SSI heat exchangers

SSI heat exchangers are back!

SSI heat exchangers are back!

For years American owners of classic 911s have worshipped at two stainless steel altars called SSI heat exchangers. They are basically a better-than-original replica of the pre-1974 heat exchangers used by Porsche until 1975.

That’s great if you have a US model Porsche 911 built after 1975. Because that’s the year much stricter US emission laws were passed. Laws which meant that Porsche engineers had to severely limit the flow capacities of the engine.

Luckily it’s not difficult to undo this mid-70s calamity. Simply pull out the catalyst, the old heat exchangers and the standard muffler and replace the whole thing with SSIs and a sport muffler and voila: You get much more ummph – and a biiig serving of noise to go along with it!

SSI heat exchangers


Great, right? But then earlier this year it was announced that the successful 35 year run of SSI was over. They had stopped production and sold the company to JP Group; a Danish company which among other things manufactures the DANSK exhausts and heat exchangers.

There was much hand-wringing and lamenting when the news broke. And speculations ran wild. Would JP Group discontinue the SSI brand? Would they lower the renowned quality? Or would they paint the heat exchangers pink and call them Judy?

Well, stop speculating. I asked them.

And here’s what they told me: Production of the SSI heat exchangers has started again. They are being sold by for a retail price of DKK 11,000 excl. VAT. They will ship overseas for an estimated DKK 400 excl. VAT.

For those not too familiar with exchange rates to Danish kroners, it translates to a retail price of approximately EUR 1,530/USD 2,020 shipping included. On top of that you have to pay the VAT man.

So, there you go. The SSI heat exchangers are back. The question is: Should you buy them? If you have a US model 911 built from 1975 and onwards, you can expect a very nice performance boost by changing to SSIs and a sports exhaust. Expect a 10 % increase in horsepower and a 25 % increase in torque at 3,000 RPM.

If you have a ROW model 911, your car will most likely already have a less restricted air flow than the American models. So you won’t get all those extra horsepower or the increase in torque. What you will get though, is a high quality product that is near indestructible. What’s more, in the eyes of many a 911 petrol-head, the heat exchangers from SSI are also a work of art in stainless steel.

Just keep in mind that there are many different models, with each one designed specifically to a specific engine and model year. For example the 1976 cars had a mid-year switch in configuration to the later-style gasket with the ring inside. If you use these gaskets on your 1976 car, order the later style heat exchangers. Be sure to order the style of heat exchanger that matches your engine, not your chassis, if somewhere along your car’s life it had its engine swapped.

It is also important to note that all cars with cross-over exhaust systems (all 1978-89 911SC and Carrera) require the replacement of two oil lines with two older-style ones when installing the SSI heat exchangers (or any 1974 and earlier exhaust). These lines are part numbers 911-107-729-10-M127 (cars with a front-mounted cooler) and 911-107-728-00-M20 (no front-mounted cooler) and 911-107-739-10-M127

While you’re at it. Take a look at JP Group’s DANSK mufflers. They make a nice companion to your new heat exhangers. And the noise they make is simply glorious. 

SSI heat exchangers - DANSK makes exhausts too
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