Turbo sizing for compounds

[DieselJpower]

1500 shipped. It has the 1.23 housing

 

[DieselJpower]

Or make me an offer

 

[Charles]

If I put together a setup to roam the streets today and I was willing to fit a second charger, I would run stock compression, partially filled block, 300/200's, 38R and GT55 with GT4718 Compressor....

That last part seems strange, but the turbine is just so efficient in the 55, but the 88mm GT47-88 compressor is sized and trimmed well for the low boost / high flow you need in a first stage.... plus is makes noise. The whistle, while it may seem trivial, or subjective is paramount for safety on a daily driver. With the 55 compressor I couldn't hear anything the motor was doing. Half a dozen times, in a truck I had been driving at the same basic power level for years, I found myself caught off-guard by a sudden onset of power at the wrong time because I could not HEAR the truck coming up on boost. On the track it doesn't matter. So what, you're focused. But driving on the street that little pitch change the 47-88 makes when the back tires lose the pavement with the cruise set on a rainy interstate drive is something you take for granted until it's gone... Or something as simple as not realizing you're under the chargers and for the last half mile you just blotted the sun from the sky behind you because you never heard them lay down. On a turbo diesel you're basically driving a turbo, the engine is just a box that holds pressure, and if you can't hear anything from the turbo, you lose orientation for shift timing and general engine status.

Anyway, the turbine in the 47 was the only thing I would have changed about the 38R/47 combo. It was 1:1 (or better) up to ~65psi, then it would start to flip and by 90+ it was over 100psi. With the 55, the boost drive was always positive or even. The 55-94 was functionally great with the 1.12 turbine housing. But without sound, it was very disorienting on the street for anything other than flat -out where you fully knew what you were doing with or without any audible feedback.

 

[Arisley]

Very good points Charles. You always put the real world back in peoples minds. Good to see you again.

 

[ja_cain]

If I put together a setup to roam the streets today and I was willing to fit a second charger, I would run stock compression, partially filled block, 300/200's, 38R and GT55 with GT4718 Compressor....

That last part seems strange, but the turbine is just so efficient in the 55, but the 88mm GT47-88 compressor is sized and trimmed well for the low boost / high flow you need in a first stage.... plus is makes noise. The whistle, while it may seem trivial, or subjective is paramount for safety on a daily driver. With the 55 compressor I couldn't hear anything the motor was doing. Half a dozen times, in a truck I had been driving at the same basic power level for years, I found myself caught off-guard by a sudden onset of power at the wrong time because I could not HEAR the truck coming up on boost. On the track it doesn't matter. So what, you're focused. But driving on the street that little pitch change the 47-88 makes when the back tires lose the pavement with the cruise set on a rainy interstate drive is something you take for granted until it's gone... Or something as simple as not realizing you're under the chargers and for the last half mile you just blotted the sun from the sky behind you because you never heard them lay down. On a turbo diesel you're basically driving a turbo, the engine is just a box that holds pressure, and if you can't hear anything from the turbo, you lose orientation for shift timing and general engine status.

Anyway, the turbine in the 47 was the only thing I would have changed about the 38R/47 combo. It was 1:1 (or better) up to ~65psi, then it would start to flip and by 90+ it was over 100psi. With the 55, the boost drive was always positive or even. The 55-94 was functionally great with the 1.12 turbine housing. But without sound, it was very disorienting on the street for anything other than flat -out where you fully knew what you were doing with or without any audible feedback.

Good stuff as always. Glad to hear the internet/forums are not completely dead to you. Lol! Maybe, just maybe you will share your latest file in the tuning thread and also share some more of your wisdom.

 

[lincolnlocker]

If I put together a setup to roam the streets today and I was willing to fit a second charger, I would run stock compression, partially filled block, 300/200's, 38R and GT55 with GT4718 Compressor....

That last part seems strange, but the turbine is just so efficient in the 55, but the 88mm GT47-88 compressor is sized and trimmed well for the low boost / high flow you need in a first stage.... plus is makes noise. The whistle, while it may seem trivial, or subjective is paramount for safety on a daily driver. With the 55 compressor I couldn't hear anything the motor was doing. Half a dozen times, in a truck I had been driving at the same basic power level for years, I found myself caught off-guard by a sudden onset of power at the wrong time because I could not HEAR the truck coming up on boost. On the track it doesn't matter. So what, you're focused. But driving on the street that little pitch change the 47-88 makes when the back tires lose the pavement with the cruise set on a rainy interstate drive is something you take for granted until it's gone... Or something as simple as not realizing you're under the chargers and for the last half mile you just blotted the sun from the sky behind you because you never heard them lay down. On a turbo diesel you're basically driving a turbo, the engine is just a box that holds pressure, and if you can't hear anything from the turbo, you lose orientation for shift timing and general engine status.

Anyway, the turbine in the 47 was the only thing I would have changed about the 38R/47 combo. It was 1:1 (or better) up to ~65psi, then it would start to flip and by 90+ it was over 100psi. With the 55, the boost drive was always positive or even. The 55-94 was functionally great with the 1.12 turbine housing. But without sound, it was very disorienting on the street for anything other than flat -out where you fully knew what you were doing with or without any audible feedback.

Right on charles!! Always good to read your input. Actually been waitig for you to poke your head in a few of the threads on here. Good to see you post!!!

live life full throttle

 

[Strokinbronco]

So how do you think the s369/gt4718 combo would perform? I know I probably sound stuck on the s369 but that's cause I already run that charger and would like to utilize it (it's less than a year old). I know how to read compressor maps but im still learning and trying to figure out this whole compound thing. I'm not the type to just slap something together and run it, I actually want to understand what makes the compressors match up well and compliment each other

 

[Charles]

So how do you think the s369/gt4718 combo would perform? I know I probably sound stuck on the s369 but that's cause I already run that charger and would like to utilize it (it's less than a year old). I know how to read compressor maps but im still learning and trying to figure out this whole compound thing. I'm not the type to just slap something together and run it, I actually want to understand what makes the compressors match up well and compliment each other

I have no doubt it would do perfectly well. I imagine it might spool a bit slower than a 38R, so out of the hole it might show that a bit, but a compound truck is rarely under the chargers... so I doubt it would be a big deal. I don't know what kind of boost those can take and stay together, but you'd want to be careful during initial setup that you didn't accidentally hurt it as it might not be as forgiving as the 38R to say a blown wastegate signal line and running 55lbs as a single for a sec. Although with compounds any initial foo-foo can get out of hand with triple digit manifold pressure coming faster than you can imagine, so engine block might be an issue before the charger anyway...

Conceptually the chargers don't necessarily "work together" as much as the second stage (small charger) compresses air into the engine and is sized for that engine in the range of rpm you intend to operate, whereas the first stage (large charger) is sized for the resultant "engine" that is created by that second stage charger. For instance, with say 20lbs on the engine from the second stage, you might as well have the first stage hanging off the side of a 950 cubic inch engine, because to it.... that's what's happening.

 

[ja_cain]

I think the KC38R would make an excellent second stage charger. Being a dual bb charger, it would probably take a beating like the Garrett.

 

[mcnance865]

I think the KC38R would make an excellent second stage charger. Being a dual bb charger, it would probably take a beating like the Garrett.

I would like to do this some day since I have the KC38r already. Swamps comp motor, full billet, KC38r and an 88mm, 300/200, etc. Tuned for super quick response and lower end power to make it the ultimate daily driver.

 

[ja_cain]

I would like to do this some day since I have the KC38r already. Swamps comp motor, full billet, KC38r and an 88mm, 300/200, etc. Tuned for super quick response and lower end power to make it the ultimate daily driver.

That's awesome! I love those guys at swamps. I think should should pick up the KC line. I hear they are starting to mess with the V6 Powerstroke now. Should be interesting to see what they can do with it. Anyway,. Have you towed heavy with that setup?

Sent from my Pixel 2 XL using Tapatalk

 

[mcnance865]

That's awesome! I love those guys at swamps. I think should should pick up the KC line. I hear they are starting to mess with the V6 Powerstroke now. Should be interesting to see what they can do with it. Anyway,. Have you towed heavy with that setup?

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No, I have not towed anything yet I don't think. I used to tow a bobcat trailer around and some other random stuff. Sometimes I pull trailers of metal or tools (I'm in construction), but mainly just a driver. It went in this morning to get the Dorsey Stage 2 trans installed and I am hoping it makes a big difference. I have been glad I did not need to tow anything because I don't think the stocker would have been able to hold on towing with the fuel I have haha.

 

[mcnance865]

That's awesome! I love those guys at swamps. I think should should pick up the KC line. I hear they are starting to mess with the V6 Powerstroke now. Should be interesting to see what they can do with it. Anyway,. Have you towed heavy with that setup?

Sent from my Pixel 2 XL using Tapatalk

Just read your post again, I'm guessing you cannot see my signature... I want to get the Swamps motor, 300/200s, etc. someday.

Currently, I have 238/80, KC38r, adrenaline, irate fuel system, 1023 tunes. Just to clarify.

 

[Strokinbronco]

Okay so I spoke with forced inductions about running the gt55 turbine in the gt4718r and they told me that they can't do the conversion on a ball bearing center section. That being said here's my question, should I gate the gt4718 to control drive pressure? Also what ar turbine housing should I run with it being ball bearing, I want it responsive but need it to remain "streetable" so I don't need it lighting off to fast.

 

[Charles]

Ball bearings are a waste IMO for the first stage. I have never had an issue with spool and you will definitely never, ever, ever drive that first stage anywhere near the limits of the chra in a compound setup so strength is a non-issue.

As for drive pressure, that's specifically why I would not run a 4718. Drive pressure through that turbine is inefficient in this application above ~60lbs of boost in my experience, as the drive/boost exceeds 1:1 and climbing.

 

[Strokinbronco]

In that case what turbo would you recommend?

 

[Charles]

In that case what turbo would you recommend?

Depending on what you're doing, either a GT5594, or what I would probably do if I was going to run a compound setup on a 7.3 right now, would be a GT5594 with a GT4718 compressor....

Jose at forced inductions has done this long ago. Some dodge guys made huge gains with a compound setup that was running a 4718 when they swapped to the 5594 turbine and kept the 4718 compressor side. I want to say they picked up around 200 wheel horsepower on the turbine swap alone.

For me that verified my data pointing to my 47 turbine as a bottleneck. Even though the truck was already down over 100 horsepower due to electrical issues I still picked up around 60rwhp swapping over to the 5594 and I think nearly all of that was in the turbine.

 

[Strokinbronco]

Okay so I've narrowed it down to 2 chargers, both are built by work turbochargers. One is a Garrett with an 88 compressor and 96 turbine, the other is a Garrett with a 88 compressor and a 111 turbine (pretty sure it's a gt55 just waiting on confirmation). That being said if I run the larger turbine would I still need to gate it or could I get away without one... safely?

 

[Charles]

Okay so I've narrowed it down to 2 chargers, both are built by work turbochargers. One is a Garrett with an 88 compressor and 96 turbine, the other is a Garrett with a 88 compressor and a 111 turbine (pretty sure it's a gt55 just waiting on confirmation). That being said if I run the larger turbine would I still need to gate it or could I get away without one... safely?

You can't do anything without a gate and compounds unless you tune the truck for very, very low power. With the two largest turbine housings available for the 38R and 47 I was running pretty large amounts of gate to stay under triple digit boost.

Without gates you would have to be making like 300hp to stay out of insane boost.

If both chargers loafed at 30psi without gates, that would put just over 121 lbs of boost on the manifold...

 

[Strokinbronco]

Okay well that answers that question, so here's another lol. I'm pretty clear on how to tune the wastegate for the atmospheric charger, but how do I tune the one for the high pressure turbo?