Exhaust Maze for Middle Year 911s...

1yearonLy · 1yearonLy's Garage

Ok, I'm grappling with smogging my '77 911S and have researched my options. A few questions arise:

-Bursch replacement thermal reactors. These look to be direct replacements without doing any damage to the engine. Is that right?? These guys won't heat the motor up any more than the SSIs?? I wonder if they will pass the visual inspection out here...

-Will the EGR stuff work with the Bursch replacement units?

-Heat Exchangers. Nobody other than OEM makes replacements for these that work with the reactors?? Ouch.

mb911 · mb911's Garage

I think any thermal reator will heat up more than ssis. Really thats the answer if possible (ssis that is) . I also have a 77 and if you live in an area where you can get collector Plates or something close to it than we don't have to smog but once than for ever more you are free from testing and you can do the conversion to get rid of the thermal reactors and either go test pipes or ssis,headers whichever. The only issue is that most states that offer this restrict when you drive the car foe example in wisconsin I can't drive my car in january Oh no 0 degress out fine with me

deanp · 06-23-2005, 11:57 AM

Not sure what you are looking to do, but it seemed like there were three choices with my '76.

Keep stock - thermals, h/e's and two in / one out muffler. Not the answer for longevity.

Modify slightly - Bursch 3 into 1 reactor replacement, sort of like a header, but not equal length tubes. Goes in place of the thermal reactor, doesn't build up as much heat but probably won't allow you to pass smog if the inspector knows what he is looking for. I saw about a 10-15 degree difference in oil temps with these.

Completely modify - SSI's or '74 h/e's. Will not pass smog visual inspection.

I started out with option 2 as I was on a budget last year. Found a set of used Bursch 3 to 1's kept everything else. This year I swapped out for SSI's. I have the original thermals, the bursch 3-to-1's and the original heat exhangers if you are looking for parts/options. PM me if interested in any or all.