Maybe with some dyno results everyone has been waiting on :yum:

I'll get you some new cad pics for fapping. :rofl2:

Soon, soon!! 11 days

Just a thought, but i came across this, and wanted to give you a heads up.. You might wanna pick this up

http://www.the370z.com/parts-sale-pr...tor-cover.html

Wow :eek: pornography is sayin little, absolutely :yum:

That's basically option 2 from the first post, you have to have a custom lower manifold, cut intake piping, and get custom fuel rails. Would be nice if it was plug n play, but that's the point of this thread ;)

Avery370z got his manifold extrude-honed, got decent gains after tune. http://www.the370z.com/intake-exhaus...-intake-3.html

^ that was gains from headers and manifold. Still no real knowledge on manifolds alone. :/


Well anyways I got my manifolds off yesterday, started doing some measurements and such on breaks from installing headers (a pain in the *** to do alone btw, passenger done, drivers side getting done sometime this week). Got to thinking about what options for manifolds can be made and what will be most efficient.

Equal length manifolds
Pros - easiest to design, equal air to all cylinders
Cons - more bends in piping, reducing efficiency

Shortest runners direct from TB
Note - a smaller plenum with short runners is also an option to help with harmonics of opening and closing valves
Pros - least bends, probably most efficient
Cons - very difficult to design, lots of math, will need to look into pressure changes from opening and closing valves, piping diameter will be different for each cylinder, longer piping slightly narrower to start. This will increase airflow velocity and overall volume to that cylinder vs equal size, this will ensure all cylinders receive equal air.

Large Plenum, equal runners
Pros - better application for turbo/boost, the plenum acts as a surge tank for when the valves open and close (pressure not released by the bov) These will have the shortest runners possible
Cons - my goal is more for a NA vehicle, but this is something to consider.

Take a peek at the Jenvey site in the UK .. here:

Throttle Body Selection with Jenvey Dynamics - Jenvey Dynamics

There are a plethora of factors that influence induction system design, none-the-least of which is intake runner length - for an NA engine.

There is no doubt that longer runners generally improve torque and shorter runners improve throttle response, so that is trade-off #1

There is also the trade-off between ultimate power at 9 gazillion rpm and the ability of the induction to support optimum engine acceleration at or around peak torque

If you are not already familiar with induction system design, I suggest you prepare to spend a significant time on the web researching.

The other point is that the induction for a full-race engine will be a pig on the road - it will p155 and f4rt on the road and generally not be tractable, BUT it will howl like a banshee between peak torque and peak HP.

The other extreme can offer monster torque in the low/mid-range but have the engine fall off a cliff when the rpm rises.

Be prepared to do lots of work on the dyno unless you have access to CFD tools and can map your chosen design to do the research in the virtual world.

None of this stuff is simple !!

Have you got or can you build a flow bench? That alone would be a good starting point to see where you have room to make improvements in cfm.

On a related note, if you haven't already played with some calculators, check these out!

http://www.wallaceracing.com/runnertorquecalc.php <-- this one is especially handy if you have measurements on the OEM runners -- start from there and see where you can make changes.

https://www.rbracing-rsr.com/runnertorquecalc.html

http://www.bgsoflex.com/intakeln.html

Some very useful tips and maths here too
http://www.team-integra.net/forum/bl...culations.html

Thanks for the links guys. I'm fully prepared for lots of research and always considering advice/comments. Otherwise it would just turn into dumping money into a crap shoot as Kinetic did...

I do not have a flow bench yet, but I DO have full CFD tools.

One thing I haven't seen anywhere yet:
When a valve closes, obviously the air that was accelerating towards the opening will rebound and send a pressure wave back towards the plenum (the point of a plenum to start with). Ideally I would think the runners should be tuned so that this wave is reaching the plenum at the same moment an alternate valve is opening, thus creating a minimal boost in pressure going to the next cylinder. This may only be optimal at a peak rpm or range though as the pressure wave frequency changes based on rpm and vacuum.

intake valve timing can be tuned quite a bit, so you may have a good bit of wiggle room there. It might be worth seeing if someone with the protuner cable can datalog some info you might be able to use as a reference point.

Actually, on that note, as you get a prototype or two built, I'd definitely see if you can team up with someone who has/borrow a protuner cable.