We are going to discuss how Tim picked up 15 rear wheel kilowatts from simply swapping an existing product for a far more superior one.

Tim was able to accomplish this without needing to go to extremes OR having to sacrifice anything to gain this power.

In fact, He didn't do anything else except upgrade this product to one that has proven itself time & time again.

Let's take a look at Tim's set-up PRIOR to the upgrade

Tim approached us to help find a solution for his build. He owns a VY SS Ute which has had the factory 241 heads CNC ported, Camshaft upgraded, Intake & all other necessary valve train components done to suit the package.

Exhaust is a set of 1 3/4" short length 4 into 1 headers, 100 cell cats & 2.5" cat back system.

This set-up was producing 280 rear wheel kilowatts.

Like many of us, Tim knows his car well enough to know that there is something holding it back BUT you can't quite put your finger on it.

After all, It could be a number of things & it can be very expensive to play the process of elimination game!

We discussed his concerns & pin pointed the issue to the exhaust system being restrictive for his build.

Once we identified the issue, It was an easy one - 

Solution: We needed a full DPE Manta Pro Series exhaust system!

Kicking things off with the process of elimination

By identifying that the exhaust system was very restrictive on this build, We were able to work with Tim to run through the advantages of upgrading the restrictive exhaust system.

We begin by breaking down the comparison of each component individually - Starting with the headers:

Headers

This set-up already had 1 3/4" 4 into 1 headers on this build which is a great size headers for most naturally aspirated street builds, However the design, Length, Material & quality were all factors in WHY there is significant restrictions on this system.

Solution to a Problem

We begin the upgrade by starting with the headers.

The problem with the existing headers in particular are two key things;

1. Material Quality: Most systems are made from a 304 grade stainless steel which is not good for headers - Here's why;

304 grade stainless steel expands significantly when they get hot, If they get exposed to water they instantly are subject to shrinkage & prone to cracking.

By utilising a 409 grade stainless steel, You are ensuring the foundation of your exhausts material is far less subject to expansion at their peak temperatures compared to a 304 grade stainless steel.

409 grade stainless steel lasts around 10 x longer than other grades of steel due to its material inclusions.

2. Design: You Are Leaving VITAL HP & TORQUE On The Table Without The Right 4 into 1 Tuned Length / Long Tube Header Design

DPE Manta Pro Headers are the bi-product of the pursuit of perfection.

After all, These headers were designed & developed by one of the country's fasted nitro drag racers who also happens to own and drive Top Fuel Dragsters, Nitro Funny Car, Fighter Jet powered Dragsters and is responsible for building the world FIRST nitro Doorslammer.

It's fair to say the man knows a thing or two about manufacturing proven race winning competitive products.

So, What Makes These DPE Headers SO Much Better?

Well, The devil is in the detail, Or in this case the design.

The key is in the execution of the correct lengths - For instance, The DPE headers range between 28" - 32" & come together at the 14 Degree mark to form a merge collector.

The merge collector is between approx. 8" - 12" in length.

To determine the ideal collector length, This was done by real world testing on a drag track multiple times.

The collectors were ran down the track a few times. From there they were trimmed back to find where the 'grey ring' was identified. Identifying this grey ring is the point where the ideal results for collector length is determined.

Testing & development of the right determined length for the collector allows the gasses to speed up & assist with scavenging.

This vital development alone is worth approx. 4 - 5 horsepower by pure design innovation over far less comparable products.

Cats

Tim had 100 cell 2.5" cats on his previous set-up.

Much to the shock of some, 100 cell cats ARE NOT more free flowing than 200 cell cats.

Again, It is all in the design & quality of the material that makes the cats support the system to product its power, So we upgraded to the DPE Manta Pro Series 3" 200 Cell high flow cats

Middle Muffler

As mentioned earlier, Tim had a full 2.5" cat back on his VY SS, Which is a great size system for mild modifications such as intake exhaust & tune, However Tim has done CNC head work & camshaft package meaning that the LS1 is producing far more output than the 2.5" can support.

This 2.5" middle muffler was producing a restrictive sound, Inadequate flow & was resonating throughout the cabin on certain RPM which can be very annoying!

We upgraded the cat back to a 3" system.

This also provides us with two key changes;

1. X Pipe Over ALL 

DPE systems utilise an 'X' pipe middle muffler design rather than a traditional 'H' pipe design. This again is another advancement of decades of development into the search for the perfect system.

Fact is that nothing flows better than a straight through, well designed stainless steel perforated tube muffler found in the DPE systems.

The 3" system also support the flow much better than the far less comparable 2.5" system that was running on this build.

2. Drone Prevention

This is a big factor in ANY exhaust system. Understanding the importance of design, We now look to ensure there is little to no drone in the system.

This is achieved by ensuring the middle muffler is a straight through, Well executed 'X' pipe design that ensures the increased gas speeds are able to get through your system unrestricted.

DPE's 'X' pipe design delivers its signature smooth & deep note because the pulses from each side of an engine are evened out & flow through the premium system.

More importantly, Knowing that gasses are produced from BOTH sides of the engine need to flow & increased gas speed through the high flowing exhaust. This is the answer to a great sounding system & if done right, There is very little to no drone in the car.

Droning occurs when there is interference in the design which causes the gasses from each side of the engine to slow down the speed in which the gasses are trying to exit the system.

This build up causes drone.

The above innovation has proven to see 40 Nm of torque increase over a far less efficient system.

Rear Mufflers

No surprise here, We retained the same 3" system throughout.

The Results: Check Out The BEFORE & AFTER Dyno Run

What did Tim have to say about the new system?

"Definitely much better throttle response and it revs a lot more freely throughout the rev range. I also love that it can cruise (with absolutely no drone) and you can hear the radio clearly and have a conversation and then under wide open throttle it just sounds amazing"

So there you have it, All of the benefits of upgrading to a quality system to support the horsepower that his engine is producing.

Tim was able to achieve;

• Proven optimum flowing headers
• X pipe designed, Hand made cat back system
• NO drone
• Better throttle response
• More free revs throughout the entire rev range
• Picked up 15 rwkw!

The important thing to take from this is that a little bit of careful planning & advice from the right team can make a world of difference in achieving the results that you set out for.

If possible, Avoid settling for something purely based on price as it could end up far more expensive in the long run if having to upgrade the same parts twice!