Jump to content

The Ford Order Tracking System Is No Longer Available.  THANKS Cyberdman For Making Available All Of These Past Years.  More Here.

Stray Kat

The New 6.8L V8 Thread

Recommended Posts

23 minutes ago, 30 OTT 6 said:

Looks like a lot more complication and cost for a fuel economy bump no one will ever notice.


Its more about the $3K (just guessing) premium they can now charge for the 7.3L.

Share this post


Link to post
Share on other sites
57 minutes ago, akirby said:


Its more about the $3K (just guessing) premium they can now charge for the 7.3L.

 

The 7.3 was already a $1700 up-charge over the 6.2, so what's another grand?

 

HRG 

7.3 upcharge.JPG

Share this post


Link to post
Share on other sites

Looks like the math is off slightly!

bore and stroke of 4.22 X3.68 gets you to 411.76 cubic inches not 415!

The 3.68 might actually be 3.70 or about 94 mm.

However, if we use metric 107.2 X 94 we get to. 6.787 liters or 414 cubic inches

Makes me wonder if the 3.68 and 415 are mis prints?????

edselford

Share this post


Link to post
Share on other sites
56 minutes ago, edselford said:

Looks like the math is off slightly!

bore and stroke of 4.22 X3.68 gets you to 411.76 cubic inches not 415!

The 3.68 might actually be 3.70 or about 94 mm.

However, if we use metric 107.2 X 94 we get to. 6.787 liters or 414 cubic inches

Makes me wonder if the 3.68 and 415 are mis prints?????

edselford

Seems to be a problem with Ford marketing. They also list the current 5.0L Coyote as a 302 CID, not the mathematically correct 307.

Share this post


Link to post
Share on other sites
1 hour ago, 30 OTT 6 said:

They also list the current 5.0L Coyote as a 302 CID, not the mathematically correct 307.


Thats on purpose…..

 

The old “5.0” was really a 4.9…..

Share this post


Link to post
Share on other sites

Yep, Ford has a history of fudging the liter number for marketing reasons. 5.0 v8 must be better than a 4.9 6 cylinder, it's .1 bigger!

Share this post


Link to post
Share on other sites
1 hour ago, akirby said:


Thats on purpose…..

 

The old “5.0” was really a 4.9…..

 

Gen 1 and 2 Coyotes actually were 302ci.  

 

Gen 3 and 4 are 307

Share this post


Link to post
Share on other sites
33 minutes ago, ESP08 said:

 

Gen 1 and 2 Coyotes actually were 302ci.  

 


As was the original 302.  302 ci = 4.94L.

 

307 = 5.03L.

Share this post


Link to post
Share on other sites

Splitting hairs but technically both of the Coyotes round to 5.0 liters  

 

302W (4.000 bore x 3.000 stroke):   301.6 ci - 4942cc 

Gen 1/2 5.0 Coyote (3.6299 bore x 3.6496 stroke):  302.2 ci - 4951cc 

Gen 3/4 5.0 Coyote  (3.6614 bore x 3.6496 stroke):  307.4 ci - 5038cc    

 

 

Edited by ESP08

Share this post


Link to post
Share on other sites

Since the 6.8 is roughly 10% more capacity than the 6.2, does that mean the torque and horsepower could be 10% more?

That would mean the 6.8 could have 420 hp and 470 lb ft, enough to pip the GM 6.6 L8T’s 401 hp 464 lb ft.

 

GM L8T

 

image.jpeg

image.jpeg

Share this post


Link to post
Share on other sites
1 hour ago, ESP08 said:

Splitting hairs but technically both of the Coyotes round to 5.0 liters  

 

302W (4.000 bore x 3.000 stroke):   301.6 ci - 4942cc 

Gen 1/2 5.0 Coyote (3.6299 bore x 3.6496 stroke):  302.2 ci - 4951cc 

Gen 3/4 5.0 Coyote  (3.6614 bore x 3.6496 stroke):  307.4 ci - 5038cc    

 

 

 

And the larger bore of the gen 3/4 was made possible by the switch to PTWA cylinder coating in lieu of steel liners.

 

I believe I read in some of the coverage of the 2024 Mustang that the Mustang's version of the Coyote was adopting the "bottom end" of the truck version meaning the crankcase design. They were touting the switch to a steel oil pan. I assume that also includes the belt driven oil pump but they didn't actually say that. The old crank driven oil pump design was the weak link, especially when adding forced induction. The "fix" was to replace the cast factory pump gears and housing with aftermarket billet parts. When the 2021 F-150's 5.0L was introduced the Ford engineers made a point of the fact that the new belt driven pump had been tested to withstand up to 1000 hp output.

 

 

Share this post


Link to post
Share on other sites
4 hours ago, Captainp4 said:

Yep, Ford has a history of fudging the liter number for marketing reasons. 5.0 v8 must be better than a 4.9 6 cylinder, it's .1 bigger!

I think it had more to do with the 302's partner in the F-150, the 300CID I6. Its metricized displacement also comes out to 4.9L, and was listed as such in the marketing materials, so bumping the 302 to 5.0 avoided confusion between the two.

Share this post


Link to post
Share on other sites
1 hour ago, SoonerLS said:

I think it had more to do with the 302's partner in the F-150, the 300CID I6. Its metricized displacement also comes out to 4.9L, and was listed as such in the marketing materials, so bumping the 302 to 5.0 avoided confusion between the two.

Ironically in the Aussie market, the 302 Cleveland engine was marketed as the 4.9 and the 351 as 5.8 (Australia going metric in 1974).

 

Noticing that the US switched to litres for engine capacity decades ago, so rounding up or down is the norm, thanks for explaining 5.0 sbf vs 4.9 I6

Edited by jpd80

Share this post


Link to post
Share on other sites

So how do we find the real bore and stroke of the new 6.8 liter V8?

edselford

Share this post


Link to post
Share on other sites
Posted (edited)
11 hours ago, 30 OTT 6 said:

Looks like a lot more complication and cost for a fuel economy bump no one will ever notice.

Think about the justification process behind that change after a decade of direct drive on Coyote and two decades before that on MOD motors. Probably costs 50 cents cheaper to do the new way…….. engineers saying the new oil pump will support up to 1,000 hp, whatever that implies….

Edited by jpd80

Share this post


Link to post
Share on other sites
4 hours ago, jpd80 said:

Looks like Andre's information was incorrect and the Ford guy apparently misheard him or was just mistaken, because the published numbers show the same 4.22" bore for both the 6.8 and 7.3.

Share this post


Link to post
Share on other sites
25 minutes ago, SoonerLS said:

Looks like Andre's information was incorrect and the Ford guy apparently misheard him or was just mistaken, because the published numbers show the same 4.22" bore for both the 6.8 and 7.3.

Correct and is suspect that he inadvertently misspoke and meant the reduction in capacity to be just the stroke.

 

I’m curious to see the torque curve for the 6.8, it’s gotta be a better low speed performer than the 6.2

which can be quite “hollow” when starting heavy loads. Would love to see it show up the GM’s 6.6 V8.

Share this post


Link to post
Share on other sites
11 hours ago, edselford said:

So how do we find the real bore and stroke of the new 6.8 liter V8?

edselford

 

 

Assuming engine is metric, the 3.68 inches could be 93.4 mm (3.677 inches) or 93.5 mm (3.681 inches), but using 93.4 stroke with 107.2 bore yields a displacement that would round down to 6.7 liters.  I expect the most likely real bore and stroke is 107.2 X 93.5 mm, for a displacement of 6.751, which rounds up to 6.8 liters.

 

In cubic inches that is 412.  If I had to guess, the listed 415 in specs is due to someone converting exactly 6.8 liters to cubic inches, which doesn’t seem to apply in this case.  

Share this post


Link to post
Share on other sites
Posted (edited)
16 hours ago, blksn8k2 said:

 

And the larger bore of the gen 3/4 was made possible by the switch to PTWA cylinder coating in lieu of steel liners.

 

I believe I read in some of the coverage of the 2024 Mustang that the Mustang's version of the Coyote was adopting the "bottom end" of the truck version meaning the crankcase design. They were touting the switch to a steel oil pan. I assume that also includes the belt driven oil pump but they didn't actually say that. The old crank driven oil pump design was the weak link, especially when adding forced induction. The "fix" was to replace the cast factory pump gears and housing with aftermarket billet parts. When the 2021 F-150's 5.0L was introduced the Ford engineers made a point of the fact that the new belt driven pump had been tested to withstand up to 1000 hp output.

 

 


I always suspected Ford used a belt to drive the oil pump on Gen 4s to help reduce harmonics of the chain drive.    
Harmonics are what tended to shatter oil pump gears and crack timing crank sprockets on high power Coyotes.   
 

The billet parts never addressed the root cause, only used a softer material that is less prone to cracking.   

Edited by ESP08

Share this post


Link to post
Share on other sites
15 hours ago, SoonerLS said:

Looks like Andre's information was incorrect and the Ford guy apparently misheard him or was just mistaken, because the published numbers show the same 4.22" bore for both the 6.8 and 7.3.

 

Another possible advantage of using the same bore size is that if the valve sizes, placement and angle had been optimized for the 4.22" bore none of that would need to be changed for the 6.8. In other words, the 7.3 cylinder heads could potentially be used without any adjustments for a smaller bore. 

Share this post


Link to post
Share on other sites
15 hours ago, jpd80 said:

Correct and is suspect that he inadvertently misspoke and meant the reduction in capacity to be just the stroke.

 

I’m curious to see the torque curve for the 6.8, it’s gotta be a better low speed performer than the 6.2

which can be quite “hollow” when starting heavy loads. Would love to see it show up the GM’s 6.6 V8.

Do you know what the stroke of the 6.2 was? I think the tall deck mods (5.4/6.8v10) were 4.15, 460 was 3.85, 400 was 4 even. I know heads/cam profile(s)/intake runners and vct make as much difference or more as the physical dimensions of the engine, but the mod engines always seemed to have a lot of low end grunt to me in my personal experience. The 2v v10 seemed to be the most comfortable with a heavy trailer behind it out of the ones I've driven. Never liked the 6.2 with a load behind it.

Share this post


Link to post
Share on other sites
31 minutes ago, Captainp4 said:

Do you know what the stroke of the 6.2 was? I think the tall deck mods (5.4/6.8v10) were 4.15, 460 was 3.85, 400 was 4 even. I know heads/cam profile(s)/intake runners and vct make as much difference or more as the physical dimensions of the engine, but the mod engines always seemed to have a lot of low end grunt to me in my personal experience. The 2v v10 seemed to be the most comfortable with a heavy trailer behind it out of the ones I've driven. Never liked the 6.2 with a load behind it.

 The 6.2 used a 3.74" stroke.

Share this post


Link to post
Share on other sites
45 minutes ago, Captainp4 said:

Do you know what the stroke of the 6.2 was? I think the tall deck mods (5.4/6.8v10) were 4.15, 460 was 3.85, 400 was 4 even. I know heads/cam profile(s)/intake runners and vct make as much difference or more as the physical dimensions of the engine, but the mod engines always seemed to have a lot of low end grunt to me in my personal experience. The 2v v10 seemed to be the most comfortable with a heavy trailer behind it out of the ones I've driven. Never liked the 6.2 with a load behind it.

Yes, 3.74” stroke as blksn8k2 said in his post. The 6.8 would seem to cure  a lot of perceived mistakes with the Boss 6,2.

 

The 2V mods generally had smaller ports and valves which promoted more low end torque but tended to run out of horsepower. 

Conversely, the 6.2 was give large intake ports which tends to make the engine a bit “hollow” down low where heavy duty trucks would be looking for more torque when starting heavy loads. I can’t find a torque chart for the 6.2 but my research points to it being 95% of the GM 6.6 V8, so maybe the extra 10% capacity of the 6.8 has enough torque to be a winning combination…

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×