For those of you new to the forum or not familiar with Vengeance Racing please take a few minutes to search our name. We have literally hundreds of C5/C6 builds posted on Corvette Forum and we specialize in late model GM performance. We pride ourselves on offering the most powerful & reliable performance packages in the industry. For this to happen we spend countless hours testing not only our own products, but all manufacturer supplied products to ensure the best combination possible for our customer.

Vengeance Racing recently purchased a C7 for development purposes. We have taken a step by step approach modifying our C7 to show individual performance gains. More information on our C7 can be found here:

http://forums.corvetteforum.com/c7-t...o-updates.html


This thread details our results after testing the following header systems.

American Racing 1 7/8" 4 into 1 longtubes with ORX
Pfadt Race Engineering Tri Y longtubes with ORX
Kooks Custom Headers 1 7/8" 4 into 1 longtubes with ORX

A couple of things before the results:

• This testing was performed on our modified and tuned C7
• The results are specific to our combination and might not be the same for your application.
• All testing was performed on our Dynojet 224x chassis dyno.
• All three header systems were installed/tested within a 12 hour window to avoid issues with weather corrections.
• Testing conditions were monitored and recorded for each system.

Coolant Temp- 208-212*
Oil Temp-160-165*
Timing-25*
Air Fuel-12.8

• Tuning adjustments were made for each test to achieve the best results from each system.
• Run File #3 is posted from each system for comparison.
• Vengeance Racing is a dealer for American Racing & Pfadt Race Engineering/Pfadt Power Products.
• Vengeance Racing has agreed to sign back on with Kooks IF their headers out perform the competition.
• We have invited LG to send us their headers for testing, with no reply.

Along with dyno results we will include Fit/Finish/Installation Notes for each system

All that being said..... Our initial set of headers that were installed with our VR Cam Kit were the Pfadt Race Engineering Tri Y Design with ORX. Here is a side by side comparison of the Pfadt system Vs the OE manifolds/cats/H pipe



Finish:The Pfadt headers offer an amazing look and include V Band connections as well as a brushed stainless finish. Their system comes packaged extremely well including everything needed for a complete installation.

Fit: Install was a bit more difficult than we anticipated. The passenger side header takes a little work to install including lowering the cradle/removing oil lines and starter cover. We attribute this to the tri y design and consider the header fitment part of the packaging.

We also experienced a bit of difficulty installing our X pipe getting the V bands to line up correctly. Once installed everything seems to fit well, although our X pipe is shifted to the left of the tunnel a bit. We have forwarded this information to Pfadt and they seem very eager to correct these issues as soon as possible. I am sending my system back to them for testing/fitment this week.







Dyno Results: Results from the Pfadt Headers/VR Camshaft are 511RWHP/442RWTQ.




Next up Are the American Racing 1 7/8" Longtubes with ORX.



Finish: Similar to the ARH mid lengths the long tubes look well engineered with extremely long primaries and include everything needed for a complete installation. The only thing lacking was 02 extensions (which the Pfadt system and ARH mid lengths did not require). We extended our current 02 sensors to complete testing.

Fit: Surprisingly the ARH long tubes fell right into place. We literally had to use a ratchet strap on the bottom of the car to hold the headers in the engine bay until we were able to lower the vehicle to bolt the headers to the engine.





Dyno Results: Peak #s from our baseline jumped from 511/442 to 519/458 along with a noticeable increase in torque in the lower RPMs..



Next up are Kooks 1 7/8" 4 into 1 Stainless Longtubes with NON Catted X pipe...

Finish: As with the Pfadt and ARH systems the Kooks headers showed up packaged well and included everything needed for a complete installation. Comparing the ARH 4 into 1 to the Kooks 4 into 1 there are some noticeable differences

Primary length- The ARH primaries measure up to 10" longer than the Kooks system.

The Kooks system located the front 02 provision right at the end of the primary while the ARH system moves it further back in the collector.

The Kooks header offers a straight collector while the ARH header offers a merge collector











Fit: The Kooks headers installed without issue. Like the ARH Headers we had to use a ratchet strap under the vehicle to hold the headers in place while we lowered it down to bolt the headers to the engine. The X pipe fit well although after bolting everything up and adjusting the axle back our tips set out about an inch further than stock.




Dyno Results:

Kooks Vs ARH- Both 1 7/8" Primary/Both 3" ORX

Peak #s were close with Kooks coming in at 516RWHP/449RWTQ and ARH coming in at 519RWHP/458RWTQ. From approximately 2500RPM to 3800RPM the ARH system had up to 50lb ft advantages over the Kooks system



Kooks Vs Pfadt- Kooks 4 into 1/Pfadt Tri Y Design/Both 3" ORX

Again, Peak #s were close with Kooks coming in at 516RWHP/449RWTQ and Pfadts #s coming in at 511RWHP/442RWTQ.... From 3000RPM to approximately 3800RPM the Pfadt system actually has 25 to 30lb ft advantage over the Kooks system, but the Kooks system averages approximately 10rwhp/10rwtq more than the Pfadt system from 4700RPM and up



Here is a three way comparison of the final results of all three systems

Pfadt Race Engineering -511RWHP/442RWTQ
American Racing -519RWHP/458RWTQ
Kooks Custom Headers-516RWHP/449RWTQ




I will state again the results posted are what we saw on our modified C7. Others results may vary.


We will be conducting more testing in the coming weeks to ensure our customers get the best performance possible from their investment. We will continue to post unbiased results of our testing as well.


IF YOU HAVE NOTHING INTELLIGENT TO ADD TO THE INFORMATION POSTED ABOVE PLEASE DO NOT BOTHER POSTING.