,
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| The XS Engineering hard pipe kit has bigger diameter bends coming out of the intercooler. |
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| The tube from the compressor discharge to the intercooler is considerably larger than stock with gentler bends. |
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| You can see the hardpipe going into the intercooler is larger and smoother in routing than stock. |
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| Surprise! The XS Engineering hardpipe kit made a pretty decent gain in power over the stock hoses |
It’s a well known fact that the Karman mass airflow meter equipped EVO is very sensitive to changes. Even simple modifications can play havoc with the air/fuel ratio as the MAF is easily thrown out of whack. Usually to get the most out of any mod requires some tuning of the ECU afterwards, especially with mods forward of the turbo. Another issue is that the factory timing map is probably optimized for 93 octane gas and is too aggressive for our crappy California 91 octane pee water. The EVO ECU monitors knock and when the knock count goes above 3 for any cell in the spark map, it starts to pull out timing. If the knock count gets too high, the ECU switches to less aggressive high octane and even several different low octane maps to protect the engine. This makes for inconsistent running.
Another issue with the stock tune is that the ECU only makes use of about half of the MIVEC systems command authority for advancing the intake cam, when up to 27 degrees of advance is physically possible by the MIVEC mechanism. Higher numbers can be entered into the MIVEC maps but the cam will only move 27 degrees. Large gains in low and mid range power can be had with MIVEC tuning because of the factories conservative tuning. We speculate that perhaps this is done for emissions reasons.
So it was time to tune our ECU. MotoIQ Beyond the Dyno columnist and tuning guru Eric Hsu fired up his laptop and reflashed our ECU using ECU Flash software with a map known to be a good base for a stock vehicle with a catback exhaust. Eric tweaked the fuel and spark maps, the boost control tables, the MIVAC map and raised the rev limit to 7800 rpm. An advantage over reflashing the ECU vs piggyback fuel and spark management devices is that reflashing the ECU gives you what you are going to get as it is tuning the same way the factory does. With piggyback devices the factory ECU senses what the piggyback is doing and gets into a tuning fight with it, automatically adjusting the long term fuel and spark trims trying to return to normal parameters. Because of this, piggybacks will run well for a couple of weeks, and then things start to conflict and the car begins to run poorly. On a car tuned more aggressively, this is not only annoying but potentially dangerous for the engines health. Another advantage to flashing the stock ECU is that all of the factories electronic safeguards for overboost, knock detection and overheating are all left in place.
Back at the dyno we were amazed at the results of Eric’s handiwork. We gained 5 peak whp so our EVO was pumping out 289 whp @ 7100 rpm. This only tells a fraction of the story. Our power gains were huge across the board, as much as 18 whp in some places. Our car gained power from idle all the way to the fuel cut. All of the dips and squiggles of the power curve were filled in nicely with hardly any drop toward the fuel cut. Our car made a solid wall of power from 3000 rpm all the way to 7800, a whopping 4800 rpm wide power band! On the road, the car felt like a completely different animal, the turbo spooling much faster and always wanting to be on the boost. The seat of the pants feel was even greater than the dyno chart suggests. We think our reflash is very safe, perhaps even safer than the stock tune as our knock count was lower than stock and our car was more consistent from run to run on the dyno.
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| Eric Hsu’s reflash of the ECU made the most difference of all of our mods |
Had we known about all of these positive benefits, we would have probably flashed the ECU as a first step. Eric’s reflash was by far, the best thing we have done to date with the biggest bang for the buck.
Overall we are very pleased with our EVO IX. With a few simple bolt ons and a reflash of the ECU we gained nearly 30 whp across the board from idle to the fuel cut. How the car now feels is how it should have been delivered from the factory. Stay tuned, we will be working on our IX to see how far we can push it with a stock turbo and simple bolt ons.
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| Project EVO IX, the final gains. Lots of power under the curve, little money spent, mission accomplished! |
Sources
XS-Engineering
4WD Dyno, Dyno turning, Intercooler hard pipe kit
www.xs-engineering.com
Phone: (714) 698-8300
Greddy
TiC Exhaust system
http://www.greddy.com
(949) 588-8300
K&N
Drop in high flow air filter
http://www.knfilters.com
(800) 858-3333
Motul
EngineLubricants, Gear Lube and Brake Fluid
www.motul.com
(800) 926-6685
Robispec
Ultimate suspension systems
http://robispec.com
(760) 912-4337
Moton Suspension Technology Inc.
The Ultimate 3-way adjustable dampers
www.motonsuspension.com
(770) 886-8777
Nitto Tire North America
NT01 Tires
www.nittotire.com
(800) 648-8652
Makin Industries
Volk CE28N wheels
www.mackinindustries.com
(562) 946-6820
Nukabe Automotive
Cusco chassis reinforcement
www.napsusa.com
(217) 235-6060
Energy suspension
Suspension Bushings
www.energysuspension.com
(949) 361-3935
Global Performance Parts
North American distributors for Whiteline
www.globalperformanceparts.com
Phone 616 399-9025
Ground Control Inc.
The ultimate EVO camber plate
www.ground-control.com
(530) 677-8600
WORKS
Pillow ball rear shock mounts, Chassis braces
http://www.worksevo.com
(415) 226-2500
M-Workz
Ultimate anal chassis setup
http://www.m-workz.net
info@m-workz.net
(310) 713-8396
Technosquare
The best damn shop in town
http://www.technosquareinc.com
(310) 787-0847
Eibach
ERS springs
www.eibach.com
(951) 256-8300
