Outer Limits 4x4 Board

Gooday guys, i just recently got my car dyno tuned in Warragul (vic).And all is good. The guy put the probe in the end of the exaust pipe to get the temp reading. Diesel only 570 at 100 kls and 625 at 100 kls diesel/gas. my question is why does every body put their probes in a hard to get to spot directly after the turbo, cant you put it anywhere along the pipe within reason. I thought it might easier for access for drilling etc, i am asking because it was recomended for me to install one to monitor my temps. especially when towing. Any input would be great , even what brands to look out for , costs etc.
Thanks Gazza

Weird!?

The temps coming out the tailpipe will be 100's of degrees cooler than that coming out the back of the turbo let alone in the combustion chamber...

Give that dyno guy a slap up side the head for us?

Post turbo is easy as its just a matter of drilling a hole and welding in a threaded bung.

Pre turbo is more accurate to true combustion temps due to energy losses that i wont go into. But its a hard spot to put a probe.

If you have the $$ buy a VDO gauge and Thermocouple.

Good luck

surely closer to the turbo would give you an accurate reading..

also depends if you go pre or post turbo... in that small area it gives a difference of 100+ degrees. going 1/2 a klm down the exhaust IMWO would be useless.

YMMV

DITO to all the above, your exhaust gases will be way cooler at the end of the pipe, just because someone operates a dyno doesn't mean they have half a clue what they are doing. Some are good at petrol injection and don't understand diesel visa versa.
A VDO PYRO kit approx $300+ is a good investment, way cheaper than rebuild or new motor, tell the handbrake that it's cheap insurance.

&%%^$$##$!@

gazza 1 wrote:Gooday guys, i just recently got my car dyno tuned in Warragul (vic).And all is good. The guy put the probe in the end of the exaust pipe to get the temp reading. Diesel only 570 at 100 kls and 625 at 100 kls diesel/gas. Any input would be great , even what brands to look out for , costs etc.
Thanks Gazza

Hi Gazza, I'm guessing that those temps were fahrenheit cause if they are not, you are in big trouble...

As the others have mentioned, VDO seem to be a reputable brand and placing the coupler in the dump pipe (1-2" away from the turbo) is easiest for installation.

You just need to keep the temps below 550c in that position.

Cheers

The probe stuck in the end of the exhuast surely has to be an 02 sensor? Why would you both putting a temp probe there?

nzdarin wrote:The probe stuck in the end of the exhuast surely has to be an 02 sensor? Why would you both putting a temp probe there?

Thats what i reckon. With a car at full load (100% output) you could quickly whip your hand past the tailpipe, however trying to do something like this (albeit impossible) would peel the flesh of you quick-smart.

As said, fit a pyro as close to your turbo as possible for the best results.

Agree it must have been an 02 sensor up the tailpipe, If you had 600c. at the tailpipe you would have a lump of molten metel that used to resemble a turbo bolted to you manifold.

I have my Pyro mounted pre turbo and i am getting just over 600C when i push it up a hill.

Surely pre or post turbo postions counldn't differ as much as 100 degree's..... or has someone tested this theory? Some people say after the turbo would be hotter? I think it would be almost the same, maybe a few degree's lower. the exhust gases heat the turbo not the other way around. Maybe I'm wrong.............

I have run pre and post simultaneous pyros on th dyno( 3"inches from outlet) the pre turbo under full boost will be approximately 200 degrees C hotter, and I say that toungue in cheek as the restriction of the exhaust housing and manifold will cause deviation on this figure. At low boost like cruise there is very little difference in pre and post turbo temps. At the tailpipe to read is an absolute waste of time, and if you were seeing 500 degrees at the tailpipe I'd say start saving for a motor!

Joel

So mounting a pyro guage probe in the dump pipe would not be accurate enough for a guide if under full boost? I'm going to fit one in the next few months as I'm going to up the boost etc. When I was driving on the beach with a full car in the soft sand it was boosting at 10 pound for the entire time I was traveling in the soft. I had to pull over and let the engine temp come down a bit coz it was getting close to the higher side of the stock guage. I would like a little more accurate warning of engine exhurst temps when I'm on the beach again so I can stop before anything bad happens! Thanks for your knowledge

Gee wiz, thanks everybody for your input. Looking at the dyno details i think the temps are in celcius ?, but he said for the diesel only reading it was what he expected (not high not low ) for my type of car. His main concern was the readings were high when the gas was on. (high for him).
Thanks gazza

It is commonly accepted that 740 degrees C pre turbo is the safe maximum(530-550 after), it is relative to the amount of time at that temperature, I will run a comp truck that does short bursts hotter than a heavy tow vehicle that can sustain high temps for long periods. I have seen factory TD42 GU's that will get as hot as 600 after the turbo (untouched) and any vehicle fitted with a catalytic converter will run around 600-650 degrees c to keep the cataliytic converter lit. Engine design, clearances, piston material and the efficiency of the cooling system all factors into the ideal temperature for running where maximum performance with minimum wear is acheived.

Joel

When adjusting the fuel what conditions should you be testing the egt's under e.g. up a hill revving the motor out or making it labour in say 4th gear instead of 3rd? My thoughts would be that making the engine labour in a higher gear at lower revs would produce higher egt's then revving it higher in a lower gear, is that correct?

dead right chunks

Going off my pyro, i'd have to say just load it up at its hottest within your engines driving RPM range.

Eg. My driving RPM range is 1200-3500RPM. Any lower and i'll change down a gear, any higher and i'll go up a gear. If i can find a "hot point" within that range, i'd then tweak the pump to my max EGT around that hot point.

Thanks fellas.