Engine/Transmission (1994 - 1998) HIGH BOOST-Low EGT's Experienced...to good to be true?

[RKraiza]

Question: AT what point will the head gasket/head on my dodge, go into orbit? I just drove up and back from quebec. Truck ran awsome, here's what i experience for most of ther 7 hrs... 25 to 35 lbs boost constantly!. . egt's never over 800*ussualyy ran around 600*,. . speed around 80mph's,. . RPMS around 2200, outside temp -10 to 8 F. above. Want to no if it is safe to run 30#lbs boost for that long a time on a fairly stock truck? NOte: pump is turned up a tad, gauges are correct. thanks for any and all imputOo. ...

 

[pwerwagn]

I dont see how you could make 25-35psi constantly. Mine is way over fueled for the turbo, the turbo spools real quick, and with the cruise on 80 the most boost I see up big hills is maybe 20psi. and thats for a second or two. Flat ground, most I see at any speed (constant speed, not accelerating) is 12 or so psi. Even with the camper/boat in tow, it doesnt sustain that high of boost.

Now, while accelerating, I can hit 45 or so. Havent had any headgasket issues yet, but im sure they will surface soon...

--Jeff

 

[KingS]

yeah while cruising you should only be seeing like 5psi.



If you are seeing that high somthing is wrong.



Now I was pushing 40psi for 2 years and never had an issue except just a small leak at 245,000 or so but that was just wear and tear put stock gasket on drove it more then I put injectors in and timing well good bye head gasket.

 

[RKraiza]

Hey guys, don't beat me up hear, just tellling you what i experienced , and am still experienceing... I really haven't taken the truck on long highway drive since i did the pump and timing(15. 5* advance, 191'd-valves, marine injectors,)... so, this is new. The gauges were acurate. The fuel milage was normal, to improved on this trip. There was little to no smoke. I had to kick the cruise off when accelerating up hills so as not to spin the boost gauge needle past the 35(were the #'s stop). It is a srtock turbo. I do no the waste gate is stuck closed, because the boost would not dump around 30 like it is suppose to. All imput welcome hear... and thanks.

 

[NHays]

If your truck ran at 35psi boost for any length of time you are fixing to have serious problems with the stock HX35 turbo. The stock turbo is not rated for that kind of boost and can come apart, it WILL also start to leak, if it has not already. I have seen comp wheels come apart and shafts break at 35-40psi. I ran my stock turbo once " i forgot to hook the waist gate back up " at 37psi and it popped. I rebuilt it and have it for spare, and I got a SuperB after that. Your head gasket my already be compromised. The general rule on the stock turbo is keep it under 40psi or you will pop the head gasket. The main problem with the stock turbo is not boost, rather the drive pressure, with 40 psi boost, your at around 80-90 psi drive pressure. Correct me if I am wrong here guys. I think the efficiency map for the HX35 is maxed between 28-32psi. Higher than that and it starts make really hot air. Now, on a side note. My neighbor is running his truck at 40 psi and hot rods it. He is not the sharpest nail in the box, but his truck is still holding together. I am just waiting for him to call and need my extra charger..... that will be a fun day..... anyways, hope this helps.

 

[pwerwagn]

Im just curious, how are you sure the gauge is accurate?



I drove home yesterday with your numbers in mind, if I hold 20+psi for any length of time im at 100mph before I know it. If I try to hold 35, I black out lanes, spin tires, etc.



--Jeff

 

[TyThompson]

Just a thought, is your pyro post or pre- turbo?



When I bought my truck, it would hit 38 psi, about 850 degrees max pulling skidsteer uphill. I moved my pyrometer probe to preturbo, and could hit 1450 empty on a flat road. Needless to say I moved the previous owner's "homemade" plate back a little. (For now )

Now I can hit 32 psi, about 1150*.



The boost numbers sound a little high to me, too. At 80, cruising on flat land, (somewhat rare in Colorado) i run about 13-15 psi.

 

[RKraiza]

thanks for getting back guys! i aprecaite. Pyro is preturbo. CT and newengland are fairly hilly. watched closely past couple days. . on highway, around 70-75,1900rpm, cruiseing boost is around 11 to 18lbs. when going up grade, or with heavy weight, cruiseiing is at 20 easily. temp never goes past 1000*When cruiseing 80mph, 2200rpm, boost is 15 to 24 depending on grade. when climbing grade, easily hit 30lbs. experience lower egt's in this range too... ussualy 650 to 900. i did have the pump calibrated annd set on the "hiigh' side when it was redone recently at Metro-deisel. stock plate, marine injectors, 191 dvs, timing 15. 5. thanks again for input... am fxing wastgate soon. .

 

[pwerwagn]

7 hrs... 25 to 35 lbs boost constantly!. .

Were you going uphill for 7 hours? Or were you towing?