SPA Temp Gauge reads low

[gruffalo]

Hi All,

I am sure I remember a thread either here on on Face book about thse with SPA temp gauge saying it reads 10C below the ECU sensor.

I was wondering if anyone has found a fix for this, there was some speculation about the SPA sensor being shielded from the true water temp by not sticking out into the water flow far enough but I cannot remember if there was a resolution to the issue.

[Penelope Stopit]

Chimpongas topic?

[QBee]

Ask Phazed - he had a Spa gauge on his Chimaera.
Don't remember him commenting about it.

[pmessling]

I've found the gauge and ECU temps to be pretty good. This is using a Bosch Motorsport coolant temp. And as for the flow question around the sensor yes, even worse on the ACT water manifolds the boss is too long and the sensor doesn't make it to the end of the boss.

[gruffalo]

pmessling said:

I've found the gauge and ECU temps to be pretty good. This is using a Bosch Motorsport coolant temp. And as for the flow question around the sensor yes, even worse on the ACT water manifolds the boss is too long and the sensor doesn't make it to the end of the boss.

I have the Bosch sender as well but I also have the ACT stainless coolant pipes so I think there in lies the problem.

I spoke to the tech support team at SPA and they don't do a longer sender so I guess I will live with it and turn the car off at 100C on the Spa gauge.

unless I can find someone to reposition the sender boss on the coolant pipes so the sender can actually get into the flowing coolant.

[pmessling]

Cut the top off the boss and thread the remaining, should lower into the flow better. The boss is suited to the capillary type not a electronic sensor.

[WIL35]

It could have been my thread:

https://www.pistonheads.com/gassing/topic.asp?h=0&...

Unfortunately haven't fixed it! I looked through all the SPA manuals and there doesn't seem to be any way of recalibrating it, although I did manage to stop the oil pressure reading from flicking around too much by increasing the time lag

[Jhonno]

As Peter says, machine the boss down.

[gruffalo]

WIL35 said:

It could have been my thread:

https://www.pistonheads.com/gassing/topic.asp?h=0&...

Unfortunately haven't fixed it! I looked through all the SPA manuals and there doesn't seem to be any way of recalibrating it, although I did manage to stop the oil pressure reading from flicking around too much by increasing the time lag

I spoke to tech support at SPA and because of the way thermistors are non linear in there output re-calibrating the gauge is not possible, it actually has to use an algorithm to work out what the display should be reading so re-calibration would mean reprogramming the chip inside that does this.

Apparently they use a very accurate Thermistor, less than .1% error so the answer is to machine the boss down which I will get done at the next service.

[Adambul]

Bit of a thread resurrection. I too have a SPA gauge which reads about 10 deg low, mine is also installed in the ACT stainless steel water pipes which is considerably out of the water flow. I've just moved the sensor and installed it in to one of the water rails bleeds screws.

I haven't tried it yet but I'm hopeful it will now be more representative of the actual water temperature as the probe is directly in the water flow, albeit only now on one bank of the engine. Once I've finished the other 100 little jobs I'm doing to the car I'll start it up and report back on the findings.

[gruffalo]

I am getting the boss in the ACT pipe machined down next week so it should read correctly going forward.

[Adambul]

Do you have a cost for the machining work at this stage?

[gruffalo]

Adambul said:

Do you have a cost for the machining work at this stage?

Not much, it is being done at a local engineering works near me.

Last time I used them to spark erode all the bleed nipple from my callipers and that cost me £20 so much the same I would think.

[gruffalo]

I have been trying to find find somewhere to get the boss machined down but every where says that the only real solution would be to get the pipe with the correct boss already fitted.

I spoke with ACT and they are happy to do a production run of some designed for the SPA sensor at the same price as the original item.

So the question who wants one?

If there is some interest Tim will get them made.

[pmessling]

Do you have an adapter in yours for the different thread?

Even if you didnt you could shorten it. Drill it out for an adapter and go from there

Or cut the old one out and Tig weld a new boss in machined to the correct thread. Think it was 1/8th npt when I put the gauge in.

I did actually make some bosses up as I started making some pipes for myself but was in a rush and brought an Act pair.

So basically what I'm saying it that don't get ripped off again as there are plenty of ways to adapt the pipe.

[pmessling]

This is what I started but never finished. Sorry for the rubbish photos had to take them from a detailing world thread I started years ago

[gruffalo]

I do have an adapted but the whole this is so long that the sensor is at least an inch from he water flow and so is measuring the temp of the metal rather than the water.

Even looking at your photos the boss looks way too long for the sensor to be in the water flow.

[pmessling]

They were just an example of what I made at the time. I'm saying that if a simple engineer like myself can think of a solution to the problem of what I said above then you can still use the adapter.

Simple was would be to cut the excess off. Tap the remaining and use adapter again which will lower the sensor into the coolant.

If you want to go all out then a new boss could be welded in.

I certainly wouldn't be buying a whole new pipe. Not for half hour on the lathe and another half hour Tig welding with back purge.

[gruffalo]

pmessling said:

They were just an example of what I made at the time. I'm saying that if a simple engineer like myself can think of a solution to the problem of what I said above then you can still use the adapter.

Simple was would be to cut the excess off. Tap the remaining and use adapter again which will lower the sensor into the coolant.

If you want to go all out then a new boss could be welded in.

I certainly wouldn't be buying a whole new pipe. Not for half hour on the lathe and another half hour Tig welding with back purge.

So was all you had to do to get a proper reading to cut down the adapted and tap it to get everything to seat correctly?

I have about a centimetre of thread showing on the adapter and probably two centimetres of the sensor thread showing.

But my point is that ACT will also make pipes for the gauge sensor so if people want a pipe that actually fits the sensor out of the box does any one want one.

I have no lathe or welder and so by the time I have paid someone to do the modification for me I can buy the pipe with the correct boss fitted so peeps can get an accurate reading.

[WIL35]

I would be interested seeing as it looks like I can't fix it myself with a hacksaw and tapping the thread in the tube a bit deeper. Anyway, it would probably leak and need lashings of PTFE tape!

Presumably ACT will sell the pipe individually, rather than as the set of both pipes they currently have on their website?