6.6 gas

[2018GMC]

I think the new 6.6 has good power numbers. Hopefully GM pairs it with the 10 speed in upcoming years. 

 

Especially compared to my 1979 k10 6.6L 400cu that GM rated at 185 - 195hp & 300tq. All put thought a 3 speed turbo 350, full time np203 (I converted to part time) and 3:73 gears. Even though the old truck weighs 4900lbs, the best I can get highway is 10mpg. The 8.5:1 compression and swirl port heads were a dark time in GM history. 

Edited March 15, 2019 by 2009GMC

[ApertureX]

So... I got bored and found the SAE graphs for the L96 and L8T. They were not aligned the same so I did my best to overlay the graphs and I believe them to be 95% accurate (compared to each other). I did this for my own reference, but I thought I'd share in case someone else found this interesting.

 

 

Credit to ThomCannell who posted the SAE chart for the L8T on this forum:

 

Edited June 13, 2019 by ApertureX

[C/K Man]

^{Wow, over 400 ft. lbs. @ 2000 r.p.m..} 

[ApertureX]

12 hours ago, C/K Man said:

^{Wow, over 400 ft. lbs. @ 2000 r.p.m..} 

Yeah. When I finally found the SAE chart for the L8T it let me know that I will have no problem using the 6.6 gas for my daily driver or towing a fifth wheel RV.

 

I mean, this thing idles with almost as much torque as the L96's peak output.

[C/K Man]

And I think 3.73 gears will be just fine.

[ApertureX]

On 6/12/2019 at 10:02 AM, C/K Man said:

And I think 3.73 gears will be just fine.

Might get better fuel mileage using the 3.73 while still applying more power to the ground. You can also swap in a 4.10 later for some serious power to the ground if someone wanted even more.

Edited June 13, 2019 by ApertureX

[magnum74]

I'd guess that the 10-speed is max 2 years away or possibly 2021. Either case, 3.73 should be more than fine. The dyno curve on this engine really puts the L96 in it's place. I'll drive one before I pass judgment but on paper it obliterates the outgoing engine. 

[SierraHD17]

Well it should... the stroke and extra cubic inches should make some torque.  This just reinforces me wanting one of these engines on the stand to play with.  Be fun to see what a tune does to one in one of the HD trucks but I doubt you will ever get to see it.  A tuned L96 is impressively strong when you let it run premium gas.. but this should have no problem beating up on that stock.  

[Cowpie]

I have never found an application in a gasser pickup truck that the 4.10 ratio would not be the ideal choice.  1/2 ton on up.  Heck, even on the rural roads in my area I use manual mode and rarely let my 2500 go into top gear unless I am running 65 or more.  Saves all the constant shifting on the rolling hills and that saves as much or more fuel and wear on the transmission than letting the pickup lug around in top gear and shifting every time it hits a ridge in the road.    So I wouldn't want 3.73 even with the 6.6.  I liked 4.10 with my previous 2500 454 and I like it with my 6.0L gasser.  Even the new 6.6 wouldn't change that perception.  I have liked the 4.10 ratio since the 1960's in several different vehicles.   The driver has more effect, negatively or positively, on fuel economy than the difference between 4.10 and 3.73.  I rather the onus for better fuel economy be on me than being nannied by a bunch of dweebs in cubicles at GM on what they think I need out here in the real world.  To do enough of that already.

[kenny_r]

I believe once ford drops the numbers for the 7.3 plus that 10 speed it won’t be long before something changes with the 6.6 and 6 speed. I guess time will tell how they both perform though.

[Polo08816]

On 6/15/2019 at 11:15 AM, kenny_r said:

I believe once ford drops the numbers for the 7.3 plus that 10 speed it won’t be long before something changes with the 6.6 and 6 speed. I guess time will tell how they both perform though.

+1.  Latest video reviews are good but it would be nice to have a larger gas engine ie. 8.1L V8, with the new 10 speed auto.  Would bridge the gap between the 6.6L V8 and the Duramax.

[kenny_r]

I don’t think the 8.1 is necessary when this 6.6 shits all over it. More gears or 4.10 woulda been the way to go.

[MaverickZ71]

On 3/14/2019 at 10:48 PM, 2018GMC said:

I think the new 6.6 has good power numbers. Hopefully GM pairs it with the 10 speed in upcoming years. 

 

Especially compared to my 1979 k10 6.6L 400cu that GM rated at 185 - 195hp & 300tq. All put thought a 3 speed turbo 350, full time np203 (I converted to part time) and 3:73 gears. Even though the old truck weighs 4900lbs, the best I can get highway is 10mpg. The 8.5:1 compression and swirl port heads were a dark time in GM history. 

Agreed.  But that was the state of the marketplace due to the manufacturers trying to figure out the smog regulations back then.  Not just a dark time for GM, but for all auto manufacturers.  That '79 400 K10 was totally competitive back in the day, especially if compared to a F-150 with a 351M and a C6.  Hopefully the new L8T will prove to be just as competitive or even more so with the new Fords and Rams.