engine Hp again!

ratio411 · Sep 17, 2009

I ran the engine again, I ONLY changed these items:
*600 Holley 1850 was changed to 750 Holley 3310 (both vacuum secondary)
*Heads were changed from stock 71 302 to professionally ported 69-73 351w.
*Intake was changed from Performer to Wieand Stealth #8020.

New numbers:
Peak HP: 330 FWHP @ 6000 (see note*)
Peak TQ: 331 @ 4500
Avg HP: 238
Avg TQ: 289

*The 'peak' is actually very flat from 5000 to 6000 RPM. Starting at 320 HP and ending at 6000 with 329. The VE is at/above 100% from 4500 to 6000. Peaking at 101.5%@ 5000 RPM. The torque curve is nice and fat from 2500 to 6000 RPM.

This is a very nice combo and was what I was shooting for with my 302.

Edit:
Oh, 330 FWHP equates to 264 RWHP, call it 265 and compare to your estimate of 275, and IMO you were right there.

ratio411 · Sep 17, 2009

Cometman64 said: ↑

that cam is good for 350hp...
Click to expand...

Just for giggles, I tried your statement and you're right.
All I had to do is change the carb from vacuum secondary 750, to double pump 750. Then changed the intake from Stealth to Vic Jr, and I got 348 at 6000 RPM.

The torque curve was more peaky, but was nice and strong from 3000 to 6000... Very strong.

ratio411 · Sep 17, 2009

Here is the report from that simulation, just as an example.
I hope this is helping the original poster, but it feels like a semi-threadjacking, so I will quit now.

Analysis Report for Street/Strip Engine with Desired HP Peak at 5500 RPM

Peak Tq =348. @ 4500 RPM 1.14 Ft Lbs per CuIn
Peak HP =348. @ 5500 RPM 1.14 HP per CuIn

Maximum Tq/CuIn is 1.137 Ft Lbs/CuIn.
This is somewhat high, indicating good performance, but will
produce high cylinder pressures and temperatures.

High cylinder pressures require precautions to protect against
detonation, blown head gaskets, damaged engine components like
pistons, rings, exhaust rocker arms, bearings, etc.

Maximum Exhaust System Backpressure 'Exh Pres' is 1.7 PSI.
This is typical for a street/strip vehicle with a free flowing,
full exhaust system. To simulate open headers, select the
'Open Headers' from the Exh System Type combo box.

Typical ranges of Exhaust System Backpressure are listed on page
32 in the User's Manual. You can lower the Back pressure by
increasing Exh System CFM Rating in the Exhaust Specs menu.
Lowering the Exh System CFM Rating will simulate a quieter, more
restrictive exhaust system. Most dyno tests are done with open
headers, which are simulated by selecting the 'Open Headers' from
the Exh System Type combo box.

Maximum Intake Manifold Vacuum 'Int Vacuum' is 1 ''Hg.
This is somewhat high and is limiting air flow and HP.

Reduce Int Vacuum by specifying a larger Carb-T/B CFM Rating in the
Intake Specs menu. Some classes of racing limit performance by
specifying a small Carb or a restrictor plate. In these cases,
you must try to improve performance with this small Carb CFM Rating
or legally make small improvements in the Carb CFM Rating.

Maximum Fuel Flow 'Fuel Flow' is 215 lbs/hr GAS.
This is equal to 36.8 gallons per hour of fuel flow.
For an injected engine with one injector per cylinder, you will require
at least 27 lbs/hr injectors.

Fuel Flow will only change if air flow changes or if you inject
nitrous. The Engine Analyzer assumes 12.5:1 A/F for gasoline and
5:1 for alcohol (methanol) and 3:1 for 'Very Rich Alcohol' for all
conditions. You can not richen or lean out the fuel mixture.

Minimum A/F Mixture Quality 'A/F Mxtr Qlty' is 86.6 %.
This is somewhat low and represents a real power loss in your
desired operating range. This can be improved by reducing intake
runner sizes, carb size, going to fuel injection, heating the intake,
increasing compression ratio, going to a lower octane fuel (the
program assumes high octane fuel has lower Reid Vapor Pressure and
therefore does not atomize or mix as well), smaller plenum, etc.

Most of the above suggestions will hurt air flow and volumetric
efficiency, and therefore hurt performance. This is where you
will have to come up with the desired compromise of good air flow
and good A/F Mixture quality.

Mechanical Efficiency 'Mech Eff' is 75 %
at the current Peak HP RPM of 5500 RPM.
This is somewhat low and represents a real power loss in this
engine's current operating range. This can be improved by paying
close attention to details in the Short Block Specs menu.

Mechanical Efficiency can be improved by:
- Better matching the Supercharger size or Belt Ratio to
the engine if the engine is Supercharged
- Reducing piston skirt size or piston ring tension
- Minimizing 'power robbing' accessories
- Reducing crankcase windage
- Reducing stroke
- Reducing valve spring loads
- Reducing the engine's operating RPM range

The Intake Valve Mach # 'MACH #' is .402
at your 'Desired HP Peak RPM' of 5500 RPM.
This is low and indicates perhaps too much intake cam duration.

MACH # is the BEST INDICATOR of the usable RPM range of this
engine with the current cam & head specs. Air flow and performance
drop rapidly (the engine 'runs out of breath') when the MACH # goes
over approximately .55 for low RPM engines or .45 for high RPM
engines.

MACH # is explained on page 53 in the User's Manual. You can
lower the MACH # by specifying larger Valve Diameter or Valve Flow
Efficiency in the Head Specs menu or larger Intake Duration, Tappet
Lift or Rocker Ratio in the Cam/Valve Train menu. MACH # is
also affected by Intake Port Diameter, Intake Manifold Runner Diameter
and Runner Flow Efficiency in the Intake System menu, but to a lesser
extent.

Your 'Desired HP Peak RPM' you entered for the Analysis Report
matches the 'For Peak HP at this RPM' spec you entered in the lower
right corner of the Running Conditions menu (the menu containing
the Weather Conditions, RPMS to Run, etc.)

Check the 'Approx Cam for HP Peak' suggestions at the bottom of
the Special Calculations section of the calculated test results.
They will suggest APPROXIMATE cam specs to produce a HP peak at
this RPM with your current cylinder heads. (If you don't see the
Special Calculations section, click on View, then click on 'Show
Special Calculations'. Then click and drag the scroll bar button
on the right side of this section down to see all the Special
Calculations, including these suggestions.)

The Maximum Average Piston Speed 'Piston Spd' is 3250 ft/min
at the Performance Calculations Maximum RPM of 6500 RPM.
This is somewhat high (if you want to run this entire speed range),
requiring light, high strength reciprocating components.

A street/strip engine should limit Piston Spd to a range of 3000-4000
ft/min. However, even to run at 3000 ft/min or higher, you will need
'better than production', high quality reciprocating components
(connecting rods & bolts, pistons, etc.).

Piston Spd (average piston speed in ft/min) and Piston Gs (peak
piston Gs) are indicators of how severely you are stressing the
engine's rotating components. To lower Piston Spd and Piston Gs,
you must shorten the piston Stroke or design the engine for a lower
RPM range.

Maintaining low Piston Spd and Piston Gs are critical for 'keeping the
engine together'. OVER-REVVING PARTS BEYOND THEIR INTENDED LIMIT IS
UNSAFE FOR THE ENGINE, YOURSELF AND BYSTANDERS.

The Inertia tuning of this intake is tuned to 5596 RPM,
which is close to your 'Desired HP Peak RPM' of 5500 RPM.
Since this RPM is about where the HP peak should occur, peak HP
should be good. If you specify longer and/or smaller diameter intake
runners, you will likely gain Peak Torque and lose some Peak HP.

Your 'Desired HP Peak RPM' you entered for the Analysis Report
matches the 'For Peak HP at this RPM' spec you entered in the lower
right corner of the Running Conditions menu (the menu containing
the Weather Conditions, RPMS to Run, etc.)

Check the 'Intake Port+Runner Dimensions' suggestions in the Special
Calculations section at the bottom of the calculated results. They
will suggest APPROXIMATE dimensions for Intake Runner Length
and Runner Diameters you can try to produce strong intake inertia
tuning at your Desired HP Peak RPM. (If you don't see the Special
Calculations section, click on View, then click on 'Show Special
Calculations'. Then click and drag the scroll bar button down on
the right side of this section to see all the Special Calculations,
including these suggestions.)

IMPORTANT: These runner dimensions are for the entire runner from
the valve to the plenum, which includes the port in the head and
runner in the manifold. Be sure to divide these suggested lengths
between the port AND runner. For example, if the suggested Intake
Length is 15, and 5 inches is in the port, use 10 inches in the
manifold runner.

IMPORTANT: These runner dimensions are based on the CURRENT engine's
CAM SPECS. If you change cam specs (for example to the cam suggested
in this section), these runner specs will also change. Therefore,
if you are following these suggestions, put in the suggested cam specs
first, recalculate performance, then put in one of the sets of
intake runner dimensions suggested with the new cam specs.

End of Analysis Report
Click to expand...

seth · Sep 17, 2009

i dont know if this will help u out the cam and intake specs

Cam StyleHydraulic flat tappetBasic Operating RPM Range1,300-5,600Intake Duration at 050 inch Lift218Exhaust Duration at 050 inch Lift224Duration at 050 inch Lift218 int./224 exh.Advertised Intake Duration262Advertised Exhaust Duration270Advertised Duration262 int./270 exh.Intake Valve Lift with Factory Rocker Arm Ratio0.493 in.
Edelbrock Performer Intake Manifolds Engine Block StyleStock/OEM standard deckCarburetor QuantitySingleIntake StyleDual planeBasic Operating RPM RangeIdle-5,500

CARB- 600cfm 4b holley carb

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