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[GreenMadness]

But this is spacing the plenum from the runners, is it not?

We're talking about a plenum spacer, not the intake manifold gasket... at least I am!


If the plenum spacer does not have runners built into it, it does not increase the length of the runners. It increases the volume of the plenum... and as I said before, unless that increase is properly engineered, it could make a mess of things. It wouldn't cause major problems (though improper mixture could cause a lean condition in one cylinder, and rich in another... meaning any leaning out of the fuel mixture via ECU tuning could seriously damage the lean cylinder)

EXCEPT: the spacer everyone is refering to DOES have runners built in... thus increasing torque, and power

[owequitit]

Like it has already been said, they DO increase runner length. Therefore they increase power and torque.

In fact, with two of the blacktrax spacers stacked on each other, and the IAB plate removed, you gain about 10WHP and almost as much torque, but with no IAB restriction, and no loss of low end.

[The G-Man]

Like it has already been said, they DO increase runner length. Therefore they increase power and torque.

In fact, with two of the blacktrax spacers stacked on each other, and the IAB plate removed, you gain about 10WHP and almost as much torque, but with no IAB restriction, and no loss of low end.

But don't the IABs help with low end? Or are you saying by increasing the runner length you increase the torque enough to compensate for the torque lost by removing the butterflies?

[owequitit]

But don't the IABs help with low end? Or are you saying by increasing the runner length you increase the torque enough to compensate for the torque lost by removing the butterflies?

Look at the link to the Blacktrax page.

The spacers effectively increase runner lenght. That is the same thing the IAB's do, but they do it with a set of butterfly valves. By double stacking 2 of the spacers, and removing the IAB plate, you increase runner length enough to offset the loss of the IAB butterflies.

Since the IAB butterflies are somewhat of a flow restriction at high RPMs, and they create turbulent airflow, their removal in this case, also allows more top end HP, because the flow volume goes up.

Not to mention the fact that they are also made of thermo plastic (like a heatshield IM gasket, and thus drop intake temps even further, which leads to a few more HP.

In all, double stacked on a mostly stock H22, there was a 10WHP gain or so, with no loss in bottom end, and large gains all the way through the mid-range and top end. It wasn't a mod that just affected peak power, or a small powerband.

They are a little pricey, at $65 each, but there are very few mods that will give you 10HP for $120 this side of nitrous oxide.

[deevergote]

Ok, runners built in, then I agree. If it was just an open spacer, then it would create problems. I was imagining it differently.

For $120, I may give that a shot!

[HondaFan81]

I have this Bisimoto gasket & it is installed, it is not a spacer in purpose. It is not thick enough to validate being one, it's a sturdy phenolic reusable gasket.

[trevelyan1234]

so if i stack one plenum spacer on my iab and if i also remove the butterflies, i would get the equivalent of two spacer stacked together minus the heat resistance but only for one of those ghetto spacer

[d112crzy]

1 space+stock IAB's= more low end and torque.
1 spacer=stock IAB's=more top end with loss of low torque
2 spacers-stock IAB's= more than option 1


Removing the IAB plate and replacing it with the blacktrax spacers is kinda pointless IMO.