I'm just back yesterday from an epic, 1750 mile round trip to do a Tourist day at The Ring, and a session at Spa, in my trusty mk2. Couldn't complain about anything aside from the noise of the engine at 80mph speeds . It's a fast Road Digi, ported head, cam, and a Miltek / Tsr tubular mani . Stock, undrilled airbox. I changed the front and middle boxes for new Bosal items, and tried a new but unknown cheap brand back box, but it's still noisy at speed . If you lean back into the rear it seems quieter, and louder if you lean close to the windscreen ,whilst driving. Anyone else found a 4 branch to make their car louder?
I found the same when I had one, apparently it gets better with age as the manifold starts to coke up. not sure how true that is, I didnt leave it on for long enough to see as it was such garbage it was quickly removed and sold on lol
Tubular manifolds MIGHT make the engine a tad bit hissy in the engine bay. But you can only asscess this if the rest of the exhaust system is not changed.
I was wondering was it a resonance issue , and if welding a few different sizes of small billets onto each of the runners would cancel it out.
Stainless steel makes a difference compared mild steel stainless just dosen't absorb the sound as well Also if it has the daft spring loaded flexi joints do make them a bit more noisy
Standard 8v system after that Ed. I changed the front and middle boxes to try quieten it, back box is going to be replaced regardless as it's getting rusty. I'd probably not lose any performance going back to the oe twin downpipe set up and cast exhaust mani .
My Magnex 4 branch on the Mk2 16v was noisy, lagging it helped a lot. Notice it quite often pn motorcycles as well going from mild steel to stainless. I'd describe it a "tinny" for want of a better word.
I've a bit of that , and it's well wrapped from head to the flange . I'm very tempted to change it back to cast iron ... I'll get a new back box first though.
So, 3 new Bosal exhaust boxes.... And it's still droning more than I'd like. However, I was troubleshooting another issue, and richened the fuel mixture... And it's idling a lot sweeter and dare I say not as droning as before.
