dual stage intake hybrid?

[tenshi_R]

it makes me sad that so many people ditch the gsr intake manifold for a single stage
althought its a great concept, in practice the older b18c design did not work out too well for people who want to increase power.
then they made another attempt at dual stage in k20 intake manifold, replacing butterflies with rotary valve.
making much less turbulence and better flow.
looking at both intakes side by side.
i thought it would be nice if someone designed the butterfly plate of the gsr IM with rotary valves instead

so after port polish and portmatching maybe the gsr IM wouldnt be so bad...

 

[mirrorimg]

People do pull out the butterflies in the GSR intake and port/polish it, but then again that defeats the purpose of the economy side of the intake manifold.

 

[tenshi_R]

yea i red about that but after testing they actually loose power in both.

 

[Aussie]

People who modify their cars do so for performance reasons, they usually want their car to be faster. With this in mind, this design does not work as well as others. This is why no one bothers making aftermarket intake manifolds with a dual runner design.

 

[tenshi_R]

but the idea behind it to increase the mid range while keeping the topend as well
if you look at the stock itr vs gsr dyno, even with this intake gsr makes more power low and mid range
the only reason type r wins is becasue it pulls that extra 2000 rpm on top at peak power
with a reworked gsr dual runner intake i bet you can increase that power even more
and gain some power at top RPM as well...

 

[suspendedHatch]

No one makes them aftermarket because of the expense. Also, in racing no one cares about low to mid RPM. You launch in high RPM and keep it there the whole time.

The 2 stage is great for driveability. It's the exact same concept as VTEC so I don't understand how anyone can argue against it. You don't need VTEC for racing or for peak power.

 

[Aussie]

If your willing to sacrifice top end for more midrange power you can design an intake manifold for that purpose that will work better then the dual stage. They made these manifolds for the vtec motor to complement the change in airflow that resulted from the secondary cam profiles. This manifold would be pointless on a non-vtec motor.

 

[tenshi_R]

guys im talking about in theory. not practical
seeing that k20 still uses dual runners i thoght they must have some use after all, otherwise honda would not waste time redesigning it.
the purpose is to get most efficiency througout the whole rpm range not just top end.

you dont redline your car at every stoplight right?

so if the car has more power at low end it will get to your real powerband much faster.

 

[mirrorimg]

guys im talking about in theory. not practical
seeing that k20 still uses dual runners i thoght they must have some use after all, otherwise honda would not waste time redesigning it.

Again, the point of economy comes in. VTEC is Variable Valve Timing and Lift Electronic Control. Low end is economy side, once the hier RPM's come in to play the cams shift over to the aggressive lobe, and the runners open up.

you dont redline your car at every stoplight right?

If its a race car, VTEC is pointless, as it stays in the larger cam profile at all times, not utilizing the lower stage of the GSR intake.

They kept it because people dont race their cars all the time up and down the streets, hence the first stage for economy, the smaller cam profile.

so if the car has more power at low end it will get to your real powerband much faster.

Through first gear, yes. But if you are racing, once you get through that first gear power band, you are shifting in higher RPM's all the time, with no step down into the smaller intake runners (first stage).

When you shift, you dont go from 8500 down to 1000. You go from 8500 to 7000. There is no point for the dual stage.

 

[tenshi_R]

so if i did make the sandwich plate with rotary valves like the k20 and had endyn(for example) do the porting on the intake manifold, and head with flowbench testing and all.
if i put it on otherwise stock gsr after proper TUNING how would my powerband change?

 

[Aussie]

There is way to many variables to answer that question. Runner length and size matters, porting matters, honestly it is not worth the trouble. They use these variable intakes to make the vtec transition and power band smoother, not to make more power. This is them trying to appeal to other customers.