I have a agressive street port on my engine along with two egt gauges, what i want to know is should they read the same as the primary intake ports are smaller then the secondary intake ports so am i right in thinking my egts will both have a different reading.

regards

Erdin

 

Erdin, EGT is after the exhaust port, not at the intake ports.

But with EGT probes for each port, you will still see different figures. But they should be close.

Dan

 

Yeah, they are called Exhaust Gas Temperature gauges for a reason; as in they measure the exhaust temp...

 

i know what egt are, what im trying to say is if the secondary intake ports are bigger, then does that not mean that there is more air going in to one side of the engine being used in the combustion process which means the heat in one of the chambers is gona be alot more so that would Influence the exhaust gases or am i wrong if u get what i mean.

 

You are wrong. Both rotors have primary and secondary ports. That means each rotor has a set of small and large intake ports. Therefore the EGT of both rotors will be similar. If they're really different, it means the engine has a problem.

 

What's the normal or acceptable varient of EGT readings between rotors?

 

what brand of egt gauges do you have?
matt

 

Im useing the greddy peak hold gauges, so let me see if iv got this right the readings on both gauges will be slightly different but not by much, are we talking somthing like 50c.

thankfully

Erdin

 

If everything stays the same, the ported engine will run leaner, so it might be hotter.

You really should be retuning the engine for the ports, so the EGT's should not vary by much.  Ideal EGT should be pretty much the same, even though you have a street port.


-Ted

 

I don't think you will ever see them the same but
if they are 100F apart i would say that would be close,
and the higher it gets the closer together it will get.
I think the rotaries see between 1300F and 1500F
1500 being very high. I cant remember at the exact numbers at the
moment, but can check and see what the highs were on
a turbo engine.
matt

 

that would be great Matt thanks.

 

Iould want to see less than 50C difference. Remember that the rear rotor runs hotter.

Dan

 

I would want to see less than 50C difference. Remember that the rear rotor runs hotter.

Dan

 

Forgive me but why do the rear rotors run hotter?

 

Design 'FEATURE'. It is on the end of the fuel rail, and the air doesnt get to it aswell as it could.

When mapping this has to be allowed for, by adding more fuel to cool down temps.

Dan

 

Thanks Dan i always heard about the rear rotors being hotter but never knew the exacet reson.

 

But the EGT temp also depend on the location of the PROBE. the furter the the proble , u will got a colder reading.

 

Where is "ideal" location to locate the EGT probe? I imagine a seperate gauge for each rotor, so plumbed into the manifold between the engine and turbo?

 

Yes this is what iam having done at the moment on each exhaust port and befor the turbo but i do think it would be best not to have them to close to the exhaust ports cus the temperatur probe with time could fall off and damed the turbos due to the extream heat they would be subject to.

 

Ideally the probe tip should be far enough into the exhaust stream to reflect actual temps but far enough away from the wall of the manifold to avoid the thermal drop (up to about 100 degrees F) that is associated with the temps close to the metal walls. The metal manifold acts as a heat sink causing a dissapation of the heat of the gas in contact with it.

Generally you should not place the probe deeper than 1/3 of the way into the exhaust stream. The greater the unsupported probe length, the more susceptible to exhaust pulse damage. Contrary to popular opinion, it is the exhaust pulse, not the high temps, that eventually cause the failure of a probe tip.

A standard type K thermocouple can withstand constant temps of 1785 degrees F and maximum instantaneous peaks of about 2200 degrees F-----either of which exceed the temps your engine can handle, so any concern about the thermocouple tip being exposed to high temps is unecessary.

 

That makes me feal better cus i was a bit worried about the probe falling in to the turbo.

Thankfull

erdin

 

Pre-turbo placement is ideal because it give the most accurate readings of maximum egt and it allows for discrete analysis of both the front and rear rotor temps. In a case where the temp difference between the chambers is significant, you can notice the problem immediately.

I have three T/Cs mounted in my 3rd gen. 2 are pre-turbo and are installed in the A'pexi mainfold for my RX6 turbo. The remaining T/C is installed in the DP immediately after the OEM placement for the O2 sensor. The preturbo T/Cs are monitored by the datalogit and the post is monitored both by gauge and datalogit.