On a tuned primary/collector exhaust system, when the inertia of escaping high velocity exhaust gases from one primary tube is occurring in the collector section, what is that doing to the other primary tubes connected to that collector? Is it pressurizing them? Is it helping to evacuate them?
Time to go Stage II!
- Thread starter Alky V6
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This is a latest engine analyzer sim output for the Stage II project. This calculation is using the cam file that I created by taking actual measurements, every 2 degrees of crankshaft rotation, of the cam I plan to use.
Instead of using the generic ramp rates supplied by the program that are used with general cam spec inputs, the program is using actual ramp rates and dwell over the nose of the actual cam profile that will be used. It's interesting to see that it appears the top end is pumped up more than previous outputs that were done without using the actual, much more accurate cam profile.
This calculation was also done with an exhaust turbine nozzle diameter of 2.38", rather than the usual 2.40" that I normally use. It also assumes a .81:1 exhbp to intbp ratio at 28 psi boost, rising to a .86:1 ratio by 40 psi boost.
She's getting quite a boost of energy there at about 7,800 rpm.
It sure looks like this new engine configuration will only be able to produce 39-41 psi boost, with this turbine housing.
Instead of using the generic ramp rates supplied by the program that are used with general cam spec inputs, the program is using actual ramp rates and dwell over the nose of the actual cam profile that will be used. It's interesting to see that it appears the top end is pumped up more than previous outputs that were done without using the actual, much more accurate cam profile.
This calculation was also done with an exhaust turbine nozzle diameter of 2.38", rather than the usual 2.40" that I normally use. It also assumes a .81:1 exhbp to intbp ratio at 28 psi boost, rising to a .86:1 ratio by 40 psi boost.
She's getting quite a boost of energy there at about 7,800 rpm.
It sure looks like this new engine configuration will only be able to produce 39-41 psi boost, with this turbine housing.
Boost creep? Dunno . It's a guess.
On N/A motor it's pressurizing, and on on force induction motor evacuates. Another Guess?
When mounting the pipe that will feed the wastegate onto the exhaust pipe, do we want the WG pipe pointing in a manner where the flow into the wastegate is inline with the flow of exhaust gases flowing through the exhaust pipe? Or, do we mount the WG pipe at a right angle to the exhaust pipe? Or, do we mount the WG pipe so that the flow has to reverse direction to get to the wastegate?
Think about this some more.
Prasad taught me this! Want to say mount the WG pipe at a right angle to the exhaust pipe!
Close, but no cigar.
It is best to have the flow feeding the wastegate inline with the flow of the exhaust pipe.
The point I was trying to make is, if the tube feeding the wastegate was mounted to the exhaust pipe in a manner that the flow had to reverse direction to feed the wastegate, the flow would have a very hard time doing that, and I would imagine the wastegate would not be as effective as it could be if mounted properly. Why is that?
OK, good.No, he did tell me that Donnie, but I can't remember everything.
Did you buy the fixture? If so, do you want to rent it out in a few months. We have the cutter head, but not the buick v6 specific plate.
Sorry, Mike. I stopped lending out tools, particularly precision tools, when they began being returned damaged.
No, I don't remember. If I recall correctly, I believe the cost is on their website.
Now, what if instead of talking about a wastegate pipe that's mounted in reverse to the flow of exhaust, we were talking about other exhaust system primary pipes meeting at a collector?
In our situation of a high rpm, turbocharged, even-fire V6 with tuned exhaust, and a low exhaust backpressure to intake boost pressure ratio, what would be the best exhaust collector design to use?
Baffle style? Or, merge style? And, what would be the advantages and disadvantages of each style in this particular application?
With a four stroke, even-fire, 90 degree V6 engine, firing bank to bank, we have a very unique situation here. Unique only to this particular engine configuration. Pick either bank of cylinders and what you have is a very strong exhaust pulse that is peaking pressure and velocity coming from one cylinder just as the exhaust valve on another cylinder, on the same bank of cylinders, is closing or seating. Provided, of course, that the camshaft timing has been figured out to take advantage of this timed event.
How do we best take advantage of the above situation to encourage better cylinder evacuation of exhaust gases and ultimately raise volumetric efficiency?
Kinda makes one curious about those long primary tubes (40+ inches long) that are often seen, and recommended for the Buick V6 in high end racing.
How do we best take advantage of the above situation to encourage better cylinder evacuation of exhaust gases and ultimately raise volumetric efficiency?
Kinda makes one curious about those long primary tubes (40+ inches long) that are often seen, and recommended for the Buick V6 in high end racing.
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