is it stamped on the spring? Also I didn't really think about the metering valve, that makes sense that the plungers do not reach full travel because the valve controls how much comes into the pumping chamber. I have a question about the governor. Is the governor always acting against the throttle position. From what I understand in reading the manual, the weights, which swing out a certain amount depending on rpm act to pull the metering valve through the linkage and spring closed while the throttle shaft is trying to keep it open. Is this a progressive force? What I mean is the weights are always swinging out when the engine is running, so they are always applying a force to close the metering valve, the strength of which is determined by how fast they are spinning. So the governor spring keeps the force from the weights from closing the valve, but as rpms increase, the force from the weights increases and therefore begins to overcome the gov spring and pulls the metering valve closed. This is progressive right? The reason I ask is because I was wondering if a stiffer spring would keep the metering valve more open through the rpm range since the gov weights can't overcome it as well. It would also increase the max rpm I guess but I am not too worried about that.

turbonator, I am thinking somewhere between 20-25 psi max. I know right now I am overboosting for the fuel I have, since I have the VGT too close to closed, and the IP being worn out. The truck almost never smokes and thats with a standard, but I am not that hard on it either. 950 with that much weight., thats really good for EGTs. I can hit 900 going up a short, but steep grade near my home, but I usually am in fifth , which puts my rpms a little too low to build boost (I can hit 12 psi) and it somewhat bogs.

Slim, I talked to Gary last night and he is going to use hardened material, and he is going to match the factory plungers. He said he was going to use reamer blank, which he had in .375, .390, and .406. I told him to use the .390. He said he may not have any of that in stock so I told him to use the .375 if he has no .390 material. I also opted not to have the charge holes enlarged. I will start out with the fuel turned down a good bit, and then work towards a good spot like you said.

I see what you mean about fuel delivery, it makes sense to me that it should take less throttle to get down the road, so theoretically mileage should be similar I would hope. But that's if I can keep my foot out of it. I wouldn't mind more touchy as for some reason my throttle seems to have a decent bit of resistance (??), maybe something in the linkage. This is in comparison to our 95 t-tag which is by wire and the pedal is so soft and touchy.

As far as heads, I will hold off for now and see what I can get with this combination, although I do love to experiment. Same with the precups, I just bought new ones. Sounds like you may have turbonator as a guinea pig

 

[Slim Shady]

how much boost is too much for you? we run 20-28 psi at WOT with the pugg (2831-5088 IP) and have not missed fuel.... if you are not boosting to match your fuel output, then the extra fuel will be going out the exhaust, wasted...the WMI has worked good to reduce EGT's with 14000lbs on the trailer, and the weight of the truck(truck weighs 17000lbs loaded) keeps the EGTS around 950 on a 2.5km hill..... and slim, would be interested in trying your pre-cups, but we just got a set of Diamond cups machined to try on our 6.2l build..... slim, have you ever looked into machining piston tops like kennedy does on their low comp ones? when you did your pistons, did you shaved them down, or machine them?

I had my pistons machined down they are 6.2 liter pistons which have a thicker crown. I can get you a set of pistons machined flat dihed concave how ever you want. I would have to ask my machinist if he would do them. He is probably one of the most talented machinists I have ever encountered. He makes anything that you want. Sometimes he doesn't want to do it because of the time involved but he is one of the best.

 

[Slim Shady]

6.2, I didn't realize there were different springs, is it stamped on the spring? Also I didn't really think about the metering valve, that makes sense that the plungers do not reach full travel because the valve controls how much comes into the pumping chamber. I have a question about the governor. Is the governor always acting against the throttle position. From what I understand in reading the manual, the weights, which swing out a certain amount depending on rpm act to pull the metering valve through the linkage and spring closed while the throttle shaft is trying to keep it open. Is this a progressive force? What I mean is the weights are always swinging out when the engine is running, so they are always applying a force to close the metering valve, the strength of which is determined by how fast they are spinning. So the governor spring keeps the force from the weights from closing the valve, but as rpms increase, the force from the weights increases and therefore begins to overcome the gov spring and pulls the metering valve closed. This is progressive right? The reason I ask is because I was wondering if a stiffer spring would keep the metering valve more open through the rpm range since the gov weights can't overcome it as well. It would also increase the max rpm I guess but I am not too worried about that.

turbonator, I am thinking somewhere between 20-25 psi max. I know right now I am overboosting for the fuel I have, since I have the VGT too close to closed, and the IP being worn out. The truck almost never smokes and thats with a standard, but I am not that hard on it either. 950 with that much weight., thats really good for EGTs. I can hit 900 going up a short, but steep grade near my home, but I usually am in fifth , which puts my rpms a little too low to build boost (I can hit 12 psi) and it somewhat bogs.

Slim, I talked to Gary last night and he is going to use hardened material, and he is going to match the factory plungers. He said he was going to use reamer blank, which he had in .375, .390, and .406. I told him to use the .390. He said he may not have any of that in stock so I told him to use the .375 if he has no .390 material. I also opted not to have the charge holes enlarged. I will start out with the fuel turned down a good bit, and then work towards a good spot like you said.

I see what you mean about fuel delivery, it makes sense to me that it should take less throttle to get down the road, so theoretically mileage should be similar I would hope. But that's if I can keep my foot out of it. I wouldn't mind more touchy as for some reason my throttle seems to have a decent bit of resistance (??), maybe something in the linkage. This is in comparison to our 95 t-tag which is by wire and the pedal is so soft and touchy.

As far as heads, I will hold off for now and see what I can get with this combination, although I do love to experiment. Same with the precups, I just bought new ones. Sounds like you may have turbonator as a guinea pig

I think you made a VERY wise choice on the plunger size. You can always go larger but not smaller. You will eventually want to go to a larger turbo, (trust me) you will have potential from 2000 up that you have not experienced before and a little larger turbo will enhance that.

 

[turbonator]

I had my pistons machined down they are 6.2 liter pistons which have a thicker crown. I can get you a set of pistons machined flat dihed concave how ever you want. I would have to ask my machinist if he would do them. He is probably one of the most talented machinists I have ever encountered. He makes anything that you want. Sometimes he doesn't want to do it because of the time involved but he is one of the best.

its funny like that with machinists and welders too... they do the same thing for years, and tend to develop serious bad attitudes along the way...LOL.....

 

[vdb11]

I think I will be happy with the size, we will see I guess

Actually Slim, I am running a Holset VGT like turbonator has/had on their pugg, I have had it on since March, before the rebuild. You are very right though, the GM-x turbos gotta go when you really want performance.

I know what you guys mean, my local machinist kinda has a bad attitude as well, I always feel bad asking him to do anything because he makes it sound like he is always incredibly busy.

 

[Slim Shady]

I think I will be happy with the size, we will see I guess

Actually Slim, I am running a Holset VGT like turbonator has/had on their pugg, I have had it on since March, before the rebuild. You are very right though, the GM-x turbos gotta go when you really want performance.

I know what you guys mean, my local machinist kinda has a bad attitude as well, I always feel bad asking him to do anything because he makes it sound like he is always incredibly busy.

I know you have the VGT but you are still going to need a bigger turbo, The vgt is made for a 5.9 liter motor you are already driving it with a 6.5 liter and the VGT was designed for the 1700 rpm max torque on the Cummings. You will be running open most of the time and I would be interested in drive pressures before the turbine. I think that you might be surprised. There are no free lunches everything is a trade off. Just my opinion.

 

[Woody35]

the vgt is capable of 400hp but at twice the boost your running it at. this of course would kill a 6.5 pretty fast so you need a bigger turbo that flows more air at less boost and drive pressure than the vgt

 

[SmithvilleD]

For the sake of accuracy, if the VGT turbo being discussed is the HE351ve, most come OEM on the 6.7L Cummins, not a 5.9. Don't want to stray too far off the thread topic, just wanted to keep the info offered accurate.

 

[Slim Shady]

It is an appropriate, bit of information. I think you need to change your post number quickly, not a very good number.

 

[turbonator]

It is an appropriate, bit of information. I think you need to change your post number quickly, not a very good number.

LOL... yeah, do an x-2 or sumthin....

what turbo would you suggest slim? the vgt is, when fully open the same give or take as an hx-40.... i would suggest maybe a schwitzer s-400, or maybe the ATT? would the ATT be recommended slim? its a pretty large exhaust housing on it....:???:

 

[vdb11]

correct this is the OEM turbo off a 6.7. But you make a good point slim. I do have a pressure gauge plumbed into my crossover so I am monitoring drive pressures now. Of course, the VGT is a very large turbo, or at least it seems to me. Now I know I am not running it at the boost it was designed to run to make big #s, but I would imagine the 6.7 from the factory doesn't run anymore than 30 psi (???).

I think I will keep the VGT for now, as I have little in it. But I am anxious to see turbonator try the VVT off the Dmax. But like always, I am open to suggestions.

6.2 turbo, haven't you run a couple different turbos??

 

[Woody35]

i talked to the guys at fleece about running the garret vvt turbo since you can get them on ebay for about the same price as the holset vgts but electrical standalone controller is about 900 bucks. i would be intrested how the turbonator guys are going to control it?

 

[turbonator]

i talked to the guys at fleece about running the garret vvt turbo since you can get them on ebay for about the same price as the holset vgts but electrical standalone controller is about 900 bucks. i would be intrested how the turbonator guys are going to control it?

as of right now we are kinda on the fence about that.... starting to talk again about leaving turbocharging behind and going with a supercharger instead..... lot less work involved fab wise, and a lot less charge air heat.... first things first, we need to build a good motor... the ol crack pistons motor is not the one to push the boundries with...LOL

 

[vdb11]

as of right now we are kinda on the fence about that.... starting to talk again about leaving turbocharging behind and going with a supercharger instead..... lot less work involved fab wise, and a lot less charge air heat.... first things first, we need to build a good motor... the ol crack pistons motor is not the one to push the boundries with...LOL

Now that I would like to see. I don't know much about superchargers other than they are belt driven and provide instant boost, but how much boost can they run? Plus can they flow as much air as a turbo? A while back I remember reading an article in the DP magazine about a Dmax with a supercharger and a turbo. I guess they would have no drive pressure since they are not exhaust run, but then wouldn't something be needed to create some exhaust back pressure? Aren't they also pretty expensive. I see on youtube that alot of guys outside the U.S. with 6.5 landrovers run superchargers and they seem happy with them.

 

[turbonator]

Now that I would like to see. I don't know much about superchargers other than they are belt driven and provide instant boost, but how much boost can they run? Plus can they flow as much air as a turbo? A while back I remember reading an article in the DP magazine about a Dmax with a supercharger and a turbo. I guess they would have no drive pressure since they are not exhaust run, but then wouldn't something be needed to create some exhaust back pressure? Aren't they also pretty expensive. I see on youtube that alot of guys outside the U.S. with 6.5 landrovers run superchargers and they seem happy with them.

they will run boost in conjunction with what size pulley is used... with diesel it is fuel and air.... we are thinkin either a set of headers from stan's, or just a set of flanges and build our own..... they can flow as much or more than a turbo, and they dont make near as much heat....

 

[vdb11]

Oh ok I see, I was doing some quick searches on youtube and found quite a few vids. Turns out I was thinking of Toyotas they were outfitting with supercharged 6.5s, a company called bullet diesel. Seems like a cool idea, I would like to see it done. So does boost rise linearly as rpm increases since it is pulley run?

 

[turbonator]

Oh ok I see, I was doing some quick searches on youtube and found quite a few vids. Turns out I was thinking of Toyotas they were outfitting with supercharged 6.5s, a company called bullet diesel. Seems like a cool idea, I would like to see it done. So does boost rise linearly as rpm increases since it is pulley run?

it depends what size pulley you start out with... theoretically you could start off at idle with 10psi boost with the right pulley, and it would build from there... the superchargers we are looking at top out(lose efficency) around 25-28psi boost, they are set with a wastegate similar to a turbo.... also the oil system if self contained..... they are selling rebuilt for around 500-800... the only real fabbing is the mounting plate to the intake, and a good free flowing exhaust to be efficient... also the matter of the belts to run it, but we are looking into a v-belt set-up from a hummer with like 6 belt capacity....

 

[6.2 turbo]

I had to paint the grooves yellow,they seem to be.015 thousands wide,and about the same in depth.

 

[vdb11]

Alright thanks! I think Gary is starting on the plungers this week I may give him a call and let him know about these grooves. Are they like a semicircle profile?

Thanks again, and turbonator, I am very interested in this supercharger idea. I also looked up the s-400 that you mentioned before, if I was searching correct they are borg warner turbos off of 60 series detroits? Also an ebay search reveals they are a bit pricey and hard to find.

6.2, what turbo are you planning on running on the Tahoe?

 

[6.2 turbo]

The grooves go completely around just like a piston ring groove,except very small. I assume they are supposed to hold fuel,and help with lubrication. I bolted a HX 52 on the Tahoe . Hopefully it works even half as good as it did on the 5.9 Cummins it came off of .