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So, is the Ferd 7.3 awesome or not?

I didn't mind my ZF6 behind the 7.3 (with 3.73 gears)

I wasn't towing all the time though. Just driving along, it's fine.
 
TRINDU said:
I had an 8.1L ZF6 with 4.10s & 265s and it was kickass and righteous. Worlds better than an allison.

I can only imagine a ZF6 behind a 7.3L gasser would be awesome as well. I keep a lazy eye out for guys parting out SDs for the modular zf6, for that reason.

I like the built 4r100 in my PSD. Prefer my 5600 to my build 48re in my 5.9s.
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We have the aisin's in our 6.7 5500's.

Honestly I'm not a fan. It takes a lot out of an automatic to make me enjoy driving something.

I'm assuming the 7.3 gasser uses the modular bellhousing pattern then? I haven't done much reading on them. Just like the sound of big lazy power over these new whizz bang pop diesels.
 
Pt_Ranger_v8 said:
I didn't mind my ZF6 behind the 7.3 (with 3.73 gears)

I wasn't towing all the time though. Just driving along, it's fine.
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I was planning on srw and 3.55's.

Don't plan on using it for farm shit. Just dd, getting fire wood, towing a jeep on a 28ft trailer around. Mostly flat here in the sticks. Planned on cranking some juice out of the dust covered 7.3 in the barn, too. Were 3.73's easier to find?
 
MuntCuffin said:
Theres an Eaton 6 spd behind a mechanical dt466 out in the driveway.

I love that fuckin' truck.
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Im jealous. Our Es have been real good, three Eaton 6s, but Id love a mechanical. Although the CARB fist of fury makes me forget them real fast.

At least the 8.1L is carb legal :homer:
 
MuntCuffin said:
I was planning on srw and 3.55's.

Don't plan on using it for farm shit. Just dd, getting fire wood, towing a jeep on a 28ft trailer around. Mostly flat here in the sticks. Planned on cranking some juice out of the dust covered 7.3 in the barn, too. Were 3.73's easier to find?
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No clue - came stock :laughing:

If you're swapping axles, throw in the 2008+ F250/350 axles. They're common, and relatively cheap. And come with an e-locker.
 
Wilson said:
Just wait until the plastic roof trim pops loose in the back!
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Yep had that happen in the first week of ownership. Already repaired under warranty. Was told by the service writer it's a common issue. Factory rivets the plastic on with a machine that cracks the plastic mounting tab.
 
Dam. Did you guys watch Harop’s second video. 1015 hp and 981 torque. It’s hitting peak torque at 3800 rpm. With the stock cam and heads
 
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JR4X said:
Dam. Did you guys watch Harop’s second video. 1015 hp and 981 torque and they’re not spinning it over 4600 rpm. It’s hitting peak torque at 3800 rpm. With the stock cam and heads
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Didn't watch the video, but it's impossible for peak power to be bigger than peak torque unless the peak torque RPM is over 5252.
 
77K5 said:
Didn't watch the video, but it's impossible for peak power to be bigger than peak torque unless the peak torque RPM is over 5252.
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Care to expound? I don’t doubt you. Never heard that before, so looking to learn
 
aczlan said:
The formula to determine horsepower is: (Torque X RPM)/5252=Horsepower
as such, horsepower cannot be higher than torque unless the RPMs are higher than 5252.

Aaron Z
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FAKE NEWS Just because you have sound logic and reasoning, does not make it fair to assume it to be correct! Silly math and engineering BS- listen to what you are told. Clearly they stated it was more HP than Tq- accept that and listen to the man.
 
aczlan said:
The formula to determine horsepower is: (Torque X RPM)/5252=Horsepower
as such, horsepower cannot be higher than torque unless the RPMs are higher than 5252.

Aaron Z
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And due to that formula, when you're looking at dyno graphs, you'll notice the torque and horsepower lines always cross each other at the 5252 mark

I'm waiting to see what people really start pulling out of these engines as they get more and more extreme with the modification. Doesn't seem overly popular yet, but looking at some of the numbers I've seen I bet people are going to be having some fun with them
 
Watched the video.
2021-09-26 (2).png
 
Chzbrgr said:
Watched the video.
2021-09-26 (2).png
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I shouldn’t have posted while I was driving. By that screen shot they are going up to 6250. And tq/hp are crossing over right at 5250 just like y’all said.

I did not say that it was making more hp than tq at 3800 rpm. The shock for me was that it’s making 988 tq at 3800 rpm.
 
77K5 said:
Didn't watch the video, but it's impossible for peak power to be bigger than peak torque unless the peak torque RPM is over 5252.
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Are the dyno results complete shit if it shows peak tq at 3800 rpm and peak hp at 6250?
 
DozerDan82 said:
Let me save you some rainy day time- not worth it. The zf6 is garbage behind a 7.3L diesel splits and slow shifts make it annoying to drive in anything but ideal conditions (not start stop) The Low gear is great, but you can not shift into 1st fast enough to maintain the 7.2 mph you can go in low. I swapped one into my F350, then just took it out last year for a semi built 4R100. Worth every penny.
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DozerDan82 said:
From what I can gather, they just kinda added a gear, but split all the other ones to the point it did not really help. Low is LOW, like pull a house down low, but 1 is to high to comp for the added help by the time you get there. 2-3 is short - not enough rpm to make them happy. 3-4 is not bad, but 5 is not high enough for speed, not low enough for not having to down shift.

Some guys love them, I do not miss it one bit. In traffic it was hateful, there was no good gear to just kinda limp along with. Towing it had plenty of umf, as long as you did not mind rowing gears slowly and running them out to their fullest every time.
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110% Agreed. I've got a 6spd ZF6 in my '99 F-350 7.3L. If a built 4R100 weren't so expensive, and the swap more of a pain than it's worth...I'd dump the 6 speed in a heartbeat.

Towing uphill (e.g. the passes here in CO), and you're limited to the gear you're in many times (3rd or 4th), simply because as soon as you go to shift...bye bye boost. It has a hell of a low first gear, but you're doing all of 40-45mph in third.

I'd love to be able to just set it, and go. Getting up to speed? Much easier with the auto given I'm not having to shift through 3 or 4 gears just to get up to 50. It's one reason I will be happy to (one day) move to something like a 2015+ 6.7L.
 
JR4X said:
Are the dyno results complete shit if it shows peak tq at 3800 rpm and peak hp at 6250?
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I didn't say anything about the dyno numbers being shit.

You said they only revved it to 4600, when the real number was more like 6200. That math didn't add up, simple as that. Big difference.
 
JR4X said:
Dam. Did you guys watch Harop’s second video. 1015 hp and 981 torque and they’re not spinning it over 4600 rpm. It’s hitting peak torque at 3800 rpm. With the stock cam and heads
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The marine version is dropping next year, I’m keeping my eyes on it as a replacement for my 460.
 
aczlan said:
The formula to determine horsepower is: (Torque X RPM)/5252=Horsepower
as such, horsepower cannot be higher than torque unless the RPMs are higher than 5252.

Aaron Z
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In case any nerds are wondering where the 5252 comes from;
1hp is defined as 550 lb-ft/s or 33000 lb-ft/min
Torque is rotational while hp is linear. There are 2π radians per revolution
33000/2π = 5252.11 lb-ft-rev/min
 
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Diesels’ dyno results almost always have HP about half of torque, while gassers are closer to each other’s.

1015/981, that’s one fun 7.3 :smokin:
But that’s like 1 mpg at that point? :flipoff2:
 
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