How DA affects Compression?
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From: Albuquerque NM - The Land of 8000ft DA
Originally Posted by CamKing
Those books are flat-out wrong. A turbo engine doesn't require as much valve lift or exhaust duration as a NA engine. It also doesn't require as big of an intake port. A turbo engine also reqires a different exhaust profile then a Blower engine running the same amount of boost. I've been designing cams for Turbo race engines for over 20 years, Including the Buick Indy V6 project and Cosworth Indy cams for many teams including Penske. My father was a well know expert in Turbocharging and consulted for many of the F1 teams when they first went to Turbos. He's also written a few SAE papers on Tubocharging.
I would love to read them I'm and engineer and science geek
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Originally Posted by sscam68
Oh???? Do you have the name of the papers? I would love to read them
I'm and engineer and science geek
I would love to read them I'm and engineer and science geek
Do you know if they can be looked up by author?
That may be easier.
11 Second Club
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From: Albuquerque NM - The Land of 8000ft DA
Originally Posted by CamKing
I have the original copies in a box somewhere around here.
Do you know if they can be looked up by author?
That may be easier.
Do you know if they can be looked up by author?
That may be easier.
Originally Posted by gun5l1ng3r
When you raise the compression on a motor that is at say 8000 ft DA, do you have to raise the octane accordingly? Or does the less dense air allow more compression before detonation?
For example a motor at sea level with 10:1 CR needs about 91 octane fuel. If you have a motor at 8,000 DA, could you raise the compression to 11.5:1 and still run 91?
For example a motor at sea level with 10:1 CR needs about 91 octane fuel. If you have a motor at 8,000 DA, could you raise the compression to 11.5:1 and still run 91?
Those books are flat-out wrong. A turbo engine doesn't require as much valve lift or exhaust duration as a NA engine. It also doesn't require as big of an intake port. A turbo engine also reqires a different exhaust profile then a Blower engine running the same amount of boost.
Here in Colorado Springs the DA right now is around 9400ft. No wonder my car runs over 1.5 seconds slower than at sea level. Gas is 85, 87, and 91 for the ballas. Generally speaking for an average 14-16 sec car, the highest output engine (LS1 for a Z28), will feel like the base model engine up here (3.8l). Hard to imagine, but it sucks.
Originally Posted by Old SStroker
Let me rephrase the question:
What happens below about 18,000 mph to a craft launched from Earth?
What happens above about 24,000 mph to a craft launched from Earth?
What happens below about 18,000 mph to a craft launched from Earth?
What happens above about 24,000 mph to a craft launched from Earth?
Well, since no one else tried this one, it just occured to me what you were getting at: orbit velocity and escape velocity, right?
Not sure why that didn't come to me the first time I read it this morning.
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Originally Posted by FieroZ34
However in terms of max performance for forced induction, generally speaking the bigger the better. The bigger your intake ports, the shorter the runners, the bigger the valves and valve lift, the more power you'll make. It's all about CFM.
The biggest mistake engine builders make is believing bigger is better.
The second biggest is looking at air in CFM. You need to look at it in Lbs/Hr.
You also need to look at pressure differentials on both sides of both valves. That is what makes Turbo engines so much different then NA and Blower engines.
Originally Posted by CamKing
Nope.
The biggest mistake engine builders make is believing bigger is better.
The second biggest is looking at air in CFM. You need to look at it in Lbs/Hr.
You also need to look at pressure differentials on both sides of both valves. That is what makes Turbo engines so much different then NA and Blower engines.
The biggest mistake engine builders make is believing bigger is better.
The second biggest is looking at air in CFM. You need to look at it in Lbs/Hr.
You also need to look at pressure differentials on both sides of both valves. That is what makes Turbo engines so much different then NA and Blower engines.
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Originally Posted by FieroZ34
I said generally, and it holds true for forced induction engines.
Originally Posted by CamKing
You can not lump Turbo and Blower engines together. They are two different animals. The exhaust side of a turbo engine is nothing like an NA engine.
The exhaust side of a turbo engine is very much like that of a N/A engine. The design is still very similiar. The only difference is that there is probably more exhaust gas on the FI motor. But equal lengh and scavaging still plays a big role in the design, just primary length takes a back seat because it is more critical to keep exhaust temperature high. The optimum turbo manifold is still equal length though.
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Originally Posted by FieroZ34
The exhaust side of a turbo engine is very much like that of a N/A engine. The design is still very similiar.
NA engines don't have pressure differentials anywhere near that of a Turbo engine.
Think about what happens when you've got a turbo evacuating 8,000lbs/hr of exhaust, and the exhaust valve closes.
Originally Posted by CamKing
Not in any form of racing I've seen.
NA engines don't have pressure differentials anywhere near that of a Turbo engine.
Think about what happens when you've got a turbo evacuating 8,000lbs/hr of exhaust, and the exhaust valve closes.
NA engines don't have pressure differentials anywhere near that of a Turbo engine.
Think about what happens when you've got a turbo evacuating 8,000lbs/hr of exhaust, and the exhaust valve closes.
Originally Posted by Old SStroker
Let me rephrase the question:
What happens below about 18,000 mph to a craft launched from Earth?
What happens above about 24,000 mph to a craft launched from Earth?
What happens below about 18,000 mph to a craft launched from Earth?
What happens above about 24,000 mph to a craft launched from Earth?
