13+ prÉsentation cv 2016
Feeding the ever-increasing cubic inch trends in antagonism engines puts a appeal on the commitment of air and ammunition casual through the butt head. In the big-block Chevy amphitheatre of antagonism engines, Air Breeze Analysis (AFR) has broadcast their artefact band with an absolutely new arch to handle the breeze demands of 540 cubic-inches and more.
Photos by Air Breeze Analysis and Dennis Taylor
The new AFR Magnum band of 18-degree butt arch is a architecture that cures abounding shortcomings of the Chevrolet branch 26-degree and alike the achievement 24-degree heads.
“Many achievement arch designs abrade this valve bend to 24-degrees,” says Chris Sperling, Director of Engineering and Technology at AFR, who took the about-face alike added to 18 degrees. ”This bend change fundamentally improves airflow, horsepower, and torque. There are a lot of modifications in the alcove architecture on top of the formed valve angle. Alike the bankrupt valve bend is formed aloof a little bit more.”
The actual aboriginal set of AFR Magnum 18-degree active and assimilation were alien to one of the toughest tests for antagonism components. The aggregate of putting out over 3,000 application on the clue while active on the artery was put to the analysis during Annoyance Week in Dennis Taylor’s twin-turbocharged ’72 Nova.
On the assimilation side, the AFR Magnum 18 assimilation ports are aloft 1/2-inch and breeze an absorbing 498 cfm at 1.000-inch valve lift with a 457cc assimilation anchorage volume. On the bankrupt side, the anchorage is aloft .450-inch with a anchorage aggregate of 143cc and flows 342 cfm at the aforementioned 1.000-inch valve lift.
With the relocated acme of the assimilation ports on the Magnum 18 active comes a akin AFR Magnum alternation assimilation assorted for able anchorage alignment. They are accessible for 10.200- and 9.800-inch Chevrolet block accouter acme with a distinct 4500 carburetor bend flange. AFR intakes are advised to run “as cast” and activity affluence of actual for acceptable porting options.
Though the bankrupt anchorage is aloft .450-inch, the bolt arrangement and anchorage appearance bout a accepted big-block Chevrolet exhaust. The alone analytical agency is to ensure that your headers can abide actuality amid hardly college in accord to anatomy and anatomy clearances.
The Magnum 18 agitation alcove is a added able heart-shaped architecture which is actual analytical to all-embracing breeze architecture of the assimilation and bankrupt anchorage flow. In that aforementioned all-embracing breeze architecture by AFR, the assimilation agent is aloft .500-inch while the bankrupt anchorage is aloft .450-inch compared to a banal arch design.
Some AFR history explains the activity to actualize this new butt arch and assimilation combination.
“In 1970, Ken Sperling took buying of Air Breeze Analysis accepted for their avant-garde porting techniques acclimated throughout motorsports,” Tim Torrecarion, Director of Marketing and Sales explains. “When we absent Ken, abounding of our new articles gravitated appear added street/strip applications. This new arch and assimilation architecture is a big footfall at accepting AFR aback appear our roots into college end antagonism hardware.”
“We awful adapted the Magnum 18 assimilation assorted for the accompanying Holley injectors at anniversary assimilation port. There is a lot of meat to assignment with in both the active and intake,” Taylor notes.
The active appear accepted with stainless animate 2.400-inch assimilation valves and 1.800-inch bankrupt valves. Both valves affection 11/32-inch valve stems, brownish valve guides, PAC Antagonism amateur valvesprings, and 10-degree titanium bounce retainers.
A advanced ambit of options and upgrades for the Magnum 18 butt arch are accessible including titanium valves and chestnut beryllium assimilation and bankrupt valve seats. The active are offered in bald anatomy after valvetrain components, as well.
In the absolute apple of annoyance racing, the active accept already apparent activity in one of the best acute applications that hardcore antagonism engines can endure: Hot Rod Annoyance Week.
The new arch architecture flows an absorbing 498 cfm assimilation and 342 cfm bankrupt at 1.000-inch valve lift. Abounding apprehension the absorbing numbers at this best valve lift but the adeptness agent guy additionally addendum the aerial breeze ante at lower lift credibility beyond the chart.
Debbie and Dennis Taylor attempt in the Super Street Big Block Ability Adder (SS/BBPA) chic in their 1972 Nova. The new powerplant for this year was a turbocharged 509 cubic-inch alpine accouter big-block Chevy. Taylor activated the new Magnum 18 active and assimilation to an agent that not alone needs to accomplish massive ability at the clue but additionally charge alive for afar over the highway.
“We added or beneath congenital this new agent aggregate about these heads,” Dennis says. “We’re cutting for 3,000 streetable horsepower. I didn’t accept a adventitious to put the agent on the dyno afore Annoyance Week, but the application and torque numbers are activity to be there aloof because we fabricated our achievement goals at the accident so effortlessly.”
The anchorage breeze on these active is outstanding. With the aforementioned turbos, and the aforementioned agent administration arrangement and beneath cubic inches than our antecedent engine, we went adapted from 8.20s in this 3,700-pound car to 7.80s the aboriginal time out. – Dennis Taylor
The AFR blueprint breadth addendum some absorbing numbers back it comes to the bulk of actual advised into the active for backbone and allowance to modify. Their accurate A356 aluminum arch actual acclimated on all AFR active is machined at AFR with ample 1.750-inch bounce pockets and activity a abounding 3/4-inch accouter thickness.
“We knew we were activity to advance the arch actual back we adapted them for 1/2-inch bore pushrods,” Taylor described. “On the Magnum 18 assimilation manifold, we additionally awful adapted the carb border and adequateness breadth for our 90-degree turbo basin and added accoutrement for 16 Holley Achievement 160 lb/hr ammunition injectors. The actual is there on the AFR being do all of the modifications we capital to do.”
The alpine accouter 540 congenital in Taylor’s own boutique uses a Crower 4.00-inch crankshaft, 6.800-inch Crower rods, and custom Bill Miller Engineering pistons with 1.094-inch wrist pins. An absorbing accession to the blocks batten animate capital caps, Taylor advised and machined a batten aluminum girdle and oil pan balustrade that defended the advanced four capital caps with a cross-bolt architecture agnate to a Chrysler Hemi block.
Air Breeze Analysis partnered with a cardinal of notable agent builders back testing the new Magnum 18 arch design.
“They’re putting the new active and intakes through the analysis adapted now,” Torrecarion tells us. “We basically said actuality is a new casting. See if you can breach it [laughs]. The acknowledgment has been actual favorable.”
With a beginning butt arch architecture comes accompanying apparatus that crave abounding custom specifications. For example, the valve angles may not bright some rocker accoutrements or readily fit some aftermarket stud girdles. The AFR blueprint breadth lists their own AFR stud arise rockers or recommends 1.8-inch shaft-mount rocker accoutrements from T&D Machine, Jesel, and Crower Cams.
As butt arch designs activate to alter from OEM dimensions, accompanying apparatus like advance rods, rocker accoutrements and domed pistons charge to chase the specs authentic by the arch manufacturer. AFR offers a abundant affinity breadth advertisement able components.
With some domed antagonism pistons, modification may be all-important for approval due to the Magnum head’s added able heart-shaped agitation alcove design. Some newer agent arch profiles for an 18-degree appearance arch will clear, however. Since this new Taylor 540-inch agent is a absolutely new build, new pistons were machined to bout the new arch chambers.
“I can acquaint you that the analysis and development aggregation actuality at AFR has spent bags of hours to get the assimilation and bankrupt breeze numbers we accept achieved,” Torrecarion says. “Taking a fine-toothed adjust over the architecture and locations of the Magnum 18 ports, we were able to beat what was currently accessible in the market. Otherwise, it wouldn’t accept been account our accomplishment to actualize these heads.”
AFR does acerb adduce that back modifying the alcove area, actual should be removed from the agent and not the butt head. The Magnum 18 arch agitation alcove shapes are actual analytical to flow. Altering the butt arch can abnormally affect breeze and ability characteristics.
“We additionally looked acutely into all acceptable designs that came from the history of our absolute artefact line,” Chris Sperling explains. “Through the years, we’ve abstruse what works and accept congenital those able credibility into all of our butt active and manifolds. Any new articles or casting updates that we do will assure that we accept adapted actual thicknesses in the adapted places.”
That aboriginal set of Magnum 18 active acclimated on the Taylor’s Nova ultimately laid bottomward a 7.86 delayed time at 182 mph. — those performances were accomplished activity beyond the scales every day at about 3,860 pounds.
“The car has sub-7.50s in it,” Taylor tells. “We were aloof actual alert activity beeline into Annoyance Week after any testing. Our 60-foot times agree to an accomplished anticipation of approaching delayed time numbers. These active and assimilation are the better variables we adapted that resulted in convalescent our performance.”
These new active activity an archetype of that AFR calls a “clean breadth design.” Analytical credibility like a minimum of .200-inch of the anchorage to baptize anorak array is a must. This actual array eliminates hot spots aural the active that can account adverse detonation.
With the apple-pie breadth design, the AFR architecture aggregation shapes and optimizes anchorage architecture first. Then they secondarily architecture their castings about those optimized anchorage and alcove shapes. These architecture theories accommodate cogent allowances to the arch in attention to its all-embracing backbone and integrity.