With the electronic controller you can see the behavior of the turbo system by the amount gate pressure and set point targets.
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Does anyone make a 3.5 in downpipe that will clear my Kenny Bell headers?
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The 3.5" GN1 cleared my ATR's , I don't know if they are similar to KB's
I believe they're very similar.
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Call them , I believe you want to talk to Archie ( the Boss ) , he can probably tell you because I asked about my ATR's before I purchased mine .
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They are similar , they take up the same dimensional space, just the welds are in different spots
What is your back pressure to boost ratio?
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On the 6767 & 3" downpipe it was close to 3:1 , now with the 6771 & 3.5" downpipe and cut-out it's 1.8:1
Sam i think with the 6767 and 3 inch you were at 2:6 I was 3:1 on my setup
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Sam i think with the 6767 and 3 inch you were at 2:6 I was 3:1 on my setup
That's what happens when you get old , you get confused !!
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Whos .85 ex housing do they use or do they cut there own?Sam i think with the 6767 and 3 inch you were at 2:6 I was 3:1 on my setup
It's a pte.85
No worries my friendThat's what happens when you get old , you get confused !!
BaldMenace
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So what level does a 252" engine need to be at to support this awesome quadruple bald bearing turbo?
Interesting video on hot side back pressure, plus some of my thoughts. Like hearing about the experience of others.
Here is a good example of backpressure and what it cost. You have to look at only between 6000 and 6500 rpm for this example, because he had uncontrolled waste gates, so this is the only range that boost was equal and hence an equal comparison. He did not provide measurements on the intake side other than manifold boost, but since the same intake components were used, I bet negligible difference here. The other piece that would have been nice to know is the exhaust temperature at the turbine inlet.
The back pressure difference is close to 6 to 7 psi, which is netting roughly 50 HP on this particular engine. This is a dyno test, so spool up is not represented. Since the turbo and intake tract are the same, exhaust down stream of the turbo is the same, all of the difference is in the hot side exhaust.
The compressor side power requirement, between 6 to 6500 rpm is going to be the same. The intake flow for both cases will be essentially the same (fuel flow would have been another good piece of info), unless do to cam overlap you may be getting some more mass flow through the engine with the lower back pressure, and turbine shaft speed would have to be the same. This means the exhaust flow has to be different through the turbine. The only way that occurs is if exhaust is hotter, higher specific volume, less mass flow through the turbine at higher pressure. The higher pressure will give a higher pressure drop and more energy extraction from the exhaust to drive the compressor at the same shaft power with less mass flow, which means more is being passed through the waste gate in the lower power case. I think the better flow and volume of the SS tube headers is allowing more expansion and hence cooling of the exhaust gas, lower specific volume and hence lower pressure before the turbine. The headers are also likely dissipating more exhaust heat that the Hookers too.
My guess is the power picked up mainly due to reduced pumping losses.
On the Buicks, the stock headers and the aftermarket stuff is usually not a problem like this example with the Hooker cast manifolds, but it does show the cost of back pressure on HP, so optimizing the hot side and the turbine is important.
Here is a good example of backpressure and what it cost. You have to look at only between 6000 and 6500 rpm for this example, because he had uncontrolled waste gates, so this is the only range that boost was equal and hence an equal comparison. He did not provide measurements on the intake side other than manifold boost, but since the same intake components were used, I bet negligible difference here. The other piece that would have been nice to know is the exhaust temperature at the turbine inlet.
The back pressure difference is close to 6 to 7 psi, which is netting roughly 50 HP on this particular engine. This is a dyno test, so spool up is not represented. Since the turbo and intake tract are the same, exhaust down stream of the turbo is the same, all of the difference is in the hot side exhaust.
The compressor side power requirement, between 6 to 6500 rpm is going to be the same. The intake flow for both cases will be essentially the same (fuel flow would have been another good piece of info), unless do to cam overlap you may be getting some more mass flow through the engine with the lower back pressure, and turbine shaft speed would have to be the same. This means the exhaust flow has to be different through the turbine. The only way that occurs is if exhaust is hotter, higher specific volume, less mass flow through the turbine at higher pressure. The higher pressure will give a higher pressure drop and more energy extraction from the exhaust to drive the compressor at the same shaft power with less mass flow, which means more is being passed through the waste gate in the lower power case. I think the better flow and volume of the SS tube headers is allowing more expansion and hence cooling of the exhaust gas, lower specific volume and hence lower pressure before the turbine. The headers are also likely dissipating more exhaust heat that the Hookers too.
My guess is the power picked up mainly due to reduced pumping losses.
On the Buicks, the stock headers and the aftermarket stuff is usually not a problem like this example with the Hooker cast manifolds, but it does show the cost of back pressure on HP, so optimizing the hot side and the turbine is important.
It doesnt need to be a 252 109
Stock stroke heads and cam 109 will shine on these new turbos as well.
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Someone very close to me,who makes stupid $, asked what i want for xmas,, oh my. My stock balanced 109 rotating assmbly in my sig. With the instant power of the HTP bb6466 ,, keeping it fat on 93 and alky, low10s a/f ,, 16/15" ,,turbo 70% all in ,, how long will it be before i split it down the middle?
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