90GT Greg Brown Engine Build
01-29-2016, 09:36 AM
#46
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Originally Posted by GregBBRD
This 5.9 had to be built to see if what we were interpreting from dyno testing had any basis.
My custom intake is back on the front burner and is smoking....
My custom intake is back on the front burner and is smoking....
01-29-2016, 11:02 AM
#48
Rennlist Member
What makes this build so impressive to me is the incremental acreage above the torque curve of the motor Jim took to Greg. This motor was a pretty impressive performer to start with after Louie's initial tune and the efforts Jim has put in since acquiring the motor. The motor now produces the previous peak torque at about 2k rpm and does not drop below it again until after 6k rpm if I read the chart correctly - that is an awesome gain.
For sure you do not get these sort of gains free in a packet of corn flakes!
Well done chaps.
Rgds
Fred
For sure you do not get these sort of gains free in a packet of corn flakes!
Well done chaps.
Rgds
Fred
01-29-2016, 01:52 PM
#50
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01-29-2016, 02:36 PM
#51
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Wow that dyno figure is amazing. Hell I would just be happy with 400 at the crank in my S4, but near that amount to the rear wheels sounds incredible.
What is involved in making 968 pistons work in a 928 engine though aside from boring out? I can't think much custom work on the pistons as the recesses are cut already to accommodate the 4-valves.
What is involved in making 968 pistons work in a 928 engine though aside from boring out? I can't think much custom work on the pistons as the recesses are cut already to accommodate the 4-valves.
01-29-2016, 02:37 PM
#52
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Wow that dyno figure is amazing. Hell I would just be happy with 400 at the crank in my S4, but near that amount to the rear wheels sounds incredible.
What is involved in making 968 pistons work in a 928 engine though? I can't think much as the recesses are cut already to accommodate the 4-valves.
What is involved in making 968 pistons work in a 928 engine though? I can't think much as the recesses are cut already to accommodate the 4-valves.
01-29-2016, 02:38 PM
#53
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I edited my post to include the boring. If you bore, you just have to 're-paste' the block to polish the bores, correct as the entire block is alusil?
01-29-2016, 02:42 PM
#54
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This 5.9 had to be built to see if what we were interpreting from dyno testing had any basis.
.
I spent literally weeks on end (thanks for your patience Jim and Sue) working-up/flow bench testing these heads and intake system, just to see what the potential actually was. Jim/Sue's heads have stock valves and flow considerably more air than Rob's heads with big valves.
I'm not sure if we will ever bolt this intake onto Rob's 6.5, but it sure would be an interesting data point.
My custom intake is back on the front burner and is smoking....
.
I spent literally weeks on end (thanks for your patience Jim and Sue) working-up/flow bench testing these heads and intake system, just to see what the potential actually was. Jim/Sue's heads have stock valves and flow considerably more air than Rob's heads with big valves.
I'm not sure if we will ever bolt this intake onto Rob's 6.5, but it sure would be an interesting data point.
My custom intake is back on the front burner and is smoking....
I have no idea, but if I were going to make up an answer it would be something like this: Every time the cylinders fire, torque is imparted to the crankshaft. The crankshaft deflects under this torque, which sets up vibrations when the torque is released. At certain engine speeds the torques imparted by the cylinders are in sync with the vibrations in the crankshaft, which results in a phenomenon called resonance. This resonance [can possibly] cause stress beyond what the crankshaft can withstand, resulting in crankshaft failure.
To prevent this vibration, a harmonic balancer is attached to the front part of the crankshaft. The damper is composed of two elements: a mass and an energy dissipating element. The mass resists the acceleration of the vibration and the energy dissipating element (e.g. rubber) absorbs the vibrations. Unquote (wikipedia).
Actually I am not sure about that energy-absorbing bit, rubber seems more elastic than energy-absorbing. But in any case hard rubber is neither elastic nor energy-absorbing.
ke.
To prevent this vibration, a harmonic balancer is attached to the front part of the crankshaft. The damper is composed of two elements: a mass and an energy dissipating element. The mass resists the acceleration of the vibration and the energy dissipating element (e.g. rubber) absorbs the vibrations. Unquote (wikipedia).
Actually I am not sure about that energy-absorbing bit, rubber seems more elastic than energy-absorbing. But in any case hard rubber is neither elastic nor energy-absorbing.
ke.
01-29-2016, 05:20 PM
#57
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Yes, but still available new. Porsche is doing their best to keep demand low.
01-29-2016, 09:23 PM
#58
Rennlist Member
Now you have me thinking
Now that you have taken your car out of the hands of Mary and Greg, I have taken your place. What was once thought might be a broken valve has turned into a new motor....ta da!
Long story short and I will post it again under the "red car" but when I had the intake powder coated
even thou I cleaned the heck out of the inside there must have been a pocket of crud that I did not get to.
Thus I did a great job of sandblasting everything that moves. Greg happen to have another motor that he can swap all my good bits onto....
Now the question comes up that since I am into this what else can improve on that makes sense?
Van
Now that you have taken your car out of the hands of Mary and Greg, I have taken your place. What was once thought might be a broken valve has turned into a new motor....ta da!
Long story short and I will post it again under the "red car" but when I had the intake powder coated
even thou I cleaned the heck out of the inside there must have been a pocket of crud that I did not get to.
Thus I did a great job of sandblasting everything that moves. Greg happen to have another motor that he can swap all my good bits onto....
Now the question comes up that since I am into this what else can improve on that makes sense?
Van
01-29-2016, 11:38 PM
#60
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