Boost Relief Valve?
Thread Starter
Joined: Jul 2006
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From: Capac MI
Boost Relief Valve?
Hey Guys, I have a question. Whats a Boost Relief Valve? The discription says that it keeps the PCM from seeing 25 PSI but will the stock turbo handle 25 psi? I took the line off the turbo and saw around 20 and i got a little scared. And can you guys talk my dad into getting a chip because right now he dont think he needs one. I think he does saying he just bought a 21 foot Four winns liberator. Everytime it downshifted i tell him he should have a chip in it. But im just kidding that truck handles that boat like nothing. Hes already got Guages air box and a straight piped exhaust. Im also trying to talk him into the 5 inch system with the Down Pipe.
Postmaster
Joined: Sep 2006
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well its a boost eliminator, you put that on you MAP sensor line, so PCM wont defuel when you go over 23# of boost, so we put somthing like Overboost anihilator, and things like that to foul PCM to see max of 19-20psi, you stock turbo its not efficient beyound 25psi, so more you push the faster it will brake, and remember stock turbo has a 2:1 exhaust to drive pressure ration, not good for the motor,
now about the chip
if you dad tows a lot, tell him to get DP tuner, now he will see the Beast in his truck
but tont get him to put 5" exhaust ......to much drone for towing, 4" is plenty,
good luck
now about the chip
if you dad tows a lot, tell him to get DP tuner, now he will see the Beast in his truck
but tont get him to put 5" exhaust ......to much drone for towing, 4" is plenty,
good luck
Post Fiend
Joined: Sep 2006
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From: Millbrook Alabama
Yep I concur with Pete. You only need the OBA(relief valve) if you have a tuner that can fuel the engine enough to spin the turbo to 25PSI. With stock tuning it would just be for looks. the MAP sensor causes our trucks to defuel at 22-23PSI so as not to over tax the turbo. Now the turbo is effcient up to 25PSI but without the OBA you will never get there cause the MAP sensor tells the PCM to defuel it. It is a $25 DIY project to get those extra 2-3PSI of boost, Or you can order one from ITP diesel for ~$40. But unless you have the tuner you wont be able to boost your turbo over about 21 any way.
Postmaster
Joined: Dec 2005
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Have you dad send his PCM out to DP tuner to get a flash. Its a cheap route, and he well see the benefits from it right away.
OverBoost anhilator, you can build one at home depot, or get it premade from ITP. I got the ITP one
.
OverBoost anhilator, you can build one at home depot, or get it premade from ITP. I got the ITP one
.
Thread Starter
Joined: Jul 2006
Posts: 1,328
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From: Capac MI
Yea I found a nice 4 inch Turbo back system. We pulled the boat up a hill and saw a little over 1000 Degrees on the guage and i told him it would be a little cooler with the exhaust so hes thinking about that. But he still thinks that the chip will do absolutly nothing for him but hurt the motor big time. The last owner of the truck had a chip on it with the stock exhaust and no guages and i told him that truck would have blown up a long time ago. I dont know i need my own lol.
Elder User
Joined: Mar 2003
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From: northern Michigan
The 7.3 is used in school busses and larger trucks with a lot higher horse power. When put in the pickups Ford uses the computer to limit the horsepower so they can use lighter duty cheaper driveline parts. You should be able to boost this engine to 400 hp without too much worry on the driveline unless you have a stock automatic transmission. I see no reason for a 5" exhaust unless you are looking at getting into the 700 hp and above stuff. Adding the 4" exhaust to the airbox will give you around a 14% boost in hp and a slight improvement in mileage. Adding a chip with the proper tune will add horsepower and probably gain you another 2 miles per gallon. Just remember a tune for good mileage will not be the same as a tune for towing but the tow tune should also improve fuel consumption over stock and make the truck peppier.
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