300 HP 6.9

Laine D

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I am interested in your guys’ opinions. I have put about 10k on my 6.9 since it was rebuilt and am now slowly starting to upgrade it. I am curious if 300 horsepower is out of the question for a 6.9. It will be intercooled, already studded, and am thinking about running a Borg Warner s257 or larger.
 

FrozenMerc

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The motor will handle 300 hp no problem. Quite a few builds on here at or exceeding that power level. Heck, Banks advertises 260 Hp with his Sidewinder Turbo kit and using the stock injector pump. That said, I don't think you will be able to clear the 300 hp mark with the stock Injection Pump, though. Search some of the engine builds on here by TheWesPaul at Classic Diesel Designs for more info and specs
 
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Laine D

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The motor will handle 300 hp no problem. Quite a few builds on here that power level. Heck, Banks advertises 260 Hp with his Sidewinder Turbo kit and using the stock injector pump. I don't think you will be able to clear the 300 hp mark with the stock Injection Pump, though. Search some of the engine builds on here by TheWesPaul at Classic Diesel Designs for more info and specs
Right after I wrote this I have him a call. He cleared up a lot of stuff I had been wondering about.
 

rhkcommander

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Fuel was always the limit on these engines. That and the heads lifting under boost but studs and turbo cam help cure that. Slap on an ip and what you plan on and you're probably set.
 

Laine D

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Fuel was always the limit on these engines. That and the heads lifting under boost but studs and turbo cam help cure that. Slap on an ip and what you plan on and you're probably set.
I’d be happy if the truck could get on the freeway faster than a vw bug haha
 

FrozenMerc

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Getting on the free way is no problem with mine. 8 forward gears and the 4.56 rear end allow it to get moving just fine. I just wish I could climb a hill with the trailer on the back with out down shifting 4 times and cresting the top at 38 mph while flat on the floor and turning the side of the trailer black. But the Turbo I just ordered from CDD should help with that problem.
 

Laine D

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Getting on the free way is no problem with mine. 8 forward gears and the 4.56 rear end allow it to get moving just fine. I just wish I could climb a hill with the trailer on the back with out down shifting 4 times and cresting the top at 38 mph while flat on the floor and turning the side of the trailer black. But the Turbo I just ordered from CDD should help with that problem.
It will for sure. I’m on the opposite end from you. 5 speed with 35’s and 3.55’s. Great for staying at 75-80. Terrible at getting there..
 

Oledirtypearl86

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My 86 I have a top speed of like 60 with a t19 but I can pull anything I have a hypermax turbo a maxed out up and run like 14 psi of boost and I'll hold grades in 4th gear and I tow my 34 foot 5th wheel no problem
 

chris142

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I’d be happy if the truck could get on the freeway faster than a vw bug haha
Where is your timing at? Mine was -2atdc and the truck was a real ****. Advancing it to 6-8btdc made a huge difference.
 

Macrobb

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My own 2c - With a stock pump and turbo kit(any), you are looking around ~200 HP at the wheels max. That's probably 260-270 at the crank, which is about what Banks advertises.

You'll probably need an upgraded IP if you want more than that; plain and simple. RD2-110 will net you 250 RWHP with a kit turbo, and probably around 300 RWHP with a better turbo setup(CDD, R&D etc).


Personally, my DD's just got a worn IDIT motor, WW2, stock pump cranked, 4.10s and a 5-speed with GVOD... she probably makes around 180 RWHP.
It's both plenty and not enough - towing a 3K lb flatbed yesterday at 70MPH, I'd go between double OD(equivalent to 5th with 3.55s) and OD; maintaining 70 wasn't too hard.
Towing a decent load back(I'm thinking about 7K on that trailer, so total of 10K), I was in single OD, and had to downshift to 4th occasionally on hills. Maintaining 60 was easy, 70 was really pushing it(~900-1K EGTs in 5th at like 2500 RPM on flat-ish ground).

I've also towed ~14K behind me; it takes a bit to get to 60, but is very easy in the 0-40 range for back roads.
It's very much one of those things where once you get to speed, it's not hard to maintain, but going from a stop requires winding her out in every gear.
 
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