BD twins, who runs them and how do you like 'em?
#17
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I drove a BD truck with there twins and that had a set of 100rwhp injectors installed. Yes they spooled nice, but the mid to top end seemed to me to fall off. They made lots of torque down low. I ran them up to 50psi. My twins are more sluggish but after 10psi that BD truck would be smelling my smoke. Remember to get to the 600rwhp area, they are using drugs. Christian truck put down a 610 run, running drugs. That was on a mustang dyno, at their dyno days. A street set of PDR twins would operate pretty much worked as well as your stock turbo just with a bigger and wider torque curve. I'm not gonna say that PDR twins are the best in the world but lots of guys run them.
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Originally Posted by 1qckdodge
Sitting here on overtime so I can pay for these things
Notice Jims precise aim while in the overtime position
What, no comeback??
RJ
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Originally Posted by Mike Holmen
I drove a BD truck with there twins and that had a set of 100rwhp injectors installed. Yes they spooled nice, but the mid to top end seemed to me to fall off. They made lots of torque down low. I ran them up to 50psi. My twins are more sluggish but after 10psi that BD truck would be smelling my smoke. Remember to get to the 600rwhp area, they are using drugs. Christian truck put down a 610 run, running drugs. That was on a mustang dyno, at their dyno days. A street set of PDR twins would operate pretty much worked as well as your stock turbo just with a bigger and wider torque curve. I'm not gonna say that PDR twins are the best in the world but lots of guys run them.
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Hey Mike looking at a set too,later on,just about to drop some more coin on a Kore Chase system(installed next week hopefully) along with the fender flairs---Latter bars are finally on .For now i figure i'll do the suspension before NADP's August Blackout,then look at doing the twins over the winter/spring.I'm not looking for all out race set,looking at Piers too,but i'v heard mostly good thing about the BD set.i only looking for a daily driver,nothing race or to extreme,hopefully a mild set of twins with the Smarty/Mach 4's will work.LaterDW
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Originally Posted by 1qckdodge
Sitting here on overtime so I can pay for these things
Notice Jims precise aim while in the overtime position
#25
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Tiger Rag, probably the biggest power hinderance is your HO pump. 500 is a low number for mach 6er's. You should be in the mid 600 area. My twins wont clean up the macher's until at least 50-60psi of boost. BD might have tweaked the turbo since I drove then as I told them what I was building. They told me over and over again that my truck would never make power or run decent. That was the last time that I was at their shop, about three years ago. The next day I bought a set from PDR. Must have been their good salesmanship. For trucks towing often and are around the 500 area, they are a good set of twins. If you push the 600's, I would like to see the egt's # and drive pressure with the bigger sticks.
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Originally Posted by Mike Holmen
Tiger Rag, probably the biggest power hinderance is your HO pump. 500 is a low number for mach 6er's. You should be in the mid 600 area. My twins wont clean up the macher's until at least 50-60psi of boost. BD might have tweaked the turbo since I drove then as I told them what I was building. They told me over and over again that my truck would never make power or run decent. That was the last time that I was at their shop, about three years ago. The next day I bought a set from PDR. Must have been their good salesmanship. For trucks towing often and are around the 500 area, they are a good set of twins. If you push the 600's, I would like to see the egt's # and drive pressure with the bigger sticks.
BTW, I've got a HRVP ordered. I guess I'll see what the 6's will do then. I may get hotter than a french hooker on nickel night then....who knows....hope not though. I think I'll be able to dial it down though. Head work to follow as soon as I find a good head. I'm a little afraid of the one I've got a lead on. It's already been machined for orings, but it's blown head gaskets before and after the machining...... Thought maybe after the head was shaved and re-machined it might be ok. I can pick it up cheap but I've been advised against it......guess I'm still looking.
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I would also consider porting and installing a cam into your truck. To bad your so far away as I have a good stock spare head sitting on my bench. Your new pump should dump some fuel into your engine. I'm guessing that's your limitation. As for new set of turbo, just sell your old set-up and buy a new set. I'm sure that lots of guys would be interested. Drive pressure would more than likely your limiting factor for your twins. If you can run 60 psi of boost with less than 60 psi of drive pressure running 600 plus HP, you got a sweet set-up. Typically your egt's start to become less managable as drive pressure starts to exceed boost pressure. My set-up I'm around the 1 to 1 ratio, for 60 psi of boost. My twins just start to clean up the smoke at 60 psi.
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Originally Posted by Mike Holmen
I would also consider porting and installing a cam into your truck. To bad your so far away as I have a good stock spare head sitting on my bench. Your new pump should dump some fuel into your engine. I'm guessing that's your limitation. As for new set of turbo, just sell your old set-up and buy a new set. I'm sure that lots of guys would be interested. Drive pressure would more than likely your limiting factor for your twins. If you can run 60 psi of boost with less than 60 psi of drive pressure running 600 plus HP, you got a sweet set-up. Typically your egt's start to become less managable as drive pressure starts to exceed boost pressure. My set-up I'm around the 1 to 1 ratio, for 60 psi of boost. My twins just start to clean up the smoke at 60 psi.
Yeah, that's too bad we're so far apart. I've got a shop I trust to do the head, just need to find a head not too far away. Freight would be brutal coming from Canada.
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Originally Posted by qmcdt
What are the boost levels off these setups? Is anyone checking boost pressure/temperature after each turbo? If so how much does each turbo make? (I've read high intake temps, combined with the additional heat of compression in the 2ndary turbo can get the temperatures high enough that the aluminum compressor wheel can soften/weeken causing bad things. 150 Degrees C or 300 Degrees F I've heard is the limit on these wheels. Read a while ago Holset and others where working on a cast titanium wheel to get around this heat issue) Has anyone seen a setup with two intercoolers? Warning, answers will probably be met with more questions! Thanks for you input gents.
Boost levels in twins can vary wildly, from 50psi on the low and to well over 100psi for the "big dogs".
Each turbo doesn't "make" a set boost amount, per se. It's not additive, like big turbo+little turbo=total. Instead, the small turbo multiplies the pressure it receives from the big charger, just as the big charger multiplies atmosperic pressure.
Let's say we build a theoretical twins set where each turbo runs at a 3:1 pressure ratio or PR. Ignoring losses and inefficiency, we'd get a theoretical 9:1 multiple of air pressure, or (14.7*9-14.7) 117.6psi of boost!
But very few turbos are efficient at 3:1 PR, so 2:1 is mor realistic (and more efficient), giving you an overall PR of 4:1, and changing your 14.7psia atmospheric to 44.1PSIG.
jh