| Author | Message | ||
| Norm Edlebeck (Bandleader)
Registered Member Username: Bandleader Post Number: 62 Registered: 2-2004 Posted From: 98.135.136.131 Rating: N/A |
I have a 1970 MCI Model MC-7 with DD 8V-71. I am now a full timer and will be going up mountains and high elevations. At these elevations, I don't have a lot of power. In fact, I'm belching out black smoke and also (I believe) even black soot. Can I, and would it help, to install a turbo to this engine, or is it something that CAN'T be done, or won't help if it is added???? | ||
| peter river (Brightstone)
Registered Member Username: Brightstone Post Number: 2 Registered: 8-2009 Posted From: 24.234.166.174  Rating: N/A |
I was belching soot, and when I examined the tailpipe, it had a 30% constriction. once that was eliminated, no more soot. do the best to open up the intake and exhaust, let your engine breathe. | ||
| Ralph Peters (Ralph7)
Registered Member Username: Ralph7 Post Number: 44 Registered: 3-2004 Posted From: 206.251.5.175 Rating: N/A |
If you have a turbo block you can go to 400hp, without aftercooler you stop at 350hp. Also auto trans adds heat to motor, I used a firetruck engine set at 375hp, and used an air to air trans cooler. My old 8-71 non turbo was set at 325hp, it has 70 injectors smoked under acceleration. You can add a turbo, but the$$$$$ to mod the intake & exhaust will be the same as adding a 8-71TA. How big are your radiators, misters may not help much, also do you have the large muffler? I did not need to change the muffler on my MC-8. If you like call me, check my profile. | ||
| Sean Welsh (Sean)
Registered Member Username: Sean Post Number: 965 Registered: 1-2003 Posted From: 67.142.130.33  Rating: N/A |
Yes you "can" add a turbo. But understand that this is not a simple as bolting the turbo onto the engine -- turbocharging the engine will change the mixture, so you will likely need different injectors and cams, and, as noted, you may also need larger radiators and fans, as well as changes to the intake and exhaust plumbing. Plus, you'll want the charge air cooler. When all is said and done, the cost to turbocharge a normally aspirated engine tends to be prohibitive; it you want a turbo, swap the engine out for one that already has it. You will be money ahead. JMO and FWIW. -Sean http://OurOdyssey.BlogSpot.com | ||
| Len Silva (Lsilva)
Registered Member Username: Lsilva Post Number: 285 Registered: 12-2000 Posted From: 24.164.20.23  Rating: N/A |
"When all is said and done, the cost to turbocharge a normally aspirated engine tends to be prohibitive; it you want a turbo, swap the engine out for one that already has it. You will be money ahead." I would like to add the precaution that you check the serial number of any replacement engine to be sure it was born that way, and not upgraded by who knows who. | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 941 Registered: 10-2006 Posted From: 76.202.165.190  Rating: |
"I was belching soot, and when I examined the tailpipe, it had a 30% constriction. once that was eliminated, no more soot. do the best to open up the intake and exhaust, let your engine breathe." Excellent advice , listening to the truck shows on XM , they all believe the $160 muffler sold by Pittsburg power is well worth the cost. Even tho we don't roll 150K + per year , it still should help. Think of it like glass packs for your 48 Merc. But there claimed not to add noise. FF | ||
| Larry Baird (Airhog)
Registered Member Username: Airhog Post Number: 172 Registered: 1-2001 Posted From: 159.115.178.66  Rating: N/A |
I have an MC-7 with a 8-71T (348 HP on the dyno)all new parts, heads, pistions, sleeves and anything else I could find new, stock injectors. I also have a dual oil cooler 2 extra radiators and 5" pipe from the turbo to the tail pipe, short muffler 5" stright through. I run an 10 speed RTO trans and 24.5's. Sunday I took the bus pulling my car from Big Bear, CA (8'000 ft.) the back way down, same way I went up 16% grade, I do have Jakes and yes they work great on a 2 stroke. I went to Lone Pine, CA where I keep the bus for the winter and Spring. It was 110 degrees sunday at 2PM and it's a good climb up 395, the slowest I got was in 7th gear about 45 mph and the motor was at 190-195 degrees. I had a lot more power but couldn't use it without the temp climing so when the pyro went up the gear went down, gota love that 10 speed! I will be adding misters. It is my understanding that you must change the pistons if you add a turbo, I went for the complete turbo motor. As for the fab work on the turbo part that was easy and I installed a large dry air filter. If your doing all this work you can beef up the frame, I found a lot of cracks and MCI had a fix using plates on the sides of the frame so I did that when it was out. I have a new 740 trans I was going to put in but went with the 10 speed for milage and less heat to get rid of. | ||
| Tom Christman (Tchristman)
Registered Member Username: Tchristman Post Number: 114 Registered: 1-2006 Posted From: 66.218.33.156 Rating: N/A |
I have a transit with 8V-71 and V730 (3 spd) Allison transmission with 4.56 rears that gives me 1800rpm at 58mph, or 66mph at 2100rpm. I too had black smoke at altitude with lower power-couldn't live with that so looked into turbocharging the 8V-71. Had Don Fairchild in Bakersfield, Cal. do the work. First I had a custom air to air intercooler made and mounted it in front of the radiator. Once Don had it, he pulled the engine (easy with a V drive) and popped one of the pistons out and found they were two piece with the "tight" rings, so turbocharging could be done even though the pistons were the high compression at 18.7 to one (17 to one is the norm for turbocharging). Don went from brown tag N65 injectors (304hp with 800lb/ft torque) to 9G75 injectors (375hp with 1125lb/ft torque on the engine dyno) and added a fuel modulator to cut down on the black smoke from start (still smokes at first, but then the Series 60 turbo kicks in and no smoke when pulling a hill). Ultimately I had to upgrade the radiator from a 5 row straight fin to a 6 row serpentine fine core (the biggest I could go), added 15 misters to the radiator (over 90 degrees have to go slow on hills), changed the muffler (already had a 5" system), air cleaner, added an auxiliary transmission cooler, had the transmission overhauled at the same time (that was $6,500.00), and rebuilt the starter since the engine was out. With trans overhaul, I spent about $17,000.00 total over about a year on it. Was it worth it-yes! The performance difference was dramatic. Where I would have to down shift on rolling hills, now just powered over them. On long steep grades-about 15mph faster (which from 28 to 43mph is a lot). Also, went on California highway 4 from the east at highway 89 to the west to Angels Camp this summer. With 24% grades on some switch backs, can tell you without the turbo, would have gotton stuck (wouldn't have even tried). Changing out the engine to something different will cost at least the same if not more. I can tell you that turbocharging the 8V-71 REALLY wakes it up. Good Luck, TomC | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1626 Registered: 10-2003 Posted From: 71.58.110.9  Rating: N/A |
For the kind of money you'll get into, just upgrade to a newer coach with the larger engine that was built for the greater horsepower. Used coaches are pretty cheap to get nowadays, as there is a glut of used ones out there. | ||
| David Lower (Dave_l)
Registered Member Username: Dave_l Post Number: 197 Registered: 11-2007 Posted From: 67.58.201.132  Rating: N/A |
Larry what was the cost of the 740 if you dont mind me asking. Dave L | ||
| Norm Edlebeck (Bandleader)
Registered Member Username: Bandleader Post Number: 63 Registered: 2-2004 Posted From: 166.164.148.214 Rating: N/A |
Thanks everyone for your input on adding a turbo to my MC-7. From your answers however, I think the cost at this time is prohibitive. I just changed the four cartridge air filters - old ones were about half clogged - couldn't see light through them. Also, I DO have the large muffler, and actually have no problems with excessive black smoke and/or power down near sea level. Today I was running 70 - 75 mph without any smoke or overheating. Of course I had a tail wind and was going across Nebraska, AND it was cool out, so ideal conditions you don't usually get. I can live with it the way it is, but don't know the working of engines - anything else, I usually can fix. FastFred - what is this $160 muffler you're talking about. Would this help some, and if so, where do I get one??? Otherwise, the coach is running pretty damn good for 40 yrs old. Thanks Again Guys!!!! | ||
| David Lower (Dave_l)
Registered Member Username: Dave_l Post Number: 198 Registered: 11-2007 Posted From: 67.58.201.132 Rating: N/A |
It's a straight flow muffler 5 inch inlet and outlet, 10 inch diameter and 51 inches long, as Fred said it is about $160. they said it would help alot for my engines breathing if I can make it fit. pittsburgpower.com is there web site they do say good things about it on road dog on sirius/xm Dave L | ||
| Larry Baird (Airhog)
Registered Member Username: Airhog Post Number: 173 Registered: 1-2001 Posted From: 173.58.244.25 Rating: N/A |
If you pick it up you can have it for $3500.00 with the shift tower, no cable. Thats about half what is cost. | ||
| ED Hackenbruch (Shadowman)
Registered Member Username: Shadowman Post Number: 161 Registered: 11-2003 Posted From: 75.216.140.36 Rating: N/A |
If your air filters were that dirty that could cause a lot of your problem. As they get plugged up you are getting less and less air which means that your fuel to air mixture is getting richer which means more fuel is not combusting as it should. The result of that is more black smoke/soot/less power/worse mpg, and more engine heat. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 996 Registered: 11-2005 Posted From: 208.54.200.69  Rating: N/A |
Norm, If all else is in good shape black smoke on grades means you are over fueling the engine, in other words you are pushing too hard on the go pedal. If you push and the bus won't accelerate you are pushing too much. Back off and the smoke will stop. Higher elevations mean less oxygen so the engine can't take the normal amount of fuel and still burn it all. |
