Quote Originally Posted by 53 Chevy5 View Post
" high performance exhaust " with 90 deg angles, really how dumb are they.

Does any of that air pump egr stuff really hurt performance or is it just the clutter people hate.
Those 90* joints remind me of the "custom" exhaust that was under the Healey when I got it. It had a 3" single exhaust with one side ran at a 90 into the the other. Crazy.

As far as the EGR and air injection goes, it's hard to believe that diluting the intake charge with exhaust and blowing air back into the exhaust ports will not hurt power. Maybe it doesn't, but I would have to see dyno runs on the same engine with and without to believe it.

The exhaust manifolds I've looked at that are for air injection have nozzles that aim the air straight back into the exhaust port. Looks like it would form an eductor type of pump and force exhaust gases back into the port.

Most of the air injection engines had retarded timing at idle, too. The idea was to dump most of the fuel/air mix into the exhaust manifolds at idle and burn it off with the air injection. That's why these engines ran ported vacuum to the distrbutor. They weren't concerned with what this stuff did to power or under hood heat. Whether you think this was a good idea or not, it was all about passing the EPA tests.