My attempt at gutting the '99 intake
#21
Slowest Progress Ever
Thread Starter
iTrader: (26)
Join Date: Oct 2007
Location: The coal ridden hills of Pennsylvania
Posts: 6,022
Total Cats: 304
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.
#22
Slowest Progress Ever
Thread Starter
iTrader: (26)
Join Date: Oct 2007
Location: The coal ridden hills of Pennsylvania
Posts: 6,022
Total Cats: 304
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.
#23
Elite Member
iTrader: (2)
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,682
Total Cats: 130
The bottom half of the intake manifold was untouched with VICS active. I can only assume that the ported top disrupted flow enough to lose power. I'm putting it back to stock until the whole manifold is ported and I'll try again.
I'm doing some more comparisons today since I'm undoing it anyway, and it's difficult for me to believe it would be THIS bad. I'm doing a log at 19psi, and one with the wastegate disconnected (since my friend is running this setup on his NA car). I'll let you guys know how the numbers come out.
I'm doing some more comparisons today since I'm undoing it anyway, and it's difficult for me to believe it would be THIS bad. I'm doing a log at 19psi, and one with the wastegate disconnected (since my friend is running this setup on his NA car). I'll let you guys know how the numbers come out.
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.
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.
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 :|
#25
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
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
#31
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.
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.
#33
Slowest Progress Ever
Thread Starter
iTrader: (26)
Join Date: Oct 2007
Location: The coal ridden hills of Pennsylvania
Posts: 6,022
Total Cats: 304
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.
#36
Slowest Progress Ever
Thread Starter
iTrader: (26)
Join Date: Oct 2007
Location: The coal ridden hills of Pennsylvania
Posts: 6,022
Total Cats: 304
Played with the plasma cutter and die grinder today...
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.
#38
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.
#40
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.
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.