Fitting a boost gauge [Archive] - SXOC Bulletin Board

geoff_s14

17-10-2001, 09:29

Is there a concensus about where to plumb in the boost gauge? I've been looking back over past threads on this subject, and notice that there seems to be quite a lot of variability in the amount of peak boost people are measuring.

Could this be down to different installation points?

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Geoff
Emerald S14a, with God's Own Transmission.

http://www.animfactory.com/animations/transportation/cars/mirror_md_clr.gif

Tom_S14

17-10-2001, 10:18

I wondered about this too.
Mine is plumbed in to the intake plenum on a small hose which runs from the main body to a small pressure regulator down by the knock sensor in amongst the fuel injectors.
I read steady state 0.5bar and can rise to just under 0.7bar over 6k revs.

Might be worth noting the MAP sensor (if fitted) plumbs into the main hose which feeds the intake plenum.

Tom

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1996 Blue/Green S14 (manual)
K&N cone filter
2.5" Tube-torque Cat Back Exhaust.
TechTom MDM-100
Race-Technology AP-22
http://tom.marshall.tripod.com

geoff_s14

17-10-2001, 10:31

Tom,

Do you happen to know if there is an oil temperature sender already fitted to the SR20DET which I can splice a gauge into? Surely the ECU needs to monitor engine operating temperature via the oil temp, yes?

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Geoff
Emerald S14a, with God's Own Transmission.

http://www.animfactory.com/animations/transportation/cars/mirror_md_clr.gif

Tom_S14

17-10-2001, 11:21

Geoff,
If there is an oil temp sensor, it definitely isn't connected to the ECU.
I don't think there is one !

I think the ECU decides on the operating temp of the engine from the coolant temperature instead from what I can gather.
How closely does the oil temperature follow the coolant temperature ?

Tom

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1996 Blue/Green S14 (manual)
K&N cone filter
2.5" Tube-torque Cat Back Exhaust.
TechTom MDM-100
Race-Technology AP-22
http://tom.marshall.tripod.com

geoff_s14

17-10-2001, 12:14

Originally posted by Tom_S14:

How closely does the oil temperature follow the coolant temperature ?

Not very, from what I understand. On a typical day my car gets up to normal operating water temperature within a couple of minutes, but I've read things on sites to do with oil performance which suggests it may take around 15 minutes for oil to get up to temp. Which is why I'd like to monitor it - my journey to work only takes about 20 min max, and I normally drive very gently, on the assumption that the oil never has a chance to warm up properly.

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Geoff
Emerald S14a, with God's Own Transmission.

http://www.animfactory.com/animations/transportation/cars/mirror_md_clr.gif

Reeph

17-10-2001, 12:23

I've had exactly these thoughts. I would very much like to be able to guage when it's safe to thrape the car and I don't think coolant temperature will follow oil temperature at all. I did some fluid dynamics as part of my degree and the two fluids in question are so completely different I don't think the temperature of one would have much bearing on the temperature of the other.

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Grant Smith
Blue T 'reg' Manual

geoff_s14

17-10-2001, 12:34

Right then, it looks like we do need a means of monitoring oil temp. Anyone got an idea of how/where to fit a sender?

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Geoff
Emerald S14a, with God's Own Transmission.

http://www.animfactory.com/animations/transportation/cars/mirror_md_clr.gif

dave_s13

17-10-2001, 13:11

Isn't the ideal place in your sump? How you'd get it there I don't know.

Can't you get senders that screw in where the pressure sender goes with the pressure sender then piggybacked into it, or something??

Tom_S14

17-10-2001, 15:08

Just to backpedal a bit here for a minute.
Good synthetic oil has an extremely stable viscosity over temperature.... does the oil temperature matter that much ?

Is it the temperature of the engine components which is important when ragging an engine from cold ? Clearances etc ? I thought this was the case.

Sounds like I'm throwing a spanner in the works here, but I'm not clear on this one.

Tom

------------------
1996 Blue/Green S14 (manual)
K&N cone filter
2.5" Tube-torque Cat Back Exhaust.
TechTom MDM-100
Race-Technology AP-22
http://tom.marshall.tripod.com

geoff_s14

17-10-2001, 16:18

Originally posted by Tom_S14:
Just to backpedal a bit here for a minute.
Good synthetic oil has an extremely stable viscosity over temperature.... does the oil temperature matter that much ?

Is it the temperature of the engine components which is important when ragging an engine from cold ? Clearances etc ? I thought this was the case.

Yeah, but surely oil temp and engine temp are linked? Presumably, while the oil is cold, it will do an effective job of cooling the components it contacts. In fact this must be the case since many bike engines are oil cooled, this is acheived by running the sump oil through an external radiator.

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Geoff
Emerald S14a, with God's Own Transmission.

http://www.animfactory.com/animations/transportation/cars/mirror_md_clr.gif

Tom_S14

17-10-2001, 22:50

Yes, but then the coolant pumps round the engine too...
All depends doesn't it ? Is it clearances in the valve train, piston rings, or what exactly ?
And not all bikes do have oil coolers do they ? Some just rely on convection due to the fact that the casing has a load of air passing over it...
I'm far from sure....
Why does the valve train warm up ? It's not because hot oil is in contact with it, more likely to be thermal conduction up from the block/head where combustion is going on I would guess. Dunno really, the coolant usually passed perilously close to the combustion chamber to take heat away, and this must play an important part in heating up the rest of the engine ?

Tom

------------------
1996 Blue/Green S14 (manual)
K&N cone filter
2.5" Tube-torque Cat Back Exhaust.
TechTom MDM-100
Race-Technology AP-22
http://tom.marshall.tripod.com

geoff_s14

18-10-2001, 09:21

Tom,

So what are you saying?

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Geoff
Emerald S14a, with God's Own Transmission.

http://www.animfactory.com/animations/transportation/cars/mirror_md_clr.gif

Tom_S14

18-10-2001, 11:11

Goeff,
Don't know what wears an engine from cold.

It's not because the oil itself is cold, if it's a good synthetic oil.

If it's the valve train, coolant temp will be just as good an indicator as oil temp, but you'd be best off measuring the temperature of the valve train !

If it's piston rings, big end bearings etc. then oil temp would probably be the best thing to measure.

Or how about just measuring the temperature of the block ?

Also it depends where in the system the coolant temperature is measured !

Basically I don't know. I'd be tempted to rig up an oil temp guage anyway, and see how the coolant and oil temp interact. Got to bear in mind the temp guage on the dash is completely non linear though. It sits on the bottom until about 60° and is up at the middle at about 78° on mine.. it sits in the middle even if the temp gets to 90°.

You see where I'm coming from though ?

Tom

Tom_S14

18-10-2001, 11:21

geoff_s14

18-10-2001, 11:25

Tom,

Yes, sort of. Interesting about the temperature gauge, I always wondered how the engine managed to run at such a constant temmperature.

So how do you reckon I can fit an oil temperature sender? Is Dave_s13 right about the existance of dual pressure/temperature senders?

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Geoff
Emerald S14a, with God's Own Transmission.

http://www.animfactory.com/animations/transportation/cars/mirror_md_clr.gif

Tom_S14

18-10-2001, 12:32

Goeff,
Yeah, I found out about the temp guage from that useless gadget I've got in the dash http://300zx.co.uk/200sx/ubb/wink.gif

This dual pressure, temperature thing does ring a bell. I've also seen photos where people have just basically wired up a thermocouple by crimping it under a washer on the sump drain plug, or any place would do. The sump is reasonably thin and there won't be much difference between it's temperature and the oil inside.

Forget who, but someone had the idea of using the "ambient" temperature sensor which displays on the speedo dial to measure intake temp... not sure where this sensor is, but if it's small enough, it could maybe used to measure sump temperature ? (input range withstanding, might not work upto 90 odd degrees).

Tom

geoff_s14

18-10-2001, 12:53

The ambient temperature sensor is sited in front of the radiator. Don't think it'd be calibrated up to the temperatures of oil http://300zx.co.uk/200sx/ubb/frown.gif

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Geoff
Emerald S14a, with God's Own Transmission.

http://www.animfactory.com/animations/transportation/cars/mirror_md_clr.gif

Tom_S14

18-10-2001, 13:01

That black plastic thing ? I know...
Well, I might be off to "mappers" to get myself one of those little digital thermometers with a remote probe on it. Have a butchers at the oil temp, and the intake temp post intercooler while I'm at it.
There's a blank intake temp field on my useless gadget, if I could find the pin on the ECU connector and the right temperature sensor from mr. nissan there's a chance the ECU might read it and shove it out the consult port if some lazy software bloke left it in. Who knows. Similar story with my absent MAP sensor, I wouldn't mind buying one and wiring it in to see what difference it might make.

Tom

David

18-10-2001, 14:40

Took me a while to sus out. Theres a T piece from the Turbo Actuator going to the elecy boost controler, the air intake and the other to the pressured side. Fit the valve to the pipe from the pressured side. This limits the amount of pressure to the actuator and the elecy thingy and works a treat! Tip if any of the pipe have a white ring round them, pull them off all together(one at a time) shuve a small screwdriver up its ass and a small brass looking effot will pop out the other end with a tiny hole in. Get shut of these and get an extra .2PSi!!

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P reg, K&N, Straight though Exhaust(tube torque), boost gauge, boost controller, modid front grill, bayley dump,1100wat sub(parcel shelf rattles like hell)14PSi ???BHP neck snapper!
www.netcomuk.co.uk/~daross\my200sx.jpg (http://www.netcomuk.co.uk/~daross\my200sx.jpg)

Stevecarter200

18-10-2001, 23:42

Just for your information, I have an oil temp guage in my S13. It takes at least an extra 5 minutes of driving to get the oil up to working temperature after the coolant temp guage is sitting in the middle. The oil temp sender is actually placed in the sump, so the reading should be pretty accurate.

Also, the oil temp can vary between 150F and 250F while the coolant temp guage sit steadily in the middle.

Not sure if this is relevant to your discussion, just thought it may assist. http://300zx.co.uk/200sx/ubb/smile.gif

Steve

[This message has been edited by SteveCarter100 (edited 19-10-2001).]