I think it will make more power than we give it credit for..... based on the injector duty cycles of the engine out of boost i will make an assumed HP rating of close to 360FWHP so lets call it 320 at the tire. With the low engine speed duty cycles being so high i bet this thing makes close to 400FWTQ
The peak rpm at maximum power goes up with the total cfm at peak valve lift. That rpm point is the measure of what the true cfm is.
On Stanley R. Weiss' calculations,
"
RPM of Peak Horse Power"
http://users.erols.com/srweiss/index.html
COPYRIGHT © 2000-2012 Stan Weiss — World Wide Enterprises
How to use the RPM of Peak Horse power
Table.1) Calculate the cubic inches of one cylinder of your motor.
2) Run across the top column and find the closest value.
3) Take the CFM for the head you are looking at a valve lift that is below maximum valve lift for the cam you are running.
4) Run down that column until the left hand column has the CFM closest to that number.--
Example --Pontiac 400 / 8 = 50 ci per cylinder.
Pontiac 16 Jim Butler has 245 CFM @ .500 lift and 504 hp
Peak Horse Power RPM from Chart 5444. This is where the cylinder volume and cfm cross.
To simplify things, Stanley R. Weiss makes the assumption that every engine has a 4456 Aspirations Index, which isn't strictly true.
A great NASCAR 351 engine has better than a 3600 ratio.
A really good 4.5 liter V6 makes just as much hp per cubic inches if done right, about 3/4's a good NASCAR V8.
The true measure of the peak power rpm is to just shove the likely CFM at 25" H20 for the given valve lift, and just factor in a very very small percentage drop in peak CFM of a bare head. Most often, a good ITB unit with the right throttle body size will drop off less than 5% of the bare head flow rate, often, no loss. 0% loss was what the Weslake 305 KarKraft GT40's were doing, the power of a 428 with the size of a 5 liter small block.
On an I6, any other kind of system (4-bbl, twin 2-bbls, triple 1-bbls) , they loose more than 10% over a bare head flow rate at the nominated peak lift of the cam considered.
So I'm spitting out 220 cfm at 25" H20 total with 528 thou real lift, and remember, CMA has done some headwork with the hogged out intakes, so whatever goodness was there in the DIYTuner tables, it'll be a whole lot "good-er-rer" with the Artist Formely Known as Mike 1157's modifications.
` Squiggle on CMA....
I'm saying power at 6050 rpm, and it'll be 380 hp, and 250 hp at the rear wheels. Automatic transmission losses on a chassis dyno are exceptionally high. On a drag strip, auto trans losses are much lower, but I haven't seen a Ford 4 speed automatic loss factor less than 1.33 on a chassis dyno. Drag strip, it computes out lower. Drive train losses are mainly tire related. Electric drive shaft or axle mounted meters without tires still show an automatic with torque converter looses a hang of a lot more than a maual gearbox. Anyways, IMHO, the biggest gain will be from the ITB, not porting the head. Porting the head wider was needed to suit the wide throttle of the BMW intake system, so its a given that cannot be gone back on. It was needed to fit all the jazz together.
I'm "edumac-cated guessing" the lack of blending of the sides of the port might prevent reaching 400 hp, as the total cfm on a bare head is often 239 cfm if the intake port is oval with the flanking walls left alone. X flow heads are kinda quirky with the twist and tumble, and mixture motion. When you go up in port sizes, its very hard to avoid grinding the side walls, and the experts seam to aggree that just going up in port size uniformly, sometimes the power gains aren't there if you take even another 20 thou of the sides. But it don't matter none. The ITB's will pulse tune the air fuel mixture, and as you fiddle with the fuel curves, you'll make it just peachy everywhere.
