EFI guys, knock sensor question

[IMR-Merlin]

I have some open channels on my tech3 and want to run a knock sensor (if even possible). I am in the process of getting my wire harness mocked up and need to run a lead for it.

Can anyone one point me in the right direction on where to mount one and what one to use?

Found this...



Thanks.

Brendon

[kenikh]

For my Tec3R, I used OEM 993 knock bars, tapped into the heads. I just used the stock 993 knock sensors.

[proffighter]

Mounting at the heads like shown is probably the best way, but only makes sense if you have two of them, one for each bank. Otherwise choose the crankcase. At the vent housing is maybe not the best area, lower more in the center and stiffer place is to prefer. There was a thread about this theme not long ago in the turbo forum. Search for it too

[IMR-Merlin]

Thanks.

I'll search. I dont feel like digging too deep into the engine at this time to run the knock sensor.

Originally Posted by proffighter

Mounting at the heads like shown is probably the best way, but only makes sense if you have two of them, one for each bank. Otherwise choose the crankcase. At the vent housing is maybe not the best area, lower more in the center and stiffer place is to prefer. There was a thread about this theme not long ago in the turbo forum. Search for it too

[kenikh]

Penny wise, pound foolish to not do it right.

[dos531]

The ideal place that people use is under the shroud. I think it depends on what year you have, but I had an unused threaded hole next to the breather cover that I was able to use for mine.

[IMR-Merlin]

Considering the way the system WAS set up, no O2 sensor or knock sensor.... I should be much better off than before.

Most of the knock sensors that I have dealt with over the years have been block mounted.

But I get your drift...

Originally Posted by kenikh

Penny wise, pound foolish to not do it right.

[kenikh]

Block mounted knock sensors are typically used in integrated block configurations, meaning cylinder and block are one piece. Porsche motors with separate cylinders have a smaller transmission surface for knock frequencies. I'm sure it will work, but you'll get a cleaner signal close to the knock source, which is why Porsche put bosses for the knock bars right on the cylinders.

[JJ 911SC]

Originally Posted by kenikh

For my Tec3R, I used OEM 993 knock bars, tapped into the heads. I just used the stock 993 knock sensors.

Kenikh,

I think its the way I'll go.

Cheers

JJ

[IMR-Merlin]

Got it.

But for me to do the 993 sensor, I will have to source the knock bars and remove all 6 heads to drill and tap. Correct?

Might be the way to go when i do a rebuild on the engine.

Originally Posted by kenikh

Block mounted knock sensors are typically used in integrated block configurations, meaning cylinder and block are one piece. Porsche motors with separate cylinders have a smaller transmission surface for knock frequencies. I'm sure it will work, but you'll get a cleaner signal close to the knock source, which is why Porsche put bosses for the knock bars right on the cylinders.

[kenikh]

You could do it in place... But I wouldn't try it.

FWIW, Pelican sells these new @ $45/ea

[JJ 911SC]

Originally Posted by kenikh

You could do it in place... But I wouldn't try it.

FWIW, Pelican sells these new @ $45/ea

I may be looking at the wrong one but it look like it.

Cylinder Bridge 99310439100 @ $20.50

#5 of http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?command=show_parts_image&Headers_Id=38717&Line_Item_Number=5

Pelican Parts - European Automotive Parts and Accessories - Porsche • BMW • Mercedes • Volkswagen • Audi • Saab • Volvo • MINI

[kenikh]

Looks right! Hell has frozen over: A Porsche part got cheaper!

[JJ 911SC]

Originally Posted by kenikh

Looks right! Hell has frozen over: A Porsche part got cheaper!

I'll check with the dealership on Monday.

The exchange rate is killing a lot of business in border town. I pickup a PP order on Wednesday and the UPS store in Ogdensburg is deserted. They went from 1000's package a day to 100's...

[IMR-Merlin]

Thanks for all the help. I think I will look for a crank case location for now and go with the head bridge when I do the rebuild.

Originally Posted by kenikh

You could do it in place... But I wouldn't try it.

FWIW, Pelican sells these new @ $45/ea

[proffighter]

Originally Posted by dos531

The ideal place that people use is under the shroud. I think it depends on what year you have, but I had an unused threaded hole next to the breather cover that I was able to use for mine.

Hey, that's my engine

[Tippy]

Quote de kenikh

You could do it in place... But I wouldn't try it.



FWIW, Pelican sells these new @ $45/ea

I may be looking at the wrong one but it look like it.



Cylinder Bridge 99310439100 @ $20.50



#5 of http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?command=show_parts_image&Headers_Id= 38717&Line_Item_Number=5



Pelican Parts - European Automotive Parts and Accessories - Porsche • BMW • Mercedes • Volkswagen • Audi • Saab • Volvo • MINI

GTFO! Only $40 for the pair? What am I missing?!?!