I recently bought that intake, so technically it's a spare. I am going to gut my upper plenum and see what happens. If it robs me on the butt dyno, I can simply swap it with my stock one.

How much different would my fuel VE table be if I swapped out my upper plenums? If it's gutted, would it need more fuel when VICS is open? I ask this, because once my upper plenum is gutted, I would like to do a dyno pull with my stock plenum, and then swap it with my gutted one.

Easy way to tell if you're losing airflow is to look at the log of your AFR. If it goes richer by x%, you're flowing that much air. It's not quite that simple, but it is a measurable indicator.

Make sure that you log on the same strip of road in the same direction. I used this method when tuning VVT, although VVT is different because it affects the amount of time for combustion.



If you are flowing more or less air, you will indeed need to retune. Should just be a couple of % scaling up or down and take like 5 minute.


Also, guys, check your boost levels too. Small changes 1-2 psi because of less or more restricted airflow or better/worse spool will obviously affect the results a lot.

Not enough people spend time trying to tune and optimize boost and spool. That's where all our power is too :|

The law of speed density:
If it does anything, it will require tuning.

If it drops pressure and leans out, its flowing more.
If it doesn neither of those things and requires no addition in fuel, its failaids.

I'm really surprised more people aren't going the OBX/Honda mani route. Its 2-300 bux all said and done, and is in every way more awesome than gutting the stocker.....Just sayin

18psi novody cares about power here so no interedt.

I mean we only have one vvt cam on the market. Sort of. Suck.

lol, so you don't care about power either?
cause you're still rocking one with the lamest excuse I've ever heard.

Hay now i have to dyno to see how it does with this tirbo. On my old trbo i held power to 8000

You realize how retarded that is right? With a ginormous turbo it will of course compensate for the restriction by cramming insane pressure through the mani and you most likely won't even see a dropoff at all. Because that turbo is probably bigger than your engine.

Anyways, back on topic.

Wut???


Me no understand. R u saying that big turbo no need intakemani?????

I'm saying just because you're not seeing the power plummet up top doesn't mean you wouldn't gain a good chunk of power from switching to the hawnduhh mani. just like the 2.5" vs 3" exhaust argument. Both make power, one just makes more of it.

I really hope thirdgen gets some really good and consistent logs when he hogs out his though. So far the 4 examples I've seen 1 gained 10hp and 3 either didn't gain anything or lost a few.

Hmm interesting. I mean honestly, I know that I would be best with a nice 4L dual plenum with medium runners.

ARTech may be helping me out with that. Gotta get car on road first

Were those examples on real dyno's? I'm not busting on virtual dyno, simply because people bust on me when I do pulls with my g-tech pro. They say "that thing is BS". Really? Then how come everytime I ran the actual 1/4 mile, my g-tech was within 2/10's on a second?
Virtual dyno may be correct, but I just like to see actual physical properties to give a genuine answer. Another difference between everybody elses results will be my turbo selection, my IC plumbing sizing, my atmospheric conditions, my IAT temp, etc.

Sav posted up real dyno comparisons of honda mani
So did levnubnin
So did leatherface

iirc

Played with the plasma cutter and die grinder today...
 

Attachment 38730

Attachment 38731

Today I cut the upper plenum out with a plasma cutter, then took a die grinder with a carbie bit and smoothed it all out.
The only thing I removed on the lower plenum was the little port between 2&3. I did this just for piece of mind to better evenly distribute airflow to the VICS.
This all took me like 2 hours of my Saturday, and I hope it'll make a difference when I eventually put it on the car.
I'm just glad I finally actually did some work on performance miata related stuff.

This is not valid. Until 5.25k the lines would be the same.

Not necessarily, although I'm always a little bit leery of virtual dyno pulls- It's possible that gutting the manifold might have a detrimental effect on how air flows into the normal intake runners at all RPM ranges. And while VD is sort of inaccurate in terms of generating absolute quotable numbers, it is useful for comparing before and after situations like this.

Honestly my experience with Virtual dyno has been horrible. I've yet to get 2 similar plots even when ran back to back.

I've got no problem with someone questioning my results, but insisting the graphs would be identical to 5250rpms between a stock manifold and one with the top of the manifold ported is just blatantly ignorant. Perhaps you've never looked in a 99 manifold before?

I can't remember where I posted the completed results (with top and bottom ported) but my results showed a decent gain up top but still lost a little down low. FWIW.