Engine Question!

[Fredward]

Kyle,
What is a "Smoke Turbo"? I'd love a little more snoose out of my 8V71 72N without going crazy on the modifications. 
Fred

[kyle4501]

My definition of a 'smoke' turbo is one that adds a small boost (~5psi) to the intake air pressure to overcome the altitude sickness that a normally aspirated motor suffers at higher elevations.
It's purpose isn't to add much power, but to mnimize the effects of thin air at altitude - hence reduced smoke in the mountains.

[Fredward]

Oh. Having run mine through a few mountain passes I can recognize the benefit. The 871 gets pretty gutless up there. Although in 1st gear at 2100 it handles anything we've thrown at it! 
Fred

[makemineatwostroke]

Zeroclearnce; the 12.7 when set at 500 hp will get about the same mileage or less than the 14L 515 hp, depending on your serial number it may cost big bucks to get the 500 hp. I like the 470 hp on the 12.7 for fuel and torque.Is your  engine a DDEC 111 or 1V and thanks again for help with the TV I have since gone to 76 inch screen what a difference. have a great evening and the name is  Cole

[steve5B]

     Hello again!


   I have shared the info from the post that I ask pertaining to the ENGINE QUESTION!  to my friend who ask me to.

   I'm  at a loss of words for all of the replies.  I personally would like to thank each and everyone of you for your post.

   Being new to this also, I have learned alot myself and I appreciate taking your time to answer the questions.


   Thanks a million!

   Steve 5B.......

[niles500]

work = torque = mass x stroke - it's all in the math -FWIW

[lostagain]

Re: "smoke turbo, 5 psi".

I installed a turbo on my 4-71 a couple years ago. It gives me about 12 psi. The only mod so far is new oil seals in the blower to sustain the bigger boost pressure. Very noticable power and torque increase. Well worth doing. I now go up hills one gear higher than before. (5 speed Spicer).

The 2 stroke DD is a tough, robust engine, and you don't need to go to "turbo specs" unless you're doing a rebuild anyway. As a matter of fact, several Detroit mechanics have told me they don't use the lower compression turbo pistons because it makes the engine hard to start at altitude.

Turbo-ing a DD 2 stroke is a lot easier and cheaper than an engine swap, with great results.

JC

[TomC]

I also used the high compression pistons.  Don pulled one piston to make sure it had the tight piston rings, and since it called for transit bus rings, they were the tight rings-as compared to the looser rings for highway trucks.  I'm getting about 15psi with the addition of the bypass blower (valve and passage that opens at 5psi boost to route some of the air around the blower to equalize the pressure on both sides of the blower so to make the blower basically freewheel when under power).  Haven't had any problems with the engine-have put on about 10,000 miles since the changeover.  Highly recommend turbocharging the 8V-71's-it REALLY wakes them up.  Good Luck, TomC

[Busted Knuckle]

Yeah what HE said! All of the above, and so on!

OK Dale, not trying to take anything away from Don's beautiful coach, and especially his talents. But my memory of his coach is sorta fuzzy since I was on the go most of what time he was here. And he left in a hurry after his dually got run over twice by the same guy on Sunday morning. But what is the weight of his coach? And honestly I really can't remember if it is a 2 or 3 axle coach. Now while I realize and admit his choice of toad is quite a bit heavier and has more rolling resistance than the typical toad. The size, weight & # of axles (rolling resistance) will effect fuel mileage too!

Now that said the first SETRA we owned # 702 aka "HOTROD BUS" w 8V92TA DDEC / HT748 @ 500+/-HP. Never ever, ever, ever, ever got more than than 6mpg with A/C off and cruising leisurely along behind dad @ 60-62 mph heading down to KATRIA RELIEF EFFORTS (very flat ground or pretty much)! Or anytime dad drove it it got between 5-6.5mpg. When I let 'er roll with it on the open road I usually got between 4.5 & 5.5 mpg! As well as quite a bit of oil consumption, about a gallon +/- per 1000 miles(depending on how hard I really pushed it!)! 
Now the guy we sold it too drove it home from our place to his in North Central (Fiddletown), CA.  AT 55 MPH! After he got home he called us and was tickled he got 7.5 mpg and only used 1 gallon of oil!

FWIW   BK 

[makemineatwostroke]

BK; like clifford said apples to apples run a b500 behind the DDEC V892 500 hp and mileage will be about the same as the 60 series 500 hp with the same gearing   

have a great day

[belfert]

If your Dina is like the ones that I have driven it is only set up for 5 speed.  With the 4.10 rear you could reprogram the B500 to a six speed and get even better than you are now.  I put a series 50 in my son's bus and it has the world 6 speed with a 4.10 rear and dose great.

Allison basically refuses to change the parameters on my B500 to turn on the 6th gear.  They will do it only for I think $600+ and a letter from an engineer at the OEM authorizing the change.  The letter is the killer plus $600 will buy a fair amount of fuel.

MCI has two of the original Dina engineers on staff and I talked to them about unlocking the 6th gear.  They said the 6th gear is locked out because they claim the engine RPM will drop too low causing the computer to downshift to 5th anyhow.  I'm not sure I believe them, but don't know what the minimum RPM is either.

Is there a third party that could unlock 6th gear?

[makemineatwostroke]

Belfert; you might find a independent Allison like Industrial to unlock 6th gear but if you don't have the 4.56 or lower most will not. I know Stewart and Stevenson won't and 6th being locked out is not only Dina, Prevost did for years         have a great day

[belfert]

I am guessing that if I had a 4.56 or lwer gear and 6th gear on the tranny enabled my MPG would probably be about the same as with only 5th and 4.10 gears.

What gearing do newer bueses with all 6 gears enabled have?

[makemineatwostroke]

 Belfert; All I saw are 4.56 down to 4.88 with the B500 a few years back some tried 4.33 with no luck   

have a great day

[blue_goose]

You have all the power that you need to get into 6th gear with your series 60.  Call TKT Sales and talk to Ted about the 6th gear.  He has the motorhome program and will reprogram it for a lot less than Detroit.  The one that I did for my son with a series 50 we used a 4.10 rear and a six speed .  He is getting over 8 MPG and it stays in the 6th gear. 
Jack