Doug Thorley Tri-Y Header Install and Review

[Alikazam]

Ok, I finally made it back home to install and test out my Doug Thorley Headers. Thanks to Josh for the great deal so now its payback time, here goes.

INSTALL: The total working time from start to finish was 8 hours. I was working in my brother's shop on a lift as well. My car is a 2009 SRT8 6-speed. I'd rate the difficulty as moderate. Once you get the hang of a few tricks, like looking through the sides carefully and the liberal usage of extensions and u-joints and wobbly sockets, it goes a bit better. One thing to note is the stock SRT8 manifolds were harder to remove than the Doug Thorleys were to install. I was able to start all 8 bolts for the Doug Thorleys from the underside for the passenger side, and 6 of the bolts for the driver side from the underside; the top two middle bolts on the driver side had to be put in from above. Removal of the stock SRT8 manifold passenger side top middle rear bolt required the most work as it took 2 u-joints with a 3" extension in between snaked around the manifold to loosen, doing it by feel as well, with a long extension to the wrench below. I probably spent about an hour trying to get a good angle on this bolt and just couldn't get it from the top. All that being said, I did not remove anything more than was required by the Doug Thorley instructions except for the forward middle passenger side coil pack to allow better access with my flex-head ratchet around the side of the valve cover. Here is a picture of the tools I used:

[Alikazam]

RESULTS: Ok I'm going to toss a few pictures in here as attachments so they maintain a good resolution, so check them out at the end of this post. I took my car to a chassis dyno before I left in February for work. She dyno'd, uncorrected (which I prefer, why try to change what it did??) on a DynoJet chassis dyno 368 whp, 367 wtq. This seemed to be in line with what most stock SRT8's are dyno-ing. After installing the headers, I went back to the same dyno, different day though, and also went uncorrected. I put 3 of the runs up, the highest horse run being the run with the longest cool down time and Coolant temperatures were below 190 deg. The other 2 runs coolant temps were around 195-205 to start. She dyno'd 377 whp, 380 wtq at the highest, and 372 whp, 374 wtq in the middle, and 371 whp, 376 wtq at the lowest. These are just the peak numbers which seem to be very related to coolant temperatures for the engine. Most of the rest of the dyno curve below 5000 rpm there was a nice increase in torque and horsepower over the stock setup. The "peak gain" for torque was 17 ft-lbs at the cursor location vs. the stock setup. There seemed to be a good mid-range increase with approx. 10+ hp at the rear wheels from 3200 rpm through about 4500 rpm. That, I believe, is where this setup shines. That increase in area under the curve is what you benefit from most vs. the stock setup. Look at the curves and see for yourself.

[Alikazam]

OVERALL IMPRESSION: I think these Tri-Y headers are a very nice product at a reasonable price considering the cost of many aftermarket headers out there for the Challenger. I am pleased with the fact that with no other changes to my car there is a noticable gain, especially given the efficient design of the stock units. This is my first experience using a Tri-Y setup and I am impressed with the torque increase throughout the midrange. The fit and finish of the produc is excellent, fully ceramic coated midpipes as well as headers. I reused the factory manifold bolts as they had a reduced 10mm head instead of the provided 12mm head bolts that were supplied with the headers. I also reused the factory gaskets that have a steel shim on the head side and a carbon-graphite face for the header, instead of the "ultra seal" style gaskets provided with the headers. I found that with the factory gasket there was no need to re-torque the headers after heat cycling (I tried, they were still very tight). I would recommend a good quality anti-sieze rated for 2000+ degrees for use in this application. Copper or Nickle anti-sieze would do. Aluminum based won't hold up to the heat as well.

Here are the remaining photos as well. Thanks to HHP and Doug Thorley for the great product as well as the chance to be part of this test. Cheers to all.

[jimmi-no]

How much for the headers and cat-less mids?

[Alikazam]

check out HHP for prices I think it runs in the $800 neighborhood.