67 lbs per minute!!
03-05-2008, 08:23 AM
#16
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the stock 04.5+ turbo is a great turbo....except for the exhaust housing...Yes it can flow 67lbs but the drive pressures at 130,000rpm are crazy dangerous.....by comparision the Super B flows less lb per minute but its exhaust housing is significantly larger and its wastegates are higher flowing...On a set of twins....you will never drive the top turbo to its max net boost as the big one is doing all the work and the top one is just along for the ride....but the better the exhaust side flows both through the turbine and wastegates....the better the twins will work...That is why the little super B is a great turbo on a mild set of twins or even a good turbo on a wildly fun set of twins....It allows alot of air flow before the drive pressure gets too high...I had an external wastegate in my Super B/ s48# twins and at my pressure balances were 75psi/70psi and 90psi, 80psi....so that set up was working about as good as you can get....with the stock turbo...you will see more likely 75psi/55psi and 90psi/60psi on the stock wastegate...big difference in drive pressure. For daily driving I wouldn't upgrade from the stock turbo to a Super B on an 04.5 and up....but upgrade to a Super B special and you will be able to easily gain 100hp...if you have the fuel and still stay cool. KS
03-05-2008, 08:35 AM
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03-05-2008, 10:30 AM
#18
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I have only seen one truck with a drive pressure guage hooked up and it just happened to be on a set up like yours... only they were the arctic air twins; stock over s400.
Relentless had these set to relief @ 55psi... with the mods on the truck (05)at the time, TST late twins program w/adj. pressure and timing, the actual boost was spiking at 55, but settling more around 50-53psi. Drive pressures were (and this is just off memory so I could be off some) 65-70+psi.
I don't want to put words in the mouth of the vendor, but IIRC, they felt they could push more air, but drive pressures would be too high and could pop a HG.
03-05-2008, 11:11 AM
#19
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67 lb/min doesn't seem like that much for a modded CTD. The maximum flow rates of many of the Holset turbochargers are available on their website. They are all listed in kg/sec, but you just have to convert them.
The maximum flow rate of the HX35 is .46 kg/sec, which converts to 60.84 lb/min, and we all know that the HX35 is quite easy to outflow with a modified Cummins. An extra 7 lb/min doesn't seem enough to make it THAT much better of a turbocharger.
Besides, I don't want to be at the top level of a turbocharger's efficiency range. At that level turbos tend to start to heat up the charge air much more than necessary.
The maximum flow rate of the HX35 is .46 kg/sec, which converts to 60.84 lb/min, and we all know that the HX35 is quite easy to outflow with a modified Cummins. An extra 7 lb/min doesn't seem enough to make it THAT much better of a turbocharger.
Besides, I don't want to be at the top level of a turbocharger's efficiency range. At that level turbos tend to start to heat up the charge air much more than necessary.
03-05-2008, 12:39 PM
#20
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67 lb/min doesn't seem like that much for a modded CTD. The maximum flow rates of many of the Holset turbochargers are available on their website. They are all listed in kg/sec, but you just have to convert them.
The maximum flow rate of the HX35 is .46 kg/sec, which converts to 60.84 lb/min, and we all know that the HX35 is quite easy to outflow with a modified Cummins. An extra 7 lb/min doesn't seem enough to make it THAT much better of a turbocharger.
Besides, I don't want to be at the top level of a turbocharger's efficiency range. At that level turbos tend to start to heat up the charge air much more than necessary.
The maximum flow rate of the HX35 is .46 kg/sec, which converts to 60.84 lb/min, and we all know that the HX35 is quite easy to outflow with a modified Cummins. An extra 7 lb/min doesn't seem enough to make it THAT much better of a turbocharger.
Besides, I don't want to be at the top level of a turbocharger's efficiency range. At that level turbos tend to start to heat up the charge air much more than necessary.
That is interesting on the HX-35... but which variant are they referring to? They can be, I think, all the way from 55 to 61cm compressor wheels...(58 to 61 are hx35/40 hybrids though I think) I am just curious about flow from those variants.
03-05-2008, 01:16 PM
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If Kerry is guessing, that is a pretty good guess!!
I have only seen one truck with a drive pressure guage hooked up and it just happened to be on a set up like yours... only they were the arctic air twins; stock over s400.
Relentless had these set to relief @ 55psi... with the mods on the truck (05)at the time, TST late twins program w/adj. pressure and timing, the actual boost was spiking at 55, but settling more around 50-53psi. Drive pressures were (and this is just off memory so I could be off some) 65-70+psi.
I don't want to put words in the mouth of the vendor, but IIRC, they felt they could push more air, but drive pressures would be too high and could pop a HG.
I have only seen one truck with a drive pressure guage hooked up and it just happened to be on a set up like yours... only they were the arctic air twins; stock over s400.
Relentless had these set to relief @ 55psi... with the mods on the truck (05)at the time, TST late twins program w/adj. pressure and timing, the actual boost was spiking at 55, but settling more around 50-53psi. Drive pressures were (and this is just off memory so I could be off some) 65-70+psi.
I don't want to put words in the mouth of the vendor, but IIRC, they felt they could push more air, but drive pressures would be too high and could pop a HG.
AFAIK the Relentless setup didn't use the S400. Last I heard they were still using the HT3B or whatever it is. That would likely make a difference as far as DP goes...although I have no idea if it would be better or worse. Nathan has done DP tests and if I recall correctly it wasn't that bad at 50-60psi with the stocker/S400 setup.
03-05-2008, 01:26 PM
#22
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The HX 35 from 98.5-02 can only squeeze 52lb/min at about 144K rpm.
That .46kg/sec is a general max number for a whole array of HX 35's. Holset is a lot like Garrett, they have frame sizes with a ton of variations in wheels.
The difference between 03-04 turbo and 04.5+ turbo is: compressor size, 54mm for hy35 early 03, 56mm for HE341 late 03 all 04. I am not certain on the major diameter of the 56mm HE341 wheel, but the HY35 54mm wheel is 78mm. The HE351 is 60mm by 87.5mm. That gives it more high boost power, or more flow at higher pressure ratios.
I don't know for certain on the exhaust turbine side what changes happened, other than the HE351 does have a 1-2mm bigger turbine wheel.
The Stock HX35 from my truck has a 19mm wastegate hole, and the HE351 stock had a 22mm wastegate hole.
As far as wastegate actuation, all of these turbos have a mechanical spring pneumatic(air) overridden actuator. Laymen terms: they all have a spring tension rod that holds the wastegate closed and a rubber balloon-like diaphram that fills with air and compresses the spring and opens the wastegate.
The only difference to this system occurred on the 04.5+ with an electric bypass solenoid. This solenoid is mounted right on the turbo pressure side and has a smallish ~2mm hole to let boost into the silicone hose and head down to the actuator balloon-like part. Within this same solenoid, there are 3 more holes that are sealed with a neoprene washer. When the solenoid is juiced up, the neoprene washer lifts and allows pressurized incoming air to vent out the three small holes. These three holes lead to a sealed off section that is about 4mm in size that vents boosted air back to the intake low pressure side of the compressor. Because the initial air inlet port is a small 2mm opening, and the three holes are larger and lead to the outside, zero pressure is able to work on the balloon-like diaphram when the solenoid is powered up. The ecm controls the powering of this solenoid and when it is not powered, it takes about 26psi boost for the balloon-like diaphram to overcome the spring tension and crack open the wastegate flapper. When the ecm wants to let boost spike a little 32psi, it powers the solenoid, lifts the neoprene washer and all of the 2mm sized incoming air is rerouted out of the system and not allowed to gain sufficient psi to pressure up the balloon-like actuator.
solenoid opens 3 vent holes
here
incoming air====[ ]=======balloon-like actuator
Now my crude drawing above might help people to visualize. So in recap, boost air is always incoming and always has an open and direct path to the waste gate assembly. The black solenoid can basically open a 3 holed vent that limits the amount of pressure on the waste gate balloon and let the engine spike boost a little.
That .46kg/sec is a general max number for a whole array of HX 35's. Holset is a lot like Garrett, they have frame sizes with a ton of variations in wheels.
The difference between 03-04 turbo and 04.5+ turbo is: compressor size, 54mm for hy35 early 03, 56mm for HE341 late 03 all 04. I am not certain on the major diameter of the 56mm HE341 wheel, but the HY35 54mm wheel is 78mm. The HE351 is 60mm by 87.5mm. That gives it more high boost power, or more flow at higher pressure ratios.
I don't know for certain on the exhaust turbine side what changes happened, other than the HE351 does have a 1-2mm bigger turbine wheel.
The Stock HX35 from my truck has a 19mm wastegate hole, and the HE351 stock had a 22mm wastegate hole.
As far as wastegate actuation, all of these turbos have a mechanical spring pneumatic(air) overridden actuator. Laymen terms: they all have a spring tension rod that holds the wastegate closed and a rubber balloon-like diaphram that fills with air and compresses the spring and opens the wastegate.
The only difference to this system occurred on the 04.5+ with an electric bypass solenoid. This solenoid is mounted right on the turbo pressure side and has a smallish ~2mm hole to let boost into the silicone hose and head down to the actuator balloon-like part. Within this same solenoid, there are 3 more holes that are sealed with a neoprene washer. When the solenoid is juiced up, the neoprene washer lifts and allows pressurized incoming air to vent out the three small holes. These three holes lead to a sealed off section that is about 4mm in size that vents boosted air back to the intake low pressure side of the compressor. Because the initial air inlet port is a small 2mm opening, and the three holes are larger and lead to the outside, zero pressure is able to work on the balloon-like diaphram when the solenoid is powered up. The ecm controls the powering of this solenoid and when it is not powered, it takes about 26psi boost for the balloon-like diaphram to overcome the spring tension and crack open the wastegate flapper. When the ecm wants to let boost spike a little 32psi, it powers the solenoid, lifts the neoprene washer and all of the 2mm sized incoming air is rerouted out of the system and not allowed to gain sufficient psi to pressure up the balloon-like actuator.
solenoid opens 3 vent holes
here
incoming air====[ ]=======balloon-like actuator
Now my crude drawing above might help people to visualize. So in recap, boost air is always incoming and always has an open and direct path to the waste gate assembly. The black solenoid can basically open a 3 holed vent that limits the amount of pressure on the waste gate balloon and let the engine spike boost a little.
03-05-2008, 02:38 PM
#23
DTR 1st Sergeant
That's my point though...a guess (good or bad) is still nothing more than speculation. Even experts in the turbo field can take guesses at DP, but the only way to know for sure is to put a gauge on it and do some testing. Too many variables involved. I just think it should be clarified so people don't take someone's guess as a fact.
AFAIK the Relentless setup didn't use the S400. Last I heard they were still using the HT3B or whatever it is. That would likely make a difference as far as DP goes...although I have no idea if it would be better or worse. Nathan has done DP tests and if I recall correctly it wasn't that bad at 50-60psi with the stocker/S400 setup.
AFAIK the Relentless setup didn't use the S400. Last I heard they were still using the HT3B or whatever it is. That would likely make a difference as far as DP goes...although I have no idea if it would be better or worse. Nathan has done DP tests and if I recall correctly it wasn't that bad at 50-60psi with the stocker/S400 setup.
03-05-2008, 11:26 PM
#26
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And to further Dave's comment, because turbine speed is not controlled, compressor continues to speed up and create more boost.
Boost Creep
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03-06-2008, 12:08 AM
#27
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boost creep? whats that? lol..
wastgate on my truck is set to 28 psi... i dont haave a boost elbow, and tonight i saw 50 psi..... think im over spinning it? lol!!!!!
yes new turbo willl be in tomorow....
wastgate on my truck is set to 28 psi... i dont haave a boost elbow, and tonight i saw 50 psi..... think im over spinning it? lol!!!!!
yes new turbo willl be in tomorow....
03-06-2008, 07:09 PM
#28
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With my ported larger wastegate, I'm getting wastegate creep, or in other words, drive pressure is blowing open the gate at 33 psi boost with zero help from the actuator diaphram as it is not connected.
03-06-2008, 07:50 PM
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03-06-2008, 09:01 PM
#30
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It's possible that I ported it too close, but when I hook up the silicone hose, wastegate pops around 14 psi. I am getting positive pressure out of the turbo at idle so I doubt much if any exhaust is getting bypassed at idle.
I'm going to add a washer or two to the waste gate actuator to put a little more preload on the wastegate. If you space the actuator up a washer thickness, it is the same thing as shortening the rod. And doing this puts more pressure on the wastegate.
I'm going to add a washer or two to the waste gate actuator to put a little more preload on the wastegate. If you space the actuator up a washer thickness, it is the same thing as shortening the rod. And doing this puts more pressure on the wastegate.