Coolant hose Inner Diameter and best place to read temps from?

[illwillem]

Im adding on some after market gages with warning features for my track car. Im about to pull the trigger on a gauges and all the other little bits. Not at home to measure but by chance does anyone know the inner diameter of the coolant hoses so im able to get the correct size inline 1/8 NPT adapter. Also where's the consensus on the best place to read the engine temp from? I imagine the main engine outlet hose will do the trick.


in-line adaptor for those that don't know

 

[greenberet]

The coolant pipe that the main engine outlet hose fits over has an outer diamter of 38mm according to my venier caliper. I measure the coolant temperature in the main outlet hose myself but I don't know whether there's a consensus regarding the best measurement point.

 

[Honcho]

I was researching this too for my anticipated gauge installs after my head gasket issue. FWIW, the factory temp sensor is in the water valve, which is the first stop after the water pump. Maybe a couple of degree drop from rad outlet to pump, but the main outlet hose is going to give you a pretty good idea of the coolant temp of the water going into your engine.

Also I was wondering if you can fit an oil temp sensor in the 10mm head orifice using the SOS adapter, which converts it to 1/8 npt. While it is post- main and rod bearings, it does give you a good idea of the oil temps inside the engine, which is really what you want to know. Anyone tried this?

 

[illwillem]

^^ I was wondering that myself, anyone? i have the SOS oil filter sandwich adaptor with the 2 ports I was thinking about doing oil pressure and temp from there but then I took a look and there is really only one usable provision since the other is so close to the crankpully an belt. If I got the two oil feel adapters that SOS sells could I read both the oil temp and pressure, one from each head?


My idea, looking for input:

could I get this: http://www.scienceofspeed.com/produ...s/NSX/ScienceofSpeed/oil_press_adaptor_block/
and just hook it up to my new oil pressure gages (will have a dead factory oil gauges)

then get this:
http://www.scienceofspeed.com/produ...cts/NSX/ScienceofSpeed/feed_pressure_adaptor/
and run it off of the provision in the head to read oil temps

then obviously something like this:

to read the water temps

 

[Mac Attack]

Unless you have a large bath to submerse the temperature sensor in (like an oil pan), you need to ensure the temperature sensor measuring tip is exposed to the flow stream to ensure accurate, responsive readings. By the time you add in the SOS adapter and then a female fitting that can accomodate the large temperature sender tip, you're pretty far removed from the oil flow....

The AEM temperature sensors I have (for coolant, oil temperature, and fuel temperature), have a 10-second thermal lag to them anyways. That's primarily based off of the thermal mass from the sensing element.

I recommend just placing the temp sender in the oil pan.

The coolant sensor above would work fine.


Dave

 

[greenberet]

Regarding the coolant temperature sensor, I put it into the main outlet hose to measure the temperature of the coolant coming out of the engine. It would be interesting to measure the temperature of the coolant going into the engine as well to see the temperature drop across the radiator, but I thought the temperature coming out of the engine would be a better indication of how hot the engine was.

Regarding the oil temperature, I tapped threads into the oil pump sealing bolt (part number 15233-PC6-000) and mounted a sensor in there.

I've never heard of anyone needing to open that bolt, so the temperature sensor is never in the way. The bolt is meant to be opened with an allen key, so you can drill that out and tap threads for the temperature sensor in there. In order to mount the bolt without an allen key, you can cut the perimeter to turn it into a regular hex bolt. With a thin-walled hex nut, it mounts right up. If you do that, just make sure 1) you cut as little of the perimeter away as possible to make sure you don't get a leak, and 2) the temperature sensor you screw in doesn't extend so far past the threads that it hits the oil pump gears.

I've had mine that way for years and it's never leaked a drop of oil, the oil pressure exactly the same as it's always been, and I don't need to remove the sensor when I change the oil.

 

[Mac Attack]

Im adding on some after market gages with warning features for my track car.

Personally, unless you need to know more precisely what your coolant temperatures are, I wouldn't get another coolant temperature sender and separate gauge. The OEM sender and dash gauge is fine for relative cooling temps. A better warning feature for tracked vehicles if you catastrophically loose coolant is having an idiot light that illuminates when coolant pressure is lost.

Get something like this, and mount it as close as possible to the water pump discharge. The 3psi setting should work fine:
https://www.pegasusautoracing.com/productdetails.asp?RecID=9749

 

[illwillem]

These are great ideas, im going to look into them both.

As far as oil pressure was I correct in assuming that I could run this with out problem as long as I dont mind having a dead factory oil pressure gauge. The only think i could think of as to why not is the ECU may be looking for a signal from this output somehow and it'll throw a CEL if its gone

http://www.scienceofspeed.com/produc...adaptor_block/

 

[Mac Attack]

The OEM ECU isn't looking for oil pressure from that particular sender.

There are two oil pressure senders that go to the ECU though: The two identical oil pressure go or no-go switches near the VTEC spool valves that allow VTEC to be actuated. You also have the 5 psi low oil pressure warning light on the dash from the sender near the oil filter, but I'm pretty sure it doesn't feed into the ECU.

The SOS adapter is a nice piece. I would have bought it had it been around the time I removed my sender (rendering my dash oil pressure gauge inoperable) and replaced it with an AEM setup:

http://www.nsxprime.com/forum/showthread.php/78153-Oilpressure-sending-unit-autopsy?highlight=sender

No leaks after a few years with my setup. It's going back on the engine when I'm finished with the rebuild.

Good luck.

Dave

 

[RYU]

I have the SOS oil filter sandwich plate if you want to take measurements Wil.

I'm also reading the OEM ECT from the OEM sensor via the OEM ECU. In my setup it's important to note what the OEM ECT reads because it affects my fuel trim and timing maps. I do notice it's a slow moving sensor (as Dave noted). The OEM IAT sensor is slow also.

- - - Updated - - -

I can also echo that the OEM ECU doesn't read the Oil Pressure. I wish it did... I'd have been able to pick it up via my piggyback.

- - - Updated - - -

Personally, unless you need to know more precisely what your coolant temperatures are, I wouldn't get another coolant temperature sender and separate gauge. The OEM sender and dash gauge is fine for relative cooling temps. A better warning feature for tracked vehicles if you catastrophically loose coolant is having an idiot light that illuminates when coolant pressure is lost.

Get something like this, and mount it as close as possible to the water pump discharge. The 3psi setting should work fine:
https://www.pegasusautoracing.com/productdetails.asp?RecID=9749

Dave, I can attest that for a track driven car I personally cannot rely on the OEM dash gauge. Asides from being a bit tough to read the scaling of the ramp up of the needle just isn't granular enough for me. I do like intercepting the signal from the OEM ECT sensor and reading it digitally.

At the last track event my ECT was near 95C and the OEM dash gauge didn't really move past one tick after the halfway mark. Then again.. my gauge is 20yrs old. It might not be working properly.

 

[Mac Attack]

Good point Regan.

If you don't have confidence in your OEM dash coolant gauge, then that should be fixed if it's the sole source of temps. Personally, it is enough for me to know if the coolant temperature is normal, above normal, or in the red. Once you release your radiators, coolant temps won't be an issue, right?!

 

[RYU]

I've been meaning to take some actual recordings of where each "tick mark" on the dash gauge corresponds to actual Celcius measurements via the OEM sensor. Someone did the analysis here but I think it was a straight average calculation/extrapolation. I have reason to believe that the dash gauge rises exponentially the closer it gets to say... 220F ECT. Which is a good thing.

The radiator development has been a fun but grueling process. Learned a ton but not sure i'd want to do it again anytime soon. You know me... I enjoy the journey. I'm not very good at actually making money out of anything NSX related (otherwise i'd have bought the rights to your exhaust design and sold a bunch of copies of it!). Based on the latest results so far these rads will be incredible. Only one last track left day to verify data.

 

[illwillem]

Thanks for the offer Regan, Ive got the oil filter sandwich plate on the car now too after measuring it with everything installed around it it really is in a less than ideal place too rin any of the needed sensors. which is a bummer because it had provisions for two ports that I need.

Sounds like for my oil pressure Im going to use the SOS oil pressure adapter block and run the pressure from my aftermarket sensor in the OEM location and just live with a dead dash gauge. Then, for oil temp, I have a few options I could try. I'll see about fitting it into the SOS sandwich plate since one provision is at least more out of the way than the other. I could also tap the oil pump sealing bolt as Green beret did, sounds like there can be a clearance issue with the oil pump gear, so im going to wait for my Defi stuff to show up so I can measure the length of the probe and see if this is a good option for me. The other option is to tap one of the brass fittings at the exit of the oil cooler to accept the 1/8 sensor.

I am going to get the coolant pressure dummy light to. Too bad you want to read the water temp on the intake hose but the pressure on the output' I could have just tapped another hole into the aluminum inline water temp fitting

Im really trying to avoid cutting into my silicone water hoses and creating another point of failure with the addition of two more hose clamps, does anyone know another place that I could read the water temps from. Unfortunately the Defi ADVANCE ZD isn't nearly as smart as RYU's HKS setup in being able to just hijack the oem ECU signals.

 

[RYU]

I have to read the rest of this thread again.. but I think you mentioned the SOS remote oil pressure sensor unit. You can buy that and run a t-fitting to it, to run another pressure sensor in parallel. I actually had thought of doing that. This way I was able to still read some sense of oil pressure via the dash and have the navigation system displayed on my monitor (which currently does dual duty and also displays the engine vitals). I'm not sure if the T-fitting will diminish the oil pressure. Someone smarter than me can answer that.

I will probably end up modifying my setup that looks like this. Will probably buy some AN adapter fittings to mount the oil pressure and oil temp sensor like this.

 

[Mac Attack]

You'll be fine just using a "T' to measure oil pressure. Since there is no flow of oil through this line to the sender, flow resistance doesn't matter "as much."

It will just increase the lag time from a change in pressure to what is sensed by the sending unit... It will actually help dampen quick pressure oscillations and make a digital gauge easier to read.

 

[illwillem]

I would do https://www.pegasusautoracing.com/productselection.asp?Product=3228-305 instead of a "T"

 

[RYU]

I really need to spend some time on that site! I've got a lot of fittings for my oil cooler to redo.

 

[Mac Attack]

If we're talking about reducing total pressure losses in the oil system, then yes, the picture above can be optimized. I would go a step further and use the bent tubes over the forged 90's to reduce the loss even more:

Then you can do an inline fitting like this for your pressure sender. The sender won't protrude into the flow so you should be good:

The back of the XRP fitting catalog has a great technical section on fitting losses. From the SM, our oil pump flow rate at 6000 crank RPM is 18 gal/min. Assuming you're using 8AN or greater diameter hoses/fittings, then you reduce the pressure drop (per fitting) by HALF using the bent tubes over the forged components. That's less pumping power (albeit miniscule in the scheme of things), and less you are heating up the oil.



But if the question is just on what to use to tap off and measure pressure, then a "T" is fine.

 

[TURBO2GO]

Wil what did you do for all this stuff? I was going to get a filter sandwich plate then read here you did not have good results so I nixed that. I very confused about the direction now as I have been on other forums as well and there is a lot of contradictory information.

For oil temp, some recommend the pan, some don't. Some say it is too far from the block, mixed with the oil coming from the cooler, and a bad place to take reads. That the block is better. Some say the block is inaccurate because the block itself affects readings, and that you want an "average" of all spots and that the pan is the best place for that. It's a long debate I read pages on this.

For oil pressure, which route did you go? did you tee off the SOS adaptor? Which of these 3 did you use?

Did you relocate with this one:

Or did you use this one off the block:

Or did you just use this and leave the OEM gauge dead?

I found this for temperature:

I think it is made by Defi.