DIY Borla CAT back + aftermarket Davidco CAT

[brokencase]

Dual exhaust would sound nice. It would actually sound very much like a V8.

I don't see any genuine 2.9L dual exhaust sound clips up on youtube (they are all cheesy 1 into 2 setups) but there are several 4.0l Mustangs that have true dual exhaust that sound really nice.

But as I said it would be a lot of work.

Another way you could do dual exhaust that might be a little easier would be as follows.
Headers that go into a dual inlet/dual outlet universal CAT (The CAT sort of doubles as an H pipe crossover).
You then exit with two pipes that head over to the area where the original Scorpio resonator was. In this area you mount two mufflers side by side.
You weld and tie them together with 1/4" stainless rod and that goes over to the factory hanger for the resonator.
Now you have just pipes that go to the back (under the diff) and then turn off and exit on either corner (with no mufflers back by the gas tank).

[my8950]

Looks good!

[PeterP11c]

I concur. Double exhaust would serve Scorpio well. I wonder, if it would improve engine performance as well. The sound issue is OK, but one would want some return on all this investment.

[brokencase]

The general consensus (as I have read in forums across the pond) is that the 2.9L suffers on the exhaust side of things. The 2.9L is only making about 50hp per liter, which is pretty anemic. Think about it...It has a decent intake manifold, it has a good camshaft, hi swirl combustion. Where did all the power go?

Answer - it was lost in the poor exhaust.

If you want to see more significant "bolt on" performance you need to install headers. After the headers, so long as everything is properly sized, I don't think it would make much difference if you have dual or 2 into 1 exhaust.

The "DIY Borla CAT back" I have done here is probably good for about 5-8 hp over stock. Supposedly the more modern CAT should flow better, the overall path is shorter, the resonator is eliminated, and the Borla muffler is a straight through glass pack. Not to mention that I have a K&N air filter installed.

But if you installed headers, and had similar but properly sized 2.25" exhaust you might see an additional 5-8 hp. Installing an adjustable fuel pressure regulator and raising the fuel pressure slightly might help with additional hp gains.

[brokencase]

How I would have done things if I were to do it over...and saved some money...

For some reason the 2.25 stainless pipe is cheaper...
https://www.ebay.com/itm/28395554812

Then I would have bought one of these and split the y-pipe
https://www.ebay.com/itm/124276148602

The above would have saved about $100 off the project and you would have better performance.

Naturally you would get a Borla muffler in the 2.25 size. But that would be about the same price.

[PeterP11c]

Somebody beat you to it. The 2 1/4" pipe is already missing from E-bay listing.

[brokencase]

Sorry bad link... Just search ebay for "2.25" stainless exhaust kit"...
https://www.ebay.com/itm/283955548121