Thread: If you could make your own intake manifold

Quality control is my main issue with intake manifolds for our cars since most/ almost all are custom besides a couple. I toyed with the idea of making my own but without easy access to a flow bench or dyno Id think it would be pointless. Especially without a flowbench for the sake of making sure all runners are running the correct/same cfm +- 2 or 3. I just feel like in the end my bottom end would hate me without super accurate measurements.

664 turbo hp right? Thought the n1 was more for n/a applications. Id love to keep close to oem with a boosted app if the n1 was an option. On a de couldn't you just cut the flange and make it work with a flange off a de mani?

Yes that was turbo hp. The car was at 28psi. And I can def see somebody swapping intake manifold flanges.

With turbo applications, flow numbers matching on the runners is not really that important anymore. Even with a very large turbo your starting to see positive pressure almost anywhere in the rpm band under full throttle.

With turbo its all about size. The ve runners and even de runners are pretty decent size so no real need to make them any bigger. The biggest hinderance in turbo applications especially when on a t3 frame turbo is the small plenum size and small throttle body.

The n1 intake manifold works well mainly because of the larger throttle body. The stock plenums flow pretty well into the runners with nice smooth bowls being a cast manifold and all.

Again for turbo aps especially large turbos, bigger runners if you desire, bigger plenum, and bigger throttle body. Plenum should flow smoothly across all runners tapering down to the #1. Velocity stacks are a plus, larger the better and the closer to each other the better.

The plenum on my manifold is a 3 liter plenum roughly double the size of a stock ve plenum. Q45 throttle body roughly 82mm inside diameter i believe vs the stock 58mm if im not mistaken. All good things to have on turbo applications.

Again runner flow being equal is really almost irrelevant in turbo aps. N/A, now thats a whole different story.

Ive seen and been that 664whp car.

Rob knows hell have no issues with that mani for making his goals.

n1 manis make no extra compared to a standard mani when it comes to na. When it comes to turbo the n1 out performs the standard mani.

Im not sure why.

when it comes to intake manis for all motor cars the needs change for whatever reason.

Stratton.

Edit didnt see ashtons post above mine

Stratton.

So the positive pressure equals out the amount of air that is going into each cylinder through the runners if im understanding it right?

From some information gathering, I "think" im on the right track. Higher hp goals would warrant the use of such a high capacity plenum as yours ashton, but on the other hand what about a road course car? From what I can see, a smaller plenum (not as small as stock) would yield decent gains but also provide less lag. Im giving a guess that the the lag between the throttle plate opening and the large air volume of huge plenum would effect engine response. Sure if the car is built for just the strip you could use a 2 step which would make the engine respond faster of course, but that kind of lag wouldn't help you out in the long run on a road course. Am I on the right track or way off?

Small responsive turbos would do fine with stock manifolds and turbos, if you want a little more power you could add the larger throttle body and shorten the runners and keep the plenum size fairly small, id say 1.5-2.0L, for medium frame turbos the size plenum im using now would work just fine as well as the throttle body size and short runner length.

Large turbos, the 3L plenum works pretty good.

For those running very large turbos which nobody in here is that I can recall, BMC makes a 6L plenum which is usually found on the outlaw cars running 72mm compressor wheels along with 100+mm throttle bodies.

Its pretty straight forward, the larger you go, the larger your plenum, throttle body, and piping need to be.

My build is very basic. The N1 manifold (ported by Andreas Miko) will be perfect. As for hp goals I am not sure yet. We'll see how it goes.

Now don't let the stock VE intake manifold full you. I know kevwal on here is over 600 whp with a 6262 using a stock manifold.

basically our motors are 1998cc's or 122ci or 2.0l however you want to convert it. If your intake is at least that size you are fine. You want to have enough stored energy for the next cycle basically. I plan on measuring mine with fluid. 2.0l is equal to 2000ml simple enough. I have a 2000ml measuring cup in the cabinet.

Your factory manifolds are made for low end throttle response and fuel economy unless you are driving some high end car. The larger plenum and runners will allow more power up top where our factory manifolds run out of breath. I can feel it in my car when I get up around 7k or better. The power just isn't there anymore. Thought it was the cams for the longest time but guys are pulling hard past 7k with 264's all the time. So, it's time for an upgrade...intake and exhaust.