BD Twins
10-11-2008, 10:33 AM
#16
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Not trying to pick a fight, but here is no way a stage 2 could support Flux 3.5's.....A stage 2 can't support 2.5's for that matter.
I believe the Smarty 4.2 would hit the 3.5's too hard over-fueling the setup as soon as you dropped the hammer. This would cause poor initial roller acceleration then just as it got going the pump would fall off and the 4.2 would run out of rpms.....Killing what little was left of the run....
You can see from my (concave) dyno curves that even the Smarty 4.4 and Flux 2.5's were over-fueling the little turbos.
Was that your first setup or something?
All in fun!
I believe the Smarty 4.2 would hit the 3.5's too hard over-fueling the setup as soon as you dropped the hammer. This would cause poor initial roller acceleration then just as it got going the pump would fall off and the 4.2 would run out of rpms.....Killing what little was left of the run....
You can see from my (concave) dyno curves that even the Smarty 4.4 and Flux 2.5's were over-fueling the little turbos.
Was that your first setup or something?
All in fun!
My first set up was Flux 2's modded pump and BD twins I did 789.
Rob
10-11-2008, 11:32 AM
#17
10-11-2008, 12:03 PM
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10-11-2008, 01:42 PM
#20
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The R700's with 90HP sticks are around a 650hp setup. The tow twins are good to about 565-575hp no matter how much fuel you toss at them. How can the tow Twin's blow the R700's away?
I think you had a "friendly Dyno".
I think you had a "friendly Dyno".
10-11-2008, 11:48 PM
#22
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When I had the BD twins installed, my truck was only able to make 596 HP one time (TST/MP8). The other 20 or so times I dynoed with the BD twins the truck always put out 570-580 HP consistently (Smarty normal or beta w/ TST). This was first with II 3-flow injectors and then with Flux 2 injectors - first with a Floor It Stage 1 pump and then with a Floor It Stage 2 pump. Each dyno run had plenty of rail pressure left, but the truck always just felt like it was choking out on the top end. All dyno runs were uncorrected on the Meridian Motorsports dynojet at 2600 feet elevation.
When MPI built my current set-up using the Super B turbo as a secondary, I took apart the BD primary and was surprised to see only a ~66 mm compressor with ~73 mm turbine. I can't remember if the compressor wheel was "extended tip" or not though. In short, the BD primary was basically similar to a HTT 66/71 or II Super Phat Shaft 66 (66/71) in size. Since the primary turbo size drives the ultimate power potential of a compound turbo set, we can expect no more power than what a 66/71 turbo will give. There is also nothing special about the BD primary; when HTT rebuilt mine they said it was just off the shelf Borg-Warner parts!
If you go on HTT's website they rate their Pro Street 66/71 at supporting 575-675 HP. Similarly, if you go on Industrial's website, they rate their Super Phat Shaft 66/71 "up to" 750 HP. Now, when Industrial first came out with their turbos they routinely (and infamously) tried to support their turbo ratings with dyno results using 10-20% positive correction factors. I really don't care about corrected numbers; I just care about what actually got put to the ground. Further, when I ran a SPS 66 turbo before the BD twins the most HP the truck got was a very hot ~550 HP. So for all intents and purposes of this argument let's just say that HTT's ratings are the most reasonable best case output of a 66/71 as a single turbo.
Now when you combine this turbo (as a primary turbo) with a Super B (HTBG) secondary turbo, it's unlikely that you'll get the same power output because now the exhaust has to flow through 2 restrictions (another turbo). It costs HP to drive a turbo. For example, when I installed the BD twins, I did before (SPS 62) and after dynos and found at the baseline settings I lost 20 HP and 80 rpm spool with the twins. I believe Idaho-CTD even posted on one of these diesel boards and stated that when a large single is used in a twins configuration only maybe 85% of its power potential is realized.
So if you use my experience, a 66/71 turbo when used in a twin set-up as a primary will only produce 555-655 HP based on scaling HTT's ratings.
If you use Idaho CTD's insight, a 66/71 turbo when used in a twin set-up as a primary will only produce 490-575 HP based on scaling HTT's ratings.
70 psi boost also doesn't mean squat if you have high drive pressure creating a restriction, which in turns helps create the boost reading, especially if the small BD primary is spinning away like mad like a hamster on speed in a cage. I know when I had the BD twins, I measured drive:boost at ~1:1 until ~55 psi boost and then drive pressure just started climbing and overtaking the boost reading.
In short, me thinks one needs to partake in your (in)famous Lower Mainland or Island granola wacky tabacky to get any higher HP than ~575 HP on #2 with BD twins.
Or I must be like Rob and have lots of bad luck with a dynojet...
When MPI built my current set-up using the Super B turbo as a secondary, I took apart the BD primary and was surprised to see only a ~66 mm compressor with ~73 mm turbine. I can't remember if the compressor wheel was "extended tip" or not though. In short, the BD primary was basically similar to a HTT 66/71 or II Super Phat Shaft 66 (66/71) in size. Since the primary turbo size drives the ultimate power potential of a compound turbo set, we can expect no more power than what a 66/71 turbo will give. There is also nothing special about the BD primary; when HTT rebuilt mine they said it was just off the shelf Borg-Warner parts!
If you go on HTT's website they rate their Pro Street 66/71 at supporting 575-675 HP. Similarly, if you go on Industrial's website, they rate their Super Phat Shaft 66/71 "up to" 750 HP. Now, when Industrial first came out with their turbos they routinely (and infamously) tried to support their turbo ratings with dyno results using 10-20% positive correction factors. I really don't care about corrected numbers; I just care about what actually got put to the ground. Further, when I ran a SPS 66 turbo before the BD twins the most HP the truck got was a very hot ~550 HP. So for all intents and purposes of this argument let's just say that HTT's ratings are the most reasonable best case output of a 66/71 as a single turbo.
Now when you combine this turbo (as a primary turbo) with a Super B (HTBG) secondary turbo, it's unlikely that you'll get the same power output because now the exhaust has to flow through 2 restrictions (another turbo). It costs HP to drive a turbo. For example, when I installed the BD twins, I did before (SPS 62) and after dynos and found at the baseline settings I lost 20 HP and 80 rpm spool with the twins. I believe Idaho-CTD even posted on one of these diesel boards and stated that when a large single is used in a twins configuration only maybe 85% of its power potential is realized.
So if you use my experience, a 66/71 turbo when used in a twin set-up as a primary will only produce 555-655 HP based on scaling HTT's ratings.
If you use Idaho CTD's insight, a 66/71 turbo when used in a twin set-up as a primary will only produce 490-575 HP based on scaling HTT's ratings.
70 psi boost also doesn't mean squat if you have high drive pressure creating a restriction, which in turns helps create the boost reading, especially if the small BD primary is spinning away like mad like a hamster on speed in a cage. I know when I had the BD twins, I measured drive:boost at ~1:1 until ~55 psi boost and then drive pressure just started climbing and overtaking the boost reading.
In short, me thinks one needs to partake in your (in)famous Lower Mainland or Island granola wacky tabacky to get any higher HP than ~575 HP on #2 with BD twins.
Or I must be like Rob and have lots of bad luck with a dynojet...
10-12-2008, 12:47 AM
#23
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And to further disprove 700+ on BD tow twins, lets look at the 13 flat 1/4mile statement. 8200 at 13 flat requires guess what, not 700+, not even 650+, but according to the very accurate Competition Diesel calculator 611 rwhp.
Was said truck weighed on a scale at precisely 8200 lbs cause every 100 lbs lighter is 7rwhp drop at that speed? Did it really run 13 flat or was it 13.099? Because 8200 at 13.099 drops rear wheel horse power down to a much more realistic 598.
Not trying to stir the pot too much, just stating some proven hp vs weight and time facts.
What the 600 hp limit really proves is that those BD twins must spool really fast and probably more fun on the street/ towing than a 700+ hp twin setup anyway.
Was said truck weighed on a scale at precisely 8200 lbs cause every 100 lbs lighter is 7rwhp drop at that speed? Did it really run 13 flat or was it 13.099? Because 8200 at 13.099 drops rear wheel horse power down to a much more realistic 598.
Not trying to stir the pot too much, just stating some proven hp vs weight and time facts.
What the 600 hp limit really proves is that those BD twins must spool really fast and probably more fun on the street/ towing than a 700+ hp twin setup anyway.
10-12-2008, 12:52 AM
#24
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Maybe that dyno was programmed to show projected flywheel hp based on rear wheel hp plus a correction factor. Most people accept/agree with 20% hp loss in the drivetrain so say we have 600 rwhp on the dyno times 1.2 correction factor, lo and behold 600 rwhp becomes 720 crank HP.
Just an idea of why the dyno print sheet could spit out numbers that high.
Just an idea of why the dyno print sheet could spit out numbers that high.
10-12-2008, 11:40 AM
#25
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When I had the BD twins installed, my truck was only able to make 596 HP one time (TST/MP8). The other 20 or so times I dynoed with the BD twins the truck always put out 570-580 HP consistently (Smarty normal or beta w/ TST). This was first with II 3-flow injectors and then with Flux 2 injectors - first with a Floor It Stage 1 pump and then with a Floor It Stage 2 pump. Each dyno run had plenty of rail pressure left, but the truck always just felt like it was choking out on the top end. All dyno runs were uncorrected on the Meridian Motorsports dynojet at 2600 feet elevation.
When MPI built my current set-up using the Super B turbo as a secondary, I took apart the BD primary and was surprised to see only a ~66 mm compressor with ~73 mm turbine. I can't remember if the compressor wheel was "extended tip" or not though. In short, the BD primary was basically similar to a HTT 66/71 or II Super Phat Shaft 66 (66/71) in size. Since the primary turbo size drives the ultimate power potential of a compound turbo set, we can expect no more power than what a 66/71 turbo will give. There is also nothing special about the BD primary; when HTT rebuilt mine they said it was just off the shelf Borg-Warner parts!
If you go on HTT's website they rate their Pro Street 66/71 at supporting 575-675 HP. Similarly, if you go on Industrial's website, they rate their Super Phat Shaft 66/71 "up to" 750 HP. Now, when Industrial first came out with their turbos they routinely (and infamously) tried to support their turbo ratings with dyno results using 10-20% positive correction factors. I really don't care about corrected numbers; I just care about what actually got put to the ground. Further, when I ran a SPS 66 turbo before the BD twins the most HP the truck got was a very hot ~550 HP. So for all intents and purposes of this argument let's just say that HTT's ratings are the most reasonable best case output of a 66/71 as a single turbo.
Now when you combine this turbo (as a primary turbo) with a Super B (HTBG) secondary turbo, it's unlikely that you'll get the same power output because now the exhaust has to flow through 2 restrictions (another turbo). It costs HP to drive a turbo. For example, when I installed the BD twins, I did before (SPS 62) and after dynos and found at the baseline settings I lost 20 HP and 80 rpm spool with the twins. I believe Idaho-CTD even posted on one of these diesel boards and stated that when a large single is used in a twins configuration only maybe 85% of its power potential is realized.
So if you use my experience, a 66/71 turbo when used in a twin set-up as a primary will only produce 555-655 HP based on scaling HTT's ratings.
If you use Idaho CTD's insight, a 66/71 turbo when used in a twin set-up as a primary will only produce 490-575 HP based on scaling HTT's ratings.
70 psi boost also doesn't mean squat if you have high drive pressure creating a restriction, which in turns helps create the boost reading, especially if the small BD primary is spinning away like mad like a hamster on speed in a cage. I know when I had the BD twins, I measured drive:boost at ~1:1 until ~55 psi boost and then drive pressure just started climbing and overtaking the boost reading.
In short, me thinks one needs to partake in your (in)famous Lower Mainland or Island granola wacky tabacky to get any higher HP than ~575 HP on #2 with BD twins.
Or I must be like Rob and have lots of bad luck with a dynojet...
When MPI built my current set-up using the Super B turbo as a secondary, I took apart the BD primary and was surprised to see only a ~66 mm compressor with ~73 mm turbine. I can't remember if the compressor wheel was "extended tip" or not though. In short, the BD primary was basically similar to a HTT 66/71 or II Super Phat Shaft 66 (66/71) in size. Since the primary turbo size drives the ultimate power potential of a compound turbo set, we can expect no more power than what a 66/71 turbo will give. There is also nothing special about the BD primary; when HTT rebuilt mine they said it was just off the shelf Borg-Warner parts!
If you go on HTT's website they rate their Pro Street 66/71 at supporting 575-675 HP. Similarly, if you go on Industrial's website, they rate their Super Phat Shaft 66/71 "up to" 750 HP. Now, when Industrial first came out with their turbos they routinely (and infamously) tried to support their turbo ratings with dyno results using 10-20% positive correction factors. I really don't care about corrected numbers; I just care about what actually got put to the ground. Further, when I ran a SPS 66 turbo before the BD twins the most HP the truck got was a very hot ~550 HP. So for all intents and purposes of this argument let's just say that HTT's ratings are the most reasonable best case output of a 66/71 as a single turbo.
Now when you combine this turbo (as a primary turbo) with a Super B (HTBG) secondary turbo, it's unlikely that you'll get the same power output because now the exhaust has to flow through 2 restrictions (another turbo). It costs HP to drive a turbo. For example, when I installed the BD twins, I did before (SPS 62) and after dynos and found at the baseline settings I lost 20 HP and 80 rpm spool with the twins. I believe Idaho-CTD even posted on one of these diesel boards and stated that when a large single is used in a twins configuration only maybe 85% of its power potential is realized.
So if you use my experience, a 66/71 turbo when used in a twin set-up as a primary will only produce 555-655 HP based on scaling HTT's ratings.
If you use Idaho CTD's insight, a 66/71 turbo when used in a twin set-up as a primary will only produce 490-575 HP based on scaling HTT's ratings.
70 psi boost also doesn't mean squat if you have high drive pressure creating a restriction, which in turns helps create the boost reading, especially if the small BD primary is spinning away like mad like a hamster on speed in a cage. I know when I had the BD twins, I measured drive:boost at ~1:1 until ~55 psi boost and then drive pressure just started climbing and overtaking the boost reading.
In short, me thinks one needs to partake in your (in)famous Lower Mainland or Island granola wacky tabacky to get any higher HP than ~575 HP on #2 with BD twins.
Or I must be like Rob and have lots of bad luck with a dynojet...
10-14-2008, 10:06 AM
#26
The Super B towing twins were never designed to be a 700+ hp setup. It was designed for 550-575hp which is what they do and do very well. The R700s are designed to do 600-750hp which again they do and do very well. We now have our R850 kit that is available that has supported over 1000hp.
10-14-2008, 02:11 PM
#27
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The Super B towing twins were never designed to be a 700+ hp setup. It was designed for 550-575hp which is what they do and do very well. The R700s are designed to do 600-750hp which again they do and do very well. We now have our R850 kit that is available that has supported over 1000hp.
10-14-2008, 03:13 PM
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10-14-2008, 03:16 PM
#29