| Author | Message | ||
| Jim Wilkerson (Wagwar)
Registered Member Username: Wagwar Post Number: 37 Registered: 12-2009 Posted From: 12.158.159.58 Rating: N/A |
I realize this probably falls under the 'religious discussion' area, but I'm willing to listen to the pros/cons if you're willing to share! The bus I'm looking at is an '81 MC 9 and has no tach. It's an automatic and the owner says that with the 6V92TA and auto trans, a tachometer is really not necessary. He's been driving these things for 40 years so I'm sure he's developed some sixth sense that I don't have. I'm used to having a tach in my vehicles and it seems to me that a tach is a good idea w/ these 2-stroke diesels. What is the consensus here? | ||
| Tim Brandt (Timb)
Registered Member Username: Timb Post Number: 505 Registered: 10-2003 Posted From: 66.165.176.62  Rating: N/A |
Tach is all I have no speedo  I also have a manual transmission so I see it as a necesity. | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 1243 Registered: 12-2000 Posted From: 173.126.40.216  Rating: N/A |
I am sure I could drive without it, but I really would miss it. I guess I am a "data nut", but the more information I have the more comfortable I am when driving. I watch the tach, especially in the hills and manually shift our automatic, rather than wait for the transmission to do it. Waiting for the transmission to do it, sometimes lets the RPM get to low. Jack | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 1106 Registered: 10-2006 Posted From: 69.19.14.32  Rating: |
You have a slush pump so you dont have to shift . On a stick running to the gov takes care of shifting up, a couple of pips on the speedo takes care of downshifting . An extra top pip on the speedo takes care of over speed in high. 10c worth of colored tape ,no wiring, no maint , same information. FF | ||
| Justin Burie (Justinb)
Registered Member Username: Justinb Post Number: 8 Registered: 1-2010 Posted From: 209.254.23.194 Rating: N/A |
Given that my diesel experience came on at the demise of "V" configurations, I'm used to upshifting at 1600pm & downshifting at 1050(MBE4000) to 1200rom (all else). No Tach on the 6V lands in the "You really don't wanna' know..." category. lol | ||
| Jim Wilkerson (Wagwar)
Registered Member Username: Wagwar Post Number: 38 Registered: 12-2009 Posted From: 12.158.159.58 Rating: N/A |
"An extra top pip on the speedo takes care of over speed in high." Sorry, I'm new to this bus stuff: What's a pip? What's an extra top pip? So, Fast fred, you're saying save my money and use some colored tape on the speedo at the speed that the auto shifts at? JustinB wrote "No Tach on the 6V lands in the "You really don't wanna' know..." category." Is that a good category to be in? Sorry I don't understand. Thanks! | ||
| John & Barb Tesser (Bigrigger)
Registered Member Username: Bigrigger Post Number: 374 Registered: 9-2007 Posted From: 96.42.5.35  Rating: N/A |
Gladys Night had pips... | ||
| Patrick levenson (Zubzub)
Registered Member Username: Zubzub Post Number: 184 Registered: 5-2007 Posted From: 70.52.29.59  Rating: N/A |
I have a tach on everything but my bus...but as soon as I get an alternator my bus will get one too. I like having a tach, helps me understand the engine better, some days rpms feel different so without one I worry too much. | ||
| john degemis (Degemis)
Registered Member Username: Degemis Post Number: 95 Registered: 3-2008 Posted From: 68.113.39.64  Rating: N/A |
If that is the only thing you do not like about the coach I would say go for it. You should be able to add one. | ||
| Justin Burie (Justinb)
Registered Member Username: Justinb Post Number: 9 Registered: 1-2010 Posted From: 209.254.23.194 Rating: N/A |
Jim, The "Don't wanna know" is related to how much faster the "V" configuration engines turn to do the same work. I am used to engines that spin at a much slower rate. The higher rpms on the 6V92 would take some getting used to on my part. | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 1092 Registered: 7-2006 Posted From: 74.162.82.139  Rating: N/A |
Just one more distraction, if ya' ask me.. With a standard, you know your shift points associated with your speed; A tach is redundant. With an automatic, it's essentially the same. The auto tranny takes most of the human factor out of it, but you still know the usual shift points to do it manually. Even with a passenger full bus and no speedo, you could always feel the engine vibration through the shifter for upshifts, and coming downhill, the passengers screaming when you miss a downshift. A tach isn't a necessary instrument, if it was, every passenger bus would have had one. But if it's what you enjoy looking at, go for it! | ||
| Tony Gojenola (Akbusnut)
Registered Member Username: Akbusnut Post Number: 46 Registered: 11-2006 Posted From: 208.98.151.220 Rating: N/A |
There are other things to consider besides shift points in this debate. I have a good quality large-sweep tach running off the alternator in my 4106, and with a V-730 the ordinary shifts don't care what it reads - so that part of the argument is valid. However - I like to know the rpms when cruising, and diligently try to keep it around 1850 to 1900. That's where it's supposed to be most efficient (the sweet spot as they say.) Secondly - and this has been even more useful at times - It constantly tells me if the charging system is working as it should. Any erratic movement or bouncing of the tach needle indicates a problem in the system that needs attention. tg | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 1161 Registered: 7-2006 Posted From: 75.243.189.10 Rating: N/A |
Bigrigger... If I had a choice...and I do at present, Tach is primary....having said that, I have been trying since last fall to "repair" my speedometer- new cable, front to rear, new gear at Transmission, speedo checked out etc. Alas, SPEEDOMETER NOT working! However....this is the second time around for this scenario; with the first, because I have a Tachometer, I learned very quickly the shift points, the speeds at which I was traveling and feel very comfortable with it that way...have traveled several thousand miles without a speedometer "working". Now...having said that, I had the Tach go out when the fuel pump went south (Speedometer also not working)....really felt lost and could not "get things just right" till the Tach was back in service. My vote is definitely for a Tachometer...but, just because the coach you are considering does not have one, no matter...just add one> FWIW RCB | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 1093 Registered: 7-2006 Posted From: 74.162.82.139 Rating: |
A nice GPS unit is the best speedometer around! For what that's worth? | ||
| Laryn Christley (Barn_owl)
Registered Member Username: Barn_owl Post Number: 647 Registered: 10-2006 Posted From: 151.199.88.171  Rating: N/A |
"A nice GPS unit is the best speedometer around!" That was home run and I couldn't agree more. I added a tach to my bus, but like most have said, it is not something I have to have. | ||
| Paul Lawry (Dreamscape)
Registered Member Username: Dreamscape Post Number: 639 Registered: 5-2007 Posted From: 64.40.215.225  Rating: N/A |
I like a tach because I can't hear my DD much. It's good to know what rpm you're running especially when climbing. That's my story and I'm sticking to it! It's like the ford chevy thing, some like it some don't. | ||
| Cory hart (Chart1)
Registered Member Username: Chart1 Post Number: 22 Registered: 1-2010 Posted From: 67.184.212.122  Rating: |
Not everyone has that nitch to feel the engine as they are driving. That is something that you acquire over time on the road. The tach is a good tool to use for detecting a potential problem before it turns bad. For instance if you run down the highway at 60mph @ 2000 rpms and thats your norm. Next trip out and all of a sudden your doing 65mph but your rpms are at 2300 there could be tranny slipage , a low tire holding you back or many different possiblities. But you do know something, there is a problem somewhere. I had this happen to me where a tranny oil filter come loose and was leaking and i noticed the rpm where higher than normal for the speed I was going so I pulled over and sure enough tranny fluid dripping down. Bottom line is my tranny didn't burn up (because of the tach), and I was back on the road in 30 min. | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 1107 Registered: 10-2006 Posted From: 66.82.9.49 Rating: N/A |
I like to know the rpms when cruising, and diligently try to keep it around 1850 to 1900. That's where it's supposed to be most efficient (the sweet spot as they say.) Take your tire size and stick them in Darises great computer. What ever the 1800-1950 economy spot gives as a road speed MPH will be accurate till you buy new tires. No tach needed. FF | ||
| Paul Lawry (Dreamscape)
Registered Member Username: Dreamscape Post Number: 640 Registered: 5-2007 Posted From: 64.40.215.225 Rating: N/A |
Just because some do not like tachs does mean that everyone should feel that way. If it feels good, buy it and install one. I think they are a necessity, but that's my opinion and mine only. Besides I like the way they look! | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 1094 Registered: 7-2006 Posted From: 74.162.75.121 Rating: N/A |
Re: "Just because some do not like tachs does mean that everyone should feel that way." Amen !! Ya' gotta' do what feels good to ya'! It doesn't hurt to have all the gauges you desire to provide all the data you desire. Well..... as long as the pile of After Market Gauges, GPS Units, Radar Detectors, Satellite Receivers, Back-Up Camera Monitors, Inverter Monitors, Generator Monitors, and various other neat, great looking dashboard stuff doesn't obstruct your view and concentration of the road ahead... Personally, I never bothered looking at a tach, even in a V12 Brockway; the shift of a Roadranger came easy compared to a bus, since you could hear the engine roaring away. In a bus, the governor will let you know when you can't shift, and most every bus nut figures that out pretty quick. Even without a speedometer, it's fairly easy to judge the right shift points by how quick crap is flying by your window, and the engine vibration we feel while driving... But the bottom line, is that it's fine to have anything you want to have, regardless if it's absolutely needed, or not. There's no right or wrong, just preferences. And that's What Jim wanted to know... who feels what way about it... | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 861 Registered: 8-2006 Posted From: 74.32.83.4 Rating: N/A |
A tach would be good for you on a 92 series engine they are not like a 71 series 1800 rpm is where they like to run that is where the top of their torque curve is. good luck | ||
| john degemis (Degemis)
Registered Member Username: Degemis Post Number: 96 Registered: 3-2008 Posted From: 68.113.39.64 Rating: N/A |
"A nice GPS unit is the best speedometer around!" Would like more info on this. My speedo is not working. | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 1163 Registered: 7-2006 Posted From: 75.242.244.32 Rating: N/A |
Tough to watch a GPS and the kids....in a School Zone... Audio would be a great idea....but then what does one do about counting the miles trip by trip, day by day. Or do Gps's come with an Odometer?....neither of mine do. Seems like a pain to me. To quote FF...."do it your way"..... RCB | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 1095 Registered: 7-2006 Posted From: 74.162.75.121 Rating: N/A |
I have an old Garmin, but they all usually have a speedometer and odometer as part of the readout. On the Garmin, the display can be with the speedometer fairly large, and easy to read. You can also set the trip meter, and alarms, so the package on some of these units (even the older GPS models) can be damned nice! The accuracy is better, since it's via GPS readings, and has nothing to do with tire size, etc. (I use it to check my vehicles speedometer's for accuracy). My bus is long gone, but the speedo was about 8mph off, probably due to the 315 tires I had on it. I paid $15 for my used, older Garmin with a black and white screen; it does a lot more than a speedometer... | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 1165 Registered: 7-2006 Posted From: 75.242.244.32 Rating: N/A |
Good fer ya' JTNG!...Tom Tom is...apparently short of attributes...so is Co-Pilot 10. RCB | ||
| John MC9 (John_mc9)
Registered Member Username: John_mc9 Post Number: 1096 Registered: 7-2006 Posted From: 74.162.75.121 Rating: N/A |
RC Not sure about "co-pilot 10", but the Tom-Tom has a built-in speedometer/odometer on most models. Have you checked to see if there's any upgrades to your Tom-Tom? | ||
| Tim Brandt (Timb)
Registered Member Username: Timb Post Number: 506 Registered: 10-2003 Posted From: 74.244.14.221 Rating: N/A |
They are really pricey but they do make an analog speedometer that uses GPS for the signal http://www.google.com/products?hl=en&q=gps+speedometer&um=1&ie=UTF-8&ei=qPaaS4DqMIH-8AaJg9 mtDg&sa=X&oi=product_result_group&ct=title&resnum=1&ved=0CDAQrQQwAA | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 1167 Registered: 7-2006 Posted From: 75.242.244.32 Rating: N/A |
And when it is not ..."on"???. RXB | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1825 Registered: 12-2000 Posted From: 76.69.141.216  Rating: N/A |
Hello Jim. Your 4 speed auto tranny only has three shift points, and with only 4 gears, the overlap is only a handful of mph. Basically, you are in the gear that road speed dictates. You don't really have any choice. So, putting a little "pip" of nail polish, white out, paint, etc on the speedometer at the speeds that each gear is against the governor does the job in the style of FF. Even with a manual transmission, the same conditions apply: there is very little overlap in gears in a bus, road speed dictates the gear. A tachometer is a fun thing, however, there are lots of necessities to pay for before I would bother with a tach. Also, an automatic in a coach of that vintage behaves much better if you shift it yourself. Leave it in 2nd, the transmission can be trusted to behave for the 1-2 and 2-1 shifts, in town. Beyond that, you choose when to allow the upshifts. The transmission often will attempt upshifts too early, and then downshift with a bang under any greater throttle. Lots of threads on shifting your automatic. happy coaching! buswarrior | ||
| Tom Christman (Tchristman)
Registered Member Username: Tchristman Post Number: 191 Registered: 1-2006 Posted From: 66.218.33.156 Rating: N/A |
I installed a tach using the tach generator drive that was already there off the back of the blower. I'm glad I did (even though I have a V730). I found that on light acceleration, I can get a low shift where the transmission locks up in second giving 1,100rpm! Full rpm shifts are at 1950rpm, and my no load is at 2,400rpm. I cruise at 58 mph which is 1800rpm-which most any truck/bus Diesel will run all day at. I use my tach more then my speedo. My speedo is off by about 5mph (the odometer is almost right on), so I usually use the GPS for a speedometer. I have tachometers on all my cars/trucks/bus. Good Luck, TomC | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1866 Registered: 10-2003 Posted From: 71.58.71.157  Rating: N/A |
I like the importance of having a tach to avoid lugging as much as the other benefits. How about that long gradual grade that you are pulling at 1400rpms but aren't losing speed, but you don't know that you are lugging it/ Or your automatic that doesn't downshift till 1300 because the governor is off, but you don't know it.Or engine governor is off and engine runs at 2600-2800 against the governor, but you don't know it. Or you let it over rev on downgrades, but you don't know it. Tachs are cheaper than replacing cracked heads/ damaged valves/ engines. Yes, you'll know by the engine heating up that you may be lugging, but how long do you let it heat?? Anyway, just food for thought. BTW, I wouldn't have a coach without a tach. It provides useful and important information to me. It is also not as expensive as some think to get and install one. But I also have an air drier which some think is not necessary either | ||
| John & Barb Tesser (Bigrigger)
Registered Member Username: Bigrigger Post Number: 375 Registered: 9-2007 Posted From: 96.42.5.35 Rating: N/A |
Just to add to the mix, my 4107 has niether a tach or an air dryer. It doesn't mean it's better that way, but it's just the way it came from GM and through Greyhound and several previous owners. I don't have any trouble knowing when to shift as it does have an accurate speedometer. Gradual grade or steep when I reach a certain speed I know it's time to drop a gear. I do miss being able to hear the engine though like I always could in a truck, so at some point I may decide to add one on, but not because it's a necessity more of a convenience. | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1693 Registered: 12-2000 Posted From: 67.182.48.162  Rating: N/A |
Tachs are useful toys. Some folk think they're useful tools. IMHO, same difference! FWIW & HTH. . . |
