1stgenoverland
Adventurer
Feel free too post some pics of that sunrader cummins combo! That sounds epic. Thanks for following along.
1991 Dodge W250 Overland Tourer Build and Adventures
- Thread starter 1stgenoverland
- Start date
1stgenoverland
Adventurer
Yeah I'm pretty excited. Some of the current details are still a secret though.
1stgenoverland
Adventurer
Yeah! I'm North of Nanaimo in the Comox Valley. Great place to live. The promised Land really.
Kingsize24
Well-known member
Hey I already have the hook in my lip, you don't have to yank it! 🤣
frojoe
Adventurer
Awesome!! I'm pretty familiar with Van Isle, would love to live there one day. I went to UVic for mechanical engineering, and during that time spent many weekends in Cobble Hill and Duncan wrenching on friends' truck/car projects. 4 of my 6 vehicles were bought on the island, and I drove them all back to North Van with varying amounts of excitement at the ferry terminals haha.
I also have a very good friend with a place on Thetis Island that I spend a lot of time at, and have helped him build a full mechanical workshop there, as well as having another close truck friend in Nanoose Bay that I end up spending time with in his barn wrenching on his Chevy II, F450, or his tractor.
Dirt Rider
Well-known member
Welcome to the club, those trucks have a cult following, I get lots a people trying to buy mine! great for overlanding!
1stgenoverland
Adventurer
Warning: This post is full of really nerdy stuff.
As promised, The go fast parts. Although, any friend with a duramax would tease and say, "It's not actually a fast truck". They'd be correct but I don't care, I love this old truck. I call them go fast parts, and typically they would be, but in my case, I'm not really trying to make the truck go any faster. I just want things to be reliable and smooth. Also, there will be a little overlap with a previous post. One of the things that plagues a factory 12 valve Cummins, is a lack of airflow. What I can't figure out, is why Cummins would put such small 2.25" intercooler pipes on their engine. I wonder if it would be down to shareholder profits, or maybe the pipes are just good enough, but in this case bigger is better. You see, and engine is an air pump, essentially, if you make the air and exhaust go in and out of the engine smoothly, there is less parasitic draw on the engine. What parasitic draw is, is the power needed by the engine to do things other then spin the crank shaft and haul a load. So if you can go through the engine and reduced the engineered parasites, you will have better efficiency, or more power, or both. Depending what you're going for.
The 12 valve has deficiencies across the board pretty much. Turbo, Intercooler piping, Intercooler, Intake elbow, Grid heater, Exhaust manifold and Exhaust pipes after the turbo.
In a previous post I had stated that I had replaced the failing intercooler with a power stroke intercooler. This intercooler is much larger and has greater air cooling capacity. It would make no sense to use such a big intercooler, without upgrading the intercooler pipes as well. So I went from 2.25" to 3". The effect of this on the engine, is this. When a turbo builds boost, it creates pressure and heat.. My factory turbo, with a little extra fuel, was capable of making around 23psi manifold pressure. So in your intercooler system, every disturbance, creates a pressure drop after it. So, while the turbo might actually be creating 25psi at the turbo outlet, you're losing 2 psi in the system. That's a loss of potential power. More air is more efficiency, in a diesel engine. The intercooler deals with the heated created by compressing air. Larger intercooler, better cooling, denser air, means more oxygen for the given PSI entering the engine, which means better bang. All these little mods add up, and I found myself adding a little extra fuel, to match all the extra air. More fuel more power. With just these mods alone, I saw an increase in fuel mileage and power. Yes with a cummins, you can have both, to a certain degree. I was seeing about 12L/100km. (You can convert it to imperial or redneck if you like)
Next was the exhaust. I wasn't working with a lot of funds at the time, so, muffler delete and side pipe behind the cab. This takes out a lot of restriction and less of that means the turbo spools faster, which means better power across the board. Also, once again, more efficiency. I ran with that for a little while before I installed an MBRP 4" exhaust system. To my horror, it came with a 3.5" down pipe, instead of a 4" down pipe. All well, I suppose it was still an improvement over stock. Just a quick note on restriction. Every thing flows from high to low pressure. So the engine has high pressure inside, and when the exhaust valve opens, that high pressure searches for atmosphere. (Low Pressure) On its way out, It spins the turbo and then leaves the exhaust pipe. If your exits aren't efficient, the pressure will back up and the engine will have to work hard to vacate its exhaust. This is a parasitic loss.
I don't have any pictures of the exhaust actually, So you'll just have to wait for the next post. Manifolds and Turbos.
As promised, The go fast parts. Although, any friend with a duramax would tease and say, "It's not actually a fast truck". They'd be correct but I don't care, I love this old truck. I call them go fast parts, and typically they would be, but in my case, I'm not really trying to make the truck go any faster. I just want things to be reliable and smooth. Also, there will be a little overlap with a previous post. One of the things that plagues a factory 12 valve Cummins, is a lack of airflow. What I can't figure out, is why Cummins would put such small 2.25" intercooler pipes on their engine. I wonder if it would be down to shareholder profits, or maybe the pipes are just good enough, but in this case bigger is better. You see, and engine is an air pump, essentially, if you make the air and exhaust go in and out of the engine smoothly, there is less parasitic draw on the engine. What parasitic draw is, is the power needed by the engine to do things other then spin the crank shaft and haul a load. So if you can go through the engine and reduced the engineered parasites, you will have better efficiency, or more power, or both. Depending what you're going for.
The 12 valve has deficiencies across the board pretty much. Turbo, Intercooler piping, Intercooler, Intake elbow, Grid heater, Exhaust manifold and Exhaust pipes after the turbo.
In a previous post I had stated that I had replaced the failing intercooler with a power stroke intercooler. This intercooler is much larger and has greater air cooling capacity. It would make no sense to use such a big intercooler, without upgrading the intercooler pipes as well. So I went from 2.25" to 3". The effect of this on the engine, is this. When a turbo builds boost, it creates pressure and heat.. My factory turbo, with a little extra fuel, was capable of making around 23psi manifold pressure. So in your intercooler system, every disturbance, creates a pressure drop after it. So, while the turbo might actually be creating 25psi at the turbo outlet, you're losing 2 psi in the system. That's a loss of potential power. More air is more efficiency, in a diesel engine. The intercooler deals with the heated created by compressing air. Larger intercooler, better cooling, denser air, means more oxygen for the given PSI entering the engine, which means better bang. All these little mods add up, and I found myself adding a little extra fuel, to match all the extra air. More fuel more power. With just these mods alone, I saw an increase in fuel mileage and power. Yes with a cummins, you can have both, to a certain degree. I was seeing about 12L/100km. (You can convert it to imperial or redneck if you like)
Next was the exhaust. I wasn't working with a lot of funds at the time, so, muffler delete and side pipe behind the cab. This takes out a lot of restriction and less of that means the turbo spools faster, which means better power across the board. Also, once again, more efficiency. I ran with that for a little while before I installed an MBRP 4" exhaust system. To my horror, it came with a 3.5" down pipe, instead of a 4" down pipe. All well, I suppose it was still an improvement over stock. Just a quick note on restriction. Every thing flows from high to low pressure. So the engine has high pressure inside, and when the exhaust valve opens, that high pressure searches for atmosphere. (Low Pressure) On its way out, It spins the turbo and then leaves the exhaust pipe. If your exits aren't efficient, the pressure will back up and the engine will have to work hard to vacate its exhaust. This is a parasitic loss.
I don't have any pictures of the exhaust actually, So you'll just have to wait for the next post. Manifolds and Turbos.
1stgenoverland
Adventurer
One of the other issue with these trucks, is the restrictive exhaust manifold. We can tap into something called drive pressure. The high pressure leaving the engine, will drive the turbo. This drive pressure should hit the turbo at the same psi that it leaves the exhaust valve. However, the exhaust manifold is restrictive so, and so you have a loss of pressure, hitting the turbine, which means a loss of power, but also. means the exhaust is getting backed up at the exhaust valve, which means it can't flow out of the cylinder, fast enough, which means fresh air can't flow in efficiently, Which means the intercooler system can't be efficient, which means the turbos compressor has to work hard, which puts more strain on the turbine, which creates a further build up of pressure.... You beginning to see how much everything relates? Anything that doesn't improve airflow, decreases power.
So, I researched exhaust manifolds and landed on the Steed Speed website. They're a company in British Columbia, So on one of my road trips through Kelowna, I stopped in at their factory, and had a tour. I left having ordered a manifold, as I was convinced this would be the best manifold on the market, and my research of peoples experience, supports this. Yes, it improved the engine, I noticed it right away. Both seat of the pants and audibly. Turbo flashed up quicker, which meant better power off the line, and it could deal with the greater volume of flow in the top end. I just loved the way this engine sounded with the new manifold. Less crunchy, and more smooth. It also allowed me to install an EGT gauge for the first time. Highway temps with no load at 100kph, I was seeing around 600F. With the camper, about 650F at the same speed. This engine runs cool, I am happy. Going up hills, I can hit 1000F for a moment, but that tolerable.
I kept having a serious issue with the turbo. It just wasn't cracked up for running well with all these mods. Turbo surge, is a deadly (to the turbo) occurrence that happens when something is out of balance. What turbo surge is, Is when the turbo physically doesn't have the flow characteristics, to push volume and pressure into the engine. So that built pressure, tries to come back through the compressor to atmosphere with a loud chuffing sound. This would happen when I was at lower RPM, in 3rd or 4th gear, and under load. I kept backing the fuel off to try and make it go away, but to no avail. The turbo was just not well matched to the engine with all the mods. So, I installed an HX35, From a 2nd generation 12 valve, and all the problems went away. The differences between the turbos is kind of hilarious. The compressor wheel is 2mm bigger, and the turbine wheel is the exact same. The compressor housing supports better flow, and the turbine housing is smaller to promote faster spool. The turbo also has a waste gate, so in higher rpm, it still will flow properly, but also control the turbine shaft speed. This was an excellent upgrade, in my opinion, though, a good number of cummins guys think I should have gone with a bigger turbo. Maybe, but my compressor surge was gone.
The Brand new Steed Speed Manifold.
I had the nerve to gasket match it.... I suppose I can't leave well enough alone, if there's potential for a small mount of improvement.
The finished product on the manifold side.
Yes, I did the turbo too.
And a Fresh manifold installed in the cleanest engine bay on the planet. What can I say, It's a work truck. As long as its all there right?
So, I researched exhaust manifolds and landed on the Steed Speed website. They're a company in British Columbia, So on one of my road trips through Kelowna, I stopped in at their factory, and had a tour. I left having ordered a manifold, as I was convinced this would be the best manifold on the market, and my research of peoples experience, supports this. Yes, it improved the engine, I noticed it right away. Both seat of the pants and audibly. Turbo flashed up quicker, which meant better power off the line, and it could deal with the greater volume of flow in the top end. I just loved the way this engine sounded with the new manifold. Less crunchy, and more smooth. It also allowed me to install an EGT gauge for the first time. Highway temps with no load at 100kph, I was seeing around 600F. With the camper, about 650F at the same speed. This engine runs cool, I am happy. Going up hills, I can hit 1000F for a moment, but that tolerable.
I kept having a serious issue with the turbo. It just wasn't cracked up for running well with all these mods. Turbo surge, is a deadly (to the turbo) occurrence that happens when something is out of balance. What turbo surge is, Is when the turbo physically doesn't have the flow characteristics, to push volume and pressure into the engine. So that built pressure, tries to come back through the compressor to atmosphere with a loud chuffing sound. This would happen when I was at lower RPM, in 3rd or 4th gear, and under load. I kept backing the fuel off to try and make it go away, but to no avail. The turbo was just not well matched to the engine with all the mods. So, I installed an HX35, From a 2nd generation 12 valve, and all the problems went away. The differences between the turbos is kind of hilarious. The compressor wheel is 2mm bigger, and the turbine wheel is the exact same. The compressor housing supports better flow, and the turbine housing is smaller to promote faster spool. The turbo also has a waste gate, so in higher rpm, it still will flow properly, but also control the turbine shaft speed. This was an excellent upgrade, in my opinion, though, a good number of cummins guys think I should have gone with a bigger turbo. Maybe, but my compressor surge was gone.
The Brand new Steed Speed Manifold.
I had the nerve to gasket match it.... I suppose I can't leave well enough alone, if there's potential for a small mount of improvement.
The finished product on the manifold side.
Yes, I did the turbo too.
And a Fresh manifold installed in the cleanest engine bay on the planet. What can I say, It's a work truck. As long as its all there right?
1stgenoverland
Adventurer
Seems to be what all the insta famous people do, in hopes of a future patreon sponsorship... 🤣 Don't worry, I'm not that needy. haha
1stgenoverland
Adventurer
Sounds Exciting! Ever used that mechanical engineering for Overland stuff??
1stgenoverland
Adventurer
I also think it will be great for overlanding! It seems like an endlessly rebuildable truck, on many fronts.
frojoe
Adventurer
Kinda, in two ways: 1) my day job is a suspension/frame/materials engineer for a MTB company, and 2) I design and fabricate parts for every one of my vehicles.. but primarily my Dodge, and I can't help but invest engineering time and analysis in every single part that I make (and re-make). I can't really describe it in a better way short of simply saying... check out my ExPo Dodge build thread (linked in my signature) haha.
1stgenoverland
Adventurer
Can't seem to figure out how to locate it. Do you have a link?
frojoe
Adventurer
Oh whoops.. my bad, I just assumed there was a link in my signature...... but apparently not haha. Here:
https://forum.expeditionportal.com/threads/1998-5-dodge-ram-ctd-sally.167293/