Boost & Fuel Adjustment Advice

Lug Nut

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I need some advice on safe boost pressure and how many flats I can turn my pump up. Truck specs below.

93 F250 7.3 Factory Turbo, ZF5, Hypermax Intake, 4.5" exhaust, wicked wheel II in turbo. Truck has 165K original miles and motor is stock with stock lift pump. Just installed new (rebuilt) DB2 - 5069 pump.

Keep in mind my elevation is 5000 FT in and around Albuquerque and I live at about 7200 FT. I don't tow much but want the ability to tow around 8000 lbs should I need to use my car hauler without burning the truck to the ground.
 

DrCharles

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If you don't have a pyrometer, that should be the next thing you do BEFORE turning up the pump! Otherwise your pistons might be -Flame Thrand you won't know it until they fail...

Lots of discussion on here as to how much boost, what EGT is safe and for how long :)
 

DrCharles

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Glad to hear that. Now just do a search for "7.3 idi turbo kit" or something like that, and there are many discussions found... Basically if your 7.3 is stock, you don't want to go over 10 lbs boost before head gaskets are going to be a problem and studs will be needed. I think EGT is the next wall you'll hit but I will let people more experienced with IDI's than me to weigh in here.

Proceed with caution. Changing head gaskets is a PITA, but changing a burned piston is more of one!
 

Thewespaul

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1200* is the max egt. 15 psi is pushing your luck on stock head bolts. If I was tuning your truck I would set it with about 12 psi and shoot for around 1000*

Done that setup on many trucks and yet to have an issue.
 

79jasper

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Honestly at your elevation, a intercooler is a must.
And/or water injection would be great.

Sent from my SM-G892A using Tapatalk
 

Lug Nut

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Thanks for all the input, I appreciate it. How about turning up the fuel, how many flats is acceptable ? I've heard 2 but no more then 3. Does that sound about right ?
 

Thewespaul

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Well it really depends on the condition and wear on your pump, even if it was recently rebuilt it could have a worn head and rotor and not put out as much fuel as the next pump. I would go two flats at first then adjust to your liking after that.
 

Macrobb

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At 2K feet, the answer is "all of it". At higher RPMs(2200+), I've been able to use everything a stock pump can output, and more. 5K... I don't know. May be different, or it may be fine.

Basically, watch for smoke. If you are smoking black at WOT and full boost, that's too much fuel. You can have the fuel screw cranked too much and as long as you are careful with the pedal, you are fine.

You'll find that EGTs follow smoke - no smoke, and the EGTs will stay sane. Start smoking, and the EGTs will start climbing dangerously.
 

catbird7

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I don't have studs, run 8psi because I was told that was factory setting on these engines and figured it would be safe. Also, I back out of the throttle @1000 degrees. Note, it's just as important to properly locate probe for pyro. You want it as close to the piston as possible. Most drill & tap manifold. Mine is located on driver side. X2 on the "smoking = climbing EGTs". Another negative on the smoking, the more it smokes the worse your fuel mileage will be.
 

pelky350

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Tuning and fuel rate are a contributing factor into head gasket failure, running over advanced timing with tons of fuel could kill gaskets even at "safe" boost pressures. 20 psi of boost with not so much fuel and timing set down at like 5-6 for example would have similar cylinder pressures to say 8-9 at 12-15psi with heavier amounts of fuel. Not scientific numbers but just a example of what I'm explaining
 

Macrobb

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Just for reference, I'm pushing about 12-13 with my factory kit and a rd2-110, it's cleaning up, and I haven't blown a gasket yet(it's coming up on a year). I expected to blow one, considering I overheated the engine last February and the gaskets have weeped coolant occasionally ever since..... and it's a 1988 long block under it that doesn't look to have been apart...

Oh, and I tow with it often enough, I use all that power... and I still haven't gotten around to putting an EGT probe on it...
(Other rigs of mine have egt gauges, so I'm experienced in what I expect them to be.)
 

Lug Nut

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My EGT is on the manifold. Sounds like to be safe I probably shouldn't push more then 10 PSI with about 2 - 3 flats max. That should give me a good starting point with some minor tweaks from there.
 

03wr250f

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I would agree with the intercooler as well. I havent dealt too much with a turbo idi at elevations like that, but I know egts with my na at 9000' were insane. keeping 70 mph i was right around 1150*. That would be my only thing is drive by the pyro, as previously said.
 

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