Brad

Every time I look at the lower intake manifold (upper too) I cant help but think it's a major restriction to airflow. All those nipples and butterfly plates and acv holes and egr and blah blah blah. I don't need that **** and it's messing up my flow I want a tubular manifold with two nipples on it, and bung's for the injectors, and that's it!

How difficult/expensive would it be to have a custom manifold fabricated? I've seen them on car's like crispeeds and turbostreetfighter...but they are all out drag cars w/o intercoolers and running methanol.

I figure it wouldn't be too difficult, and with this I could also get a larger mono-blade throttle body and just mate that up to a custom elbow from the FMIC.

Any thoughts/ideas/suggestions/flames?

Thanks!

Speedious-Freakious

Probably not hard for an experienced fabricatior to construct. Problem lies in changing the manifold design and how that would impart performance.

I am totally on the same page as you but I fear that moving to larger runners and incorperating an actual plenum would hurt more than help.

Maybe someone has some insight.

SF

Brad

Hmmm, I don't understand how changing the manifold design would really hurt performance. But then again, I have no real experience to speak from. Also, increasing the runner size wouldn't really be necessary. Just trying to make it flow more efficiently due to not having **** in the way!

Pretty sure it would have to be for a single turbo application only. The stock twins don't offer much clearance for the manifold, which is why the damn thing is all squished up in the first place!

I dunno...maybe the stock manifold is just fine for any practical street application. I just think a nice shiny custom tubular manifold would be badass

TYSON

I just took mine off recently. It sure looks like hell. When I need to build a new motor I'll be looking at a new manifold, but the stock one is good for an awful lot of power, so I'll leave it alone for now.

rx7tt95

FYI, Pettit has in the past, made tubular/sheetmetal manifolds, specifically for their drag third gen (black car). Intake length, plenium volume, runner diameter, etc...all have an effect on power and power band, more so on naturally aspirated motors, but it'll affect response and powerband on a turbocharged vehicle as well.
Michel

Brad

So what are these effects? You say response and powerband are effected, but how? Does increasing the plenum volume increase power? Maybe increase top end but sacrifice low end? And what about the runner diameter etc?

I'm pretty sure one could be manufactured with similar to stock dimensions/volume...just with the added benefits of more efficient construction.

Mazderati

iTrader: (3)

Making an intake for the 13B wouldn't be hard at all as far as actually fabricating one. I'll second the fact that almost anything you change in the design of it will change the characteristics of how the engine acts. The same thing can be said of a piston motor, especially the V types. There are long runner and short runners, dual and single plane, tunnel ram, sheet metal, etc. All have an effect on how the engine will responds and to where and how you will make power.

Typically, shorter runners will flow more on top but will lack some low end punch. This is why some manufacturers have started using variable intake systems on their cars as stock equipment: long runner routing in the lower RPM's and short runner routing in the upper RPM's.

I think it would be neat to see some different designs and some results as to how they respond. evil7.com and cityperformancecentre.com have what appear to be sheet metal intakes on their 20B's. Perhaps you could contact them?

Good luck.

Kyle

poss

iTrader: (5)

by increasing diameter you will typically lose low end but gain top end. this is due to lower port velocities at low rpm entering the combustion chamber and causing poor fuel and air mixing as well as a lower filling ratio.

Brad

Thanks for the info guys.

fdracer

get the dalton im

Brad

Never heard of it. Any pics, links?

EDIT: Yes! This is what I'm talking about



Except all the pics they have are on RX3's...I see this pic the rotor housing says 13B....but is that series 5 or 6?

Any idea if they make one for a series 6 motor? They didn't have any info on their website about the manifold...

fdracer

yeah they have one for the fd