EGT Gauge - Pre or Post Turbo?

Submitted: Monday, Feb 11, 2008 at 19:34
ThreadID: 54480 Views:6082 Replies:5 FollowUps:2
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I am having a turbo fitted to the 1HZ motor in my Troopy.

Do EGT gauge sensors normally go pre or post turbo?

And when I see recommendations that the EGT on a turbo 1HZ shouldn't go about 550 degrees celcius, is that pre or post turbo?

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Reply By: Member - Vince B (NSW) - Monday, Feb 11, 2008 at 20:30

Monday, Feb 11, 2008 at 20:30
Thermoguard Instruments(who advertise on this site) recommend fitting the sensor upstream of turbo.
AnswerID: 286956

Reply By: Leroy - Monday, Feb 11, 2008 at 20:37

Monday, Feb 11, 2008 at 20:37
that would be pre. You have an opportunity to have it installed where you like. I installed mine post as it was most convenient. At the end of the day it's an indication of what is going on with the engine regardless of the temp being displayed.

AnswerID: 286958

Reply By: pt_nomad - Monday, Feb 11, 2008 at 21:13

Monday, Feb 11, 2008 at 21:13

Good on topic article from Ian :

Most seem to fit them post turbo - I think the tubo's often have the port present. There is apparently a 200c drop in temp across the turbo.
What I have learned from reading:
Pre turbo temps the EGT should no go above 720c.
Post turbo temps 500c-550c.

It seems the argument for post turbo is that it reduces the risk of sensor failure or carbon deposits damaging the impellor.
I think a pre turbo sensor will give you a far more accurate indication of what is actually going on in the motor.

AnswerID: 286966

Reply By: _gmd_pps - Monday, Feb 11, 2008 at 23:14

Monday, Feb 11, 2008 at 23:14
depends what you want to do with the info.
I have a sensor right in the exhaust manifold before the exhaust pipe where you gate the real and actual exhaust temperature and it is coupled with a water vapour injection which is calibrated to 1050F EGT as a trigger point. when you want a simple reading of the engine activity post or pre will do when you consider than post is always much lower than pre. I prefer pre because I want to know when my turbo runs red :)).. the turbo timer is coupled right before the turbo and not in the manifold to measure turbo temp engine cut off.. so in short .. it depends on the purpose ..
have fun
AnswerID: 286992

Reply By: SimonInAustralia - Tuesday, Feb 12, 2008 at 07:42

Tuesday, Feb 12, 2008 at 07:42
Thanks for the info.

The turbo is already installed and dynoed, so I don't think they will be too keen to be pulling off the exhaust manifold to intall it pre-turbo, so probably have to just live with it being post turbo.
AnswerID: 287006

Follow Up By: Member -Signman - Tuesday, Feb 12, 2008 at 09:09

Tuesday, Feb 12, 2008 at 09:09
We have ours at the outlet side exhaust. Normal temps around 300+, if I push it can get to 400+, and up a long, steep hill it'll touch a tad under 500
FollowupID: 552250

Follow Up By: _gmd_pps - Tuesday, Feb 12, 2008 at 10:56

Tuesday, Feb 12, 2008 at 10:56
you only put it in the exhaust manifold
when you need the most accurate temps.
otherwise you put it in the exhaust header
before turbo.. just be careful when they drill the hole
for the probe.. many of mechanics are idiots
and you get the metal bits into the turbo.

good luck
FollowupID: 552260

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