2 pyros

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2 pyros

Postby spencerdiesel » Sat Dec 26, 2015 2:58 pm

I read on a psd forum where a guy wanted to put the pre vs post bickering to rest. He put one probe in the mani, and the other in the up pipe.

Under WOT, he said there was as much as 500 degrees variance between the two readings. Obviously the higher the EGT, the greater the temp difference will be.

But has anyone run 2 pyros? Maybe hold 950 post turbo and see if it really does read 1250 pre turbo as well?
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
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Re: 2 pyros

Postby BC847 » Sat Dec 26, 2015 6:36 pm

Understand the difference between the two readings (PRE-turbo, and POST-turbo).

- The turbo-charger is powered by the otherwise wasted heat of combustion sent out the exhaust manifold.

The temperature drop represents that energy of the exhaust gasses, that the turbine is consuming in order to power the compressor. (Turbine spins the compressor = Turbo-charger).

Example: 1200*F PRE-turbo. 900*F POST-turbo.
The 300*F drop is the energy spent powering the turbo-charger.

The 300*F is typical, and may vary pending the loading, fueling, etc of the engine, as well as the turbine and compressor wheel designs, as well as the turbine and compressor housings.
David

1993 12mm VE Fueled W250 CC, Green
12.67 @ 103.35
Your basic farm truck ;)
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Re: 2 pyros

Postby spencerdiesel » Sat Dec 26, 2015 6:48 pm

Thanks for making that clearer for me BC
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
Muffler delete

Minimum 60% WMO full time since Sep. 2018
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Re: 2 pyros

Postby BC847 » Sat Dec 26, 2015 6:57 pm

The powering of turbines, in general has been / is constantly been death to death. Especially in the prime-mover / power industry (nuclear / fossil fuel electric power generation for example). It's a regular thing to have multiple stages of turbines that make use of the expanding steam (exhaust gasses in our case), some even including inter-stage reheating. It's common to find the final turbine playing into a water cooled condenser that actually develops a vacuum pulling on the outlet of said final turbine.

Image
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1993 12mm VE Fueled W250 CC, Green
12.67 @ 103.35
Your basic farm truck ;)
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Re: 2 pyros

Postby spencerdiesel » Sat Dec 26, 2015 11:19 pm

Thanks again sir. Reading through some Diesel power mag website articles, found:

"The Duramax 6.6L in GM pickups.....has a limit of 1,365 (deg. F) continuous, with 1,435 allowed for transients of five minutes or less." Information gathered from engine builders for 2006 year model engines.

A less conclusive (a number not specifically given from the engine manufacturer) estimate for P pump and later Cummins engines:

"Based on production engine indications and aftermarket experience-read wreckage, it appears that 1,350 is a safe number for P7100 and later engines."

Just trivial info for people who like numbers like me
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
Muffler delete

Minimum 60% WMO full time since Sep. 2018
spencerdiesel
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Re: 2 pyros

Postby fatty » Sun Dec 27, 2015 1:29 am

spencerdiesel wrote:Thanks again sir. Reading through some Diesel power mag website articles, found:

"The Duramax 6.6L in GM pickups.....has a limit of 1,365 (deg. F) continuous, with 1,435 allowed for transients of five minutes or less." Information gathered from engine builders for 2006 year model engines.

A less conclusive (a number not specifically given from the engine manufacturer) estimate for P pump and later Cummins engines:

"Based on production engine indications and aftermarket experience-read wreckage, it appears that 1,350 is a safe number for P7100 and later engines."

Just trivial info for people who like numbers like me

I've always heard 1250f continuous for 12 valves but I have never seen anything official. I know first hand they can handle 2k+ for a couple seconds
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Re: 2 pyros

Postby spencerdiesel » Sun Dec 27, 2015 11:30 am

Agreed, I've heard the same as well from just about everywhere. My rig will see no higher than 1250 as far as sustained goes. How fast were you headed down the road to see 2k :P
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
Muffler delete

Minimum 60% WMO full time since Sep. 2018
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Re: 2 pyros

Postby fatty » Sun Dec 27, 2015 12:45 pm

I wasn't on the road, I have more sense than that. I was goofing around in a snowy parking lot in 4wd.
91.5 w250
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Re: 2 pyros

Postby DMan1198 » Sun Dec 27, 2015 12:58 pm

I marshmallowed the turbine wheel on my he351ve on my 6.7 with 1900*+ egts held for more than a few seconds (maxed out at 3200rpm and 200km/h, but it'd hit 1900 well before then) my most recent run to 3200rpm (somewhere just over 200km/h because I have bigger tires now) netted 1300* max though
Ducati- professional nap taker, and thread derailer extraordinaire
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The Roo Hunter: 93 w250, lifted, 2 whistle machines, and a bunch of other go fast goodies, uhh..... not there yet
Jaeger: 12 ram 3500. Lifted, exhausted, and fed an excessive quantity of air
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Re: 2 pyros

Postby spencerdiesel » Sun Dec 27, 2015 1:26 pm

Snow's more fun anyways. Dman you'd make a great sled puller, no letting out there :twisted:
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
Muffler delete

Minimum 60% WMO full time since Sep. 2018
spencerdiesel
14mm rotor
 
Posts: 1073
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Re: 2 pyros

Postby DMan1198 » Sun Dec 27, 2015 4:23 pm

I did it without a pyro a couple times as well. That truck has definitely been through some stuff.
Ducati- professional nap taker, and thread derailer extraordinaire
Brownie: 80 dodge heavy half. Ghost cummins under the hood, and some sinister plans
The Roo Hunter: 93 w250, lifted, 2 whistle machines, and a bunch of other go fast goodies, uhh..... not there yet
Jaeger: 12 ram 3500. Lifted, exhausted, and fed an excessive quantity of air
The Huntress: 02 Jetta TDI. No muffler, egr, horsepower
DMan1198
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Re: 2 pyros

Postby spencerdiesel » Sun Dec 27, 2015 4:49 pm

One of my friends regularly grosses 22k with his W350. Not cranked on too hard but 2 turns on the screw, fuel pin, 3200 spring etc and no pyro. I probably wouldn't sleep too great at night, but I'm pretty good at worrying too.
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
Muffler delete

Minimum 60% WMO full time since Sep. 2018
spencerdiesel
14mm rotor
 
Posts: 1073
Joined: Tue Oct 27, 2015 4:02 pm
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Re: 2 pyros

Postby Deathrod » Thu Dec 31, 2015 8:23 am

ill throw in my 2 cents, aluminum melts around 1250*, I believe thats why people always give that temp as a sustained max. If i had an aluminum head duramax i think i would stick to 1250. All motors can probably handle breif stints of excessive heat because you are not heat soaking the parts.
1930 Model A, 91 non i/c, he351ve over ht3b, bagged all around, mostly built 47rh, 72 lpm sticks, 600hp/1400 ft lbs (cummins math), just needs traction
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Re: 2 pyros

Postby BC847 » Thu Dec 31, 2015 2:00 pm

In the long run, there can be cumulative effects. Potential stress-risers as a result of the quick, uneven thermal cycling.

I'm doomed. DOOMED, I say!
David

1993 12mm VE Fueled W250 CC, Green
12.67 @ 103.35
Your basic farm truck ;)
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Re: 2 pyros

Postby RCCUMMINS89 » Thu Dec 31, 2015 4:31 pm

Very well may be why cr break rings so much. I know mine will hit 1800 within 1-2 seconds of wot. I agree with that eventually causing things to crack, etc.....
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
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