EGT sensor question

[archaeic_bloke]

hey, quick question... thinking of getting an EGT gauge...

on a stock R32 GTR where do you plug this in?...

and since i only want to go with one of them.. i should put it for the rear turbo right? since the rear turbo will see hotter temps... so i can assume if the rear turbo EGT is X degrees C... then the front will be a little lower.

lemme know, thanks,

[Snow]

AFR I would put in the turbo elbow/down-pipe. EGT is in the cat. You already have a stock sensor wired in which will trigger a light on the dash when your EGT is too hot. Screw in your new sensor there and ground out the stock wires so you don't get a light on the dash.

EDIT: You may decide to take this chance and get a test pipe with an EGT bung in it while you're down there tinkering around anyways...

[DarkCaporaL]

^^ having an EGT in your cat would not serve any useful purpose. It's too far off from the cylinders. By the time the heat reaches that point, it's already been dissipated too much to give you any accurate readings.

The EGT has to be as close to the cylinders as possible. I think most people put it right after turbo, but for best mesures it should be before.

[archaeic_bloke]

yah thats what im asking about!... i heard its only worth putting it in the exhaust manifold BEFORE the turbo.. and thats what i wanted to know..

would i need to get a bung welded in for the EGT sensor... thats basically my question... or is there one already in there?

and i do already have a decat pipe with a bung in it.. but i was told thats where my wideband should go

[falcon]

I am putting mine in the turbo manifold runners. before the turbo. that's where you'll see the hottest temps. but this is on a rotary and there is only one runner per housing.

[Snow]

yah thats what im asking about!... i heard its only worth putting it in the exhaust manifold BEFORE the turbo.. and thats what i wanted to know..

would i need to get a bung welded in for the EGT sensor... thats basically my question... or is there one already in there?

and i do already have a decat pipe with a bung in it.. but i was told thats where my wideband should go

I guess it would then be best to put the EGT in the headers... just get a bung welded in.

I was told that an AFR with an O2 sensor in the cat would be useless as it's too far away... but right now I'm not doing too good in this thread so take that with a grain of salt

[GTR-Dad]

EGT must be measured in the exhaust header before the turbo to be meaningful. Substantial energy is removed from the exhaust stream by the turbine resulting in temperature and pressure drop.

You could weld a bung, but mine is just drilled and tapped. Seems to work fine. If you're worried about cuttings finding their way into the turbo, I know how you feel! Mine was done while the exhaust mani was out. Some guys drill gently with the engine running so the positive pressure in the manifold blows the chips out rather than in. (Do you feel lucky?)

Hope that helps.

Dan

[NismoS-tune]

My EGT sensor is in the CAT, I didn't want to drill into my $900 exhaust mani. The accuracy isn't as good as Dan's but the short distance shouldn't cause 200 degrees of inaccuracy if even any. Don't get a test pipe, keep the cat and reduce the nasty pollutants catless cars make. The gains are almost meaningless when comparing the change in environmental impact.

[archaeic_bloke]

sorry Stune... too late lol, came as a whole package with my exhaust and im not willing to pay a lot for another cat lol.

so we all agree then, EGT sensor has to be tapped into the exhaust manifold before the tubro... can we address the next 2 issues tho?

#1 do i need 2 EGT sensors? or is it fair enough to just read the EGT from the rear turbo manifold as thats the one that is typically the hottest?

#2 would it suffice to put the wideband in the cat bung hole, or should it be further up the downpipe?

as long as theres no exhaust leak wether its in down pipe or the de-cat pipe its the same gas mixture no?

[mcfly]

My EGT sensor is in the CAT, I didn't want to drill into my $900 exhaust mani. The accuracy isn't as good as Dan's but the short distance shouldn't cause 200 degrees of inaccuracy if even any. Don't get a test pipe, keep the cat and reduce the nasty pollutants catless cars make. The gains are almost meaningless when comparing the change in environmental impact.

an egt is useless that far downstream.

[NismoS-tune]

an egt is useless that far downstream.

That's where they are from the factory isn't it? I guess I'll deal with the 500+ degree F inaccuracy with it 5 feet from the headers since it's almost ice cold by the time it hits the cat.

[Dragon Humper]

If you look on Aircraft Supply websites (and diesel for that matter) you will find an EGT guage that has 2 scensors and 2 needles on the guage that cross each other in the middle. If you are ok with only a 90deg sweep they are an affordable alternative to buying 2. They actually cost about the same as a single.

Before the turbo is ideal. If you are worried about the probe falling off and ending up in the turbine you can mount them in the downpipe right after the turbo and just remember that the temp is about 100deg F cooler than the true port reading.



Jon.