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Re: EGT TEMPS ON 4.8 PETROL PATROL

Posted: 16 Oct 2018 11:19
by Mystical_Beast
Thankyou Peter for the interesting links
It does seem that the Temps I am reading are within ‘normal’ parameters.
Its just a shocker once you become aware of the actual heat generated and resultant EGT’S.
Without the means to measure we drive and remain blissfully ignorant.

My desire to be able to read EGT was specifically in the advent I tow through harsh conditions and so was somewhat disappointed to see how high the Temps already were.
Granted, they are high with me bombing along at around 3000 rpm, but the ‘feel’ of the car is right there.. happy place, its just the EGT’s can get to 800.
AT around 150 to 160 it generally stays at around 750 except when maintaining those speeds up long hills it can quickly get to 800 and more.

I haven’t known if I have cause for concern but in retrospect it seems no.

JP sent me something very interesting, privately, last night, JP, if you are able to, please post that pdf onto the thread.
It will be easier reading than on my cell-phone screen and very interesting without being overly technical.

The article also advises how AFR ratios reduce EGT and what will increase them.
So very interesting reading, if I didn’t misunderstand the article, you would cool EGT BOTH by leaning the AFR mixture through excessive air and by running rich you cool off the EGT through excessive fuel.
Timing also has a big role, so timing advance is beneficial and I know that in tuning for performance timing is generally advanced as much as possible, with consideration to AFR etc.
What I garnered from the article JP sent me is that at optimum AFR (stoichiometry) is where the vehicle will run hottest and because my vehicle, I’m assuming, is optimally tuned, I’m getting these high readings..

I’m reasonably assured that the correct balance has been plotted along the rev ratio and that’s where the UNI Chip comes in.
If in my particular case, should I wish to reduce the EGT it will be at the sacrifice of performance.

I have found that whacking my Patrol, aggressive driving, hard acceleration, high speeds etc. my consumption as measured at the pump was 19.7 l/100, this over 350 km trip with lots of mountains and overtaking, but generally sitting around a steady 150/160.

At a more sedate pace, same trip, but still not hesitating to overtake, but generally settling around 130/140 I measured 17 l/100.
I suspect I would get it down to 15 if I stuck to 120.

I would be very interested to know the EGT temps generated on the 4.5 Petrol Turbo Michael has just done as a comparative.

Thanks guys for your input, JP, please post the Pdf if you can!?
My course of action/prevention, will be to regularly check parameters on the Dyno.

Probably every service.

Re: EGT TEMPS ON 4.8 PETROL PATROL

Posted: 16 Oct 2018 12:18
by Michael
Petrols are a nightmare to tune.......

More timing is better, but the faster the timing, the more likely the engine will ping. Ping or detenation is bad...... very bad and will kill the engine.

General rule of thumb is to run a slightly rich AFR fir safety, it makes the combustion temp cooler.
Leaner AFR's will produce more power, but runs hotter and will kill the engine.

Thats why modern turbo vehicles are fitted with a knock sensor. Once the ECU detects a knock (from ping) it will retard the timing.

Re: EGT TEMPS ON 4.8 PETROL PATROL

Posted: 16 Oct 2018 12:39
by ces
Chaps,
I used to know very little about topics like these. Now I can actually follow a conversation and sound clever around a braai! :blonde:
Very informative, thanks... :salute:
Have a GREAT week
Christoph

Re: EGT TEMPS ON 4.8 PETROL PATROL

Posted: 16 Oct 2018 18:03
by Michael
Ha ha Christoph...... jys baie funny :lol:

Re: EGT TEMPS ON 4.8 PETROL PATROL

Posted: 16 Oct 2018 18:08
by hugejp
FAF264_tech.pdf
(472.45 KiB) Downloaded 84 times

Re: EGT TEMPS ON 4.8 PETROL PATROL

Posted: 16 Oct 2018 18:09
by hugejp
See above! :thumbup:

Re: EGT TEMPS ON 4.8 PETROL PATROL

Posted: 18 Oct 2018 20:25
by Mystical_Beast
So tonight I did some testing, thinking I would drive conservatively just to see what it really looks like at various speeds

At 100 km
100 km.jpg
100 km.jpg (49.56 KiB) Viewed 2589 times
At 120 km
120 km.jpg
120 km.jpg (53.46 KiB) Viewed 2589 times
At 140 km
140 km.jpg
140 km.jpg (54.34 KiB) Viewed 2589 times
at 150 km
150 km.jpg
150 km.jpg (55.28 KiB) Viewed 2589 times
When keeping constant speed with small throttle input it fluctuates between 600 and 650.

Depends if you’re going up or down a hill..

So in light of info supplied I guess my EGT are okay within civilized operation.

Just for fun I did a video of 0 to 100, nothing scientific or controlled but seems around 7 seconds give or take.

Not sure what standard figures should be

https://www.youtube.com/watch?v=Y-JtmwmnR8A