1980 Porsche 935 K3 Turbo by Kremer Racing

[19Bozzy92]

This is probabily one of the best racing Porsche I've ever seen. Always fantastic to hear the whistle of the two turbos while they are working and the gorgeous flames from the exhaust.

:confused:I saw it has two different exhaust systems. At the first time I thought they worked like the Ferrari F40 exhaust pipes but I saw the flames came both from the central exhausts (when the car was downshifting) and both from the 2 little ones (when the car was changing gear during the acceleration):confused:. Why this?:confused: (you can see clearly the back of the car at 1:26 in the video ;))

http://www.youtube.com/watch?v=ZYThh2rKIfw

[henk4]

welcome, my explanation would be that the large exhausts are for the engine, the small ones take care of the overboost, so you may see flames from those when upshifting...but i might be wrong.

[csl177]

No, the two big pipes in the middle are turbo wastegates from which fuel ignites from latent heat on pressure drops (as anti-lag);
the small pipes outboard are the exhaust. More info here: 1981 - 1982 Porsche 935 K4 - Images, Specifications and Information (http://www.ultimatecarpage.com/car/3671/Porsche-935-K4.html)

[henk4]

No, the two big pipes in the middle are turbo wastegates from which fuel ignites from latent heat on pressure drops (as anti-lag);
the small pipes outboard are the exhaust. More info here: 1981 - 1982 Porsche 935 K4 - Images, Specifications and Information (http://www.ultimatecarpage.com/car/3671/Porsche-935-K4.html)

thank you, when I wrote my comment I was too lazy to figure out how it really works.

[clutch-monkey]

aren't the two small outboard pipes the external wastegate/screamer pipes?

[henk4]

aren't the two small outboard pipes the external wastegate/screamer pipes?

well, have a look at this one....

[19Bozzy92]

Ok. Thanks for all your answers! ;)

[daytona 935]

Of course , Clutch-monkey is right and csl 117 made a little inversion.
The large tubes are for the exhaust gas ( after spinning the turbo's rotor ) and the small ones are those coming out of the wastegate.
This is the common installation for the 70's - end of 80's turbo powered cars.
Later came various plumbing system to "re-use" a bit of the "wasted" gas , to keep the turbo reving constantly , and minimizing the lag.

[Sledgehammer]

Or commonl referred to as recirculating valves.

[clutch-monkey]

Of course , Clutch-monkey is right
can you please explain this to my girlfriend LOL

[csl177]

Of course, Clutch-monkey is right and csl 117 made a little inversion.
Thanks for the correction, daytona 935... can you explain why the waste pipes are so small? :)

can you please explain this to my girlfriend LOL
You should have Tshirts made... :D

[henk4]

Thanks for the correction, daytona 935... can you explain why the waste pipes are so small? :)


A Porsche engine does not produce waste....

[csl177]

A Porsche engine does not produce waste....

Only the sweet parfum of success?

[clutch-monkey]

Thanks for the correction, daytona 935... can you explain why the waste pipes are so small? :)

i assumed they're only small since it's only excess gas/pressure being vented?
will wait for turbo guru's to chime in haha

[csl177]

i assumed they're only small since it's only excess gas/pressure being vented?
will wait for turbo guru's to chime in haha

Maybe someone will also explain the purpose of the long stinger on only ONE side, from the photo Henk posted. :confused:

[henk4]

Only the sweet parfum of success?

not always

[csl177]

From the looks of the car still on track, it's contagious.

[clutch-monkey]

Maybe someone will also explain the purpose of the long stinger on only ONE side, from the photo Henk posted. :confused:

yeah that one has me baffled, not a clue. slight increase in back pressure? but then why one side?

[henk4]

yeah that one has me baffled, not a clue. slight increase in back pressure? but then why one side?

they sort of explained it to me, some years ago, but I am afraid my memory is not what it used to be. (Or perhaps I did not understand enough of it to be able to properly reproduce its purpose) There were several cars at the Monterey historics that had that pipe but certainly not all of them.

[csl177]

I've seen a couple too, always wondered about it in the '80s. Will ask someone this weekend.