Thread: the best sr20ve intake manifold?

yeah thats how i have done mine



this is a general rule of thumb to follow

Longer runners = higher torque lower in the rev range but hurt torque later in the rev range.
Shorter runners = higher torque higher in the rev range but hurt torque lower in the rev range.
Smaller plenum = higher torque lower in the rev range but hurt torque later in the rev range.
Larger plenum = higher torque higher in the rev range but hurt torque lower in the rev range.

so generally if you want top end power you go for small runners and big plenum

The stock unit is designed for low end torque so uses long runners and small plenum most standard units are like this.

If you want a medium i generally think adding to the plenum size is better than shortening the runners and keeping plenum same size. But its best to find a medium, so take a little off the runners but add to the plenum as well. Finding a balance and be hard.

running short runners and small plenum i am not a big fan of, the small plenum sort of starves the top end torque added from the shorter runners

I am running short runners, just under 5 inches, but i have a decent sized plenum to match. With turbo i kinda believe that runner length or plenum design is less crucial to making power cause the air is forced in there. However with turbo the overall size of the plenum can add lag. This is because the turbocharger has to fill the plenum with air. So going too stupid with big plenum's can cause no added power and a whole wack of lag.



Yeah i think the 2.5 liter plenum is too small for the 5 inch runners. Would be interesting to see how the 5inch runners would go with a 3.5 or possibly even bigger. In saying that 5 inch runners is still very small, the only reason i went so small is because its turbo, so thought the added length to the runner to achieve midrange might not even help as it might just create lag. This may not be the case but we shall see

^^^ thank you sir.

I have always gone by the rule of thumb that the plenum size should be the same volume as the engine. 2.0l engine, 2.0l plenum. It seems to work well.

some people recommend it should be 1.5x capacity

Have you tested how well that fit under hood? I did have same style intake manifold and it did hit a hood...



i'm planning to build smething like this:



and it will have itb's also...

Yeah it should fit, we did measure it, if not then maybe we will have to modify

yeah i have seen those manifolds you are planing on running before, its designed for equal flow to each runner. Would be nice with itb.s but would give way too much throttle lag with a conventional tb and turbo imo

almost finished my sr20v plenum

here are some photos of it

basically milled of the standard runners of the flange plate so i could reuse the flange plate



then port matched the flange plate to my cylinder head ports

looks great but arent the runners relitivly short for a turbo setup i thought i read in full races intake manifold design that longer runners were more optimum for a turbo setup? the manifold looks great non the less

i wanted longer runners but i was limited to space, im working with wat space i have and this is the best i could do

my brake master cylinder is on the intake side of my engine bay and ive got brake lines going all the way to the turbo side of the engine bay so it limits me to how much room i have to play with

i wanted the longer runners for more torque and so i could fit 2 fuel rails ontop of the runners but because im limited for room i can only fit one fuel rail on the one so the other fuel rail will be placed on the under side of the runners

yeah that manifold is still bad ass, quality looks excellent, how much did that run you?