997 Turbo / GT22004–present Turbo discussion on the current model Porsche 911 Twin Turbo. Sponsored By SharkWerks, Inc
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I too ask about the RPM. Is this really what you are going to rev the engine to? This along with the use of Ti Valves in a Turbo engine is contrary to proven conventional wisdom.
I too ask about the RPM. Is this really what you are going to rev the engine to? This along with the use of Ti Valves in a Turbo engine is contrary to proven conventional wisdom.
I wouldnt say so, the Toyota Supra 2JZ and Nissan Skyline RB26 motors when custom built can rev that high and both run high boost levels no problem.
I totally understand what your concerns are with high RPM Boxer motors, but if one puts in the time, effort, and funds to ensure the build is done properlly, then the spoils of one efforts are his to enjoy and brag about all he wants.......until "something" happens and then you have to improve on what you have and the circle of performance tuning continues.
I totally understand what your concerns are with high RPM Boxer motors, but if one puts in the time, effort, and funds to ensure the build is done properlly, then the spoils of one efforts are his to enjoy and brag about all he wants.......until "something" happens and then you have to improve on what you have and the circle of performance tuning continues.
I'm really not sure where you are coming from. The above motor "pushes" 9200 rpm's. My motor does 9400 rpm's. I state that I hope the 10,000 rpm's EVO is shooting for is attained and that my designers say that is in the realm of destroying a boxer designed motor.
I do not know of any Porsche boxer motors pulling 10,000 rpm's. Again I hope EVOMS achieves it, however how does the 9200 rpm boxer motor shown above add anything to what I have said?
In addition touching 10K for a moment doesn't prove a thing. People have done that in over revs. Sometimes they survive, other times they don't. Drive there or hold it there for awhile (like GT3's do at 8600 to 9100) and that is what we are talking about.
If you have another video that disproves my contention ....... I really want to see it. Believe me, I really hope you do. I'd love my people to be wrong.
""In addition touching 10K for a moment doesn't prove a thing. People have done that in over revs. Sometimes they survive, other times they don't. Drive there or hold it there for awhile (like GT3's do at 8600 to 9100) and that is what we are talking about.""
I've been known to do this on several occasions. However, it was not in the design plan.
Your correct about holding the engine at 10K. A short burst on a dyno to show it ran at 10K is one thing, running it up there continuously is another.
I'm no expert on engine balance or the design criteria, but I do know that these engines have really good primary balance up to a certain engine speed. As they have opposing cylinders the balance is good until the speeds get above the point where the 2nd order of (un)balance takes over. The weight of the Pistons and the rest of the parts is far greater than Crankshaft can handle. These Cranks have very little counter weight to balance out the secondary forces. This allows them to rev up quicker at the lower speeds and because of the opposed engine configuration, do not require the counter weights.
Looking at the Crank in the photo, it looks pretty standard for a Porsche Crank. It is also streamlined for windage. This is only working against the high engine speed. I have seen Cranks made for these engines where the "counterweights" are loaded and offset to help with the secondary forces.
It also looks to have standard oiling. At 10K this may be an issue. Testing will tell. I hope not for their sake. I do not see the need to rev the engine anywhere close to that number. I would guess the engine will make its peak power well below this number. Friction and all of the other losses will no doubt take over, least of all the air flow should max out at a lower speed. There are other more serious issues that need to be addressed when running an engine at this speed. Not sure if they have been addressed. I would hope so. Most of the internal parts of these engines were not designed to be used at this speed. Some will show up sooner than later. I expect this engine to be a used at that speed very little, so hopefully all will be well. I hope so. Not to find fault, but when this sort of engine is built professionally, it is expected that all of these design issues are understood, considered and addressed.
I have seem many Porsche cranks in two pieces due to high engine revs.
""In addition touching 10K for a moment doesn't prove a thing. People have done that in over revs. Sometimes they survive, other times they don't. Drive there or hold it there for awhile (like GT3's do at 8600 to 9100) and that is what we are talking about.""
I've been known to do this on several occasions. However, it was not in the design plan.
Your correct about holding the engine at 10K. A short burst on a dyno to show it ran at 10K is one thing, running it up there continuously is another.
I'm no expert on engine balance or the design criteria, but I do know that these engines have really good primary balance up to a certain engine speed. As they have opposing cylinders the balance is good until the speeds get above the point where the 2nd order of (un)balance takes over. The weight of the Pistons and the rest of the parts is far greater than Crankshaft can handle. These Cranks have very little counter weight to balance out the secondary forces. This allows them to rev up quicker at the lower speeds and because of the opposed engine configuration, do not require the counter weights.
Looking at the Crank in the photo, it looks pretty standard for a Porsche Crank. It is also streamlined for windage. This is only working against the high engine speed. I have seen Cranks made for these engines where the "counterweights" are loaded and offset to help with the secondary forces.
It also looks to have standard oiling. At 10K this may be an issue. Testing will tell. I hope not for their sake. I do not see the need to rev the engine anywhere close to that number. I would guess the engine will make its peak power well below this number. Friction and all of the other losses will no doubt take over, least of all the air flow should max out at a lower speed. There are other more serious issues that need to be addressed when running an engine at this speed. Not sure if they have been addressed. I would hope so. Most of the internal parts of these engines were not designed to be used at this speed. Some will show up sooner than later. I expect this engine to be a used at that speed very little, so hopefully all will be well. I hope so. Not to find fault, but when this sort of engine is built professionally, it is expected that all of these design issues are understood, considered and addressed.
I have seem many Porsche cranks in two pieces due to high engine revs.
M42racer, here is another stroker crank. Go ahead a critique it.
""In addition touching 10K for a moment doesn't prove a thing. People have done that in over revs. Sometimes they survive, other times they don't. Drive there or hold it there for awhile (like GT3's do at 8600 to 9100) and that is what we are talking about.""
I've been known to do this on several occasions. However, it was not in the design plan.
Your correct about holding the engine at 10K. A short burst on a dyno to show it ran at 10K is one thing, running it up there continuously is another.
I'm no expert on engine balance or the design criteria, but I do know that these engines have really good primary balance up to a certain engine speed. As they have opposing cylinders the balance is good until the speeds get above the point where the 2nd order of (un)balance takes over. The weight of the Pistons and the rest of the parts is far greater than Crankshaft can handle. These Cranks have very little counter weight to balance out the secondary forces. This allows them to rev up quicker at the lower speeds and because of the opposed engine configuration, do not require the counter weights.
Looking at the Crank in the photo, it looks pretty standard for a Porsche Crank. It is also streamlined for windage. This is only working against the high engine speed. I have seen Cranks made for these engines where the "counterweights" are loaded and offset to help with the secondary forces.
It also looks to have standard oiling. At 10K this may be an issue. Testing will tell. I hope not for their sake. I do not see the need to rev the engine anywhere close to that number. I would guess the engine will make its peak power well below this number. Friction and all of the other losses will no doubt take over, least of all the air flow should max out at a lower speed. There are other more serious issues that need to be addressed when running an engine at this speed. Not sure if they have been addressed. I would hope so. Most of the internal parts of these engines were not designed to be used at this speed. Some will show up sooner than later. I expect this engine to be a used at that speed very little, so hopefully all will be well. I hope so. Not to find fault, but when this sort of engine is built professionally, it is expected that all of these design issues are understood, considered and addressed.
I have seem many Porsche cranks in two pieces due to high engine revs.
Simon,
Our motor power and longevity wise is designed to run all day long between 7800 and 8400 rpm's. Then again, I'm sure you already know that.
We were trying to get the engine completed for the Texas Mile but we ran into a few snags and couldnt finish it in time. We are slammed with customer builds right now but we are still working on this as time permits. We had to redesign the pistons and once we get the new set back, we will be completing the assembly. I estimate that in 2 weeks we will have all of the needed components to get it assembled and installed. I will be sure to update this thread as we make some more progress. Thanks for your interest.
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Home of the Worlds Fastest Porsche(s) and the Gumpert Apollo
996TT - Standing Mile = 231.4 MPH
996TT - 1/4 Mile Time = 9.67 Seconds
996TT - 1/4 Mile Speed = 150 MPH
996TT - 0-300 KM = 14.41 Seconds 997TT - Standing Mile = 196.7 MPH
Gumpert Apollo - Nürburgring Nordschleife = 7.11,57
""Yes, this is a problem with the 996/997TT engines. If you run too hot of a spark plug, you can fire the mixture but the cylinder temperatures go through the roof. With a better firing coil, you can run a colder plug which lowers cylinder temperatures. It is a tough game. """
???? Are you sure you understand how Ignition works?? I am hoping you mis spoke.
This is contrary to what most experienced knowledgeable performance engine experts say. Not trying to challenge your statement here, but spark plugs do no generate temperature in the chamber. They move the spark out into the chamber or back it out, and have the ability to remove temperature from themselves into the heads. In fact, all the engine people I have talked to want increase spark energy to increase the temperature not lower it.
Maybe I read this wrong, so I would like to hear what you mean here.
what the hell is this, WOW, it makes my modded 997 tt to look like a tricycle
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My motor does 9400 rpm's. I state that I hope the 10,000 rpm's EVO is shooting for is attained and that my designers say that is in the realm of destroying a boxer designed motor. 
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