EGT's pre and post turbo

Paccool · 06-26-2007, 01:18 PM

I originally posted this on TDR but also thought this might be of interest to some of you guys.

I have always wondered about what people have said about the difference in the readings before and after the turbo. I had to see for myself. Was hard to believe that the readings could be that different in a span of about 8". I know about expanding gasses and all that but seemed hard to accept that kind of difference. I originally had a direct reading (thermocouple)US Gear pyro located after the turbo and just last week installed a new ISSPRO electronic pyro in the ATS manifold (in front of the turbo) I put on last year. I went on a trip to Washington last Friday and returned Monday. Pulled a 5500 pound load up, came back with an empty trailer at 2250 pounds. Took a series of reading both directions and only took "stable state" readings. some were pulling a grade and some were on flat ground. Found some scary things and thought I'd pass them along.

The direct reading pyro is very slow to respond when compared to the new ISSPRO pyro. I could put the new pyro into the red and then cool back down before the old pyro hardly moved.

Also took readings with the tranny in OD going up a hill. Got the pre turbo temp up to 1200 degrees then shifted out of OD to get the RPM's up a little. Saw an immediate 150 degree drop in the EGT. This alone is a good reason to shift out of OD when towing up a hill!

Here are the readings I took pre and post turbo-at idle the readings were basically the same as the turbo wasn't working at all.

PRE POST TURBO
600 400
700 500
750 550
800 580
875 620
900 640
1000 700
1100 750
1150 800

As you can see, there is a 350 degree difference at the upper end of the scale. Based on this, I would try to keep the post readings at 900 or less if that was the only reading I had. I used to push it to 950 and a little higher when towing which put me up at 1300 degrees. Sure glad I put the new unit on as it is a much more realistic reading!

__________________
Stan

93 D250, PDR Twins HX35&HT3B, 60+# boost,PDR stage 2 head w/o-rings, PDR Cam, modified VE Pump, piston style lift pump, modified 5" intake w/AFE, ATS ported manifold,DTT 89% converter, 4" RIP exhaust, modified tranny, EGT/boost/tranny/tach gauges, TPS removed, a little chrome under the hood. Mag-Hitec tranny and diff. covers. Rear sway bar. Line-x bed liner, after market seats. Front end rebuilt with new springs - 2 " taller now. Single stage Water/Meth system installed. Oversized intercooler w/3" IC lines.

05 Chevy 2500 HD, Duramax W/Allison, 17" Hummer wheels w/285-70-17 BFG's, modified air box, ported turbo mouthpiece. Predator programmer.

BBRam · 06-26-2007, 01:24 PM

Great Post Stan. I believe that info hold's true for all of the Gen's as well. :thumbsup

__________________

03-3500, DRW, QC, 4x4, R850 BD Twins, BD IC Boots, BD Billet Flexplate, Full Billet DTT Trans, Lockup Switch, SMARTY TNT-R / TS MP-8, Wicked Diesels Eliminator Fuel System & Coolant Bypass, Floor It Stage 3 CP3 & Rail Cap, BIG Stix's by FTE, ARP Head Stud's, Springs, Fluidampr, ATS ARC-FLOW, Mag-Hytec, AFE, Boost, Drive Pressure, Pyro, Fuel Pressure, Tran's Temp, Rail Pressure Gauge, GDP Ladder Bars, GrandRock 7" Miters. (R/T .021, 60' 1.76, 1/4 ET 13.03 @ 102.05 mph)

July 2009 Cummins Forum ROTM Winner

95 1500 Sport 2wd Cummins Drag Truck under construction.

"In search of the Magic Dyno"

06-26-2007, 01:18 PM	#1 (permalink)
Paccool Admin Join Date: Nov 2005 Location: NorCal Posts: 3,256 Thanks: 3 Thanked 34 Times in 27 Posts Paccool's Truck Pics	EGT's pre and post turbo I originally posted this on TDR but also thought this might be of interest to some of you guys. I have always wondered about what people have said about the difference in the readings before and after the turbo. I had to see for myself. Was hard to believe that the readings could be that different in a span of about 8". I know about expanding gasses and all that but seemed hard to accept that kind of difference. I originally had a direct reading (thermocouple)US Gear pyro located after the turbo and just last week installed a new ISSPRO electronic pyro in the ATS manifold (in front of the turbo) I put on last year. I went on a trip to Washington last Friday and returned Monday. Pulled a 5500 pound load up, came back with an empty trailer at 2250 pounds. Took a series of reading both directions and only took "stable state" readings. some were pulling a grade and some were on flat ground. Found some scary things and thought I'd pass them along. The direct reading pyro is very slow to respond when compared to the new ISSPRO pyro. I could put the new pyro into the red and then cool back down before the old pyro hardly moved. Also took readings with the tranny in OD going up a hill. Got the pre turbo temp up to 1200 degrees then shifted out of OD to get the RPM's up a little. Saw an immediate 150 degree drop in the EGT. This alone is a good reason to shift out of OD when towing up a hill! Here are the readings I took pre and post turbo-at idle the readings were basically the same as the turbo wasn't working at all. PRE POST TURBO 600 400 700 500 750 550 800 580 875 620 900 640 1000 700 1100 750 1150 800 As you can see, there is a 350 degree difference at the upper end of the scale. Based on this, I would try to keep the post readings at 900 or less if that was the only reading I had. I used to push it to 950 and a little higher when towing which put me up at 1300 degrees. Sure glad I put the new unit on as it is a much more realistic reading! __________________ Stan 93 D250, PDR Twins HX35&HT3B, 60+# boost,PDR stage 2 head w/o-rings, PDR Cam, modified VE Pump, piston style lift pump, modified 5" intake w/AFE, ATS ported manifold,DTT 89% converter, 4" RIP exhaust, modified tranny, EGT/boost/tranny/tach gauges, TPS removed, a little chrome under the hood. Mag-Hitec tranny and diff. covers. Rear sway bar. Line-x bed liner, after market seats. Front end rebuilt with new springs - 2 " taller now. Single stage Water/Meth system installed. Oversized intercooler w/3" IC lines. 05 Chevy 2500 HD, Duramax W/Allison, 17" Hummer wheels w/285-70-17 BFG's, modified air box, ported turbo mouthpiece. Predator programmer.

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06-26-2007, 01:24 PM	#2 (permalink)
BBRam Super Administrator Join Date: Jan 2006 Location: Chelsea MI Posts: 23,419 Thanks: 173 Thanked 248 Times in 162 Posts BBRam's Truck Pics	Great Post Stan. I believe that info hold's true for all of the Gen's as well. :thumbsup __________________ 03-3500, DRW, QC, 4x4, R850 BD Twins, BD IC Boots, BD Billet Flexplate, Full Billet DTT Trans, Lockup Switch, SMARTY TNT-R / TS MP-8, Wicked Diesels Eliminator Fuel System & Coolant Bypass, Floor It Stage 3 CP3 & Rail Cap, BIG Stix's by FTE, ARP Head Stud's, Springs, Fluidampr, ATS ARC-FLOW, Mag-Hytec, AFE, Boost, Drive Pressure, Pyro, Fuel Pressure, Tran's Temp, Rail Pressure Gauge, GDP Ladder Bars, GrandRock 7" Miters. (R/T .021, 60' 1.76, 1/4 ET 13.03 @ 102.05 mph) July 2009 Cummins Forum ROTM Winner 95 1500 Sport 2wd Cummins Drag Truck under construction. "In search of the Magic Dyno"