I need to source a sensor boss which needs to be size M10 x 1.25 pitch (fine metric) in order to fit an air temperature sensor in my FMIC pipework.

I can find plenty of standard metric pitch (1.5) bosses but I can't find any fine metric pitch, can you recommend a supplier?

 

Why not fit it directly in to the FMIC pipework? What make of FMIC?
Drill a pilot hole and end up at 8.5mm drill then tap 10mm x 1.25 pitch. Depending on the sensor you may have to pack it out as some of them are not threaded for the last 4mm. If you have doubts about the integrity of the tapped hole you can use Epoxy resin such as Araldyte to secure the sensor in position, seal it and ensure it does not come loose.
If you go down the boss route you need an aluminium boss obviously and someone that can weld aluminium and there are not too many of the aluminium welders about.

 

Thanks Harvey, I had considered as you have suggested drilling and tapping a thread directly into the FMIC pipework (it's a APS DR525). I can get that done very easily at work but I think a welded in boss would be a better solution.

I can get a boss welded in either at work or by a mate who is a engineer with access to all the required machining.

He did suggest that he could make a boss at work but I don't want to take the proverbial if he does the welding as well, I thought it would be a relatively quick and easy task to source a suitable boss rather than have him 'waste' his time making one.

But it looks like his offer is the best option, and I will of course owe him my soul after he sorts it out for me.

 

Not sure I'd be happy tapping a hole in the relatively thin FMIC pipework - usually about 1mm thick and with a 1.25 pitch thread, not much "meat" to screw into, surely?

I would look at Demon-Tweaks or Merlin Motorsports for a boss.

 

Drilling and tapping heat sensors either for Simtek ECUs or ACT guages, as described above is something I do on a regular basis and have done for several years without any problems.
It is quick, may take 15 minutes once we have the FMIC hard pipe off until we start refitting, including getting electric drill, drills, tap, epoxy etc.
I may be luck in that I think the Hybrid/HDi hard pipe, where we drill it is a lot more than 1mm thickness. It works for me and I cannot remember any failures at time of fitting or in service.

 

I have done just this, on Harvey's advice, to fit an ACT gauge. I reinforced it with a little of that epoxy stuff that costs ££££££ to buy, my lad had some, so we mixed up a few grammes and tried it out. Works great.

 

I've been pondering the issues of retro-fitting an IAT sensor for a few weeks, hence my interest in this thread.

I've recently formed a new company - website and Scoobynet trader presence in the pipeline - that designs and manufactures a number of niche accessories aimed at those fitting after-market ECUs.

Fitting an IAT is a bit of a faff, and I'm looking to design a solution that makes it reliable and easy. Something that would only take 5 minutes to fit maybe, and that comes complete with the sensor itself.

The sensors themselves are around £15, but can I be REALLY cheeky and ask how much a complete fitting assembly might be "worth" on the open market? Since, as Harvey says, an IAT technically can be fitted with just a drill, a tap and some sealant, just how much is an easy solution worth: £75? £50? Or really just a small amount more than the sensor itself?

Honest opinions appreciated, if you can be bothered

 

The ACT guages I sell retail at £82.50 inclusive of postage so I think your costings are a bit OTT. Forgive me as I do not want to be confrontational but you did ask for honest opinion.
The next reason for fitting a sensor is when we install a Simtek or similar and this is a frequent occurence. The sensor is supplied with the new ECU so we remove the hard pipe to the throttlebody, 5mins work and 10mins max if there is an issue, finding drills and taps plus araldyte and some packing washers and doing the job is 15 mins max and reinstall the hard pipe a further 10 mins. Start to finish the job is typicall 25 mins and not more unless there is an issue. It is part of fitting the Simtek and therefore included in the price so the customer is only paying the agreed fixed price for his Simtek or whatever.
Furthermore, while the sensor is being fitted other work is carried on in parallel like fitting the ECU or rigging up the mapping equipment like wide band lambda, DET cans, knock sensor, boost guage, putting in base map and so forth.
Why add £70 to the customer bill needlessly and have another batch of components to fund/stock/look after???

 

Not taken as confrontational at all Harvey - and the comments really are appreciated.

The £70 was simply a means to start a discussion, not a serious suggestion of a viable price

25 minutes is still an appreciable time for a one-man-band fitter/mapper, who's perhaps mobile, and may not have assistants around to be carrying on other work or access to a workshop.

Most of the solutions I have conjured up are, bluntly, too expensive and not worth doing. But I will keep pondering and maybe I'll eventually come up with a solution that is inexpensive but does the job better than araldite - but my business does not depend on such a solution I hasten to add.

 

Tim: The araldyte is only to stop the sensor vibrating out over time and it may not do any more than prevent an unscrewing and indeed at the beginning I don't think I even bothered with that and was only adding belt and braces.
I would guess that at £10 or £12 you may get some takers but not at £50 or £70.
Sorry to be negative as I am all for cost effective improvements and performance benefits within the Subaru community.