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200+mph
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738 Posts
Discussion Starter #1
hi guys

I´m wondering why my EGT is so high, when i´m cruising on the highway it shows about 700-750° Celsius when doing 70-80mph - A/F ratio 14.7-15.8. This is on Shell V-power pump gas

and i can´t do any long highway pulls it always goes over 900° celsius.

what can i do to fix this ? i have a very safe map in the AEM EMS, the ignition numbers on WOT @ 18 psi go from roughly 7.5 - to 15.0 the highest
 

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Boost4fun
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Where is your EGT probe located at? If it´s in one of the runners it´s not soo far off. But an AFR of 15.8 is a lil too lean BTW..
What is your AFR under WOT condition?
 

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200+mph
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738 Posts
Discussion Starter #4
Where is your EGT probe located at? If it´s in one of the runners it´s not soo far off. But an AFR of 15.8 is a lil too lean BTW..
What is your AFR under WOT condition?
here is a picture of where it is, it´s down there on the turbo , right by the exhaust manifold

And thanks Chevyeater


 

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Boost4fun
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Well ok, since it is directly in the turbine housing the EGTs aren´t soooo bad. What is your AFR at WOT?
Try to aim for around 11.5.
What octane rating has your V-Power? Like here in Germany 100 ROZ?
 

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hi guys

I´m wondering why my EGT is so high, when i´m cruising on the highway it shows about 700-750° Celsius when doing 70-80mph - A/F ratio 14.7-15.8. This is on Shell V-power pump gas

and i can´t do any long highway pulls it always goes over 900° celsius.

what can i do to fix this ? i have a very safe map in the AEM EMS, the ignition numbers on WOT @ 18 psi go from roughly 7.5 - to 15.0 the highest
This is not to say that you absolutely don't have some kind of issue, but those numbers are NOT necessarily high. The EGT really IS that temperature under those conditions. I had 6 open-element probes on my header and a GReddy probe in my header collector for about 3 years and as a result have a lot of EGT-monitoring experience. What you report here is exactly what I saw -- running 700+ on at a good cruise speed and going over 900C on 3-gear pulls. My engine is still in good conditon after 5 years of this. Most 'conventional wisdom' about EGT readings is WRONG because the probes aren't in the right place and of the proper type to accurately measure it.

If you move that exact probe to immediately after the turbine outlet, your EGT readings will drop by about 200 C. I did exactly that (moved the probe) and went from seeing 920C indicated on the gauge to NEVER seeing more than 720ish (and usually not more than 700), even after a pull from 20-180 MPH at 30+ PSI, 11.8:1 AFR on the factory ECU that is claimed to give TOO MUCH timing.

With the probe where you have it, you will probably see the maximum EGT readings at high RPM, even compared to a probe in the header runner. The header runner has less exhaust flow per second per area volume, so it may indicate a lower temperature even though it's closer to the cylinder. The EGT will in fact be higher closer to the head, but a thermocouple type gauge will not indicate it to be higher because of the amount of heat that is radiated to the atmosphere via the probe sheath. Only at high velocites and essentially constant exhaust pulses (such as in the collector where all 6 cylinders are feeding in) will the thermocouple type probe indicate close to the actual temperature. I hope this makes sense with the limited explanation, but I was TRYING not to write such a long post... :)
 

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My EGT prove is right where 3 runner's meet up(divided housing) and my EGt's at cruising is around 650-700C and WOT pulls are at 820C, which is pretty safe.
 

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200+mph
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Discussion Starter #8
well i think this is has been fixed, my EGT Shows now max 870° C at WOT in 4th gear

and plus i got more power out of the car by tuning the ignition map better, now i need better tires i´m spinning my 275/40R 18´s through out 3rd gear @ 17 psi

but now i have another problem i have 2 pumps in the car 1 denso and 1 walbro but it seems that one is not working because i keep going lean @ the end of 3rd gear and the upper gears 4th , 5th and 6th. I´ve tried adding fuel in the fuel map but it doesn´t fix the problem. I thought 1 pump was good to 550rwhp max. Could i be maxing out 1 pump on running 16-19 psi ? with my setup ?
 
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