Thermal Reactor Replacement VS....

[DP911-70-2,7]

Hi...

How are the Thermal Reactor Replacement vs the stock pre-73 exhaust...??? Anyone here whit experience ???

I know they were built by Bursch, and i do like the shape of them, but don't know if they are any good. I have bought a pair from a friend, and the plan is to put them on a 2.7 Weber engine.

So...anyone tried them out ??

Regards
B.A Andersen

[Flat6pac]

Back in the day they were thermal replacements but they are not tuned in length and go into a heat box that was just used in 76 and 77.
I think they require long studs because the thermals were thick flange.
Bruce

[Henry Schmidt]

Those parts served a purpose back in the day but they had a tendency to crack at the welds and offered poor performance at best.
Stock heater boxes or SSI are the way to go if you need heat and the engine is making less than 240 hp.

[notmytarga]

I have 2 sets of these, somewhere. One of the four even has a leaky weld as described by Henry. I am now running SSI's. The other set are from an identical core engine I came across. (Both are 1975 California engines, which had the thermal reactors even earlier) The volume of each exhaust path is not matched and thus they are less than ideal. The manifold inside of an SSI has all the tubing the same length and beautifully curved to make it all work out to where they are joined. It is oft said that the performance increase with the SSI or stock pre '73 is 10 HP over the bypass or TR. My butt dyno felt it - but there was 8 months and other changes in there too.

I talked with Harvey Weidman (wheel guy) about how these thermal reactors replacements were fairly quickly made up when those engines were dying early. My '75 S had them on when I acquired it. The car hadn't been driven much since 1984 and only had 40K miles on it. It also had tensioner collars (one broken and thus worthless/dangerous) and the toilet flapper in the airbox - pretty good updating in its first 9 years.

[DP911-70-2,7]

Thx guys.....

I have one 2.2 T engine whit 70.4 crank and 2.2 T Pistons, 40 mm Webers (31 mm Venturi, 1.35 main, 185 air c, F2 and 55 idle jets) , and a 2.7 engine whit RS pistons, E cams and 40 Webers.

The 2.2 is going in my -73 E Coupe (-74 RS replica) and the 2.7 in my other 911. 1970 Targa ( -86 Turbo Look, just have rebuilt cars...) The 3.0 thats in there now is in need for a valve fix....and have this two exhausts to use..... nice to know what to put were..... a bit wiser now....thx

The -74 RS i will sell soon, when i`m done whit it......

Have a nice day

Regards
B.A Andersen
Norway