DD two stroke engines

[gus]

Tom,

I would love to turbo my 671. I asked Don about this and as I remember the cost was about half what I have in the bus!!   

I'm an old man, I may not be able to travel in my 4104 very many more years.

I doubt that I would ever get my money back for that investment and I'm not in much of a hurry anyway!

[Lin]

I agree that a turbo would be a nice upgrade.  I don't think it is on my real list at this point though.  Wouldn't it require a bunch of extra cooling capacity also?  I think that, when I get to it, my first attempt at a power upgrade will be propane injection.

[TomC]

A couple of reasons why I turbo'd.  When we took a trip to Arizona a couple of years ago and went through Flagstaff (7,000ft) to Grand Canyon (6,000ft), because I had N65 injectors, it would smoke with full throttle.  In this day and age, that's not acceptable in my book. Also, the power was down quite a bit.  While that wasn't a problem with not pulling my car on that trip, if I were to pull my car and went to Colorado-I'm just afraid I could stall out on one of the big hills there.  The power of the 8V-71NA wasn't a big deal with me-I never minded going up the hills at 30mph.
I had Don Fairchild turbo the engine.  I had an air to air intercooler made that is in front of my radiator.  Then Don installed an early 12.7 liter Series 60 turbo with waste gate to keep the boost down to about 15psi since I didn't change the pistons (which were two piece with proper rings). With the extra heat, I had the radiator enlarged from a 5 row straight fin to 6 row serpentine fin, added a auxiliary trans cooler with thermostatically operated electric fan (can turn it on continuous also), changed the air cleaner from a 6" to 7" opening, changed the stuffed up muffler to a turbo muffler, cut vents into the back engine door, and added 15 misters to the front of the radiator running off my house water system.  Alot of modifications, but man what a difference in performance with no smoking at altitude except when first starting out from a signal.  Still the same 5-6 mpg, but that's a function of 4.56 rear ratio and the poor aerodynamics inherent to my bus (the old sign in front juts out to create an effective air dam).  But, I cruise at 1800rpm which is 58mph or 2100rpm is 67mph.  I can top out at 76 mph at 2400rpm.  Just a point-still a whole lot easier than trying to install a completely different engine into the bus.  Good Luck, TomC

[Dallas]

Jack,

I made that same mistake in the 80's.. I bought a White "Road Commode" from a local Cummins dealer. They promised me that the engine would perform way past my expectations, and if I had a problem, they would take care of it.. at no cost to me, other than labor.
I explained to them that my loads ran in excess of 150K lbs. many times and that I needed to have confidence in my engine. They said, No Problem, if, after 200,000 miles you have problems, we'll install any Cummins engine you want, as long as your transmission and drive train is rated for it.
After a month, they replaced the engine.
After 3 months they replaced the engine again.
After 8 months, they said, "We'll make you a deal"
The deal was, they put in a Cummins BC II at 375HP, change out the transmission and rear gears, and warrantee the truck as new.
They couldn't handle having to pay a wrecker to come haul me in when the engine trashed out on me by swallowing a valve or even just having one haul me up a hill.

Dallas...an exception to what you wrote on the VT903, (VT 90-Nothing LOL) was that a trucking company I worked for in the 80's and 90's (For 15 years) Thomas Produce, later Thomas Transport, Greensboro, NC bought a bunch in the lates 70's early 80's.  Cummins told them for every one they brought in without an overhaul in 1,000,000 miles...they would give them a new one!  After what I think was 7 new ones, Cummins said, "Look, we have to stop this!"  (We ran west coast, team, we could put a million on in just over 4 years!)
If that engine did not ever run hot, and if the oil was changed regularly...you coundn't stop them!
(Of course when it saw a hill...it jumped into high range reverse!

Most folks I have talked to that had them in their boats love 'em!

Jack

[JeffsMagicBus]

                           SCREAMIN' JIMMY!
  I Don't Condone Speeding But Sometimes You Have To Just Go With The Flow...
All I Can Say Is My Non Turbo 8V-71 Only Has About 318 Horses I Think It Is And I Can Pass ANYTHING I Want To No Matter How Many Horses They Have. The 1,000 Mile Trip Bringing Her Back Home Was Quiet Interesting With All Those Big Rigs Pulling Up Beside Us Just Trying To Pass Us. I Had All My Bays Full Of Parts And They Would Get Me On The Downhill Side But I'm Not One To Go Hammering It Downhill Either! Uphill's A Different Story!
Once When I Was Asleep In The Seat Behind The Driver's Seat, While My Friend Frankie Was Driving, I Thought I Was Still Driving And That I Had Her Kind Of Wound Out And That I Should Let Up On The Acclerator But It Didn't Let Up When I Lifted My Foot Up! I Mean I Tried Letting Up On It A Couple Of Times Until It Startled Me, Or Scared Me, Awake! All This Time I Was Hearing These Obnoxious Whining And Whistling Noises... I Looked Up To See Those Big Rigs Hammering Down On Us While We're Just Minding Our Own Business In The Middle Lane. Turbochargers Whistling On The Right, Superchargers Whining On The Left. It Was Kind Of Weird Seeing Their Hoods Even With The Bottom Of The Windows And We Were Crossing The Bridge Into Memphis To Top It Off! Man What A Sight Seeing Memphis Lit Up At Night And You Should Have Seen The Panaramic View Through The Whole Right Side Of The Bus! Needless To Say, The Hoods Weren't There Long Buddy! I Thought They Were Going To Blow Both Their Rigs As They Were Wound Out. And Remember Kids... Don't Try This At Home!
Let's Just Say A Professional Driver On A Closed Course Could Cruise At About 83-85 In My Crusader.
  And It Was Not Designed To Get Any Kind Of Gas Mileage So That's Irrelivent! I Think It Was Originally Designed In The Mid To Late 30's. That Says It All! Why's It Still Around? Cause You Have To KILL Them To Get Rid Of Them! And There IS Absolutely Nothing That Compares To The Sound Of A Screamin' Jimmy! There's Been More Than One Kind Of Unidentified Flying Object Coming Out Of Roswell...
                                                             
                        Take Care,
                                        Jeff