FI Plenum Design, MS'ing my 2270 Options

[Tom Perso]

Hey Guys,

I am designing a MS system for my 2270 (163.86b cam, 48x38 valves, future Triad header). I am looking at running stock intake runners and possibly making a new plenum to run my Ford TB (probably from a 4.0L Exploder/Ranger).

Are there any "design guidelines" that should be followed when making a new plenum, such as a certian volume required for engine displacement?

Looking at space requirements, I see running the TB on top of the plenum is the only way to go. That, of course - begs the question... Is the stock 914 2.0L plenum a good starting point to modify to allow for the Ford TB?

Here are some pics for reference... I had a Bus 2.0L intake system to borrow, so I am basing my measurements and ideas off of that.

http://www.qtm.net/~persot/MS/

Any ideas, suggestions, etc, are appreciated!

Thanks,
Tom

[Reiche]

QUOTE (Brett W @ Feb 3 2005, 09:41 PM)

Remember all engines are a compromise.  Factory stock engines will have compromises made in order to:   make the engine fit the engine bay   Meet emmisions and noise regulations   Make the car easy for grandma to drive to the grocery store   ETC. Assuming that Porsche built it right from the factory is not the way to settle an argument.  Porsche made the 3.0 litre S2 with 208 hp.  Not really impressive if you ask me.  Yes it is good but hell the 1.8 litre Intergra engine made 180hp from 1.8 litres.  The first production car to make 100Hp per litre.

Hey now, take it easy Brett W. Assuming Honda built it "right" isn't going to settle any arguments either, especially in a Porsche forum. And I doubt Porsche made many compromises for Grandma. Ever. (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

Back to the original question.

QUOTE (Tom Perso @ Feb 1 2005, 05:41 AM)

I am designing a MS system for my 2270 (163.86b cam, 48x38 valves, future Triad header). I am looking at running stock intake runners and possibly making a new plenum to run my Ford TB (probably from a 4.0L Exploder/Ranger). Are there any "design guidelines" that should be followed when making a new plenum, such as a certian volume required for engine displacement?

I never claimed to be settling any argument by what I wrote. I was asking how you figured a 300%+ increase in plenum volume for a 13% increase in displacement, given the stock intake runners. I'm still not sure. But I can respect what you know. Just don't read more into what I wrote than I intended. Like most here, I am trying to learn.

My suggestion was simply to look at something that works and start from there. You can look at Hondas, I am looking at Porsches (including type 4s.) Maybe Porsches don't work the same way your Hondas do, but I think I can assume Porsche's engineers know a thing or two about engine design. Did they build it "right?" I think you answered that yourself: "all engines are a compromise..." Not just factory stock engines. Yes, even Honda engines. So why dis the Porsche engineers for the compromises they chose? Don't agree with them? Fine. That hardly makes them wrong.

Speaking of compromises, just for fun let's look a little closer at the two engines you are comparing.
944S2 3.0: 208 HP @ 5800 RPM, 206 lb.-ft. @ 4100 RPM
VTEC 1.8: 178 HP @ 7600 RPM, 128 lb.-ft @ 6200 RPM
Obviously they are tuned for significantly different results. While the specific output of the Acura is impressive, that is only one of the many compromises that make the whole package. And those compromises may or may not have anything to do with the original question that started this thread.

I'm serious about that dollar. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) All good bro.