I just wanted to post this as a reference. I measured the runners on my Skunk2 manifold. They were 11.25 - 11.75

Based on 3 formulas I've used with my cam specs, 11.50 is the optimum length for 9000 rpm. This will work out great for my motor.

Manifold (Calico Coated):

 

care to post your setup?

 

Setup:
1995 Honda H22A Engine
Golden Eagle Sleeves
IB Spec/Wiseco 89mm Strutted & Gas Ported Pistons (To Be Polsished & Calico Coated After Clearanced)
Eagle H-Beam Rods
Balanced & Polished H22 Crankshaft
DPR Stage VI+ Headwork w/ Exhaust Ports, Combustion Chambers, & Outside Calico Coated
Crower Stage 3 Cams w/ DPR Grind
Ferrea Valves w/ Calico Coating
Ferrea Valve Springs & Retainers
All Valvetrain Coated w/ Microlon
Golden Eagle Cam Gears
Skunk2 Intake Manifold Ported By DPR w/ Inside & Outside Calico Coated
STR 70mm Throttle Body
Custom ranta18 4-1 Header & Intake
Golden Eagle Fuel Rail
Aeromotive Adjustable Fuel Pressure Regulator

 

wanna post the formulas that you used, I'm interested because I'm building my own intake right now and could use the help

 

Was that measured to the backside of your intake valves? 9000 RPM is pretty high, I hope you have the required duration to make power there. Been following your build threads in All Motor. Looks very nice.

Pirate

 

I'll post up the formulas tonight.

The "optimum" length for 9000 was around 14.7". Subtract the 3.2" from the face of the head to the face of the valve and you have 11.5" for the intake runner length.

 

The three forumlas I found and used Excel to solve

= (((720-(315-30)) * 0.25 * 1300 * 2) / (9000 * 2)) - 0.5 * 2

= 132000/9000

= ((60/9000)*((720-315)/360)*1300*12)/8

variables in some were: 315 advertised cam duration, 9000 rpm, 2" diameter runner

 

what do you think about the distance from the tb to the runner entrance? i noticed that the plenum isnt tapered down at the #1 cylinder end to counteract this. i dont know just wondering your thoughts. kick *** setup by the way!

 

The inside of the manifold transitions smoothly. Its not as sharp as it looks from the outside. The throttle body could be a little farther away from the runner, but maybe Skunk2 was trying to keep it close to the stock location.

 

Can anyone tell me is it good to install Skunk2 intake mainfold to Prelude 97, H22A5? I have some mods and now 215.9HP and 222.4Nm.
I read here that skunk2 is worst than Euro-R but some of the guys said that it give up to 8HP.
Could anyone tell me what to do because i dont wanna spend money and loss power

 

Honestly this is not the thread for that. There are a lot of threads out there that can answer your questions or you can post a new one. This thread is about the runner length of the manifold and what rpm it may be optimal for. Thank you.

 

sorry