Installing a EGT/Pyrometer

[craigcd]

Was wondering where the best location to put the probe on the manifold is? If anyone has a detailed description or pictures that would be great.

Thanks

Craig

[vboyq]

i put mine on the 4 runner in the exhaust manifold, drilled a hole right on top then used some loctite and threaded it up.

but afterwards realized i should used the 3rd runner(1st one being the closest to radiator), cuz the little black box thats connected to the blowby tubes are right where i put the sensor, so i just removed it and put a hose connecting it straight to the valve cover with a breather on it.

[msaskin]

Any reason you say you should use the 3rd runner??

I tapped mine into the cylinder 1 runner, about 4" or so from the head. My train of thought was that the #1 cylinder was at the end of the fuel rail, and therefore the most likely to run lean.

~matt

[WeldingHank]

put the probe on the runner of the cylinder that runs the leanest. which is usually the cylinder farthest from the fuel pressure regulator.

[msaskin]

put the probe on the runner of the cylinder that runs the leanest. which is usually the cylinder farthest from the fuel pressure regulator.

Interesting. In the DSM world we've always done it on the cylinder closest to the FPR since that's the one that runs the leanest.

I can logically explain to myself reasons for the closest and furthest running lean...now I'm not sure

~matt

[robbbby]

Cylinder 4 runs the hottest. It's also furthest from the FPR.

[msaskin]

Once again, anyone care to explain? Has anyone logged EGT's or A/F directly in the runners of each cylinder?

All I've heard so far is people saying cylinder X runs hottest/leanest, but not giving any explanation.

I keep reading on 240sx boards that cyl 4 (furthest from the FPR) runs leanest, but all of the DSM guys take it as gospel that the cylinder closest to the FPR runs leanest on DSM's.

~matt

[vboyq]

i was told that when there is a problem its with cylinders 3 or 4 so that just makes sense to put the probe there, to monitor the cylinder thats most likely to see a problem

[S13240]

I put mine on the collector and gets an average reading of all 4 runners.

[msaskin]

I put mine on the collector and gets an average reading of all 4 runners.

What temperature do you see @ idle in the collector? What temp at a highway cruise (say, 3K rpm in 5th gear)? Is your car stock (or close to it?), no tuning, etc.? Stock manifold? Heat shield/heat wrap?

I'm interested in seeing just how much the exhaust cools by then.

~matt

[WeldingHank]

the cylinder farthest from the FRP runs leanest as it gets less fuel pressure once its been spent on the other 3 injectors/cyinders.

[msaskin]

the cylinder farthest from the FRP runs leanest as it gets less fuel pressure once its been spent on the other 3 injectors/cyinders.

That makes no sense, since the FPR sits at the END of the fuel rail. Fuel enters the rail (on an SR20) from the back of the engine (cylinder 4), goes through the rail towards the FPR (cylinder 1) which regulates the pressure. The excess fuel is returned back to the tank.

~matt

[S13240]

What temperature do you see @ idle in the collector? What temp at a highway cruise (say, 3K rpm in 5th gear)? Is your car stock (or close to it?), no tuning, etc.? Stock manifold? Heat shield/heat wrap?

I'm interested in seeing just how much the exhaust cools by then.

~matt

At idle in the collector it sits around 600 F. Highway cruise at 3k rpm in 5th gear is around 12-1300 F. Car has basic bolt ons like 3" dp and exhaust with filter. Other mods are just for traction. No tuning, stock manifold and no heat shield or heat wrap on any exhaust part either.

At stock boost when racing it, max temp reaches around 1350 F and then up it to 14 psi and it'll get to 1450+ F (never went pass 1500 F yet).

And now I have an egt in my Celica all trac in the collector as well and it idles around 600 F as well and on a highway cruise it's a bit higher than the sr20 which sits at about 1300 F at 3k rpm in 5th gear. And my Celica is stock besides an hks filter that came with the car.

[msaskin]

Interesting. I'll have to take a look at mine and do the conversion (my gauge is in deg. celsius).

~matt

[S13240]

I can also change my readings on my gauge to Celcius as well, but I'm just too lazy to change the temp readout. I have a digital boost/egt gauge by SPA Technique.