Let's talk intake manifold design

[Miasma]

http://www.rossmachineracing.com/intakepartspage.html

Lots of parts to make a intake.

I am going to make one for ITB's when I turbo the swap I am planning.

[z31maniac]

what dimensions do you need?
specifically?

All of them basically. :D

Runner length/diameter (is there any taper to the runner?), plenum width/height/depth (so I can determine the volume).

Are there velocity stacks inside the plenum?

[der affe]

^Dimensions on the Dbilas setup would be a great starting point!

Thanks Greg.

what dimensions do you need?
specifically?

[rs4pro3]

When I was doing research on mine, I found that for the plenum size you want the internal volume to be at least as large or larger then the total engine displacement, My plenum ended up having a volume of 3.2 liters. Runner length all depends where you want peak power, look up Helmholtz frequencies. In my case I ended up using a runner 3 inches shorter then I calculated I needed, but it ended up working perfectly, I may of miss calculated or just got plain lucky :twisted:

[Julien]

designing an intake manifold isn't really something you come decide on with a drawing. there are certainly trends to follow, but nothing is going to be more important than a little flow analysis (or a lot of it)

hai ian

[moatilliatta]

get em skills, find people with them skills! im sure there is a bunch of people who would help out.

[z31maniac]

I don't have ely's skillz to rig up a homemade ITB setup, nor I'm going to spend $2500+ or whatever it is on the Dbilas setup.

[tubby17s]

why bother with a plenum? why not just spend your time and money on setting up some ITB's and run them with either a large filter or 6 sock filters???

I have looked a lot at manifold design when i wanted to build my old m20 into a high output NA monster. alfa runs a pre chamber within the plenum to better distribute the air as opposed to the 1st cylinder receiving more air than the 6th cylinder. This also helps resonance. I have a couple of books with some good information in them. Ill try and scan them in for you guys. There is plenty of information on the web for other engines about plenum design.

But as i said originally, if it were me i would just go some open to air trumpets or the like like an old school race car.. less restriction than having a plenum, intake tune to the plenum plus a maf if your not going to be running a map sensor

[z31maniac]

^Dimensions on the Dbilas setup would be a great starting point!

Thanks Greg.

[der affe]

OP:
if you want any pic or deminsions on the Dbilas stuff let me know and i will help you out.

Greg

[der affe]

i am actually trying to figure out a cheaper way of doing this using a hacked GM ECU and what ever else it will take to make it work.

forced firebird here is doing the same thing.

we are both in the begining stages though

WAY better than MS, if i can get it to work correctly too!

[moatilliatta]

do you mean like a Ford T-bird MAF?
that is what the splitsecond/BMP kit uses they are everywhere at the pic a parts. if anyone is interested, i'll give you the Ford part number for it.

I was thinking no maf at all... use map sensor with megaquirt. and the valve for the control of the higher rpm runners controlled by rpm and not amount of air.

The runners should have an estimated rpm efficiency before built so there wouldnt really need to know amount of air going in. IMO

[alpinaclone]

With the "big bang" bikes that Honda did (the RC45 or RC51, I can't remember, one of the v4s) they had all of the power pulses very close together. They did this to make the bikes more tractable. Instead of 4 smaller almost constant power pulses, they just lumped them together, big bangs further apart apparently are better for traction than consistent smaller ones. I don't know how or why Yamaha did the big bang engines, but the way Honda did it, a massive plenum would have been required, If they even used one, I don't know.

Back to the topic. A good article can be found here, http://www.team-integra.net/sections...?ArticleID=466 . It is geared toward the Honda boys, but the theory still applies.

Good luck with it and keep me posted, I love this kind of shit.

[der affe]

i was thinking that the VR-6 intake would be more akin to our motors since it is a narrow angle V-6 as opposed to our in line six. maybe a different starting point

[DCColegrove]

designing an intake manifold isn't really something you come decide on with a drawing. there are certainly trends to follow, but nothing is going to be more important than a little flow analysis (or a lot of it)

That's where having a high volume bench comes in really handy...

Still a lot of FM and Voodoo though...