AU2 XR8 Stroker Exhaust System Buildup - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

Aussie Pete · 03-14-2002, 01:11

***PLEASE DON'T POST TO THIS THREAD UNTIL I CONFIRM THE PHOTO SERIES IS COMPLETE***

Aussie Pete · 03-14-2002, 01:15

Firstly, this car had standard Tickford 220kW extractors with integral cats. The cats are large AC brand and the extractors were Jet Hot coated right to the last flange. Behind this was the Herrod single 2.5 inch mandrel system with optional resonator.

This system was good enough for around 205-210rwkW. However, it sounds very nice with most of Herrod's cars. I cannot say that with the 347 and the heads etc this exhaust is good enough to keep up.

The components are shown here removed from the car.

Aussie Pete · 03-14-2002, 01:22

I chose to go with 4-1 long primary headers. These are full stainless and were purchased from Herrods. Here shown with collector flanges still in place.

Note that stainless headers retain heat far better than mild and so jet hot coating is not necessary, although doing so will keep heat levels down further.

Aussie Pete · 03-14-2002, 01:29

Many X-Pipes were looked at for the system. One of the better ones was from Magnaflow, however inspection of many found interior finish which was less than satisfactory. So, looking at some tech information out there a dimension was decided on for the cross area length. This was essentially the longest length without compromising cross sectional area. I chose a symmetrical X-pipe, however you can tune the rpm range of the pipe by changing the exit and entry angles. By having a 'true' X shape the theory is that the effect is best for mid range - exactly what I wanted. I have heard that the shallower exit angles help more with top end.

The X-Pipe was made from two 2.5 inch mandrel bends plasma cut and mated before TIG welding the two halves together. Here is a pic of the outside of the X-Pipe.

Aussie Pete · 03-14-2002, 01:32

Importantly, showing the work of the shop doing the system, the X-Pipe was linished internally so that the joins and internal changes are smooth. Attached is an internal view of the X-Pipe.

Aussie Pete · 03-14-2002, 01:36

Supercats were chosen for this system because of internal finish. Basically the internal flanges and transitions are entirely smooth with no abrupt flow interruptions. The inlet and outlet are both 2.5 inch, however with the extractors being 3 inch at the collectors the Supercats were able to be pumped out to match.

Here is the inlet of a Supercat.

Aussie Pete · 03-14-2002, 01:42

Muffler choice is critical both for flow and sound. After lots of research (some companies were surprisingly short on web info - one of which was Lukey) I narrowed the choices down to Dynomax and Magnaflow.

After discussing this with the installer, and then speaking with the Magnaflow distributor their centre-offset mufflers were chosen. These fit well under the Falcon floorpan and have been proven to be top performers on Mustangs in the USA. They are also far better finished etc than common chinese import stuff used in many exhaust shops. Some nice features include fully welded construction, lifetime guarantee, super-neat internal finish, and quality internal sound packing.

One of the mufflers is shown before installation.

Aussie Pete · 03-14-2002, 01:49

The last major component in the system is a rear resonator. This isn't always necessary, however I do a lot of highway miles and droning etc is a pain.

There were no rear resonators available that fit at the rear of an AU and have twin 2.5 inch inlet and outlet. The best solution found was to take a Genie Super Turbo twin-pipe resonator, bore it out and take out the twin pipes, and then insert the required twin 2.5 inch stainless holed tubes.

Whilst this shot shows the resonator already partially fitted, it is clear how the conversion was done. The holed pipe was run to the end flanges to allow easy TIG welding of the pipes at each end.

Aussie Pete · 03-14-2002, 01:53

Now to the start of making the system.

This shows the headers after being fitted and the collector flanges removed. Whilst these are big collectors and the headers have long primaries they fit well and do not cause ride height clearance problems. Collectors are 3 inch and include oxygen sensor holes which allow sampling of all four cylinders.

Aussie Pete · 03-14-2002, 02:01

Actually went to work for a while :s3 so missed some of the action. Here the front end of the system is completed. The cats are welded directly to the rear of the headers to aid heat transfer (emissions issue) before flanges are fitted that match Ford OEM and so hanger brackets are rigid and complete.

Behind the flange point is the X-Pipe which was fitted as close as practical to the engine. All pipes are mandrel 2.5 inch and were plasma cut to fit. The pipes are then tacked in place using a MIG before being completely removed and TIG welded off the car. This ensures good weld finish and minimal internal dagging at weld joins.