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3” exhaust

Posted: Sun Oct 24, 2021 10:37 pm
by Zamani
Has anyone fabricated a 3” exhaust system on the 75? I tried to mock up a 3” system with bends and straight sections around the dedion subframe, and over the half-shafts, but the space around there is very tight. I’m thinking of keeping my 2.5” exhaust system for now but if anyone has already done so and want to share photos or tips, please share. Side exhaust is an option but will fail sound check at a few tracks.

Re: 3” exhaust

Posted: Sat Oct 30, 2021 12:46 pm
by MD
Hey Good Buddy,

Now if you went by the name of the Greekster, my suggestion for you would be to get some string and a three inch steel ball. Attach the string to the ball with some super glue. Use the string to pull the ball through your present system that will act like a reamer and expand it to 3 inches.
I was tempted to ad some other advice but but Mr Discretion tapped me on the shoulder and waved his index finger in disapproval.

Now for something that is actually useful info. I have a three inch system on the Alfetta GTV racer. The next time it is on the hoist, I will take some photos for you and post them here. It's virtually a new system as well as I have had to have it remade for getting black flagged with the previous one on it.

The car lives on the trailer and it might be possible to get under it but I suspect the images may not be so good. I will try.

Stay tuned. BTW, 75, 90, GTV. Apart from the wheel base being a little shorter on the GTV, the system layout will be the same BUT there will be other things that will need to be accommodated for as the photos will show.

Re: 3” exhaust

Posted: Wed Nov 03, 2021 6:22 pm
by Zamani
Haha ok always good advice from you. Just so you know Jim is quite satisfied with…..drum roll….2.5” ….. :mrgreen: hey I’m talking about exhaust here…

Anyway I’ve fabbed my exhaust 3” after the header secondaries merge, but shrinks back down to 2.5” as I tried the 3” v-band clamp setup and it wouldn’t clear the rear roll bar and spaced brake calipers (I have vented rear rotorS).

Re: 3” exhaust

Posted: Wed Nov 03, 2021 10:03 pm
by MD
All good. Understood.
The issues I referred to earlier are:-
The tyre well has to be cut out.
The fuel tank needs to go into the trunk (boot) like the GTV6.
That provides the flat area to install a pile of stuff.
So if you are not contemplating doing that anytime soon, I wont bother with the photos ?

2.5" for the Greekster is too generous. He's so old he's forgotten where the first 2 go. :mrgreen:

Re: 3” exhaust

Posted: Thu Nov 04, 2021 8:27 am
by Zamani
Mate, everyone loves photos. You know it, you have lots... :wall: :mrgreen:

Post them up.

I'm gonna post my latest 3" exhaust setup. OK they're up. Wells are kinda shite (local fab shops kept on asking me to wait days, or had no time), but nothing a few cans of fosters won't fix, will "smoothen out" the visuals...

Re: 3” exhaust

Posted: Thu Nov 04, 2021 1:00 pm
by MD
Mate, looks to me like you have taken the python off the Alfa emblem, magnified it and sprayed it with a stainless new paint coat. A feat only accomplished by a select few. The gong award is coming soon. Look for it in your letterbox. It will accompanied by a parcel containing an Indiana Jones safety hat you can wear on the track. :D

Perfect example how hard it is to make a system without a mandrel bender. You got my sympathy mate.
BTW, is your engine boosted or NA? I Take it that it is a track car? I am trying understand why you would need a 3" system.


Re: 3” exhaust

Posted: Thu Nov 04, 2021 10:13 pm
by Zamani
Every exhaust shop there seem to have a mandrel bender. Not here.

It’s a track car with a 3.2 24V NA, 275 bhp, possible supercharger next. AlanQ4 here, has a 3” system on a modified 3.0 24V and it works well. Lots of K24 conversions also went from 2.5” to 3” system with good gains.

Re: 3” exhaust

Posted: Mon Nov 08, 2021 3:37 pm
by MD
Like I said, the car is on the trailer and taking complete system photos is near impossible. The inboard rotors are just for a hydraulic handbrake.