Finally finished my downpipe

[discopotato03]

A full on day but Ellie lives with a 2.25" system from turbo to breakfast .

It starts as a 2.25" mandrel bend that was modified from a 90 into an ~ 45 degree bend .
From there a straight section drops to another 45 where it goes horizontal and doglegs to approximately where the std swivel joint should have been (behind the std dump/cat pipes rear flange) .
It uses the std rear gearbox mounting point (multi layered plate) and the exhaust has a tab welded onto a piece of tube that was cut in half and mig welded to the exhaust tube itself , Subaru do this as well to spred the load and stop the tab breaking off the tube . The other (side) gearbox mount to the tube (cat in std form) is done the same way .

The Rally people had a 3" swivel joint on hand so that went on in the std position and handily was just right for the 3" cat that was unused from a previous project . They tacked and welded on the bench reducers to step up to the 3" swivel joint and down to 2.25 past the cat .
Close behind the cat is a 2.25 oval straight through resonator that was "massaged" on its rear edge to miss the bottom of the tailshaft .
Next they used more straight tube with a 45 deg mandrel bend and a two piece flange joint again approximately where the std one was .
The exhaust mount off the back of the std mid section was carefuly removed
and fitted towards the back of the new mid section .
Then another 45 mandrel bend and part of a 90 to lead over the NS axle shaft and into the rear muffler .
This muffler is a 2.25" double offset oval one and again straight through - well really a gentle "S" shape perforated tube - but noooo baffles .
The rear mount bar was reshaped (cold forged) and bends down to go under the last section of pipe out the back . This bit of tube needed another cut so that it follows the std path out the back and points very slightly upwards and lines up with the back face of the rear bumper bar .

And the result is ... drum roll ... an exhaust that sounds hardly any noisier than the dog it replaced and we KNOW that it has a lot less restriction than Fido had . No real boxer burble just a little deeper - I'm impressed .

The differences drive wise are subtle , there is a faint whistle as the turbo spins up under load and its just a tad torquier everywhere than before . It revs a bit more freely and has a bit more urge in the 2800 - to maybe 4000 + rev range .

I was probably expecting a bit more performance but I have to remember that this 86 RX is probably on it's original 296 + K old engine and its lowest pot measured something pathetic like 85 odd pounds compression pressure when I got it (had either 250 or 260 back then) .

Its "rings" must be more like shims now but the new engine should be going in in a couple of months time , expecting much better things then .
Just need to sort out spider manifold (the one modified to take a std L TB) and the accelerator cable .
I have read that these sometimes warp and leak so will get all the flange surfaces checked and if necessary machined flat/parallel .
The turbo and header can wait till later .

Cheers A .

[nncoolg]

for piggy back engine management, I would recommend the apexi S-AFC.

[discopotato03]

I prefer the Jaycar Digital Fuel adjuster , much cheaper .

A .