Richard Holdener - How to Build New Hemi Performance on the Dyno: Optimal Parts Combos for Max Horsepower

Table Of Contents

Accufab, Inc.

1326 East Francis St.

Ontario, CA 91761

909-930-1751

accufabracing.com

Aeromotive

7805 Barton St.

Lenexa, KS 66214

913-647-7300

aeromotiveinc.com

Air Flow Research

28611 Industry Dr.

Valencia, CA 91355

661-257-8124

airflowreaserch.com

American Racing Headers

880 Grand Blvd.

Deer Park, NY 11729

855-443-2337

americanracingheaders.com

ATI

6718 Whitestone Rd.

Gwynn Oak, MD 21207

877-298-4343

atiracing.com

ARP

1863 Eastman Ave.

Ventura, CA 93003

800-826-3045

arp-bolts.com

Brian Tooley Racing

2100 Filiatreau Ln.

Bardstown, KY 40004

888-959-8335

briantooleyracing.com

Comp Cams

3406 Democrat Rd.

Memphis, TN 38118

901-795-2400

compcams.com

CP Pistons/Carillo Rods

1902 McGaw Ave.

Irvine, CA 92614

949-567-9000

cp-carillo.com

Crane Cams

866-388-5120

cranecams.com

CXRacing

1627 Chico Ave.

South El Monte, CA 91733

CXRacing.com

626-575-3288

DNA Motoring

801 Sentous Ave.

City of Industry, CA 91748

626-965-8898

dnamotoring.com

Eagle Specialty Products

8530 Aaron Ln.

Southaven, MS 38671

662-796-7373

eaglerod.com

Edelbrock

2700 California St.

Torrance, CA 90503

310-781-2222

edelbrock.com

FAST

3400 Democrat Rd.

Memphis, TN 38118

877-334-8355

fuelairspark.com

Fel-Pro

felpro-only.com

Holley/Hooker/NOS/Accel

1801 Russellville Rd.

Bowling Green, KY 42101

270-782-2900

holley.com

JE Pistons

10800 Valley View St.

Cypress, CA 90630

714-898-9763

jepistons.com

K1 Technologies

7201 Industrial Park Blvd.

Mentor, OH 44060-5396

616-583-9700

k1technologies.com

Kenne Bell

10743 Bell Ct.

Rancho Cucamonga, CA 91730

909-941-0985

kennebell.net

Lil Johns Motorsport Solutions

2049 Filiatreau Ln.

Bardstown, KY 40004

888-583-4408

liljohnsmotorsports.com

Lucas Oil

302 N. Sheridan St.

Corona, CA 92880

lucasoil.com

Lunati

8649 Hacks Cross Rd.

Olive Branch, MS 38654

662-892-1500

lunatipower.com

Mancini Racing Enterprises

33524 Kelly Rd.

Clinton Twp., MI 48035

manciniracing.com

586-790-4100

Magnuson Superchargers

1990 Knoll Dr.

Ventura, CA 93003

805-642-8833

magnacharger.com

Meziere

220 S Hale Ave.

Escondido, CA 92029

800-208-1755

meziere.com

Milodon

2250 Agate Ct.

Simi Valley, CA 93065

805-577-5950

milodon.com

Mopar Performance Parts

mopar.com/en-us/store/performance/mopar-performance-parts

Moroso

80 Carter Dr.

Guilford, CT 06437

203-453-6571

moroso.com

MSD

490 Henry Brennan Dr.

El Paso, TX 79936

915-857-5200

Msdignition.com

Paxton Automotive

1650 Pacific Ave.

Oxnard, CA 93033

Precision Turbo

616 S Main St. A

Hebron, IN 46341

219-996-7832

precisionturbo.net

ATI Procharger

14801 W. 114th Terr.

Lenexa, KS 66215

913-338-2886

procharger.com

SCAT

1400 Kingsdale Ave.

Redondo Beach, CA 90278

310-370-5501

scatcrankshafts.com

Speedmaster

1101 W. Rialto Ave.

Rialto CA 92376

909-605-1123

speedmaster79.com

Total Engine Airflow

285 West Ave.

Tallmadge, OH 44278

330-634-2155

totalengineairflow.com

Turbo Smart

8580 Milliken Ave.

Rancho Cucamonga, CA 91730

909-476-2570

turbosmartusa.com

Vortech Superchargers

1650 Pacific Ave.

Oxnard, CA 93033

805-247-0226

vortechsuperchargers.com

Westech Performance

11098 Venture Dr., # C

Mira Loma, CA 91752

951-685-4767

westechperformance.com

Wilson Manifolds

4700 NE 11th Ave.

Ft. Lauderdale, FL 33334

wilsonmanifolds.net

954-771-6216

Wiseco Pistons

7201 Industrial Park Blvd.

Mentor, OH 44060-5396

800-321-1364

wiseco.com

Whipple Superchargers

3292 N. Weber Ave.

Fresno, CA 93722

559-442-1261

whipplesuperchargers.com

Whether you have a stock, street, or strip Hemi application, the intake manifold is one of the three major players in terms of power production. Unlike the LS, the aftermarket has not stepped up with an abundance of aftermarket Hemi intakes, although we did manage to test just about everything available. Contrary to popular belief, intake designs do more than just allow airflow into the ports, they actually provide a tuning effect that aides in power production over a given RPM range. Not surprisingly, factory Hemi intake manifolds for the truck, Magnum, and SRT versions were not designed with peak power production in mind, but rather a combination of peak and average power combined with ease of production and even fuel mileage. Just as a poorly designed manifold can (literally) ruin an otherwise good Hemi, the right intake can help you produce impressive power, especially when used in conjunction with the right cam and ported cylinder heads. More than any other single component, the intake manifolds runner length will determine where the engine makes effective power. Match the runner length to produce power in the same operating range as the cam profile, and you are a long way toward making a powerful Hemi.

All of the factory Mopar intakes perform very well, including the aluminum SRT8 manifold.

For 5.7L, 6.1L, and 6.4L Hemis and any other engine, intake manifold design may be broken down into three major elements, runner length cross section as well as taper ratio and plenum volume. These elements are listed in order of importance or, more specifically, in the order they most affect the performance of a given manifold. By this we mean that changing the runner length has somewhat more of an effect than altering the cross section or plenum volume. This is not to say that all of the elements are not important, it is just that proper care should be given to the elements in accordance with their eventual effect on performance. Intake designers, take note of this perspective, because fabricators often spend countless hours altering the plenum volume in an attempt to change the effective operating range when they should have simply increased (or decreased) the runner length. It should be stated here that manifold design is sometimes limited by production capability or rather ease of construction. Building a set of runners with a dedicated taper ratio and a compound curve is difficult if not impossible for the average fabricator. Despite the fact that this design produces the best power, it simply isnt going to get produced unless a major intake manufacturer, such as FAST, Holley, or Edelbrock, steps up to the cost of such a complex combination.

The first element in intake design is the runner length. The overall intake runner length actually includes the head ports, but the discussion will be limited to those in the manifold. Unlike their carbureted counterparts, fuel-injected Hemi intake manifolds seem to be broken down into two distinct groups, long and short. Its obviously not very scientific, but the terms long and short do not properly describe intake manifolds. The reason for the long and short designations is that, generally speaking, the longer the runner length, the lower the effective operating RPM. Obviously, the opposite is also true; shorter runner lengths improves top-end power. Production Hemi intake manifolds typically have a long-runner design to help promote torque production even though the SRT8 intake differs in length compared to the Ram truck or Magnum. It is often possible to design an intake that offers more low-speed or top-end power than a stock Hemi intake, but doing both can be proven difficult. The SRT8 intake was designed to produce power at a higher engine speed than the Magnum or Ram truck, but the trade-off is a loss lower in the rev range (also see in this chapter where the author adjusted the runner length).