Z4M Pre-Cat Temperature Sensor Male Thread Specs

Ed Doe

Senior member
Ashbourne or Frimley
Hi all,

Bit of a long-shot but does anyone know what the Pre-Cat Temperature Sensor Thread Type/Size/Pitch/length is for the male thread on the Cat-section?

The thread in question is highlighted below;


Pre-Cat Tem Sensor Thread.PNG

Long story short this has obviously been heatcycled to death on my race-cats and when I came to remove the temp sensor the male thread just twisted and pulled out of the cats(!) Looking to get a replacement welded back in over winter, so I can get these fitted back onto the car :)

Thanks in advance!

Ed
 
Ed Doe said:
Hi all,

Bit of a long-shot but does anyone know what the Pre-Cat Temperature Sensor Thread Type/Size/Pitch/length is for the male thread on the Cat-section?

The thread in question is highlighted below;


Pre-Cat Tem Sensor Thread.PNG

Long story short this has obviously been heatcycled to death on my race-cats and when I came to remove the temp sensor the male thread just twisted and pulled out of the cats(!) Looking to get a replacement welded back in over winter, so I can get these fitted back onto the car :)

Thanks in advance!

Ed

Hi Ed,

What race cats are you running and does the car still pass the MOT emissions test? Did they make a noticeable difference?

Thanks,
GT Spec
 
GT Spec said:
Hi Ed,

What race cats are you running and does the car still pass the MOT emissions test? Did they make a noticeable difference?

Thanks,
GT Spec

Hi,

Hayward & Scott Race Cats - Link: https://www.haywardandscott.com/bmw/bmw-z4m-100-cell-high-flow-cats.html

- they're quite old now though. The 'on the record' answer to your second question is 'of course they pass emissions test every year'. If there was an 'off the record' answer to that question I'll let you infer what that might be :roll:
In terms of difference, I bought the car with them fitted, so can't really comment on the before/after.

In terms of noise, the exhaust is otherwise standard, it's a little louder/raspier than normal I'd say, but it's quite subtle, and for me most importantly doesn't put me at risk of any trackday noise limits, and there's no resonance meaning I can travel long distances in the car without feeling like someone is hammer drilling my cranium!
 
Ed Doe said:
GT Spec said:
Hi Ed,

What race cats are you running and does the car still pass the MOT emissions test? Did they make a noticeable difference?

Thanks,
GT Spec

Hi,

Hayward & Scott Race Cats - Link: https://www.haywardandscott.com/bmw/bmw-z4m-100-cell-high-flow-cats.html

- they're quite old now though. The 'on the record' answer to your second question is 'of course they pass emissions test every year'. If there was an 'off the record' answer to that question I'll let you infer what that might be :roll:
In terms of difference, I bought the car with them fitted, so can't really comment on the before/after.

In terms of noise, the exhaust is otherwise standard, it's a little louder/raspier than normal I'd say, but it's quite subtle, and for me most importantly doesn't put me at risk of any trackday noise limits, and there's no resonance meaning I can travel long distances in the car without feeling like someone is hammer drilling my cranium!

Haha! Understood 😉
 
Ed Doe said:
Bit of a long-shot but does anyone know what the Pre-Cat Temperature Sensor Thread Type/Size/Pitch/length is for the male thread on the Cat-section?
I replaced my egt last month, pretty sure it was M14. Google says;
Manufacturer Part Number: 11787831624
Connector Color: Black
Thread Diameter: M14
Thread Pitch: 1.5 mm
Tip Width: 7 mm
Wire Harness Length: 615 mm

I's not from an official BMW source but fairly sure that's right. Belt and braces I guess just order one from them, measure it and then send it back. It'll be a uk stock item no doubt so you'll just lose postage on the way back.
 
If it came off with the sensor, can you not now simply measure the thread on the sensor?
Must be fairly easy to remove that section from the sensor now?
 
TomK said:
Ed Doe said:
Bit of a long-shot but does anyone know what the Pre-Cat Temperature Sensor Thread Type/Size/Pitch/length is for the male thread on the Cat-section?
I replaced my egt last month, pretty sure it was M14. Google says;
Manufacturer Part Number: 11787831624
Connector Color: Black
Thread Diameter: M14
Thread Pitch: 1.5 mm
Tip Width: 7 mm
Wire Harness Length: 615 mm

I's not from an official BMW source but fairly sure that's right. Belt and braces I guess just order one from them, measure it and then send it back. It'll be a uk stock item no doubt so you'll just lose postage on the way back.

I decided earlier this afternoon the sensible thing was to call H&S, who very sportingly have popped a replacement threaded male socket in the post to me foc :) should have just done that in the first place! Thanks for the info all the same Tom!


enuff_zed said:
If it came off with the sensor, can you not now simply measure the thread on the sensor?
Must be fairly easy to remove that section from the sensor now?

In my rush to get it mot ready I swapped an alternative setup on with a new temp probe and bunged the old probe straight in the bin. This was back in June so no chance of lookimg at it now! :(
 
I use one of these. it covers all the usual metric and unf/unc sizes. Currently about £11 from Amazon. Speeds up the trial and error no end !
 

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Spriteracer said:
I use one of these. it covers all the usual metric and unf/unc sizes. Currently about £11 from Amazon. Speeds up the trial and error no end !
that's a really useful tool! Thanks will probably get one of those!
 
Already have the (euro) sensor thanks, it's the actual male thread that gets welded into the cats that's the bit I need
 
Just in case anyone else can help, after exploring a few avenues I'm still unable to verify the thread so any help on this would be gratefully received!
 
Ed Doe said:
Just in case anyone else can help, after exploring a few avenues I'm still unable to verify the thread so any help on this would be gratefully received!

Hi Ed,

Finally got round to measuring it for you. It’s M14 x 1.5. Measured it with a vernier and a thread pitch gauge :thumbsup:
 
GT Spec said:
Ed Doe said:
Just in case anyone else can help, after exploring a few avenues I'm still unable to verify the thread so any help on this would be gratefully received!

Hi Ed,

Finally got round to measuring it for you. It’s M14 x 1.5. Measured it with a vernier and a thread pitch gauge :thumbsup:

You absolute gentleman, thank you very much! :thumbsup:
 
Martyn said:
M14x1.5 is what I told at the start of december :thumbsup: :D

You said 'I think it's M14 x 1.5' - I just didn't want to buy the replacement thread without being certain! :oops:

Fair play though you called it! :)


Any more updates on your DCT MC project? Always enjoyed reading the updates!
 
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