plenum size
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
plenum size
if you were sourcing an intake manifold, or fabricating your own, how does plenum size affect engine performance, assuming that throttle body size and intake runner diameter/length were fine? Can a plenum be too large for a given application? Is there a rule of thumb/formula for determining its volume? Maybe the combined volume of each runner?
I just finished fabricating a new plenum for my engine. I spent a lot of time searching the web for information, and I would suggest that you do the same.
The info I got indicates that there is an optimum size for the plenum, throttle, and intake runner volume/cross section, that will tune the setup to increase volumetric efficiency at a certain very narrow rpm range.
The way I see this is that if you are setting something up to run most efficiently at a particular rpm range you could spend the time to make the calculations and you may see some results. But the efficiency at other speed ranges may suffer due to restriction of air flow.
My plenum is slightly larger than the stock one and the runners are about 20% shorter and 10% fatter. My throttle is huge (70mm) for my 2.4l engine bu I did this so that I could get the air in the plenum to slow down and increase in density so that the engine (at WOT) would be pulling air through the runners as though they were pulling from open air.
I'm sure that this has had some effect on low speed performance but it still runs pretty good down there, and it rips right past 6000rpm
I would recommend spending some time searching the net using plenum size, runner size and hemholtz resonator as search criteria. there is a lot of math involved and I think you would likely need to try several configurations to arrive at the optimum setup.
The info I got indicates that there is an optimum size for the plenum, throttle, and intake runner volume/cross section, that will tune the setup to increase volumetric efficiency at a certain very narrow rpm range.
The way I see this is that if you are setting something up to run most efficiently at a particular rpm range you could spend the time to make the calculations and you may see some results. But the efficiency at other speed ranges may suffer due to restriction of air flow.
My plenum is slightly larger than the stock one and the runners are about 20% shorter and 10% fatter. My throttle is huge (70mm) for my 2.4l engine bu I did this so that I could get the air in the plenum to slow down and increase in density so that the engine (at WOT) would be pulling air through the runners as though they were pulling from open air.
I'm sure that this has had some effect on low speed performance but it still runs pretty good down there, and it rips right past 6000rpm
I would recommend spending some time searching the net using plenum size, runner size and hemholtz resonator as search criteria. there is a lot of math involved and I think you would likely need to try several configurations to arrive at the optimum setup.
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'93 Toyota P/U 22RE V3.0 MS2/Extra 3.1.2 Full Sequential Spark and Injection
'93 Toyota P/U 22RE V3.0 MS2/Extra 3.1.2 Full Sequential Spark and Injection