2.3L L20b custom tri-y piping size

[gumby510]

Hello all,

Have a quick question on header piping size. Would a stepped piping size of 1.5in primary 1.75in secondary and 2in collector. Or a 1.75in primary 2in secondary and 2 1/8in. Will these piping sizes be to large for a 2.3L l20b efi itb and cam in the neighborhood of 290-300/.485-.500, a87 peanut chamber head ported with largest stainless valve you can fit, to a 2.25in exhaust. I'm trying to beef up the midrange to transition better into the cam powerband.

Any insight would be appreciated.

Gumby

[okayfine]

In general, a smaller tube size increases torque at the expense of top-end. You could probably take a look at headers for KAs and see what size tubes they're running. I'm pretty sure most of them are just straight 1.625 primaries, and most are also 4-1, so no secondaries. I'd suggest sticking to 1.625s, but extending the collector as far back in the system as you can, to enhance torque.

[gumby510]

Thank you,
With looking over what the ka uses primaries range from 1.5-1.75 and are split if there a 4-1 or 4-2-1 (only found 5 different designs). In that aspect there not to different from the s2000 f20c piping sizing.

I was planing on having the mid to 3/4 point of the secondary be at the firewall and the collector end a littlbiways before the shifter. Still have some numbers to crunch and a bit more research to do (still a novice at some of this stuff)

[okayfine]

You're spec'ing a decent cam, but KA pipes are built for the larger exhaust volumes from the dual exhaust valves.

[gumby510]

Thanks again, your insight is always appreciated. Think I'll probably go with the stepped 1.5in primary-1.75in secondary with a 1 7/8 or 2in collector. Still have to looking into a few things.

[okayfine]

Might also look into the reverse cone, taper from a 2" collector to your 2.25" mid pipe. Some information at Burns Stainless.

[Three B's Racing]

For that monster motor I'd go 1.75 Tri-Y design 32" in lenght total. l do cylinders 1-4 mating at the Tri-Y and cylinders 2-3 mating at their Tri-Y with primaries as equal lenght as possible. The reverse cone taper mentioned by Jules is a very good point. Personally I'd built that header for mid to top end. I have a headers for my NA S14 SR with these exact dimensions.

[Three B's Racing]

For that monster motor I'd go 1.75 Tri-Y design 32" in lenght total. l do cylinders 1-4 mating at the Tri-Y and cylinders 2-3 mating at their Tri-Y with primaries as equal lenght as possible. The reverse cone taper mentioned by Jules is a very good point. Personally I'd built that header for mid to top end. I have a headers for my NA S14 SR with these exact dimesions.

[gumby510]

I was planning on doing equal length runners. What is your reasoning behind the 32in total length. Seems a little short.

[Three B's Racing]

Is what my header design length is, weird I know but it can easily be tuned longer at each Tri-Y.