Disappiontment In The Mountains

[DragRag]

I had an intercooler on my last truck with a waste gated ats. The truck was unstoppable, and egt's easily kept in check. Reading the OP's comments about only 5lbs of boost makes me think there is now way enough fuel being moved. At w.o.t. He should be getting 10+. You want power? Add fuel. You want low egt's, add an intercooler, and then don't look back. Been there, lived that.

 

[dunk]

Sounds like an intercooler is required on these trucks. Unless variables between turbos make some run well with lower EGT and still hold speed. Mine is an early Banks non wastegate setup. How does the turbo affect EGT if at all? Does exhaust housing size and wheel affect it? Wastegate or not make a difference? If mine could sit at 10+ psi hard into the pump and hold a reasonable EGT it would likely be slow but tolerable. I'm tempted to bump another degree of timing because on the cold advance the truck actually feels quick, but I'm worried about glow plug damage if I do.

I do appreciate the scenery at 35 MPH comment. lol Definitely more time to take in the sights. Hypermax kits are expensive and wouldn't be a direct drop in since I have a Banks. Any improvements for me are on hold until I get a ZF5 as that may require me to end up with a totally different turbo setup and if I'm pulling the trans I may do head studs at the same time and new gaskets and seals for any leaks. I just want this truck to pull somewhere near as well as my 460 does. Don't care if it's not a hot rod barking 35's on the 3-4 shift, 35 MPH up hills is not cool.

 

[david85]

I don't have first hand experience with an intercooler a 6.9 or 7.3 IDI, but my sister's diesel ranger is indirect injected (1985 mitusbishi 2.3L). After I added the intercooler, it did make a noticeable difference and I didn't turn the fuel up either. Boost is still limited to less than 14 PSI due to the OEM blow off valve in the intake manifold. It made me a believer in intercooling even at relatively low boost pressures.

 

[jayro88]

I have heard it can make a real difference in both power and the ability to use it. Keeps your EGT's down while working it hard and allows you to turn up the fuel more. End up making more power at slightly lower boost levels as well.

 

[Agnem]

Our F-350 CC dually will pull our 30' 5th wheel up Sideling Hill with a basic stock turbo pump, stock injectors, Hypermax turbo, Hypermax intercooler and Gearvendors overdrive with ZF-5 speed, and 4.10 rear at 55 MPH @1800 RPM, 5 PSI of boost, with egt's of about 1000-1100 for as long as the water temps will hold out. Being up against the governor doesn't help you when your way out of the torque band. Max torque is 1400-1800 in my experience and that's where you want your hard pulls to happen. It's torque that flattens mountains, not horsepower.

 

[laserjock]

Thanks for that data point Mel. Thats a grade I am very familiar with. How do you fare on Big Savage near the continental divide? If your truck will pull that camper up that hill, I feel pretty good about the combination I'm planning and a sizable camper.

 

[Black dawg]

Our F-350 CC dually will pull our 30' 5th wheel up Sideling Hill with a basic stock turbo pump, stock injectors, Hypermax turbo, Hypermax intercooler and Gearvendors overdrive with ZF-5 speed, and 4.10 rear at 55 MPH @1800 RPM, 5 PSI of boost, with egt's of about 1000-1100 for as long as the water temps will hold out. Being up against the governor doesn't help you when your way out of the torque band. Max torque is 1400-1800 in my experience and that's where you want your hard pulls to happen. It's torque that flattens mountains, not horsepower.

I agree, and have noticed that I can hit a big hill with the truck running hard at 2500 ish, and it will lose speed until it drops to around 2k, then it will hold, until coolant temps get out of hand. I can hit that same hill at 2k and never lose speed.

 

[Greg5OH]

i dont like this "coolant temps get out of hand" buinsess im reading from a few members. Perhaps some secondary electric fans are needed? Id like to use all the power the engine has under whatever contitions it is put under and not have to worry about overheating. Is that too much to ask of an idi becuase of its natur?

 

[dunk]

I don't have a real temp gauge on mine yet but it hasn't got to overheat range on the factory gauge when towing uphill. Can definitely feel it on an incline when the fan clutch locks up, speed decreases more rapidly, and the cool air coming through the kick panel vents gets warm. I've never had reason to be concerned about overheating or boiling the coolant, gauge pretty much stays stable once it's up to temp but I don't tow real heavy. One of these days I'll get a real gauge on it and see exactly what it's doing.

 

[snicklas]

The cooling system is part of it, but Gary has done some extensive comparison, between the 6.9 and the 7.3. One issue with cooling is in the 7.3 there is a cooling passage for the head that has a freeze plug in it on the head, and block. One the 6.9 this passage is open. This is the only difference between the heads, the 6.9 gasket has an opening for this passage the 7.3 doesn't. Many have seen here the 6.9 is much easier to keep cool than a 7.3. I think it was Farmer Frank that just did a transplant in his slantnose from a 6.9 to 7.3 and was asking about temps the first day he drove it. I know several members that have upgraded radiators to help pull heat out of the radiator, and there is where some have settled on the aluminum radiators. The 7.3 is just harder to keep cool, guys have been battling this since they started to "turn them up". I know that Travis struggled with this on the Enterprise, and had more that 1 radiator built, and finally got one that would keep it cool towing up Jellico, to the point he was on the phone with the shop owner when he hit to bottom of the mountain........ It worked, but took a few tries, and it was a huge radiator (Copper).

I even remember a story of a guy that could make any 6.9 run like the wind.... but would not touch a 7.3...... maybe the same issue.

 

[icanfixall]

There is a lot of reasons for the 7.3 running hotter than the 6.9. Mainly its the closed off coolant passages in the block and heads. Then you really need to know what the radiator design is. From my investigations originally our 7.3 radiator was a 4 row with 15 or 16 fins per inch of tube. Then some engineer came out with a "new design" of less rows but dimple them. So as the coolant drops down the turbes it drops slower giving up more of the heat. Well that sure didn't work in the real world plus having 12 fins per inch is a joke... I tried it from Oklamhoma City drive to home in cali. Less rows of tubes and less fins per inch did not work well at all. I had a custom 5 row made up and it worked fine but. I added more hest and needed more cooling. So I purchased the Rodney Red. It has 15 fins per inch of tube and only has 2 rows of tubes but.... Those tubes are 1 1/4 inch wide. Being all welded aluminum and the best aluminum radiator money can buy says plenty about it. I believe maybe 6 members here have this very expensive radiator. Typ4 just got the best deal on a very slightly used Rodney that I was looking closely at buying. I don't need another Red but for the price it was a no brainer. I keep telling myself when I break open my now engine it will get a typ4 cam and the 6.9 head gaskets plus open up the plugged coolant ports. If all this runs the engine too cool I can always block off some of the radiator for the non pulling drives. I also really need to install my Hypermax turbo intercooler. Thats been sitting here for too many years. I need 220 in my shop and a tig welder capable of welding aluminum. My Hypermax intake hat wont fit my Banks turbo. In closing please know what you have and check what your buying for rows of tubes and fins per inch. Otherwise your probably going to be upset cause you still run hot.

 

[FordGuy100]

Torque is rotational force. HP is power over time. You can put a 10' cheater bar on the pinion nut and hang off of it and make 2000+ ft lbs, but it won't go fast. Fact is pulling a grade requires a certain amount of work, and dropping a gear helps multiply torque power output, to pull said grade.

500ft lbs in direct with 4.00 gears creates 2000 ft lbs at the wheels. 350ft lbs at 1.5:1 (say 3rd) and 4.00 gears makes 2100 ft lbs.

 

[david85]

Are there any photos or diagrams showing the difference between the cooling passages between the 6.9 and 7.3 style heads? I've heard of the difference before but never got much on specifics. This is also the first I've heard that the block casting is different too. Interesting.

 

[vegas39]

i dont like this "coolant temps get out of hand" buinsess im reading from a few members. Perhaps some secondary electric fans are needed? Id like to use all the power the engine has under whatever contitions it is put under and not have to worry about overheating. Is that too much to ask of an idi becuase of its natur?

Between my two trucks, my 6.9 never had heating issues, even with the timing advanced and old original radiator.
My 7.3 however was a different story, always ran hot, even with a new radiator.

My cure for the quick heating on the 7.3, was to retard the timing a bit and also turn down the fuel and what a big difference that made. Towards the end of summer when it was still hot out, I could lay into some pretty heavy grades and stay pretty well in the 215 degree range or lower. With my timing advanced and fuel turned up, I was hitting near 230.

Funny thing is, I must have found the perfect fuel-timing combo, because I have almost zero smoke and less rattle but the power is great, even on steep grades.

 

[TahoeTom]

Here is a 6.9 head.
Edit: Picture is big, to view entire pic right click on picture then select view image.