adam c

iTrader: (2)

Dale,

I decided that I didn't want to tap the t-stat housing for the exact reason that you are experiencing. Instead, I chose to install a Greddy aluminum radiator hose adapter (38mm). You simply slice out about a 1" section of the upper radiator hose, and insert the adapter. Then clamp it down with two hose clamps. I installed mine right after the t-stat housing to get to highest possible temp readings. It comes with a threaded opening for a sensor. They are about $30, and are available from any Greddy dealer.

With this installation, if you don't like it, you can simply replace the hose.

Adam

KevinK2

The wp housing location shown will read lower than t-stat since the t-stat can crack upen at 185, and then part of the pump flow will be water cooled by rad. I would like to know the pressure there ..

t-stat and upper hose are good spots, esp if stock gage is used as a back-up if t-stat is not opening properly.

Hose from eng rear to TB hsg is a very good spot ... before any cooling from tb on cold days with high low boost air flow. other TB hose exits at back of wp.

Stock switch and sensor locations are the highest temp of bulk coolant flow (turbo exits will be higher). If threads are right, a sensor could replace stock 226F switch, and a miata switch could be installed in the TB line.

DamonB

That's not true. I have my gauge in the TB coolant line and the temps I read on that gauge match exactly with the ECU controlled fan speeds each time they switch. My gauge doesn't lag in time either as the fans will turn on or change speed within seconds of the gauge saying they should.

Since my sender is behind the thermostat and reads the exact temps that the ECU sees with no lag it is the perfect spot IMO (other than the block where the stock gauge sensor is as maxcooper pointed out). In the back of the thermostat housing where the ECU reads it's temps would be great but there is no room there. The front of the housing requires the thermostat to be open and if one day your thermostat stays shut your gauge won't tell you. That's a dumb idea IMO as the reason I have a gauge is so I will know about things like that!

People always poo-poo the throttle body coolant line because they feel there is not enough coolant volume flowing through it. There's certainly less there than in the thermostat housing or radiator hoses but that doesn't mean there is not enough for the gauge to respond quickly. I see nearly instantaneous changes in temp when I run the car hard at the track as well as during warmup on the street. No issues at all.

DaleClark

iTrader: (55)

Bunch of good points made here.

Really, in my mind, I want to know the water temps ALL the time, not just after the thermostat opens. I think it's dumb driving around with my temp gauge sitting at 30 deg.C for a few minutes, then all of a sudden it shoots up to 80 deg. C. That just screams "hack". Hell, the stock coolant gauge that we all lambast tells you the whole story all the time - we're IMPROVING on that, not making compromises.

I can understand if installing the sender in the thermostat housing was easier, but it's not by a large degree. Cutting the TB coolant line and adding in a brass T takes VERY little time - cut hose, put hose clamps on hose, insert T, tighten clamps, done. If you use a portion of the hose closer to the block, the T is even totally hidden behind the intake manifold.

Let's look at it this way -

Throttle body coolant line:
PROS: Super easy install, reads full range of temperature changes, gives accurate readings, hidden and clean install.
CONS: MAY have slightly lower temp readings due to position in coolant system.

Thermostat housing
PROS: Hottest area in coolant system.
CONS: Gauge will not react until thermostat open, requires some disassembly and drilling/tapping to install, sender is visible and not hidden

The Greddy radiator hose install is just a foolish idea. Has all the cons of the thermostat housing install, requires MORE work to get to (remove air box, IC pipes, etc.), doesn't give you a full range of temperatures, etc. If you're going for an easy way to install, you just can't get any easier than the TB coolant line.

Another possibility if your car is more modified...if you have removed the thermowax from the throttle body and the coolant lines to the throttle body, cut off the nipple on the water pump housing and drill/tap that hole for the sender. You get a just-before-thermostat temp reading, and it's a better way to plug the now unused coolant nipple. Did that on my FC, and it worked awesome.

Oh, and on the NPT plug for my thermostat housing - I did get an NPT plug. It won't screw in to the hole - the plug is made at the "fat" end of the tapered pipe thread, and the hole isn't deep enough to run the NPT tap all the way in to the fat part of the tap. Even if the plug worked, I would be replacing it - that plug is just ghetto .

Dale

shawnk

I have my sensor in the thermostat housing and am perfectly happy with it there. Since I have a PFC commander that already tells me the temp of my evans at all times the greddy guage lets me know when the thermostat has opened and also lets me know when my car is fully warmed up.

So if you have a commander then you actually get more info with it plugged into thermostat housing.

DamonB

If you have to use the commander to monitor water temp (since your other gauge can't tell you anything until/if the thermostat opens) why even bother with a seperate gauge and sender?

adam c

iTrader: (2)

At least I didn't wind up with an unwanted hole in my t-stat housing

Removal of the IC pipes is not required, and you get the same range of temperatures as the t-stat housing sender location: Everything over about 170*.

maxpesce

Dale:
Just drill a bypass hole in th T-stat - 3/32 - 1/8" dia should let enough hot coolant bypass the t-stat to get a reading off your Temp sender.

DaleClark

iTrader: (55)

Yes, but why are you hacking the thermostat to MAKE a bad idea work? If it works awesome in the TB coolant line, is easier to install, and gives a good reading....

Adam - trust me, I wish I didn't end up with a hole in my T-stat housing . That's why I made this post, because I researched pros and cons of different install locations on the forum and concluded that I would get a good reading at the T-stat housing. I don't. Hopefully others will find this thread and learn there's a way that's not only EASIER to install, but gives a BETTER reading. You don't typically run into that .

Dale

Mahjik

iTrader: (1)

The fans come on at various times depending on electrical load and other things. It's a common trick to use the parking lights to trick the stock ECU into turing on the fans before 221F.

If you are getting any more strange readings, something is wrong with your sensor.

Hence why I said "heard".

I still like the idea of the t-stat location. For me, I don't care about temps until my t-stat is opened. If my t-stat is stuck, I want to know about it and mounting a sensor in that location will definitely give you heads up about it.

DaleClark

iTrader: (55)

OK, got some pics of the brass T I used. I got all this stuff from Lowe's. Can't remember total cost - probably $5-10 or so.

Parts I used -

Brass T with 1/4" NPT ports
2 1/4" NPT hose barbs with (I think) 5/16" hose barbs. The hose barbs were just the size that fit on the TB hoses - I just eyeballed it . The only other sizes were obviously too big or too small.
1/4" NPT to 1/8" NPT adapter/bushing.

As you can see in the pics, teflon tape up the fittings and screw it together. I used the 1/4" NPT to 1/8" NPT adapter to space the water temp sensor up and away. If I would have used a 1/8" NPT brass tee, the tip of the sensor would have interfered with the opposite side of the tee - best case it would have touched the brass and possibly give a false reading, worst case it wouldn't screw in enough to make a watertight seal at the threads.

BTW, all the Japanese temp sensors are 1/8" NPT - I'm not sure what Autometer is, I'm guessing 3/8" NPT. You're on your own there .

Dale

adam c

iTrader: (2)

Dale,

I actually wanted to do the TB hose, but couldn't find the right hardware. It does seem like a better location. I am going to look again, and post comparative temp results if I get it set up. And German senders use??????

Adam

DaleClark

iTrader: (55)

Beats me on German senders - I've only been around Japanese gauges mainly.

According to this page, though -

http://www.nhspeedometer.com/senders.htm

The VDO senders are 1/8" NPT and come with bushings to adapt it to 1/4" and 3/8" NPT. So, the above example would work.

Dale

novadan67

For the record, the autometer electrical water temp gauges use 1/8" NPT senders (and have 3/8" and 1/2" adapters). Their mechanical water temp gauges only use 1/2" NPT.

spike.spiegel

Thanks for all the info everyone, this has been an informative thread. I have an autometer electrical gauge waiting to be installed. Dale, do you have any photos of the parts installed? Where in the line did you install it, did you have to remove any parts, e.t.c?

In general, I was wondering why it mattered where in the cooling system the sensor is installed. If you use the fans as a reference, you should be able to monitor your coolant temp accurately enough. For example, I think the fans are supposed to come on at 221F, right? So after installing your gauge say, on the other side of the cooling system, just idle your car until they come on. Let's say they come on at 210F. Then you'll know your sensor shows about 11 degrees cooler than the stock sensor (+/- a degree or two).

On another note, what temps do you all allow your coolant to get to before stopping (relative to the fans coming on)? 5 degrees hotter? 10 degrees hotter?

DaleClark

iTrader: (55)

The throttle body coolant line is SUPER easy. It feeds into the throttle body by the firewall - you literally have to take nothing apart. Pull the hose up, cut it in half, put the hose clamps on, and stick the brass T in place. Done.

I'll get a pic of it on the car for ya.

BTW, I noticed on the customer's car that I installed the water temp gauge in that the fans kicked on JUST where the fan switch should kick them on, and they kicked off at the right temp. Using that as a reference, the TB line is fairly accurate.

You do want to have a good idea of the general coolant temp. Some locations to read the temp from are "stagnant" and don't see as good of a rate of change, etc. For example, the water coming out of the radiator is already cooled by air, so it will typically be a bit cooler than the water coming out of the motor that's already heated.

Dale

shawnk

Good question!

That was back in the day when I used to listen to what everyone told me I "needed to do" on this forum. I have since learned not to listen to most people.

And since it is already installed...

Plus I do look at it alot...

Shawn

SPOautos

Seems to me the best place if you want to tap it into a line is the turbo coolant line. That is going to reflect the hottest temp since its just past the engine outlet. The turbo coolant feed comed off just behind the thermostate so the thermostate being open or closed will have no effect. Also, it should be easy to get to....at least if you dont have an air pump. If you have an air pump it MIGHT be a pita, I havent looked at a car with an air pump in 3 years so I dont remember. If your looking at the water pump housing the coolant feed comes off on the passerger side nest to the thermostate and under where the air pump mount is located.

Hope that helps someone, its probably the best place for the sensor and with no air pump would be VERY easy

Stephen

SPOautos

Yes, I was refering to the pic you posted. That would be measuring pretty much the coldest temps of the entire system. You want the sensor on the hot side where the coolant exits the engine.

KevinK2

Yes, it will be hot ... could be too hot for control purposes. Not much pressure drop available stock, and big rads make drop even less. High flow will occur when revs are high and t-stat is mostly closed. In worst case, t-stat wide open and idle, you may even get reverse thermal flow. That is a strange loop .... driving point is close to the return, with t-stat wide open (~195-200F).

You can assume consistent flow in the TB line, not sure about the turbo line.

spike.spiegel

Dale, any chance of getting this photo taken and uploaded?

I'm gonna go for the super-awesome TB install technique sometime this week

DaleClark

iTrader: (55)

I'll do that for ya tonight.

Dale

spike.spiegel

Thanks Dale, that would be totally sweet....on a somewhat unrelated note, where is the easiest place to get power/ground from the TB location?

DaleClark

iTrader: (55)

OK, attached are 2 pics. The first shows you what you normally see - nothing . There's no sign that there's anything plumbed in there. The second is the line itself after I dug it back up - you can see the brass tee. Note there's a plug in the tee instead of the sender - that's because my sender is, unfortunately, still in the thermostat housing! I got a good used T-stat housing, but it's already been drilled/tapped for the sensor - dammit! So, I'm going to get that one welded shut and put it on.

Anyhow, you don't need power or ground by the throttle body. The sensor plumbs in there, you run the wire from the sensor into the cabin, and the gauge itself has wires going to power and ground inside the cabin.

If you need, I've got pics of the brass tee out of the car - dunno if I posted them or not.

Dale

spike.spiegel

You're the man Dale. That looks pretty straightforward. I actually picked up the plumbing as you (and the attached photos) described earlier. That's funny and sad that you're used Tstat was drilled. Mostly sad I guess. Anywho, I should've asked where you got the power for in the cabin? I guess a lot of people use the ashtray for the lights, but I'm not sure about the best place for constant power?