Is EGT Worth Knowing? NWS

[Surt]

hi all! the question's been ripening in my nut for a quite awhile - is it worth knowing the exhaust gas temperature if u already can read A/F ratio with o2 sensor? keeping in mind that the question's tied up with a turbo setup ;) just in case if it changes anything

[Redmohawk]

Doesnt hurt if your going to push it boost wise , but not essential. You can pick up a problem fast with EGT if your on the edge and temps start to skyrocket, but you need to use a light weight probe in the gas streem other wise reacion times are slow and less useful.

[latheboy]

Ideally you would want to be able to get an AFR reading from each exhaust port so you can tune each cylinder, one AFR reading in the pipe is just an average of the 2/3/4 cylinders.
The gurus at work say if you cant do that you can work it out with 1 AFR in the pipe and a temp probe on each exhuast port.

It is worth know the temp of each, one cylinder might not be firing like the rest and youd end up adjusting them all to compensate when using 1 AFR sensor

[livewire]

Having repaired auto test equipment, and datalogged pro bike, I'd always trust EGT over O2 sensor, anyday.
Both is ideal, but if things don't correlate, believe the EGT's.
O2 sensors can become 'poisoned', and rely on correct operating temperature to work properly.
And as said above, EGT's can identify dead/sad / unbalanced cylinders.
Also O2 very sensitive to air leaks in exhaust, giving you bullshit readings.
Edit: And reading plugs (old school) is always good to back up/ verify data.

[Surt]

thanks heaps mates ur help's much appreciated! i guess i should have asked directly do i need the bloody egt gauge or afr's enough? coz in my wildest fantasy i cant imagine 4 egr and 4 egt gauges on a bike [:0][:0][:0][:0] ahh shit i'm gonna have to many clocks already even with a speedo combo [xx(] (actually i hate all gauges and the only 1 i respect is an oil pressure gauge, i usually dont use them prefering to listen to the engine but in case of the turbo things r likely to change verrry fast to the worst)

yup i placed the o2s bung before the turbine to avoid misreading from a short damp pipe now im thinkin should i weld a egt sensor bung (single [:p]) on it? or damp it? i guess that the rattle will tell me not less than a egt sensor at the first approach (as well as the plugs inspection) but if anything's amiss then i'll have to check out every cylinder separately?

[Surt]

and as for tuning each cylinder separately, i cant go any further than just making sure that injectors flow rate match each other, cept valves clearances and plugs, right?

[latheboy]

Depends on which ECU you are using, some of the upper market ones you are able to change different injectors at a time.

If your going to put egt in for each port you really want to see the results all at the same time... Not changing the sensor to the next port and having the motor cool down etc etc

[Booster]

EGT can go hot from lean and rich (still burning as it enters the exhaust) , best to have 1 x a/f and 4 x egt , then you can realy set up for best power reliably

[livewire]

Agree with Booster.
And I also agree with the guage 'overload'. TBH I don't think guages really get looked at, and telltale (idiot) lights are the go. Even then it's a 'too late' indicator. O2 into Megasquirt with display (hey Dave), and a couple of dual EGT 'multimeters', whilst tuning probably the go. Then possibly a neat little O2 display into dash for normal use?
My Kat very minimalist. Has a tacho with shift light, and a 'game over' light (oil pressure).
Edit. From memory, Techedge O2 sensor can display 4 EGTs as well as AFR onto computer for use whilst tuning. Think both Booster and Evad use these as well. And can run both O2 program (tewblog?) and MSedit on 1 computer whilst tuning (dyno). Maybe Palm can do the same if you're keen (brave enough) to do it on the road.

[Surt]

im megasquirting as well ;) also got lc1 wbo sensor and gauge... yeah zaust gas temp goes high when too reach or lean so u can judge on what happening with air/fuel mixture relying on afr gauge, so i gonnah stick on it its not a skylab nor a helicopter after all. but of course if shit happens i'll have to weld 4 bungs on the runners [V] yup livewire i'm keen to play with palm tune i dont think i'll have a lot of free/gratis/ time on the dyno, though i was invited already. cept tacho combo i'll have to use boost gauge/the only 1 i luv
[:X] :D/ voltmeter, engine oil pressure, turbo oil temp (once i'll build a separate lube sys), water temp, and afr = 6! around the tacho [:0] perhaps i'll have to root [:p] the gas pressure gauge from fuel regulator to the dash board as well - only if i'll meet some fuckups with boost/fuel pressure ratio btw i saw on a top fuel dragster just tree gauges, u'll never guess which ones unless u v known it already:
air tank pressure, oil pressure, crankcase vacuum

[Booster]

I would advise against a seperate lube system on the turbo (unless you realy have to due to std oil pressures) only seen a couple in use and both had failures at some point that killed the turbo with no warning .

[livewire]

Must have been an owner/driver TF driver. If he was just a driver, they keep peddling, regardless.
TF have an audio type alarm when something wrong, a rather large bang type noise, haha.
Imagine trying to drive one of them fuckers and look at the guages!
Seen Aussie Dave Grubnic ( NHRA TF) video once. Camera up on rear wing. Motor popped and blower lifted and tilted over.
You could see the throttle linkages moving, him pumping the throttle.
When asked, he said you never give up, it might just light again.
Apparently thats the sign of a good driver, haha. Spose you can do that when it isn't your money.
Air tank pressure for clutch, but oil pressure and crank vacuum probably come just before the big bang alarm.
Actually no clutch air probably comes just before the big bang, too.

[livewire]

PS. Short answer to original question is probably yes, but only when dyno tuning.
I've also used IR thermometer to check header pipe temps.
Also be known to use 'spit sizzle' test on headers to compare cylinders as well.
Sometimes it's just 'whatever it takes'.

[Surt]

quote:Originally posted by Booster

I would advise against a seperate lube system on the turbo (unless you realy have to due to std oil pressures) only seen a couple in use and both had failures at some point that killed the turbo with no warning .


thanks Booster! i'm not a big fan of the idea either coz it has some disadvantages like the dependance on oil feed electric pump reliability and extra weight of the whole system, but also coupla advantages: feeding the turbine with a clean cooled special turbine oil and no need to keep the engine running until the turbo's cooled down... so yes, it mainly depends on the feed oil pump reliability... is it so bad? otoh if the oil scavange pump fuck up u wont be able to ride on as well (in the case of a low mounted turbo)

[Surt]

quote:Originally posted by livewire

Must have been an owner/driver TF driver. If he was just a driver, they keep peddling, regardless.
TF have an audio type alarm when something wrong, a rather large bang type noise, haha.
Imagine trying to drive one of them fuckers and look at the guages!
Seen Aussie Dave Grubnic ( NHRA TF) video once. Camera up on rear wing. Motor popped and blower lifted and tilted over.
You could see the throttle linkages moving, him pumping the throttle.
When asked, he said you never give up, it might just light again.
Apparently thats the sign of a good driver, haha. Spose you can do that when it isn't your money.
Air tank pressure for clutch, but oil pressure and crank vacuum probably come just before the big bang alarm.
Actually no clutch air probably comes just before the big bang, too.


ur right livewire, most astonishing thing that he was also a builder of the bike: the engine cept shafts and crankcase from a pommish company, ally conrods, bronze skulls, custom head, tranny, frame, wheels, bodywork, yeah he also bought the blower [:p] and even more wonderful is the fact that he made all the custom parts on his manual lathe and mill in the shed [:0] shit i lied, it was not top fueller but blown alkie, sorry for misleading mate! [B)]

[Booster]

If the oil scavenge pump dies, your turbo will still be fine ,

[Surt]

yes sure if oil goes into the turbine housing u'll see just a tail of smoke may be ur o2 sensor fucked up then to, if its after the turbo; but if oil also goes into compressor housing thats much worse aint it?

[Booster]

Just gets to ba a lot of smoke and will foul the plugs before doing any real damage
Turbo seals are mostly piston ring type, can't hurt them unless you turn the motor off with the turbo glowing red hot repeatedly
If you do oil up a turbo fix the prob and ride it, the smoke will stop after a few kms

[Surt]

ok, electric fuel pumps r reliable /or supposed to be/ to do their job constantly... why an electric oil pump cant be trusted as well? btw as many blokes im gonna use 2 nos pumps for that... what was the capacity of the separate oil lub sys u mentioned about Booster? im gonna start from 1l and increase it if needed judging on oil temp... oil cooler's size is a question as well, gonna start with a small one smth 200x100x30, can swap for a bigger one

[Booster]

Which oil pump ?? VDO are fairly good, designed like the modern efi pumps, but still fault occasionaly. not the life of a fuel pump, i think they were around a lit or so
other gear pumps with brush type motors seem to be less reliable judging from the fairly regular comments of the busa guys with Mr turbo kits also much cheaper, guess another case of getting what you pay for.

[Surt]

just a round nitros pump from ebay, says nx-nitros express, probably from procomp? i was advised on that one for using in turbo street application by yank drag guys against mr turbo's small oil pump which they say not even good for a few passes [xx(]