Element GT65 vs. Element GT65+Magnus Intake Manifold

So what happens when you take two almost identical setups but swap out the intake manifold?

Here are the contenders:

04 STI Blue Dyno Plot:
Element built 2.5 STI with Pauter Rods and CP Pistons (Heads OEM STI with AVCS)
Element prototype GT65 Turbo Kit with matched Header
Element Hydra EMS
APS 3.5” Cat back exhaust
Magnus Intake Manifold
Ported TGV
Tial BOV
TurboSmart E-Boost
Exedy Twin Plate Clutch kit

Element Time Attack WRX Green Dyno Plot:
Element built 2.5 STI with CP Pistons only (Heads OEM STI with AVCS)
Element prototype GT65 Turbo Kit with matched Header
Element Hydra EMS
Element prototype 3” Cat back exhaust
Hyperflow FMIC core
Ported TGV
Perrin Modified 816cc
TurboSmart Megasonic BOV
TurboSmart E-Boost
ACT 6 puck OEM WRX flywheel

Both cars tuned by yours truly with the same verve at the same boost pressure:

As you can see the Magnus intake is loosing some HP in the lower rpm area in trade for a solid gain in the midrange. From about 2200 rpm there’s a solid loss of about 25 whp up to 4500 rpm which is then traded for a 10-40 whp gain from 4500 rpm to 5800 rpm. From 5900 rpm to 6600 rpm you could call it a wash but past 6800 rpm you can see a loss but the 04 STIs spark plugs were on there last legs (20k + miles) and I was getting inconsistent misfires.

I think on these two cars this would be a decent intake manifold for road racing or even back country roads as you often find yourself around 4000-4500 rpm exiting many turns and then not exceeding 6K rpm. This manifold may allow you to short shift and have that extra burst of power in the 4500-6000 rpm range. Exiting turns at 5500 rpm is beyond my talent in 500+whp car.

The lack of top-end power increases (if you consider 525whp at 7k rpm a lack of power.) may be attributed to the .82 exhaust housing and not necessarily the intake manifold. This kit was designed to give the largest possible powerband while still maintaining great spoolup vs. absolute highest peak power. I think it would be interesting to see someone run this manifold on a car equipped with a 1.06 or perhaps with just a larger exhaust wheel. The intake manifold looks like it could be held back but I don’t believe it’s the heads yet as I’ve trapped with a larger turbocharger in the 132 range where this particular setup trapped at 129 mph.


Phil Grabow

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