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Old 11-19-2012, 11:14 AM   #62
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Originally Posted by PEI330Ci View Post
Would that have more to do with exceeding 125m/sec with a 3" inlet pipe, than the manifold/plenum itself?

Obviously running large pre-manifold pipe will affect transient response...so it's a trade off with response versus peak power.
Please excuse the layman question: What is special about the 125 m/s intake speed?

Originally Posted by PEI330Ci View Post
Really good point, and pretty hard to measure without high speed sensors that would catch the dynamic response. I've looked into this from a response perspective, and the only sensors fast enough to measure this cost $1100-$1300 each depending on the range. Then you have to be able sample higher than Nyquist frequency...which is well above what most motorsport data loggers are capable off. Basically...you're into lab-grade equipment to watch this properly in real-time.....

Total cost including the logger, analysis software, and sensors would be about $11-12k. Pretty hard to build that cost into a manifold design unless you are selling a lot of them. (Or it's for a Motorsport project) Maybe FSR could comment on this?
By this stage our test setup should be on an engine dyno.

I presume that the higher (or lower) than Nyquest frequency would result in a type of "multi-scan" type sensor strategy taking samples at discernible crank angles that would later be compiled into a high resolution chart based on several crank turns worth of samples?

The presumption, of course, is that the engine operation is constant during the crank turns whose samples are utilized and that can only realistically be approximated with an engine dyno.

IF that is true, then the actual cost of obtaining equipment for these types of measurements could likely be significantly higher. What about subcontracting to a firm that already has the lab and sensors? Does FSR have access to such a lab?

Last edited by FragNasty; 11-19-2012 at 11:19 AM.
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