what about the runners, round or square? I was thinking about making one, but then some one started a disscussion on another site, where Polk performance made this square one. Since this site has proff drag racers and fabcraters I though I hear it from you guys.


They are built really well, but just wana know what you guys think.


[Modified by Therumblingteg, 8:36 PM 2/22/2003]

 

A square plenum isn't really too functional.

 

Well gee, that explains it! Thanks! Oh hey, how about some explination, eh?

 

Sarcasim will get you no where!

I was going to go into more detail but after reading your comment, I won't!

Have a nice day.

edit- Therumblingteg if you want an explanation IM me and I'll explain it in more detail.


[Modified by ekb18c, 2:32 PM 2/22/2003]

 

The round plenum intake is more beneficial.I think turbulence is the reason why you dont want the forced air to pushed into a wall at cylinder 1 int he plenom. I think the harmonics of the square one is not a good as a round one if thats the correct technical term.Maybe Tony 1 can explain this more technically if I am wrong. We build ours with large round plenums for 4 cylinders and with large throttle body openings where it tapers down to cylinder one to reduce unwanted tq but more Hp on 6 cylinders.

 

I am not allowed to im, or any thing execpt make 5 posts.

 

I've read that paralelle walls in the plenum will resonate and that resonation is bad. I can only assume that it disrupts the velocity of the charge air some how. That's all I know.

 

Lets not be a Knowledge-****. I mean jesus, if you know the answer to the question and the why of it, why not share? Because one person made a sarcastic comment? Look dude, i know you know your ****, so why not just take 30 seconds to type an answer so we can all be less dumb. (or at least just me)

Thanks,
James


[Modified by bluboy, 9:01 PM 2/22/2003]

 

One thing any highschool student could tell you, is that for a square and a circle with the same area, the circle has a smaller circumfrence. A tube with a square cross section is going to have more surface area than cylindrical tube. Surface area = friction.

I'm not going to pretend to know anything about resonances or fluiddynamics/aerodynamics. I'll let others do that.

 

...Both round and square/rectangular type intakes have beenused successfully in engines producing 600-1200 rwhp on both Hondas, Mitsu's and Supras...Its more about the plenum Volume, runner diameter and transition from Plenum to runner and Throttle body size...

 

I see you have met the realColin

I personally never understood how those square plenums flowed worth a ****, so i was never interested in one, ever.. If anyone knows what mine looks like, Or Colins for that matter, a Custom Mani was the choice in the matter...

 

Not quite. It has a lot to do with surface area, and the friction it cause's which slows down the velocity of the incoming air. Velocity is what you want, and with square runners you're going to have waaay too much surface area with that long of a runner to keep the velocity up. Unless of course you can flow that much air in the first place. Which is next to impossible with-out some crazy boost levels and a fully-worked head, but on the street forget about low-end with it. Get a rounded one so you can still have some power left for daily driving if it is a daily beast.

As far as the ports go with being squared off. They are squared on the inner and outer radius's to allow higher velocities with out having to expand the the opening around the bends, which would be very hard to produce en~mass production style. There's more to it, but I won't go into it unless you wish to hear it, ok?

BTW - I know it was an overly watered down version of what happens so please keep your trash talking to yourself.

 

i dont like that manifold one bit. I met the designer at Palmdale last november, he had no clue what he was talking about and hadnt the slightest idea about anything regarding fluid dynamics.

round is very important here.

 

Hmm.. those manifolds look alot like the extreme dsm manifolds I've seen.. Anyway, besides the square shape, isn't the plenum a little small? Looks too small IMO, but what do I know..

-Mike