Originally Posted by SB

No, under 5250rpm tq will be higher than hp even if you had better heads and intake.It's just math.

The issue you have, is that peak hp is at 5100rpm if you where looking for more hp and at a higher rpm.

What where your goals ?

Originally Posted by SB

Endeavor is correct - this is what Tuned Port intakes do. They are designed around certain paramaters to boost power at certain rpm range (this range will change due to cid's) on a certain motor . Think OE motors. Problem is (for us hotrodders) si that after that rpm the power will drop off like a cliff. If you change cid's, the 'boosted power' rpm range will be lower.

Boy did we learn this with GM's tuned port motors.

I was lucky enough to be working at a shop around 1988, 89 ? that had a customer with a 350 TPI Vette manual trans. He was wealthy and older (my age now, lol) and wanted to get back into drag racing in a big way. He was like me (now), drag raced all the time until getting married. LOL.

Anyway, we (like others later) couldn't get it past 4500 without nosing over. Better cam, better heads (Brodix. Brodix only had one street headThat was all that was available at the time. The Dart II (cast iron) would come out a yr or two later. The AFR, then wholly schit this is great ! LOL.

Accel came out with a intake that gained about 100hp over the factory. 100hp people asked and claimed bullchit.

Well, yes and no. The intake upped the rpm range to about 5800rpm. At 5500-5800rpm the Accell was 100hp better then the factory at the same rpm. Remember, the factory nosed over at 4500 and beyond.

Anyway, the car was a rocket ship now and it took people a while at the track to believe it was this intake that absolutely dominated. This was a stock Vette with stock 5.7 tuned port short block, TPIS cam, those old Brodix heads, and the Accell SuperRam. Like this, the Car ran 11.88's at 122 or so if I can remember right. We later did a 406 with AFR's and...well. whole nother story. Car was an animal. So wasn't the driver. LOL.

Anyway, We where heroes for a while because everyone was stuck at 4500rpm fora bit. LOL.

Tuned Port intakes usually reach for the 2nd or 3rd harmonic wave, which one get's chosen depends on packaging constraints or etc. A carburetor intake will be between 4th-5th wave because they can not physically use runner lengths that long.

Here's an example on data I ran for someone with a 540, AFR heads, 5600-5800 peak rpm:

To measure port length, measure top of port(Roof) and measure bottom(Floor) of port. Add together. Then divide by 2.
Quote:
Pipemax:
{use Scotch 3M 218 Fine Line Tape to measure Roof and Floor Lengths}

- Induction System Tuned Lengths - ( Cylinder Head Port + Manifold Runner )
1st Harmonic= 36.977" (usually this Length is never used)
2nd Harmonic= 20.987" (some Sprint Engines and Factory OEM's w/Injectors)
3rd Harmonic= 14.652" (ProStock or Comp SheetMetal Intake)
4th Harmonic= 11.532" (Single-plane Intakes , less Torque)
5th Harmonic= 9.357" (Torque is reduced, even though Tuned Length)
6th Harmonic= 7.872" (Torque is reduced, even though Tuned Length)
7th Harmonic= 6.794" (Torque is greatly reduced, even though Tuned Length)
8th Harmonic= 5.975" (Torque is greatly reduced, even though Tuned Length)
Note> 2nd and 3rd Harmonics typically create the most Peak Torque
4th Harmonic is used to package Induction System underneath Hood

Plenum Runner Minimum Recommended Entry Area = 3.194 to 3.593 Sq.Inch
Plenum Runner Average Recommended Entry Area = 3.672 Sq.Inch
Plenum Runner Maximum Recommended Entry Area = 3.751 to 4.439 Sq.Inch

Minimum Plenum Volume CC = 1157.9 [typically for Single-Plane Intakes]
Minimum Plenum Volume CID= 70.7 [typically for Single-Plane Intakes]
Maximum Plenum Volume CC = 8861.2 [typically for Tunnel Ram Intakes]
Maximum Plenum Volume CID= 540.7 [typically for Tunnel Ram Intakes]

================================================== ====

-- Cross-Sectional Areas at various Intake Port Velocities (@ 28 in.) ---
159 FPS at Intake Valve Curtain Area= 4.524 sq.in. at .640 Lift
181 FPS at Intake Valve OD Area and at Convergence Lift = .563
223 FPS 90% PerCent Rule Seat-Throat Velocity CSA= 3.221 sq.in. at 5600 RPM
350 FPS Velocity CSA= 2.051 sq.in. at 5600 RPM Port Sonic-Choke with HP Loss
330 FPS Velocity CSA= 2.178 sq.in. at 5600 RPM Port Sonic-Choke with HP Loss
311 FPS Velocity CSA= 2.311 sq.in. at 5600 RPM Smallest Useable Port CSA
300 FPS Velocity CSA= 2.395 sq.in. at 5600 RPM Recommended Smallest Port CSA
285 FPS Velocity CSA= 2.521 sq.in. at 5600 RPM Recommended Smallest Port CSA
260 FPS Velocity CSA= 2.764 sq.in. at 5600 RPM Recommended Port CSA
250 FPS Velocity CSA= 2.874 sq.in. at 5600 RPM Recommended Port CSA
240 FPS Velocity CSA= 2.994 sq.in. at 5600 RPM Largest Intake Port Entry CSA
220 FPS Velocity CSA= 3.266 sq.in. at 5600 RPM Largest Intake Port Entry CSA
210 FPS Velocity CSA= 3.422 sq.in. at 5600 RPM Torque Loss + Reversion
200 FPS Velocity CSA= 3.593 sq.in. at 5600 RPM Torque Loss + Reversion

Originally Posted by SB

I new I did a long post on this before some years back.

Originally Posted by SB

I new I did a long post on this before some years back.

Originally Posted by bck

I seem to remember the Lingenfelter Box being the game changing tuned port intake. He sold it to one of the big companies ( accel or e-brock) and never really got the credit for it. Is this the intake of which you speak SB?

Originally Posted by SB

Bang ! I sniffed out that hunk of schit intake ! LOL.