| Author |
Message |
Roderick W. Chandler (172.130.4.185)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 9:59 am: | |
Is there a significantly higher cost of maintaining 8V92 over 6V92? Which engine is more reliable? I am currently shopping for MCI 102A3 and cannot decide which engine would be best. 6V92 is the most prevalent. Is this because in commercial application it costs less to operate because of fuel economy? |
jim mci-9 (209.240.205.60)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 12:10 pm: | |
what you pay for is horsepower.... the 8v puts out more.. and costs more... the 6v is more economical....maybe 2 mpg better....325hp vs 425hp ....higher hp means bigger radiators...at overhaul time the 8v will cost 30-50% more..... |
James Maxwell (Jmaxwell) (66.81.57.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 12:27 pm: | |
There is no appreciable difference in maintenance cost and from my experience no appreciable difference in fuel economy, perhaps 1-1 1/2 mpg of fuel. The big difference is attainable hp in the 8v92, but that may not be necessary for a 102A3. I think it weighs in at about 29k curb weight, and a 6v92 will push it just fine, while the 8v92 will give u a little advantage in the mountains. Yesterday I drove both of my buses, one a 6v and the other an 8v. After bringing the Neoplan w/the 8v and 5 spd home from the cabinet shop, I jumped in the Grumman w/ the 6v and 3 spd to take it for fuel and propane. It actually is quicker off the line, but pulls down considerable more on hills. The Neoplan is much heavier, around 35k (not loaded) as opposed to 29k fully loaded on the Grumman. The 6v can develop 350hp and the 8v can develop 500 in the DDEC version if u can get someone to set it to that for u. Normal is 425-450.
Another factor of consideration is the tranny. The Allison 4 spd is the same as the 5 spd, without the granny low. Also, look for one with a retarder trans. instead of jakes, but that part is an opinion |
john w. roan (Chessie4905) (69.162.16.88)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 12:30 pm: | |
When you drive either one, you'll think...Geez this thing sure sucks the fuel with the 8v-92. Wish I'd gotten one with the 6v-92. Or...Damn this 6v-92 sure drops down on all the long steep hills and everyone is passing me...sure wish I'd bought a coach with an 8v-92.Which would make you crazier...lower fuel mileage or lower power.You could get an 8v-92 and have it detuned to 365 to 400 horsepower. That should help mileage and surely longevity. |
Geoff (Geoff) (66.238.120.24)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 12:57 pm: | |
If you plan on pulling a trailer or spending much time out west climbing mountains I suggest the 8V92TA. On the other hand, the 6V92TA @350HP will do the job, just a little slower, while giving you up to 2 mpg better fuel milage. |
James Maxwell (Jmaxwell) (66.81.57.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 1:01 pm: | |
To add just a little for comparison. My 8v averages 7.3 mpg at 70 mph while the 6v averages 6.5, low to mid 60's. DDEC 500hp 8v is coupled to 5 spd and 3.37 rear-end; MUI 9f90 injectors 6v is 3spd and 4.11 rear-end; both are on 22.5 tires, 12R and 11R respectively. |
roderick W. Chandler (172.144.62.158)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 5:19 pm: | |
Thanks for the input. I had heard that the 8V might be more problems but I do need the horsepower to pull toys. Later I will probably try to upgrade 60 series but in the mean time I want one that will be usable to pull trailer with toys loaded in mountains. |
jim mci-9 (209.240.205.60)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 7:29 pm: | |
if you haven't commited on a specific coach yet... and are considering the series 60, then find a coach with the series 60 in it now.... the "upgrade" isnt cost effective.... |
RJ Long (Rjlong) (66.229.97.200)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 7:38 pm: | |
Rod -
Buy a coach with an 8V92TA already in it - especially if you can find one that came from the factory that way, as it will have the big radiators and squirrel cages to cool the beast. Even if you have to do a rebuild, with normal care and maintenance, it will outlast you in RV service, and be less expensive than trying to shoehorn in a S-60, plus it will give you all the power you need to pull your toys. Be aware that a Series 60 will not fit in a 102A3 without lengthing the rear of the coach, as it's about 18" too long.
The fuel mileage issue is a moot point when you're talking about a vehicle that has the aerodynamics of a brick being pushed thru the air at 70 mph!! Of course the 8V is going to get worse mileage than the 6V, but in this application, you're only talking 1 - 2 mpg overall. As I said, a moot point. . .
Shy away from any "A" series MCI that still has the manual front door operating mechanism. Those things are a nightmare (BTDT!!), with lots of skinned knuckles and, on a few occasions, a VERY sore groin. MCI spent a TON of money on warranty repairs for the weak gearbox hidden inside the dashboard that this lever operates. When it fails, you can't get the door open or closed w/o taking the dash apart.
One other item of note: If you're thinking you'll have to raise the roof, you might look for a "C" series - they already have a 3" roof raise built into them. . .
HTH,
RJ
PD4106-2784
Fresno CA |
H3Jim (68.105.103.139)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 8:11 pm: | |
On a 3000 mile trip, and paying $1.70 a gal for fuel, the difference in dollars between 6 MPG and 8 MPG is $212.50. |
Geoff (Geoff) (66.238.120.150)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 8:40 pm: | |
"On a 3000 mile trip, and paying $1.70 a gal for fuel, the difference in dollars between 6 MPG and 8 MPG is $212.50. "
I guess that is why tour operators go for the 6V92TA! I have driven my bus up and down just about every mountain range out here on the west coast, and while having that extra power would be nice, the time spent on the hills is just a mild inconvenience compared to losing 2 mpg all the time. And this is with a 350HP 6V92TA, what about the folks with 6-71's and stock 8V71's???-- I might get passed by the "big blocks", but I still pass a lot of other buses at the same time. I'm getting around 7 mpg pulling my toad, I could get 8 if I slowed down to 55-60, but I am happy with what I am getting.
--Geoff
'82 RTS CA |
BrianMCI96A3 (65.40.154.171)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 11:31 pm: | |
Well, my "A" series has a manual gearbox that is working just fine...it may or may not have been worked on at some point...
STILL, so what!
No reason to condemn a GREAT coach for heresy about the door opening mechanism... besides you could simply remove the door gearbox and install a truck type door latch.
I know a very knowledgeable Detroit mechanic who told me that in his experience the 6V92 is the engine to have, for all kinds of reasons.
Brian |
RJ Long (Rjlong) (66.229.97.200)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 26, 2004 - 1:45 am: | |
Brian - Don't misunderstand, I wasn't condemming the "A" series coach at all - I know they're a good unit, actually a better chassis than the highly touted MC-9s. But I was passing on info to Rod about a little-known problem related to the door mechanism on the early models. Later production eliminated the manual operation completely, they're all air-powered. I wouldn't be surprised at all if your coach has the revised, heavier gearbox that MCI came out with to handle the failed originals.
I also totally agree with Geoff that a 6V92TA set up for 350 hp is probably the best compromise between power and fuel economy, but if Rod should find a "102" with a factory-installed 8V92TA, that that, too, would be a good buy, since it would already have the big radiators and larger squirrel cages, reducing the overheating potential.
As you well know, Brian, everything we do on our bus a compromise in some way, shape or form, and that's part of what makes this hobby so darned, shall I put it this way: fun/interesting/frustrating/challenging/aggravating/amusing/insertyourownadjectivehere!!
Onward, then. . .
RJ |
BrianMCI96A3 (65.40.154.171)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 26, 2004 - 8:30 am: | |
"...insertyourownadjectivehere"
I'll agree with that! I spent 4, eye numbing, back aching, hours yesterday lacing a leather wheel cover (that I made) onto my coach's steering wheel with sinew. But it sure came out nice!
Brian |
Roderick W. Chandler (172.146.194.147)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 26, 2004 - 7:05 pm: | |
I have been looking at a couple of 102's with the 8V92 and allison 740. I can save about 5G going with the 6V92. I am not sure I want to give up the power advantage. I expect the loss in fuel economy. Also the prices of coaches with s-60 is still out of my immediate range. I did not know about the door gear and will put that on the list of things my mechanic will inspect before purchase. |
Gary Carter (68.25.114.21)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 27, 2004 - 6:50 pm: | |
Our 45K pound Newell 8V92TA DDEC gets 6.75 mpg overall. I doubt the 6V92 will get much better. S60 with a 740 is only about .7 mpg better. |