PDA

View Full Version : EVO III turbo exhaust *LONG*



DRFTR8
04-15-2005, 08:30 AM
dont know if this is a repost but it may help guys out there to decide which to get. This is a test that TPR magazine did to see which exhaust made better power and torque.

The Turbo Exhaust
Response, Power & Reliability
By MJ Ferrara

Aftermarket exhaust systems are usually at the top of the list in any performance buildup. When your buildup involves a turbocharged vehicle, the benefits of a well-engineered cat-back exhaust system are immense. Significant increases in turbo response, power output and reliability will be the result of just bolting on the exhaust system on nearly all turbocharged vehicles. However, some vehicles will not show significant benefits from the addition of the exhaust system by itself. On these applications, the factory engine control unit (ECU) may reduce boost pressures, change timing curves or change fuel delivery after the exhaust system is added. As a result of these adaptive ECU's and their uncooperative nature to see more power generated, little or no power is seen at the wheels on some vehicles. On these vehicles, the OEMs are making it harder to increase horsepower. Fortunately, the speed bumps to performance can be crossed as long as our intelligence is not lower than the bump itself. Understanding what to look for in an aftermarket performance turbo exhaust system and knowing how to beat the roadblocks that your factory ECU may throw at you will allow you to realize the maximum performance from your vehicle.

Seven Points of Exhaust Flow
The primary function of a vehicle's exhaust system is to muffle the sound coming out from the exhaust port of the cylinder head and to direct the exhaust gas out the back of the vehicle. If we follow the flow of the gases from the cylinder head to the tailpipe on a turbocharged vehicle, we find seven points of interest along the way. First, the exhaust port of the cylinder heads feeds its flow into the exhaust manifold. Unless this part has been upgraded, the chances are that the factory piece is a cast-iron manifold that supports and locates the turbocharger while directing the exhaust flow into the turbo. Second stop is at the turbine housing of the turbocharger. At this junction, the exhaust flow is directed through a nozzle (turbine housing) that increases the flow velocity to power the turbine wheel. While providing the power to turn the compressor, the turbine section also has a side benefit of dramatically reducing the exhaust noise. Essentially, the turbine section acts as a very effective muffler. Once the flow makes its way into and out of the turbine housing it finds its third stop at the downpipe. The downpipe provided the exhaust flow connection and direction into the catalytic converter. The catalytic converter provides our fourth point of interest. The converter aids in the conversion of exhaust gases into less polluting products. After the converter, one finds all of the "cat-back" elements. The cat-back components include the fifth, sixth and final stops (B-pipe, muffler, tail-pipe or tip). From the converter, the exhaust hits the Before-muffler exhaust pipe or B-pipe. Some B-pipes may use a resonator or pre-muffler, but it is pretty rare on turbo exhaust systems. The B-pipe feeds the sixth stop, the primary muffler. The mufflers job is to "muffle" or reduce the exhaust noise further. Finally, the exhaust meets the atmosphere through an exhaust muffler tip or actual tail pipes on some applications.

Objectives of the Turbo Cat-Back
The objective of a properly-engineered, aftermarket cat-back exhaust system is to provide additional performance while still delivering adequate sound control. Unlike an all-motor exhaust system, a turbo exhaust system suffers no ill effects from going as big as possible. Bigger is better in this case. The bigger or larger diameter exhaust pipes allow the back pressure to be significantly less than the factory exhausts system. As a result, the difference in exhaust pressure before and after the turbocharger is increased. The increase in the magnitude of the pressure difference allows the turbocharger to reach higher shaft speeds at lower engine operating rpms. As a result, boost response increases and boost pressures increase. More boost pressure at the intake manifold results more power at the wheels. Can a turbo exhaust be too big? A turbo exhaust is too big if it drags on the ground or is too large to provide adequate sound suppression. For peak performance, most aftermarket turbo exhaust manufacturers will use the largest diameter tubing that can be properly routed underneath the vehicle. A muffler will be matched that allows an adequate amount of sound suppression.

Sight, Sound & Performance
In this evaluation, we have covered both the looks and the performance available from most of the performance exhaust systems available for the EVO-VIII. One are which we cannot address with paper and ink is the sound of the exhaust system.

Adaptive ECUs (EVO VIII)
As today's vehicle ECUs become more and more sophisticated, some OEMs have incorporated roadblocks to additional performance. One such vehicle taxed by this hurdle is the Mitsubishi EVO-VIII. The EVO-VIII computer knows when the engine has been modified to produce additional power. A map of the highest expected air flow meter readings versus engine speed are burned into the computer. When these values are exceeded because aftermarket parts have been placed on the vehicle, the factory ECU responds by reducing the boost levels until the air flow meter reads values at the stock performance levels. The result is that the car generates near factory horsepower levels even though high-performance aftermarket components have been placed on the vehicle. Another performance challenge on some newer vehicles is the existence of multiple fuel and ignition maps. The adaptive ECU switches between these maps when it finds that the O2-correction or knock readings have reached a certain level. This makes some new vehicles extremely difficult to dyno test for repeatable results as the ECU jumps between different fuel and ignition maps from run to run. These are some of the potential problems that can be encountered with today's adaptive ECIs, so what are some of the potential solutions?

Part of the solution with the EVO-VIII and any other turbocharged vehicle with an adaptive, performance-limiting ECU is to take away the control of the boost pressure by the ECU. By using an aftermarket boost controller (either manual or electronic), the factory ECU is not able to adjust boost pressure. We addressed this problem by installing an HKS EVC electronic boost controller on our EVO-VIII. To address the "map jumping" issue, we had two options. If we selected to run a high-octane fuel, such as 100-octane unleaded, we could have rested assured that the most aggressive timing map would be used by the ECU, since the knock count would have been very low. This solution had both pros and cons. On the pro side, the cost is rather insignificant. For less than a $100, we could have purchased enough fuel to perform all of the dyno work needed to test all of the exhaust systems. On the con side, using race gas would not have eliminated the factory ECU's ability to change fuel delivery and it wouldn't allow us to show the actual power output that could be expected on pump gas. The strategy we employed was to completely replace the factory ECU. This strategy provided three options; the A'PEX Integration Power FC, the AEM EMS or the HKS F-CON V Pro. We selected the HKS F-CON V Pro to gain some familiarity with this plug-in solution. XS Engineering started from scratch and mapped the F-CON V Pro for the EVO-VIII. This same and consistent mapping would be used throughout the exhaust test.

Our Test Vehicle
Our 2003 EVO-VIII was equipped with the aforementioned HKS FCON V-Pro and HKS Power Flow Intake. Straight from the pump, 91-octane gasoline was used for all of the testing. Boost pressure was set to 18 psi and regulated by an HKS EVC for the dyno pulls. All exhaust components from the exhaust manifold to the cat-back exhaust remained factory issue.

Our First and Last Turbo Exhaust Test?
This is our first and maybe our last exhaust shootout on a late-model, turbocharged vehicle. Much of the information that we are sharing with regards to the Mitsubishi ECU was learned first hand. When we started this test, we attempted to run the test as we had with other vehicles. Running the test with the factory ECU installed on pump gas would not let us obtain any repeatable horsepower figures. Unfortunately, a couple of exhaust manufacturers couldn't be represented in this test because their exhaust systems were tested before we isolated the problem with the factory ECU. The bottom line is that there are some really good exhaust systems available for the EVO-VIII that didn't make our test.

Graphs
Mircale Fire 5-Zigen
power:http://www.tprmag.com/issue/5/images/5-hp.jpg
torque:http://www.tprmag.com/issue/5/images/5-tq.jpg
Mitsubishi Evolution VIII Cat-back Exhaust -Bill Boat (BB)
power:http://www.tprmag.com/issue/5/images/billyboat-hp.jpg
torque:http://www.tprmag.com/issue/5/images/billyboat-tq.jpg
2003-04 EVO VIII Cat-back -Borla
power:http://www.tprmag.com/issue/5/images/borla-hp.jpg
torque:http://www.tprmag.com/issue/5/images/borla-tq.jpg
EVO SCCA Legal Catback- Buschur Racing
power:http://www.tprmag.com/issue/5/images/buschur-hp.jpg
torque:http://www.tprmag.com/issue/5/images/buschur-tq.jpg
SCS EVO VIII -DC Sports
power:http://www.tprmag.com/issue/5/images/dcsports-hp.jpg
torque:http://www.tprmag.com/issue/5/images/dcsports-tq.jpg
Gram Lights Exhaust -by Mackin
power:http://www.tprmag.com/issue/5/images/mackin-hp.jpg
SUS Series -HELIX- Gruppe-S
power:http://www.tprmag.com/issue/5/images/gruppe-s-hp.jpg
torque:http://www.tprmag.com/issue/5/images/gruppe-s-tq.jpg
30th Anniversary Hi-Power exhaust system - HKS
power:http://www.tprmag.com/issue/5/images/hks-hp.jpg
torque:http://www.tprmag.com/issue/5/images/hks-tq.jpg
Magnaflow Ti -Magnaflow
power:http://www.tprmag.com/issue/5/images/magnaflow-hp.jpg
torque:http://www.tprmag.com/issue/5/images/magnaflow-tq.jpg
GT-2 -RS-R
power:http://www.tprmag.com/issue/5/images/rsr-hp.jpg
torque:http://www.tprmag.com/issue/5/images/rsr-tq.jpg
Works Exhale Series -Works
power:http://www.tprmag.com/issue/5/images/works-hp.jpg
torque:http://www.tprmag.com/issue/5/images/works-tq.jpg

chris
04-15-2005, 08:56 AM
great post!

DRFTR8
04-15-2005, 09:00 AM
hope it helps out.. cuz i know alot of guys out there just buys what they can afford, get the one that looks good or the name not thinking about if its makes power or not

wilson1
04-15-2005, 09:02 AM
Which one is the best?

wilson1
04-15-2005, 09:04 AM
Hummm.....................

Looks liked Helix and BB makes the least power! :?

DRFTR8
04-15-2005, 09:05 AM
Hummm.....................

Looks liked Helix and BB makes the least power! :?

no its the grams light and BB makes the less power... the helix is just where everyone is at but the one that makes the best power is american made... magna flow at 264.7 hp

trinydex
04-18-2005, 01:11 AM
hmmm this is very interesting... seems the catbacks that made good power, some actually necked down at the cat like the hks nad the magnaflow... guess i can expect bigger and better from my greddy ti and full 3" tb...

david buschur
04-25-2005, 10:11 AM
The two best performers were Magnaflow and Buschur Racing. The numbers are right there so it's easy to compare.

Magnaflow Titanium made 264.7 hp and 298 ft lbs.

Buschur Racing made 263.9 hp and 296.7 ft lbs.

Our catback costs $450 or you can get the complete turbo back for $750. Our catback weighs in at only 16 pounds.

I think weight is something that should have been covered better in the article as it is important to consider this when the HP levels between two products are pretty close.

Thanks,

SkyWarp
04-05-2007, 01:58 PM
Dave Buschur, OMGHI2U!!!