8.1 VS. 6.8

watz · April 18, 2005

I will be picking up a new 3/4 ton this year or ealry next. I am expecting big discounts with the gas prices getting out of hand. From my research i am seeing the Ford V10 around 13 - 14 mpg vs. the 8.1 around 9 - 11 mpg.

Does that sound like about what you guys are seeing? Power numbers are slightly in the Fords advantage I just find it hard to beleive they would win both power and mpg.... Seems like BS to me, but I thought I would ask...

Mattt · April 18, 2005

Im not sure where you got those Ford mileage #s, but I think they are wishful. My cousin has a V10, and its no where near those #s in real world. try more like 8-11 IIRC from what he told me.

Ive driven the V10, & the 8.1 and didnt feel a power difference. I think the V10 is a bit more,,,,get up and rev it kind of motor. Not always a comfortable thing in a big truck.

Shooter_va · April 18, 2005

A buddy of mine has the V10: 8-11.

My 8.1: 10.5-12 normal driving, 8.3-9 towing 10000lbs trailer

snoman · April 18, 2005

I will be picking up a new 3/4 ton this year or ealry next. I am expecting big discounts with the gas prices getting out of hand. From my research i am seeing the Ford V10 around 13 - 14 mpg vs. the 8.1 around 9 - 11 mpg.

Does that sound like about what you guys are seeing? Power numbers are slightly in the Fords advantage I just find it hard to beleive they would win both power and mpg.... Seems like BS to me, but I thought I would ask...

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I know ford reworked the V10 recently for more power. I have a friend that has one in a 16000lb motor home that average between 8 and 9 mpg on highway. On the 8.1 I have heard stories of 12 to 15 mpg + on highway. How you drive play a roll in MPG too. I you plan to tow I would lean toward the 8.1 because paper figures aside there is not substitute for cubic inches when it comes to low end and mid range torque that you need to get a load moving and it that area the 8.1 excells as did the old 454 it is based on. Also, one other thing, if you plan to put a performance exhaust system on it for sound , there is no contest because while the 8.1 will sound great, the Ford V10 has a strange sound that will never sound right no matter what you do to it (it sounds nothing like a V8 and more like a 6 than anything)

Daubs · April 18, 2005

Check out the ford forums (http://fordtruckworld.tenmagazines.com/) and see what people have to say about their v-10's

I installed Westers and Volant in my 8.1 Crew Cab and just got 15 MPG highway this weekend. I'm stoked. Getting just over 10 MPG around town. Not bad for crew cab 4x4 pickup.

Roofer · April 18, 2005

You are missing one thing and thats the Allison that you get with the 8.1. That should be enough to sway anyone, being the trucks are so close otherwise.

snoman · April 18, 2005

You are missing one thing and thats the Allison that you get with the 8.1. That should be enough to sway anyone, being the trucks are so close otherwise.

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If you like the Allison. For me it would be a reason not to get it because I do not like its operation compared to a 4L80 series tranny. But that is just me anyway. The 5 speed maybe be needed with the Dmaxs limited RPM range but not a problem with the 8.1. They could easily beef the 4L80 up to handle a Dmax but its four gears are not enough for its very limited power curve. ALso they make more money on a Allison sale than a 4L80 and profit is what it is all about.

XTOAK · April 18, 2005

I too had the option of the Ford V10 versus the GM 8.1 as my company has both GM Supplier as well as Ford X-Plan...in the end I went with the 8.1 as the mileage was slightly, and I said slightly, better.

The biggest reason for the 8.1 was the Allison tranny and the fact that the Chevy had the true blue crew cab with four real doors. I have guys that ride with me and I took two of them when I went to check out the two trucks....after they jumped into the Ford and we went on a test drive, we went to the Chevy dealer...no comparison on ease of entry/exit and legroom. Chevy had the Ford beat in room, tranny, and I got the 0% for 72 months...pretty hard to pass up free money.

I went with the Chevy....you should try both and go with the one that suits your purpose.

Daubs · April 18, 2005

You are missing one thing and thats the Allison that you get with the 8.1. That should be enough to sway anyone, being the trucks are so close otherwise.

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If you like the Allison. For me it would be a reason not to get it because I do not like its operation compared to a 4L80 series tranny. But that is just me anyway. The 5 speed maybe be needed with the Dmaxs limited RPM range but not a problem with the 8.1. They could easily beef the 4L80 up to handle a Dmax but its four gears are not enough for its very limited power curve. ALso they make more money on a Allison sale than a 4L80 and profit is what it is all about.

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The Allison is one of the main reasons I went with the 8.1 in the first place. Buddy has one in his D-max and literally abuses it! Runs like a champ. With the gas engine you can really hear the Allison working. It has a whine to it, almost like the old 3 speed chevy manual trannies from the 60's (My Dad has a 62 Impala with three on the tree...love what he calls the "chevy whine").

Shifts smooth, plenty of gears to keep the Big Block in power band (although that's not very difficult...cause power's always on tap). I may have opted for the 6.0, but only if I could have got the Allison behind it.

jeb · April 18, 2005

We've had 3 allisons. One in my 01 HD2500 dmax, one in our 03 Winnebago 35' class A with the 8.1 and one in our current RV, a 40' diesel pusher w/350 Cummins ISC. All have been great and I'm now a big Allison fan.

I also had the new Ford TorqShift in my 03 Excursion w/6.0PSD (bought back, bad motor). I believe ford is starting to put that behind some V10's now. The tranny was great in my Excursion.

I now have the 4L80 in my 04 Yukon XL 2500 and I sure miss that extra gear. It's a nice tranny and all but I'd take the ally any day over it, especially with the 4.10's I have.

dewfpo · April 18, 2005

Seems like BS to me, but I thought I would ask...

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Do the math.... The 6.8L has 16% LESS displacement than the 8.1L.

That being said, driving style, tune, tire diameter, trans, axles, etc.... all effect the mpg.

Don't forget, the Ford sits about 2 inches taller than the HD, this will work against it in the mpg #s.

DEWFPO

willieboy · April 18, 2005

We've had 3 allisons. One in my 01 HD2500 dmax, one in our 03 Winnebago 35' class A with the 8.1 and one in our current RV, a 40' diesel pusher w/350 Cummins ISC. All have been great and I'm now a big Allison fan.

I also had the new Ford TorqShift in my 03 Excursion w/6.0PSD (bought back, bad motor). I believe ford is starting to put that behind some V10's now. The tranny was great in my Excursion.

I now have the 4L80 in my 04 Yukon XL 2500 and I sure miss that extra gear. It's a nice tranny and all but I'd take the ally any day over it, especially with the 4.10's I have.

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Two things. The Ally's (2500?..can't remember the designation) in your RV are not the same as the Ally 1000 behind the Duramax.

Also, the Ally is not a true 5 speed. In reality it is a duel second gear four speed.

No matter, the RV community loves the Allisons, either in the GM trucks as tow machines, or the big brother Ally's in the Class A's and Diesel pushers. It gets rave real world reviews. Like many, the Ally would convince me to go for the V8.

HillHound · April 19, 2005

I bought my 2003 V10 F250 new going on 3 years ago-it has almost 32K on it now with no drivetrain problems at all. It's the 2nd generation Triton V10, 2valve, with 310hp@4250rpm & 425lb-ft@3250rpm. The new '05 3 valve V10's are rated at 362hp@4750rpm & 457lb-ft@3250rpm.

My mileage for mixed city/highway driving is always between 11mpg to 12.5mpg. For highway driving at 70mph it gets a little over 14mpg easily and will break 15 if you really baby it and keep it in OD & under 65mph (which I rarely do).

I just drove a few hundred miles highway this weekend with my 700lb atv in the bed and my mileage was about 13.5. Towing on the highway a 3000 to 6500lb trailer the mileage is in the 9/10 range.

I have a 3.73 axle and the 4-speed auto. The truck's curb weight is 6900lbs. The general consensus at the Ford sites is the 3v V10 gets slightly worse mileage. The 2005 V10 auto is the new Ford 5 speed with grade braking and tow program. It gets good reviews from the guys who have them but I haven't driven one yet.

The 2005 6.8L has more HP/torque than my '03 but I'm certainly not lacking for power. Unloaded/not towing, the truck never drops out of OD to hold 70mph on any interstate grades. In fact even with my ATV in the bed it will easily hold OD on interstate hills. Towing in 5000-6000lb range it drops to 3rd on most hills but will occasionally need to drop into second for short periods to stay at 65/70mph.

I've measured my 0-60 acceleration times and it seems to hit 60mph in about 8.4 to 8.6 seconds, which to me isn't too bad for a truck this heavy. With a 2000+ 6.8L or any 8.1L there aren't any stock 3/4 or 1 ton pickups that are going to embarass you in a street race and that's a fact!

The real-world performance of the 8.1/6.8 is a wash. I like them both and if I was buying a new 3/4 or 1 ton truck the engine would not be the deciding factor. Both of them make 400lb-ft of torque at or under 2000rpm. Mileage is similar etc. I'd be more concerned with other stuff like transmissions, clearance, interior options etc.

For example I like the Superduty because it rides alot higher and has better frame/chassis clearance, but I like Silverados because they ride and handle better under load. I spend alot of time offroad doing chores so the extra ground clearance is important to me. Silverados have a better dash and instrument cluster but I like the fact Ford still puts hubs on their 4x4s that can be locked in manually or set to lock-in automatically. I've always thought the seats in Silverados were more comfortable than my F250 too.

Just as matter of personal preference, I also love having the Dana 60 front axle on the front of my F250. Not saying there's anything wrong at all with the GM IFS but I just like the idea of having a pair of big solid axles under both ends of my truck.

Superman TNT · April 19, 2005

I have to admit I didn't look at the Ford when I just bought my new 04 2500 HD ext cab 4x4 8.1L with ally and 4:10 rear. I did look at the Dodge but the tow capacity wasn't very good.

You are right about getting a heck of a deal due to gas prices. The 04 I just bought (stoled) has a window sticker of $42k and some change and I got it for $25K. The truck is loaded to the hilt and has more stuff than I really wanted. This was a GM executive truck and had 2,500 miles on it. To me I thought it was a great deal.

I had (still have until sells) an 01 1500 Z71 w/ 5.3L. I had to change due to lack of towing power for my new camper. I really wanted a 6.0L w/ 4:10 gears "for better gas milage" but ended up with such a great deal on this truck that I bought it anyway.

Everyone had told me about the Allison tranny but I didn't even take the time to test drive one before buying this one. Having driven it for 1 month now I can't begin to tell you the difference that makes. I love that tranny. What a solid, smooth, awsome transmission. Even with everyone telling me how great it was I never thought I would even be able to tell the difference. How different could it possibly be? Let me tell you, get the 8.1 w/ the ally!

Driving the truck stock, no mods, I got 12 - 13 mpg highway going 75mph on average. Around town I'm guessing I'm getting 10ish. I don't really drive around town much with this vehicle however.

Anyway, not sure why you're after the big engine but if it is about towing, I would strongly recommend the GM. My guess is it gets better MPG than the Ford and it has a killer tranny. I can not wait to hook this bad boy up to my 9,500 5th wheel. I'm dying to introduce that camper to my new mule. The camper will move now or the mule will rip the dam hitch right off.

Good luck,

Cpl Punishment · April 20, 2005

OK, my opinion (worth what you're paying for it):

I'd rather have the 8.1. Why?

Both engines are powerful.

Both trannies are good (once they got he bugs out of the TorqShift), although I'd prefer the 6-speed in either.

The only thing engine related that I prefer is :displacement, and the sound. Nothing but a V-8 sounds like a V-8. And nothing but a big block sounds like a big block. There's no replacement for displacement. Enough cliches?

Other than that, my preferences are truck related. I like the fact that I have a tranny temp gauge instead of an idiot light. I like the Chevy interior better. IMHO, the 2500HD and 3500 have a much better frame than the Super Dutys.

But, that's one man's opinion, YMMV.