300 HP 6.9

[Thewespaul]

Overtorqued 6.9 head studs are suppling more clamping force than regular 7.3 head bolts, the math doesn’t add up here if you’re having guys pop gaskets at those low of boost numbers yet we’re running in the 20s on stock 7.3s, maybe there’s something wrong done in the assembly like the surfaces not being properly cleaned. The T19 doesn’t have a big clutch option like the 13” south bend we run on the zf5s, like you said most guys making good power are running a five speed because of the better clutch options and cruising rpms. I had a customer in New Mexico running a 130 pump on a 6.9 doing frequent towing and no issues with a drop in turbo upgrade. Both that truck and this stock 7.3 we’re pushing to 300 is intercooled, are any of those 6.9s intercooled? That’s going to make a big difference in intake temp and cylinder pressure. If someone wanted to make big power on a 6.9 a 625 arp stud kit could be put together to increase the clamping force and be pretty close to a studded 7.3. Believe me the 7.3 turbo engines are my preference for reliable IDI power, but I don’t think it’s outside the realm of possibility to build a 300hp 6.9 which was the original question, reliability can be debated but that’s only as good as the quality of the engine build and the parts used.

 

[Laine D]

Overtorqued 6.9 head studs are suppling more clamping force than regular 7.3 head bolts, the math doesn’t add up here if you’re having guys pop gaskets at those low of boost numbers yet we’re running in the 20s on stock 7.3s, maybe there’s something wrong done in the assembly like the surfaces not being properly cleaned. The T19 doesn’t have a big clutch option like the 13” south bend we run on the zf5s, like you said most guys making good power are running a five speed because of the better clutch options and cruising rpms. I had a customer in New Mexico running a 130 pump on a 6.9 doing frequent towing and no issues with a drop in turbo upgrade. Both that truck and this stock 7.3 we’re pushing to 300 is intercooled, are any of those 6.9s intercooled? That’s going to make a big difference in intake temp and cylinder pressure. If someone wanted to make big power on a 6.9 a 625 arp stud kit could be put together to increase the clamping force and be pretty close to a studded 7.3. Believe me the 7.3 turbo engines are my preference for reliable IDI power, but I don’t think it’s outside the realm of possibility to build a 300hp 6.9 which was the original question, reliability can be debated but that’s only as good as the quality of the engine build and the parts used.

I don’t NEED 300 hp, it would just be cool.

 

[Scotty4]

I don’t NEED 300 hp, it would just be cool.

Better to have it and not need it than need it and not have it. Applies here right?

 

[Laine D]

Better to have it and not need it than need it and not have it. Applies here right?

definitely

 

[CBRF3]

okay the issue also becomes the combustion pressures in a tight space 6.9 vs 7.3 there is more chamber for it to expand in the 7.3 before it lifts the head a old school trick I learned over years dealing with these motors is take a 7.3 sleeve it to a 6.9 and stud it use modified 7.3 powerstroke rods also delete the glow plugs and plug theyre holes if you do not your playing Russian roulette then shave 15 thousands off the pistons you have now got yourself down to 17.5:1-18:1 compression now you can run around 22psi boost safely I pushed 25psi for a few years on 1 towing daily the reason for the glow plug delete is because of a issue where when you get into higher boost the flame front in the swirl cup gets to hot and will melt the tip of the glow plug and drop it into the engine and stick in a piston and eventually blow a hole in a piston.

with just these few mods and a cam like R&D idi cam ( which has good top end weak low end ) hince why am looking to try TYP4's torque cam add a HX35 / HX40 i like the specialty one from turbo labs america ( The HX40 Super 40 )

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combo with a 3-4 inch down pipe to free flowing exhaust and custom up pipe to t3 mount and add a intercooler and you got a monster and simply weld a 3-4 inch 45 elbow onto the factory intake and you got yourself a easy 300+ hp setup even with a stock turned up turbo version injection pump you should be right at that 300hp mark.

I forgot to add there is a set of rings from hasting for the 6.9 engine that are the tight gap unlike the 7.3 https://apaengineering.net/HastingsCatalog/Home/partdetail/1420 same ring gap for both 1st and 2nd ring so the blowby issues are pretty much gone.

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that is a 4 inch aluminum elbow off a big rig cut down after cutting cross section out of intake then welding it into the factory intake this is on my old NA 6.9 F350 dually farm truck with over 1 million miles on it and that motor is tired now after all the years of abuse but it will still pull anything i want to even if it drinks 2-3 quarts of oil every 2000 miles and has enough blowby to scare you that motor is about to be replaced got a big motor am building that will be up there on power and using that HX40 super turbo from turbo labs america and hopefully a TYP4 torque cam.

 

[Thewespaul]

Glow plugs breaking off is an issue with the quality of the glow plugs not fuel related, I’ve had the same set of glow plugs in the shop truck for the past three engines running 150cc+ and enough nitrous to shatter idit pistons, glow plugs are still fine. I see your point about the smaller displacement leaning towards higher cylinder pressure at the same power level as a 7.3, but the 6.9 also has more deck surface than a 7.3 between the bores and coolant ports because of that smaller bore, so arguably it will hold the gasket better than the 7.3 because of that if you’re counting pennies.

and happy 6/9 day!