8V71 advantages over 6V92

[TomC]

If any of you do have a 92 series that is a total dog off the line, then you probably have whats called a throttle delay on it to keep it from smoking to much.  It is on the left head (if I remember correctly) and it looks like a small piston on the fuel rack-essentially a small shock absorber to keep the rack from opening to quickly to keep the black smoke down.  That's the old system.  The newest system is called a fuel modulator (which I have on my 8V-71TATAAC [turbocharged air to air after cooled]) and it works well at keeping the smoke down.  I can tell you without it, if you stepped on the throttle to hard, you got a tremendous black cloud of smoke until the turbo came up, which was only a couple of seconds-but too much black smoke for me.  Now with the throttle delay, I get a small amount of black smoke that clears in a couple of seconds.  The fuel modulator is an air piston that is spring loaded.  It is attached by a hose to the intake to the blower.  The spring keeps the fuel rack from opening to quickly, and when the turbo boost comes up, the air piston allows the fuel rack to open completely.  What's nice about this, is you don't get fuel until you get turbo boost.  Highly recommend switching over if you still have the older throttle delay.  The kit is about $450.00.  Good Luck, TomC

[niles500]

IMHO - the type of mill you should use is determined by the chassis you buy and use you intend - I wouldn't want a 71, turboed or not, as the mill for a 45k hill climber - you need Torque for that

[TomC]

Niles- torque is what I'm talking about.  The last ratings Detroit had for the 6V-92TA was 350hp with 1100lb/ft torque.  For the 8V-71TA 400hp and 1200lb/ft torque-which one do you think will get you up the hill faster?  Course the 500hp 1450lb/ft torque 8V-92TA would be best.   
If I was rich, I'd like a 12V-71TA that would give me 600hp and 1800lb/ft torque-but I don't have that kind of money for 4mpg-but there isn't another engine that makes the sound that a 12V-71 does.  Good Luck, TomC

[niles500]

Tom - I wasn't arguing against your post - I know you Know your stuff - when I  compared 71 series versus 92, I was talking 8v vs. 8v not 8v vs. 6v - it is hard to find a 400hp 8v71 out there unless you do it yourself - torque in these mills is more relatively a combination of bore X stroke and mass (and cube to cube the 71 series does outperform the 92, but not 168 cubes worth)- my DDECII is stamped 500hp and Prevost claims 515hp and 1650 ftlbs. (I think that Prevost dynos their shells) - now 8v92's can be set up any where from 375 hp/ approx. 1200 ftlbs. and up, and 8v71's 318 hp/ 866 ftlbs. and up (unless either has been derated), the only difference is how long the mill will last (cycles) - the "sports car" coaches do just fine with 568 cubes, but a late model behemoth that wants to climb mountains works better and will put less stress on the mill with 736 cubes (at the cost of mpg's of course) - Hope this clears up my post and HTH

[RJ]

Seems to me there was a fellow in the upper midwest a few years ago that had a 450 hp, LH, 8V92TA stuffed into the tail of a 4106.

Talk about a "sports car"!!      

(Wish I knew what happened to it. . . maybe somebody knows.)

I also know of a fellow who's got a 375 hp 8V71T in his 4106, and another local busnut who's got a 350 hp 6V92TA in his 4104.

This much power in these 35-footers is, for the most part, similar to a 500 hp 8V92TA or S-60 in a 45-foot Marathon, as Niles said.

Hey, are we all beginning to sound like Tim Allen here??  LOL. . .

 

[buswarrior]

Hello.

As winter approaches, my first consideration for any motor/coach is:

Does the heater work?

happy coaching!
buswarrior

[edroelle]

Russ,

At a Harold Green's CCO rally this summer, there was a 4106 that drove in just for an hour.  He had bought his conversion and was told it was an 8V92T/730 series.   It was packaged tightly.   He lives in Elsie, MI.

Ed Roelle
Flint, MI