How hot is your exhaust system in your car
 

I did a test with my engine using a spray bottle to spray the exhaust pipe at various places until I found the point at where is just boils when it is at normal operating temperature.

I then measured the distance away from the head to give me some indication of how efficient my engine is running.

I have ~ 78% more MPG when driven in the city at the moment and I still have timing issues under acceleration which accounts for 17% of the running time during my test so as a guess I could see another 4% increase in my MPG figures.

The test
At a distance of ~1000mm from my head, water just starts to boil eg 100 deg C.

At a distance of ~2400mm from my head, I can touch the exhaust pipe for about 1 sec (this is not a good way to check temp cause you may loose you skin)

At the end of my system the pipe is only warm to touch eg can keep hand on it forever without any discomfort.

I was wanting to know how your exhaust system compares to mine?

I have had reports of the end of the system will burn skin off.

Some cars have an exhaust temperature sensor, though the driver may not even know about it since the data is used for emissions controls. For example, PSA's HDi turbodiesels have an EGT if they are fitted with a DPF (FAP), and it is possible to hack into the signal.
Here's someone who did just that:
FAP Sensor Regeneration & Turbo temperature - exhaust gas temperature monitoring.
According to that page, the 1.6HDi turbodiesel's EGT is 200°C-400°C (392°-752°F) during normal operation, and 400°C-600°C (752°-1112°F) when regenerating the DPF.

EDIT: The EGT sensor is in the DPF can, after the turbo and cat.

My EGT reads 450-700 degrees F to the turbo inlet.

I use my EGT to regulate my driving. Keep it under 600 and you get good MPG.

I do not have any fancy stuff to tell me the EGT so I was doing it the cheapest way possible because I have no money left over to spend.
I would need several people to warm up there engine and let it idle then lean underneath with a water trigger bottle and find the distance water boils on the exhaust pipe then measure the distance and ambient temp. I am just looking for a rule of thumb at the moment.

I enjoy using the "how quickly does it cause burns" method of measuring temperature, but only for things <50°C. Hotter things call for a cheap infrared thermometer.

I really have no idea how hot my exhaust is when I'm pushing the car hard, but after driving gently around town, shutting off the engine, and popping the hood, I've seen 350°C at the catalytic converter. It's probably a few hundred degrees higher during a highway hill climb.

Smokingwheels: I like the method for its simplicity. If you want better numbers, then an IR thermometer may be a good investment (definitely cheaper than a dedicated EGT sensor), plus it comes in very handy around the house, like in insulation projects.

Smokingwheels,
Some info from another site discussing engine temps on MG B's which may be of interest.

"All this high temp and ceramic paint talk has me baffled. Just how hot do you expect these things run??
Here are some temps I did to answer a question last summer.
Jeff

Here are the readings I just took with a contact themocouple, rather than infrared.
1275, at operating temp, idling after a 10 mile drive.
All temps in Fahrenheit, surface temps only.

Top of head at thermostat housing: 163.1*
#2 stud at intake/exhaust manifold: 186.3*
Exterior of exhaust manifold: Front: 289.0*
Center: 290.1*
Rear: 287.0*
Intake Manifold flanges: Front: 163.2*
Rear: 167.4*
Head at rear exhaust manifold mating flange: 220.8*
Head at #3 plug: 158.8*"

By the way Piwoslaw's suggestion of an IR temp sensor is a good one.
Dick Smith , Jaycar etc have them in various grades and accuracies for not a lot of $.

Maybe you can borrow one for the weekend if a long term use is not needed?

Peter.

Thanks Peter for doing a test.

Do you have any idea of the ambient temperature when you did the test?