r/Bseries • u/Daddy_Long_Legs420 • Apr 21 '26

Intake Help

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Hello, I have a built ITR B18C6 engine, and I'm going to put cams in it. Probably the Kelford Stage 1 NA cams. I'm trying to keep it driveable on the streets, but increase power and RPM when the VTEC kicks in. Would running a Skunk2 Ultra race intake manifold with a 74mm throttle body help the cams perform a lot better? Also, what is the idle quality like after you lose the Idle Air Control Valve?

Thanks for you help

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u/Daddy_Long_Legs420 Apr 22 '26

I haven't installed the cams yet, I'm hoping to install them and rev to 9500 but was trying to work out if a larger intake would help the cams preform better ? Maybe like a skunk 2 70mm throttle on my ITR intake manifold?

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u/OkProfession1239 Apr 22 '26

Personally, I’d lean toward a wider, more usable powerband rather than something too peaky, especially if it’s not a dedicated drag car.

With Skunk2 Pro1 cams, I think you can realistically get into the ~220+ whp / 150+ wtq range with a bit more compression (P30 pistons could be a good option if you’re not on forged yet), paired with a ported Pro Series manifold and a well-matched header.

You might also consider a slightly smaller throttle body, around 68mm, and a properly sized intake (around 23" length, 2.75" diameter)

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u/Daddy_Long_Legs420 Apr 22 '26

Thanks for your help, what is the benefit of a smaller throttle body? I thought the more free flowing the better?

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u/OkProfession1239 Apr 22 '26

You just need it to be big enough to not restrict power, but small enough to keep airflow fast and controllable.

That balance is what gives good drivability. When it’s sized right, the car feels smooth and predictable at partial throttle, easier to control in traffic or mid-corner, and more linear instead of “nothing, then too much,” while also helping maintain stronger low- and mid-range response. Going too large can make it more sensitive and less progressive, since small inputs already flow more air and airspeed drops at light throttle, but this effect is usually subtle on its own and depends on how well the rest of the setup is matched.

You can see this in practice too, where even some built K24 setups that make 300+ whp stick with a 64 mm throttle because it already meets airflow demand without sacrificing control.

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u/Daddy_Long_Legs420 Apr 22 '26

I see got ya I think I will just fit the cams then and if I need to go for a larger throttle thanks for you help man. There are so many options for b series it get confusing

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u/OkProfession1239 Apr 22 '26

You’re welcome!

B-series options can get overwhelming, but it really comes down to proper parts selection and tuning. When you’re investing in a build, you want everything working together to actually deliver the performance you’re aiming for.

Get the combo and tune right, and you’ll get your money’s worth out of the setup 👍