UNDERSTANDING EFFICIENT TURBO EXHAUST SYSTEMS

Moving on from the factory exhaust system can be a challenging decision. Which Downpipe do you go with when there are about a hundred options and every manufacturer raves about the efficiency of their design? How about the exhaust? Which one is going to provide efficiency while also making sure that your neighbors don’t hate you?

The bad news is that there is a glaring flaw in the factory design. There is a 4.5” VBand connection to the back of the factory turbo and for some reason, the decision was made to choke down the interior diameter to a mere 3.15” at the connection point to the factory exhaust system. If you know anything about fluid dynamics, you know that the maximum flow of a system is determined by the minimum diameter of any necked down section.

THE SCIENCE

You might be thinking, “well 3.15” isn’t that bad right?”

Unfortunately, it is! Turbocharged power trains need to get exhaust gases away from the turbine wheel as fast as possible. Conventional wisdom used to say that 3” was just fine for sub 800whp. However, way back in 2011, Super Street Magazine conducted a test with a MKIV Single Turbo Supra to see if 3” was really just fine or if there was power being left on the table (Click Here to read the article for yourself, but there is a lot of power locked up in a small exhaust!!). In Summary, here was the test and the results:

• The test was conducted over the course of 3 days with the last day being the highest temperature
  
  
• The MKIV Single Turbo Supra started off the test with a 3" Downpipe and 3" Exhaust and it produced a baseline of 527whp at 19psi
  
  
• On Day 2, they decided to switch to a 3.5” exhaust section and keep the 3” Downpipe and the car went from 527whp to 567whp at the same boost level!
  
  
• On Day 3, they made a custom 3.5” Downpipe to match the 3.5” exhaust and the car jumped again from 567 to 610 whp at the same 19psi boost level and the turbo spooled 200rpms faster, all on the hottest day!
  
  
• A total gain of 83whp at the same boost level moving from a 3" to 3.5" Full Turbo-Back Exhaust System!
  

THE REMNANT PERFORMANCE APPROACH

Most aftermarket parts manufacturers are simply producing components, they have to build around the factory 3.15” exhaust restriction to allow people to use their design. This means that basically all aftermarket Downpipes reduce down to 3.15” to connect with the factory exhaust system, and virtually all exhaust systems reduce down to 3.15” to connect with the factory Downpipe.

At Remnant Performance, we’ve never been interested in simply making parts. We focus on creating true and complete solutions to properly address a problem or a need. For this reason, we ditched the typical approach and we’ve created our Leviathan Turbo-Back Exhaust for the A90/MKV Supra!

Our approach allows us to completely eliminate the factory exhaust restriction, positioning you for maximum horsepower and torque whether your build is on stock turbo, Pure Turbos, CTS Turbos,  or of course our 65 OMEGΛ Turbo Kit!

In our stock turbo dyno testing alone (check the dyno graph in the picture and the Leviathan Overview and Installation video below for more information), we gained 10whp and 9tq on an untouched custom tune over CATless Downpipe and stock exhaust. What’s even more crazy? Check the graph out from 6,700-7,000 rpm! The turbine wheel on stock turbo was struggling to maintain tq out there on the CATless Downpipe. The Leviathan Turbo Back Exhaust System reduced the backpressure and increased flow in the exhaust system which resulted in a gain of 40WHP & 25TQ in that rpm range on a completely untouched tune!

In addition, the Leviathan’s specially designed mufflers and resonators enable the maximizing of performance while keeping sound levels from getting to an obnoxious level. Warm idle is just 69.5dB with the resonators on so you can still be a good neighbor!

Check out our dB Readings video below to give you an idea of how loud the system is comparatively to both a completely stock exhaust system and a CATless Downpipe with stock exhaust.

WHY CHOOSE THE REMNANT PERFORMANCE LEVIATHAN TURBO-BACK EXHAUST?

Here are some of the reasons, that customers choose The Leviathan Turbo-Back Exhaust System over competing solutions:

• Ultra efficient, high-strength Stainless Steel design, constructed with the least possible tubing and bends for minimizing weight

• The stock Turbo-Back Exhaust system weighs 65.1lbs. At just 43.5lbs with Resonators and 40.5lbs with Resonator Delete Pipes, The Leviathan Turbo Back Exhaust System provides weight savings of 21.6lbs and 24.6lbs respectively

• Unlock the maximum potential of your turbo setup whether that is stock turbo, Pure, CTS or of course our 65 OMEGA Turbo Kit. On stock turbo and pump gas, we gained 10whp and 9tq over the typical CATless Downpipe approach with a peak gain of ~40WHP &25TQ at 6,700 - 7,000 rpms on a completely UNTOUCHED tune!
  
  
• Completely V-Banded design for minimizing leaks, maximizing adjustability and ease of installation
  
  
• Ultra-Deep tone unique to the Leviathan Turbo-Back Exhaust System
  
  
• 4" Leviathan Downpipe with flex section and 4" V-Band connection to the Leviathan Mid-Pipe for eliminating restrictions, minimizing spool up time and maximizing horsepower and torque
  
  
• 4" Oval to Dual 3" Leviathan Mid-Pipe for maximizing ground clearance, minimizing resonance and maximizing flow
  
  
• Dual 3” x 8” Remnant Performance V-Banded Resonators for excellent tone control without sacrificing performance
  
  
• Included V-Banded Resonator Delete pipes for easy “swap-ability” for those wild individuals who just want a louder, more “uncivilized” exhaust system
  
  
• Large 15" oval Remnant Performance mufflers for optimal ground clearance, excellent tone and cutting down the dB without sacrificing an ounce of performance.
  
  
• Comes with your choice of Polished, Burnt, or Black Chrome Dual Wall 5" exhaust tips that are clamped on for the best adjustability and style
  
  
• Fits stock turbo, Pure Turbos, CTS turbos and of course The Remnant Performance 65 OMEGA Turbo Kit
  
  
• Idle at just 69.5dB in Sport Mode with the included resonators installed for a system that won't anger the neighbors. The Sport button still works to enter and exit “Sport” mode even though this is not a valves exhaust system.
  
  
• 86dB WOT (Wide Open Throttle) interior cabin with the windows up and 92dB with the windows down (with resonators installed). Check the dB Video Below for more complete information and comparison

• PLEASE NOTE - Installation of The Leviathan Turbo-Back Exhaust system requires removal of the OEM center brace & The Leviathan will not fit with VERUS Diffuser

IMPORTANT VIDEOS ABOUT THE LEVIATHAN TURBO-BACK EXHAUST

dB Readings of The Leviathan Turbo-Back Exhaust System for the MKV / A90 Toyota Supra

Is there a lot of drone with The Leviathan Turbo-Back Exhaust?

Leviathan Turbo-Back Exhaust System - Complete Overview & Installation

Leviathan TBE Fitment - PRO Tips