What's the best location for a water temp guage sensor? (Not stock Location)
 

Yes, I searched.. Or, rather, i would have searched if it worked (stupid Post error!)

Either who, I need to know the best location for an aftermarket water temp guage sensor?

I was thinking on the return line for the radiator, or in the bottom section of the waterpump housing?

Anyone have the definative answer?


Thanks!


~Wonko

Stock location is the best IMHO, that's where I have my aftermarket sensor. Other than that probably in the waterpump before the tstat. Anywhere before the tstat should be ok but I'm not sure how much temperature varies as distance increase from the stock location (probably the hottest point in the coolant system).

I remember there being a post where someone took an optical thermometer and actually measured the temperatures at several different locations. If i remember correctly the differences were pretty small. 1..2 degree maybe. I'd search but its broke :)

Right before the T-state would be the best location, or maybe even on the side of the block where you have your sending unit for gauge cluster. NOT the bottom part of the water pump housing as that is water inlet from the radiator, water at location will be 10-30* colder then actual engine water temp.. maybe even colder depending on weather it won't show 200* temps if your T-stat sticks.

So right before your T-stat would be a nice location.

Awesome, good idea.. Thanks :)

I would put it in the stock location, but I'm using that for my megasquirt sensor.. when I connect that to the stock gauge, it causes my readings to go all screwy.. some sort of pulsing from the guage cluster, I can't isolate it.

If your car had the extra E-fan option and is S4 you could mount it where the sensor for the fan sits on the T-stat neck. its already threaded and works perfect for me.

Watch it...surface temps is a bit different than "core" temps.
I wouldn't want to rely on such a "bad" data collection method as this.

Rule-of-thumb is to get it as close to the thermostat as possible.
Heat rises.
It's easy to agree that it's going to be up high somewhere.


-Ted

Ah another squirter, what firmware are you using? Megasquirt extra?

I was using megasquirt extra with 12X12 tables and staged injection at 3400 rpms. worked nicly. :)

The best place is below the thermostat, which means the e-fan switch location is not recommended. The stock location should only be used if you have a sender that has the same thread as the stock sender. Thread adaptors should not be used as they space the sender back out of the water flow, slowing it's response.

yep, i'm running the latest MSnS E, with teh 12x12.. I'm staging my injectors at around 3600, so far.. I haven't really had a chance to really tune it much above 4500 RPM yet, (It's only been on the road a week with the MS), so i'm not sure where its going to end up. I also don't have my 5/6th port working, but that will be fixed tomorrow, so I can finally tune the high end properly.

what are you doing for your ignition? I'm being lazy and just ran a Dizzy, though I plan on going back to the CAS/coils after the code is stabilized for the trailing coil.

NZ - Thanks for the heads up, I'll check and see if the thread pitch is the same as the secondary fan connection, if not, i'll thread my own below the Tstat.

Thanks for the input, all :)

I used stock ecu for ignition, megasquirt for fuel. :) Worked out fine.

Althought I feel like putting it back on when they get the cas and trailing coil out of beta. :)

I think you might have misunderstood me. I meant that you shouldn't use the stock gauge sender location (on the rear plate) unless the thread matches. I wouldn't use the e-fan temp switch location at all. I'd go straight for the back of the water pump.

Ah, yes, Nz - I did misunderstand you :)

Thanks for the clarification. I can't use the stock gauge location unfortunately, so the back of the water pump will have to work.

Why'd you take it out? What are you running in its place?

Emission test, so I put the stock ecu on.. been kinda bussy so I haven't put i back on.

Running on a S5 6port N/A.

There is a boss (dimple) on the front side of the water pump housing directly in front of the stock sensor. I drilled this and tapped for 1/4 inch pipe thread. The aftermarked gauges come w/ a 1/4 inch adaptor. (sensor is 1/8 in pipe). You will need to remove the small triangular aluminum bracket for the air pump to fully expose this hole. Cut off the side of the bracket (w/ a hacksaw). This only eliminates one mounting bolt, which wont hurt a thing. If you remove the thermostat, you can stuff a rag into the hole below where you are going to drill to catch the shavings. This location puts the sensor before the thermostat to read the actual engine temp. My car is an 87, but I assume this will be the same for later years. It works great. You can keep the stock sensor to run the ECU.

Engine drain location works well..

Why not?

I have watched my Haltech engine management page and my aftermarket water gauge that is tapped into the aux fan sender location, and they match identically..

Whats the basis for your statement?

Without even thinking of the cooling system geometry of the RX-7, I would conclude that I would run my temperature sensor, at a point that is post-engine, but very close to it, to recieve the highest possible coolant temperature reading. If the sensor is not mounted where the coolant is its hottest, you'll have a more inaccurate reading of actual coolant temperature.

Performance has nothing to do with it, it's all about safety. If you install the sender on the wrong side of the thermostat, you get no reading until the thermostat opens. If the thermostat doesn't open (i.e. it jams closed) you have a gauge reading cold while the engine cooks itself to death. That is not a risk I'm prepared to take, and anybody who suggests this location should also warn others of that risk.

I think i'm going to have to side with NZ on this one, J-Rat.. but that's only because I'm super-untrusting of the thermostats.. If I believed in them more, I'd probably try and take the lazy way out :)

Thats why I have the Haltech configured to yank the hell out of the timing if temps start exceeding a preset level.

Also, if you keep tabs on your temp gauge, you would notice things like the gauge not moving..

*edit*

I hate thermostats... Now this begs the question..

What does everytone thing of the stock location using an adapter?

It's easy to say that, but the reality is you don't drive around staring at your gauges. My point is, a simple mod like adding a temp gauge should not introduce extra risk unnecesssarily, particularly when there are other suitable sender locations that don't. If you're happy with your arrangement, that's fine. But others contemplting doing this should know the whole story. Not everyone has a Haltech for starters.

Why? They are generally very reliable, last for many years, and their advantages far outweigh any disadvantages (not that I can think of any).

Did you miss my earlier post? ;)

Im actually looking to do this fairly soon as well. I have my gauge and everything, I just need to get some more wire, and get myself ready to flush the coolant at the same time. What I was planning to do is drill and tap into the water pump housing, because of pretty much everything that has been talked about in this thread. It may take longer and be somewhat of a pain getting to all of that, but from what I have read it is a good way to go.

Actually, I scan my gauges quite frequently. Its a good habit to get into.