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C/K Man

The Inevitable Comparison: GM 6.6 vs. Ford 7.3

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Remember that direct injection is the reason the compression ration could be raised without have to retard timing too much or increasing NOX emissions.  DI is an enabler.  

 

I think the Ford 7.3L will be a big improvement over the current V-10, but it will be interesting to see exactly what kind of power Ford gets out of it.  They still have not said, and the talk of how the engine runs at stoichiometric fuel/air ratios 'all the time' has me wondering.  The interior views of the prototype engine show some good, but some bad too from a performance standpoint.  Since this engine is destined for larger truck applications only, I think it may very well end up like the Ford 6.2L, an engine with little aftermarket high performance support.  I don't see it having the wide applications the LS/LT engines do.  

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7.3 numbers are out. 430 hp @ 5500, 475 lb-ft @ 4000.

 

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Biggest difference to me is the 6 spd vs 10 spd. The HP and Torque numbers are not a big enough difference for my needs. But I'd like a 10 spd

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Posted (edited)

That's true, probably any performance advantage the 7.3 would have over the 6.6 would be attributable to Ford's 10 speed transmission.  I wonder if at some point GM will offer the 10 speed Allison as an option with the 6.6L, but I have a feeling that if the rumors of an 8L+ gas V-8 are true the Allison would certainly be offered with the larger V-8.   

 

Edited by C/K Man

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Disappointing for all that displacement and still revving to 5500 rpm.   

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Noticed the Ford 6.2L continues with the Torq-Shift G 6 speed transmission.  I have been hearing that since the L8T 6.6L is the standard engine in the HD pickups it should be compared to the standard (6.2L) V-8 in the Super Duty pickups, even though it is very close in output to Ford's new 7.3L.  

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I am currently driving an F250 with the new gen 6.2 engine. Just took a trip to the Smokies pulling my TT that weighs in at 9500 lbs loaded. The engine performed great. Locking out 5 & 6 gear going up and down the grades worked like a champ. The engine stayed in it's power band more and I had no trouble keeping pace with traffic and desired speed. 

 

That being said, I'm ready to try out the new GM 6.6 gas engine. For my use which is daily driver, family hauler and towing a camper 8-10 times a year, it should be more than adequate. The Ford 7.3 seems more driven towards people who may tow more frequently (for work or pleasure) or in mountainous terrain, but they may not want the expense of a modern diesel.

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The 6.6 and the 7.3 have virtually identical torque curves as both come in around 400 fr lbs at 1500 rpm.  Other than transmission and axle ratio differences (which Ford is the clear winner) the engines themselves will perform in near identical fashion.  Pretty sad power numbers for a 445 cubic inch V8 that is supposed to be a diesel alternative.  The 7.3 would blow people away in 2005... but not in 2020 and the buzz is more like what the hell Ford.  You build an engine that is 45 cubes larger than its next closest competitor and all it does is 9 ft lbs higher at peak and starts at the same rpm for power lol.  This 7.3 should be at least 550 lb ft to make it any sort of "upgrade" but it's not... no surprise they took so long to release numbers as it would not surprise me that back when GM dropped the L8T's numbers this 7.3 was less than that and it sent Ford scrambling. 

 

The big disappointment for the fleet guys is the derated 360 hp version of the 7.3 for the 450 and up chassis..  It barely beasts the old 3 valve V10 which was like 20 cubic inch smaller lol.  

 

Gm obviously knocked the engine side out of the park here... add the 10 speed now and I don't think much will be said.  Can't wait for the Ike gauntlet test where the Gm truck runs away from the 7.3 Ford lol. 

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1 hour ago, SierraHD17 said:

The 6.6 and the 7.3 have virtually identical torque curves as both come in around 400 fr lbs at 1500 rpm.  Other than transmission and axle ratio differences (which Ford is the clear winner) the engines themselves will perform in near identical fashion.  Pretty sad power numbers for a 445 cubic inch V8 that is supposed to be a diesel alternative.  The 7.3 would blow people away in 2005... but not in 2020 and the buzz is more like what the hell Ford.  You build an engine that is 45 cubes larger than its next closest competitor and all it does is 9 ft lbs higher at peak and starts at the same rpm for power lol.  This 7.3 should be at least 550 lb ft to make it any sort of "upgrade" but it's not... no surprise they took so long to release numbers as it would not surprise me that back when GM dropped the L8T's numbers this 7.3 was less than that and it sent Ford scrambling. 

 

The big disappointment for the fleet guys is the derated 360 hp version of the 7.3 for the 450 and up chassis..  It barely beasts the old 3 valve V10 which was like 20 cubic inch smaller lol.  

 

Gm obviously knocked the engine side out of the park here... add the 10 speed now and I don't think much will be said.  Can't wait for the Ike gauntlet test where the Gm truck runs away from the 7.3 Ford lol. 

Totally agree!  The nail in the coffin will be GM's added 2mpg's across the board in all driving situations.  Only FERD guys gonna pat FERD on the back for this heap!  Sorry, the robustness of the engine is not even close either.  C/KMan hit the nail on the head with his eyes on the internals....exactly!

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Posted (edited)

At least it is geared towards low end power and torque which is what I would want myself... but it is just falling short when on paper it's torque curve is identical to something 45 cubic inches smaller.  With that 10 speed and 4.30 gears it "should" stomp the Ram and the new GM's but that's a time will tell thing.  GM is always lackluster in the axle ratio department so that is no surprise, however in the next year or 2 that 10 speed Ford is using will find its way behind the 6.6 so that will even that out a bit.  

 

The Ford guys are raving ( the real die hards) about this thing but all I see is a Ford LS engine with big displacement lol.  It looks plenty strong inside.. has an LS style skirted block ( which really GM stole from the Ford modulars lol), forged crankshaft and whatnot.. Gm went direct injection and high compression but I am betting as Ford has eluded to this port injected 7.3 will be low 9s for compression or less...  I don't like that myself as compression is efficiency but whatever.. they tested this thing.

 

The Ford guys are spitting venom on anyone hating on the low numbers saying "it's a low rpm truck engine"... Well duh because I haven't heard one real complaint about the 430 horsepower... it's the torque.  And really when it can spin to 5500 rpm ( in part for engine braking, I get it) but peaks power there.. it's not that low lol.  This is a V10 replacement but at 430 hp and 475 lb ft in the heavies.... well the 3 valve V10 was 362 hp and 457 lb ft so ummm beyond physical external package size and less complexity you aren't really doing much more than you were in like 2005...   To be fair the V10 in the 450 and higher was rated at like 288 hp or 310.. sources vary at 4000 rpm but still rated at 424 or 460 lb ft depending on the chassis.  So although the 7.3 is higher at 350/468 in the 450 up chassis you would hope it is having a 15 year and 32 cubic inch advantage on the old V10.  

 

I had high hopes for at least 550 lb ft ( i know.. dreamer right) because then I would be all over a new Tremor Super Duty..... but this?  Meh... If I figure out how to retro an e92 ecm and the new L8T into my 2017 that will do me for years to come lol.

Edited by SierraHD17

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Like I said, IF the Ford 7.3L shows any meaningful advantage over the GM 6.6L, it will be because of Ford's 10 speed transmission.  I hear that currently work is underway on a version of the 6.6L for the new Silverado 4500/5500/6500 medium duties.  It may be teamed with the Allison 2000 series, as the 6.0L L96 is in Freightliner chassis built for UPS and others.  I wouldn't be surprised if it too caries a different rating than the L8T's in the 2500/3500, but remember these differences often are the result of how medium duty commercial vehicle engines are rated, not because of any real difference in the engines.   

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The 6.0 also is going into the Fuso medium duties this year.  The 6.0 is long from dead as a viable working engine.  I am waiting a  couple of years for all the potential bugs to be worked out of the new engine offering in the HD's.  My 2015 2500 6.0 only has about 38,000 miles on it and it more than meets my needs.  It will take something special to get me to give it up and just introducing a new platform and engine is not enough.  I will have to see how it all plays out in the real world first.

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Might as well sell it and use the class 8.

  • Haha 2

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