Intake Air distribution vs TB location 4cyl

Hello Gentlemen, had anyone played with center mount TB on 4cyl inline vs the common side mount TB, how much air volume distribution differences you notice specially on NA application? , I assume Boosted application might have similar results.

If the manifold isn't a complete mess, it 'should' be better - remember, all single carb in-line 4's have a centre mount carburetor. Some carb' and single throttle body manifolds are specifically designed to have equal length,and diameter, runners from a common plenum below the carb'/body.

If anything, an end-mount may be expected to have poorer distribution, because of the potential pressure gradient within the plenum and/or the interaction of the pressure waves in it.

Do you have a specific engine and manifold in mind? Jenvey have some neat options, and there may be something available for your engine, if you're having problems packaging the intake system.

Yes, it is for a 4G63 NA, I found a place where they make center TB manifolds for that engine, is the only one I have seen build them, they are based in Malaysia.

Have someone ever measured with individual O2 sensors, how a common side mounted TB distribute the air per cylinder, which cylinders are leaner and which are richer?

To explain my self a little better

to know if any cylinder is getting more air flow than other, the Injectors need to be provide the same amount of fuel for that test to be accurate.

I only can guess that straight lug type plenums will make the cylinder closer to the TB go rich as the sharp turn to that cylinder and the air overshoot that inlet runner more than the others.

I will think that this will be more obvious at 50% or lower TB position, don't know if at WOT, it es less, same or worse.

I don't know what will happen with the furdest cylinder inlet runner from the TB as well, I only can guess that if someone has tested this then I can have a better ( guess) idea what a center TB will do to air flow and filling a cylinder.

Cheers

Can you post a link to the manifold, as I can't find it. Depends, most use different diameters, diversion ribs, and other tricks to balance the airflow.

However, for forced induction some 'centre entry' some will have large enough plenums that are specifically designed to give equal breathing, cecause it's less of a problem compared to carbie's for fuel drop-out and throttle response.

There are some chaps with a lot of experience with these engines, and they'd be better informed, maybe even with that manifold.

It is a 4.5L plenum volume, which apparently for the engine displacement it is the correct application for NA race engines, according to the keyboard experts in the interweb.

https://www.cncinnovationsmy.com/product-page/mitsubishi-4g63-evo-123-dsm-g2-center-feed-intake-manifold

Looks like a nice piece of kit, and should be good to go. If there is some cylinder variation, you should be able to trim it out easily.