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Intake Manifold Upgrade - Flow Is King! - Wrenching

Dyno testing the Golden Eagle K-series intake manifold

Evan Griffey
Sep 14, 2011

The Special K swap is the Holy Grail of Honda swaps currently, giving Civics from as far back as the EF era of the early ’90s more displacement and 21st century power and technology.

In many cases it’s a natural progression for swap enthusiasts to also add a touch of boost to the equation. Turbo K kits are plentiful, but as the pressure rises, the inefficiencies of many of the stock parts can sacrifice power and reliability. One of the major roadblocks is the intake manifold. A hindrance at about 700 whp in factory turbo Supras, stock intake manifolds can become a restriction in any big-boost application, but taking a manifold designed for naturally aspirated duty and pumping big boost only exacerbates the situation.

Golden Eagle Products has addressed the issue for Special K fans with its seductive built-from-billet big-plenum manifold. Designed using the latest CAD/CAM software for incomparable performance and precision CNC-machined from 6061-T6 billet aluminum, the manifold shimmers like a gleaming jewel when you pop the hood. Thanks to its specially designed runners and large plenum, the Golden Eagle manifold kills the stock setup in both flow and volume capacity.

Htup 1109 02+intake manifold upgrade+intake manifold Photo 2/7   |   Our dyno victim is a K-swapped ’96 Midori-hued Civic. The K20A is pressurized by a Garrett GT3071R turbo with a .48 A/R T3 compressor housing, a three-inch downpipe, three-inch exhaust system and an Omni four-bar MAP sensor. Fuel enrichment (E85) consisted of Precision 1,000cc injectors and a Walbro 255-lph pump.

SpeedFactory is a Honda-centric shop located in Tacoma, Washington, that assisted in the R&D of the manifold. When SpeedFactory set out to test the final product, we crashed the party.

A ’96 Civic running a turbocharged K20A2 fitted with the original stock intake manifold and throttle body served as SpeedFactory’s test mule. The car’s turbo system features a Garrett GT3071R turbo with a .48 A/R T3 compressor housing, a three-inch downpipe, three-inch exhaust system and an Omni four-bar map sensor. Fuel enrichment consisted of Precision 1,000cc injectors and a Walbro 255-lph pump. The Honda was set to burn E85 fuel. With this setup, the K20 baselined at 392.8 whp, with a conservative 10 psi.

Htup 1109 03+intake manifold upgrade+installed Photo 3/7   |   This before/after comparison vividly illustrates the manifold’s bling factor. But as the dyno reveals it ain’t no poser.

The SpeedFactory crew then installed the Golden Eagle manifold and a 70mm throttle body for the retest. Back on the SpeedFactory Dynapack the Midori Green EG belted out some big gains. “With the manifold change, it wanted five to 10 degrees more VTC (cam angle) on the high cam, and made 15 to 25 whp more from 4,600 to 7,200 rpm,” SpeedFactory owner/tuner James Kempf says. “From 7,600 to 8,600 rpm it picked up a staggering 36 whp!… Flow is king.” Looking at peak power, the K20 topped out at a whopping 429.4 whp after the manifold swap, with boost untouched and holding steady at 10 psi.

We were impressed that the manifold showed such a big jump at such a conservative boost level. Further, we were also impressed at how the mani showed legit increases from 4,600 rpm on up even at low boost. Kempf is confident you can expect even greater gains over a stock manifold at higher boost/power levels where the stock manifold would pose an even greater restriction. As glistening as it is, the beauty of the Golden Eagle’s K-series manifold is far more than skin deep, as it pounds out the power on the dyno—where it counts.

Htup 1109 04+intake manifold upgrade+close up Photo 4/7   |   This before/after comparison vividly illustrates the manifold’s bling factor. But as the dyno reveals it ain’t no poser.

Sources

Golden Eagle Manufacturing
San Dimas, CA 91773
909-592-4311
http://www.goldeneaglemfg.com
Speed Factory
University Place, WA 98466
253-566-4331 Main
http://www.speedfactoryracing.net
By Evan Griffey
272 Articles

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