Ok guys, check this out. I am going to get my intake manifold ported and polished to match my head. Can I get rid of the butterflies, or will it bog my sh*t too much at the lower end? I thought since the STR is pretty much just a straight shot, that this would be about the same thing. Let me know because I am doing this REAL soon.

 

I'd keep them.

 

What is the primary function of the butterfly? Will it give a CEL if you remove it? I might do this mod also.

 

The butterfly valves control the air flow into the engine. At low rpms they are closed, so less air gets in, and vice versa at high rpms. I don't think you'd get a CEL.

 

im pretty sure you wont get a CEL. but i wired my butterflies open one time and it made no difference if anything i lost some bottom end. they open at 4800 rpm if im not mistaken. but i would leave them alone

 

I made mine stay open all the time and it sucked. I got less then 240 miles per tank of gas, and when I put it back to stock I noticed that it felt much healthier down on the bottom end.

 

The IAB Butterflies help build torque down low. They then open when when more air is required (4,800). Unless your "need" more airflow, like with a turbocharger, i'd leave it alone.

 

JDM, were you running N/A or FI. I am going to be running a FI setup. Will it put too much air at the bottom end, or can I tune around it with a Hondata?

This is thing that is getting me. How is it that the STR, Golden Eagle, and other intakes differ? Has anyone here used that type of intake manifold?

This is what I think, I am no expert, but if you are running a turbo setup, and the whole goal is to get as much air, as quick as the intake manifold will let in, wouldn't that be a good thing? Wouldn't the butterflies opening when the VTEC engages, screw with the tuning? I guess SgT had better get in on this one!

Help me out guys!

 

If you are going FI, this would help out. However, on an NA car, it will lose bottom end.

 

if you are going FI, then do it for sure! those butterflies will never open under boost!

 

Well, I am almost sold, I am looking a little bit further into it, keep the posts coming!

 

Just though i'd add; Before aftermarket intake manifolds became available, it was a common practice to remove the IAB butterflies on GSRs for more flow (high RPM). But if the added airflow is not needed, it should hurt performance.

 

you won't be able to tune the opening using the hondata...it's supported on the P72 ecu but you can't modify the actuation point. You could substitute a MSD rpm switch and use it to trigger at whatever rpm you choose.

As to them not opening under boost...I don't believe that's the case, in fact I think it's the opposite. Someone that's had them off recently should be able to confirm or deny but IIRC vacuum holds the butterflies _closed_. If I'm not mistaken this would mean that when you transition to boost they'd open automatically as there is no longer a sufficient vacuum in the intake to hold them closed. This should be an ideal situation as it maintains the "factory" funtionality when off boost but then aids in flow once pressures are raised above atmospheric.

Of course I could be wrong and just talking out my ***...

--Ian