MalcolmV8

I'm installing aftermarket gauges for my turbo setup and trying to find sensor locations.

For water temp gauge. Where's a good spot on the block? is there a plug somewhere that threads out and I can put in my sensor?

What about boost/vacuum? where do most of you guys get those readings from? right after turbo? after intercooler? right up on engine intake before boost goes into engine?

Thanks
Malcolm

UKCRXTurbo

i have two on mine, one on the thermostat housing and one on the water pipe coming out of the turbo (so I can monitor turbo running temps).

my boost gauge gets its supply between the manifold and dump valve but to be honest any vac source is good enough for a boost gauge.

MalcolmV8

Is the thermostat housing a custom setup? like you welded in a bung and put the sensor in? I can certainly do something like that but if there's already a spot I can use that would make more sense.
On my Mustang there was a bolt on the driver's side of the engine block that gives you access to the water jackets. I just removed that bolt and turned the sensor in there. Wasn't sure if that's common on most engine blocks and I could do something like that on the Honda too.

I have the factory D16Y8 motor.

UKCRXTurbo

my bad! iv just checked my engine and its not the thermostat housing its the housing that bolts to the head and runs the top radiator hose. on that housing there is a bleed screw which I removed and fitted my sensor to. but my engine is a B16A1 and im not 100% on D16 engines im affraid hope that helps

MalcolmV8

OK cool. Thanks for the pointers. I'll check it out and see what I find.

UKCRXTurbo

no problem mate

IN VTEC

iTrader: (3)

You can use either thermostat housing or the upper radiator hose housing by drilling and tapping.

However, if you choose to use the thermostat housing, I found it cleanest to remove one of the coolant lines then drill and tap one of the smaller nipple locations.

njhatch4sale

Upper radiator hose is the best

MalcolmV8

Hey Guys,

I had a chance to get out and look at the car. It appears the thermostat is on the lower radiator hose. Is the coolant reverse flow on these cars? In other words does it flow from the engine through the lower radiator hose to the radiator and out the upper hose back to the motor? If so then the correct location for the sensor would be at the thermostat housing by the lower radiator hose. For my tuning purposes I need the temp of the engine and not after the coolant as passed through the radiator.

My temp sensor has a bung of 3/8" NPT. I have the tap ready to go. What all can I pull off there by the thermostat housing? Is there a housing that attaches to the block that comes off that houses the t-stat and has some extra space to tap in my fitting? I'm asking ahead because I need to get what ever gaskets I need ahead of time from the autoparts store.

Thanks
Malcolm

W!d3b0dYr3X

Im not sure about d series but I ran mine to the head where the stock temp sensor goes. The stock gauge doesn't read anything precisely so it no longer working doesn't bother me.

As for the boost gauge anywhere along your intake tract after the turbo is fine, however, for the most accurate readings always tee into somewhere on the intake manifold after the throttle body and use the least amount of vaccum line possible and smallest line possible.

civickiller

I teed off the fpr for my boost gauge. For my water temp, I spliced off the stock sensor for the stock gauge

MalcolmV8

My stock temp sensor is where the lower radiator hose meets the engine. If you pulled it out doesn't the ECU use it too? Or does it have it's own sensor somewhere else? The ECU is going to make changes to the fuel and timing tables based on engine temp.

I don't need much vacuum hose at all. My boost gauge is electrical with a remote sensor so I need just enough hose to get a sensor on and then run electrical wire from there.

portenio78

iTrader: (1)

You want to put it at the hottest point, so right out of the head somewhere around the top radiator hose.

MalcolmV8

I was looking over the temp sensors tonight and not really sure where to put my new sensor.

The upper radiator hose connection to the head has such thin metal it doesn't have enough meat to drill and tap a thread. Same where the lower radiator hose leaves the motor. That housing is way tiny.

I did some looking through the Haynes manual too and found the gauge and ECU each have their own temp sending unit and they're both right next to each other on the side of the head right under the distributor. I confirmed that was the ECU sensor there by unplugging it and pulling codes and got a 118 temp sensor code.
So what is that additional temp sensor over on the housing where the lower radiator hose connects to the motor? I have no freaking clue. It does not affect the gauge on the dash and it causes no codes when I unplug it. It must be for something though, just not sure what.

civickiller

I believe it's for the fan

kyden

fan switch.

MalcolmV8

Ah ok. I was thinking I may try and find a 3/8" NPT reducer that's made of aluminum and have it aluminum welded to the t-stat housing block since there's no place to tap another thread. What a pain lol.

civickiller

I think that's a bad idea, tstat sees lower temp water. The head is better I believe

MalcolmV8

Depends. Well I mean I agree in the head is the best spot no doubt but I don't have access to directly in the head. The best I could do is where the upper radiator hose connects to the head with some aluminum welding into the housing that the upper radiator hose connects to. My problem there is direction of flow. If coolant flows from the upper radiator house into the head I'm not getting the true hot temps of the head. Rather the slightly cooler coolant that's just come from the radiator. The reason I'm suspicious of flow direction is that the t-stat is on the lower radiator hose. I suspect possibly the coolant flows through the head, through the block, and then out the t-stat and into the lower radiator hose. If that's truly the case it would be acceptable to use the t-stat housing where the lower radiator hose goes.

Problem is nobody knows direction of coolant flow. I guess I need to just pull a hose in the morning and start the motor and see which way it goes and then clean up the mess

MalcolmV8

Well I pulled the upper radiator hose and fired up the car and achieved nothing but making a great big mess. Coolant can't flow till the t-stat opens up. Duh!! shoot oh well.
Closed it all up and cleaned mess, topped up. Then remembered my IR temp gun and grabbed it. Took the car for a drive and got it nice and hot. It looks like the bottom hose and bottom of the radiator is hotter than the upper so I think for sure the coolant flows from the bottom of the radiator up.

wantboost

iTrader: (2)

it flows from the block to the head out the top radiator hose.... theres no point in tapping the t-stat... you want to know what coolant temps are of the motor, not whats coming out of the radiator

MalcolmV8

Is this true of the D16Y8 motor too? I know the majority of you guys on the boosted forum are running the DOHC motors. You are correct I absolutely want to know the hot temps of the motor and not what's coming out of the radiator.

I'm curious though. If the t-stat is on the block at the end of the lower radiator hose and the coolant really does flow like you say from the head, top hose, radiator, and then out the lower radiator hose how does the t-stat ever get hot and open up to let the coolant flow?

I've always seen the t-stat on the head or very close to it so the hot coolant will let it open and flow. I don't see how it'll open at the end of the lower hose unless the hot coolant was coming from the other direction?

My IR temp gun seemed to support that theory in that I got hotter temps on the lower hose and bottom of the radiator than the top. I'm not saying you wrong. Just trying to understand how all this works.

Thanks for the help
Malcolm

civickiller

yes y8's too.

i just learned that there was a bypass hose from the head to tstat, to open the tstat.

MalcolmV8

OK I think I know exactly which hose that is. I found one on the back there that got warm as soon as I started the car. That must be the bypass tube. While looking around I also found a thin coolant hose that runs to the throttle body. I assume for emissions if it's warming up the throttle body... or maybe it's cooling an exhaust recirculation setup?

civickiller

i think the hose for tstat is off the im