| Author | Message | ||
| Jason (24.207.157.60)
Rating: N/A |
Is there an easy way to make a transit do 70-75? Are there any transits that will keep up to speed on grades such as the Appalachain mnts.? If so what or what engines/trans would be needed. I would prefer to get a transit and not have to switch out the enging/trans. | ||
| Bradd B. Smith (Bbsrtbusproject) (216.18.141.99)
Rating: N/A |
Hi Jason, I have an '80 Flxible. It has a 6v92ta DD engine and a 730 Allison trans. It has a 375 rear end set and will do 75 all day long. It is not bad on fuel to boot. Not all transit buses are block to block type. On the hills out west, where I am, It will climb at a good rate, but you do have to watch the temp. There are other set-up's that will do this. Henry's Crown super will for sure, and so will several others. The Crown is like a transit in quite a few ways, and designed like a brick..., well you know. Tough! If you have to make one do it, get the big Detroit turbo, do the 350 hp. number and get a tall set of rear end gears. Varooommm. The 400+ horse Cummins will do it to! There are guys adding a little propane to the air before it gets to the turbo and seem to be having good results. I personaly am not in that much of a hurry, and would not and have not tried it. That said, easy, would be something you could put in the fuel tank and go. Everything else will be work and ca$h. Or to quote, how fast do you want to go? How much money do you have? Check this boards fine keyword search, much information by folks who know mucho mas than me. Luke could tell you exactly what you need for a particular application off the top of his very experienced head. Hope this helps, and best of luck, Bradd | ||
| RJ Long (Rjlong) (24.127.74.29)
Rating: N/A |
Jason - If you search out the transits that have T-drive powertrains, then it's easy to swap out the rear axle pumpkin for taller gears to get the top speed you want. V-drives are pretty limited in the ratios that are available. Be aware that it takes LOTS of HP to push 30,000 lbs up a 6% grade at 75 mph. Even the high-end Prevosts w/ 500 hp Series 60s have trouble doing that, especially out west at 7,000 ft elevation. Understand, you're going to have to compromise. You either get a rear axle ratio that gives you lots of top speed, but poorer acceleration and hill-climbing ability; or a ratio that gives you good acceleration and hill-climbing, but lower top speed. Now, if you get a later model unit with one of the World transmissions in it, then you can go with the good acceleration axle, and have DDA unlock the overdrives in the tranny, to give you top speed cruising. But you'll have to spend the $$$ to get one. . . HTH, RJ PD4106-2784 Fresno CA | ||
| Quest (198.29.191.147) Rating: N/A |
Ok guys, let me ask this as I have never had a problem with the mountains in the RV. What happens when climing a hill, do you have to slow down to 10 mph and do a slow climb, will the bus go 40mph up the hill? I have no reason to believe that the bus will make it without slowing down some. Then the stories of Black smoke or white smoke while climbing - sheesh, what else is there, oh yeah, the engine temperature climbs and damages the seals or the pistons. Ok, now, whats a guy to expect on hills going up, but then again, watchout going down, thats a whole new plan of adventure. | ||
| FAST FRED (63.215.235.188) Rating: N/A |
DEPENDS , ya thats helpfull , but the weight and hight of the coach are critical. In my experience most grades are limited to 6% so the occasional mountain pass might be different , but much of the Slab is the same. ON my 4106 , with Mountain gears (4905 4 3/8) the unit will climb the 6% grades at top speed about 46 @ 1900 RPM in third.(C-60 injectors) With a flank speed running start it takes about 2 - 3 miles to slow from 70 , to downshift speed. However this may not be a good comparison as there are lots of coaches that weigh DOUBBLE , and have the same engine . So how fast you climb hills will be detirmined by weather you chose a light weight monocoque coach , install a simple lightweight interior , and keep a 10 ft hight , OR ???? Your results WILL vary, but the scenery is fine at 46 , you can still pass the truckers , and there is never a black smoke or overheat problem with such small injectors. FAST FRED | ||
| RJ Long (Rjlong) (24.127.74.29)
Rating: N/A |
Quest - It depends. . . (how's that for a non-commital answer???) Seriously, here's some averages for you to mull over. Most highway coaches, and the ones most frequently converted and talked about on these message boards, traditionally have been powered by the 8V71 or 6V92TA Detroit Diesels, tuned for about 270 - 300 hp. Most three-axle forty-footers weigh about 30,000 lbs in normal operating trim, with passengers & luggage, give or take a couple thousand lbs. This gives about a 100 lbs per hp operating weight, again, give or take a little. Translated, this means that most coaches as described above, will pull 6% grades around 35 mph in second gear (be it a manual 4-spd or the HT740 Allison automatic). The naturally-aspirated 8V71s will fall off of cruising speed faster than the turbo'd 6V92TAs when pulling a hill, but when you get to the meat of the climb, they will both pull just about the same. (BTDT for eight years in the charter business.) It all boils down to "power-to-weight ratio". Drop a 450 hp 8V92TA in the same bus, and it will go up the same hill near the top of third gear, about 45 mph, but you'll have to watch the temp gauge more closely. Regardless of which motor is back there pushing you up the hill, you do have to pay attention to the engine temp gauge, and watch the exhaust for black smoke. If you start seeing lots of black, then it's time to back out of the throttle some, you're overfueling the engine for the conditions, and run the risk of overheating it. If the speed falls off dramatically when you back out a little, then you're in too high a gear for the grade, and it's downshift time. All of the Detroits listed above pull best between 1700 - 1900 rpm on about a 3/4 throttle setting without overheating. A floored throttle, black smoke and 2100 rpm can get you into trouble, especially if it's over 85-90 degrees outside. Once you crest the grade and start down the other side, it's time to flip on the Jake brake and let it do the work of controlling your downhill speed. What? You don't have a Jake? Then use the gearbox and a "stab" braking method (allow the coach a 10 mph speed window, i.e. stab down to 45 mph, allow coach to roll up to 55, stab back down to 45, repeat). And consider investing in a Jake, especially if you do a lot of mountain work, like out here on the left coast. . . (Altho Fast Fred may disagree with me here, even tho he wouldn't give up his speed brakes on his 727s. . .LOL) As you mentioned, Quest, coming down the hill can be a whole new adventure if you're not careful. It's amazing how quickly 30,000 lbs will reach the governor in high gear coming down a 6% grade!!! HTH, RJ PD4106-2784 Fresno CA | ||
| bill chisholm (Billybandman) (169.204.196.24)
Rating: N/A |
Off the subject but will that Flx 375 rear end go in my GMC 4108? If it will I want it. Where can I get one. | ||
| FAST FRED (63.208.87.248) Rating: N/A |
AS RL points out its all in the power to weight ratio , so a light weight interior conversion AND a light weight coach , can be better at hillclimbing than a hot rodded A timed N75 injected smoke belching ,overheating ,behemoth. AS always , its a CHOICE you get to decide, OH did I mention the milage difference,too ? FAST FRED | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A |
Gee, thanks for the ego boost and my name is Henry and I do have a Crown Super Coach, but she only has the lowly big cam 250 hp Cummins without a turbo or intercooler. Must have been confusing me with another Henry who has a Crown also. Yea, my Banana Boat weighs about 25,000 stipped right now and she will climb a 6% grade flat wide open at around 45mph in 8th gear. Not very fast at all. And....if and ever she gets completed as a RV, she will go in at least 32,000, maybe 34,000 pounds. Kinda heavy. Soss that means the coach will go up the steep ones at around 30 or 35 or about. If the bank account holds out, I may be able to $afford$ to update the 250 into a 400 or maybe a 444 using factory used parts, but don't count on it. Not enough money. But...it would be neat being able to go up hills at cruising speed. Thanks. | ||
| FAST FRED (65.58.187.241) Rating: N/A |
...".if and ever she gets completed as a RV, she will go in at least 32,000, maybe 34,000 pounds." Depending on the materials choices YOU make an interior can be about 1000lbs. This would be for simple plywood cabinets and draws on slides. Counter top of formica , rather than slate , and a simple floor cpvering , rather than tile. Leave the Rumford Fireplace , Cast Iron Bathtub and brick wall covering for someone else. With out spending Big time or Big bucks there is always a series of choices , and one is frequently lighter than the rest. Remember all that weight you pay time & fuel dragging up to the top of the hill , gets to drag you back down at a ever increasing speed too. Most homes have NO consideration about weight , so don't use house framing techniques , chipboard cabinets , counter top underlay , ect. Get a tour of an older Superior MH to see how fast and fine a light weight interior can easily be built with stock aluminum pieces. FAST FRED | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A |
Oh well, guess I will have to chuck the 1000 gallon hot tub and the solid brick fireplace and the 6 inch armor belt. He he he. What is going to kill me is the 2000 pounds or sosss of batteries, plus the second 150 gallon fuel tank, the 250 gallon water tank.... The matching holding tanks, the big diesel APU, the three roof AC units, etc., etc., plus all the junk one usually accumlulates. Your point is well taken Fred. Already I am trying to find ways to do it $cheaper$ and lighter, mostly $cheaper$. Thanks. | ||
| Tom Caffrey (Pvcces) (64.114.233.139)
Rating: N/A |
Henry, for personal driving pleasure, I think you will like lighter, too. Tom Caffrey PD4106-2576 Suncatcher | ||
| Johnny (63.159.129.114)
Rating: N/A |
Am I alone in seeing the irony of the guy with probably the highest GVWR & chassis capacity here talking about weight issues?  *Envys Henry's 48,000lb GVWR Crown* | ||
| steve souza (Stevebnut) (24.91.90.28)
Rating: N/A |
My AM General at 23,360 pounds on a trip to vermont and new hampshire slowed down to 25 mph on the mohawk trail climbing to the hairpin turn. It has a 6v71 two valve with c60 injectors rated at 190 hp. The tranny is a vh9 two speed which would lug down from high gear to hydraulic at about 25 mph and upshift at about 29 mph so if i keep it in hydraulic or under 29 mph iwould climb steady but if i were able to accelerate above 29 it would ahift up and the motor would lug back down to 25 mph. On the real long steep grades i would actually slow to 10 mph with the pedal on the floor and wondered if i would make the hill at all. I am changing the injectors to n70 or n75 and thinking it may help a bit on power, but i achieved over 9 miles per gallon and enjoyed the trip tremendously even though my brother in-law in his class a laughed at my hill climbing ability. Some buses may be sorta slow but the ride quality with airbag suspension and large tires plus great fuel mileage make them unmatched in comfort and durability. I traveled about 600 miles with the pedal to the floor and the detroit seemed to love it! I have been told by truckers to drive them like you hate them and never lug them. Seems true I am hopeing to put in a three speed v730 thinking that i can maybee climb the hills in second at 35 or 40 mph instead of low at 25 mph. It is all fun at any speed behind the wheel of a bus. Steve | ||
| Jason (24.107.39.46)
Rating: N/A |
there is a transit on ebay with a "silver 92" Detroit and a 3 speed auto with highway gearing. How fast do you think this could go up a 6 degree grade? Is that the OEM engine for this bus? Am I asking too much to want a transit to go as fast as traffic up a grade? thanks | ||
| RJ Long (Rjlong) (24.127.74.29)
Rating: N/A |
Jason - Go back to the original post for this thread, and read my two responses. You're question has already been answered, but the Cliff's Notes version is this: NO, any bus with a 6V92TA Silver 92 and an Allison V-730 three-speed automatic and highway gearing will NOT go up a 6% grade as fast as traffic. About 30-35 mph will be about all. That's why there are truck lanes on these grades. . . Even VW microbuses will outrun you, but barely! HTH, RJ PD4106-2784 Fresno CA | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A |
I lied, but I did not see it till now. My Crown stripped goes in at 23,950 pounds, has a GVWR of 47,160 pounds and will right now only climb a 6% grade flat wide open at around 38 to 40 mph in 7th gear. Sorry I bo boed. CROWNS FOREVER!!! | ||
| Johnny (63.159.193.33)
Rating: N/A |
Wow--I thought the coaches would be better hillclimbers than that. While it's not converted yet (progressing slowly but surely), my Ford/Thomas hasn't yet seen a hill I couldn't maintain 65-70 up, still in high gear. The only time I had to downshift was when a dingbat in a box truck cut me off & dropped me to ~50 up a hill. That 460 is STRONG. Having said all that, I don't even want to THINK about taking those same hills with the stock 370. | ||
| Buswarrior (Buswarrior) (64.229.215.195)
Rating: N/A |
More grist for the mill... The brand new big motor coaches don't "roar" up these hills either. So, enjoy the view, or use the car? A brand new MCI Renaissance EL3, with a 400HP Series 60 Detroit, and 6 speed Allison B500R World automatic transmission and a bunch of bottoms in the seats climbs that big grade northbound in the bottom of West Virginia on I77 at 50 mph. 5 or 6 miles of 6% give or take? It will climb in either 4th gear, which is 1:1, or at the same speed in 5th gear, which is close to .7:1. (6th is a double deep overdrive of .64:1) Rear end is a number bigger than 4:1 in these new coaches. (Someone else help out here, memory is fading!) All numbers are IIRC, of course! Better to use 4th, as 5th promotes the temp gauge to rise. Nothing new in that! So, our older stock conversions aren't really that much slower, so, to steal an idea from the flying crowd, any speed is a good speed, if you make it over the top! happy coaching! buswarrior | ||
| RJ Long (Rjlong) (24.127.74.29)
Rating: N/A |
Johnny - Weight's the difference here. Most dog-nosed skoolies weigh between 1/3-1/2 that of a highway coach, in normal operating configuration. It's really a no-brainer: Put a 350 hp motor in a vehicle weighing 30,000 lbs and one weighing 15,000 lbs, and it doesn't take much math to figure out which one's going to go up the mountain slower. (Or, for that matter, which one's going to come down the mountain faster!!) You just don't drive a bus like you do a car. (Jason, are you listening???) HTH, RJ PD4106-2784 Fresno CA | ||
| Jason (24.107.39.46)
Rating: N/A |
Well I have thought about it and looked up in my road atlas, and there aren't that many 6 degree grades in our country except in the extreme mountains. A 6 degree grade is significant so I think that 30-35 is plenty of speed for that. The most mountains I see a little bounce of the Appalachains on my way to Florida and that doesn't come near 6 degrees so I think that I am set with 6v92ta and my Ally 4 speed. Thanks for all your help guys/girls! you are great! I am sure you'll hear from me again! | ||
| RJ Long (Rjlong) (24.127.74.29)
Rating: N/A |
Jason - From where I live, if I want to visit any other state, I've got to climb 6% grades in all directions except west - and my '06 doesn't float very well. . . As an example, check out your road atlas: I-80 EB out of Sacratomato to Reno NV. Once you start up the hill at Auburn, you've got nearly seventy MILES of 5 and 6% grades till you reach Donner Summit! No, that's not a typo, it's about 65-70 miles of hard pulling on that grade. It's no wonder Jake brakes are popular out here. . . To us on the west coast, we feel that the Appalachians are nothing more than speed bumps!! 8^) RJ PD4106-2784 Fresno CA | ||
| Peter (Sdibaja) (209.242.148.130)
Rating: N/A |
I think the Atlas must be stating %, not degrees. Grades are always, to my experience, expressed as percentages (%). A 6% grade is quite steep, I believe it is the maximum allowed on the interstate system. Percent of grade is determined by the change in elevation in 100 feet. 6% would be a climb of 6 feet in 100 feet (a little less than 3.5%) A 6 degree grade is about 10.5%, much more than is allowed on the interstate system. As a matter of curiosity: 0% is dead flat but 100% is not straight up, it is 45 degrees… and 200% is still not straight up; it is a climb of 200 feet in 100 feet. Percentage is a ratio, you can not express straight up in those terms. | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A |
Johnny cheated by hopping up a neat 460 Ford then putting it into his light weight ex-school bus. Wish we all could cheat that way. But to do soosss would cost $more$ than the entire coach. If we were all $rich$ and nuts then our coaches would climb as well as a car. Simple power and money. Like most things of human nature you can do most of what you want for about half the conversion budget. It is that last 10% or sosss that ends up costing you as much again as what you have already spent. I would love to do lots of stuff with my Crown. Economics prohibit such. Also more fun can be had... By finding ways to do nearly the same thing only much cheaper by creative imagination. Thanks. | ||
| Johnny (63.159.126.52)
Rating: N/A |
Hopped up? Kinda--except my stuff is about 95-98% factory: original block, heads, crank, rods, stock-replacement pistons, stock-size valves, a cam that's VERY close to a factory grind, an intake that is basically a stocker cast in aluminum, & may yet use a factory carb. Exhaust uses stock iron manifolds. Most of my changes were for durability (like sodium-filled valves & copper head gaskets). It's basically a stock-rebuilt truck engine with a recurved distributor & degreed cam. And could you please explain what you mean by: "Wish we all could cheat that way. But to do soosss would cost $more$ than the entire coach. I don't follow. Having said that, a local hill that drops loaded big-rigs to <45 was handled in a 1980 345 gasser-powered IH 26' box truck (GVWR 29,000, probably running ~25-26K) at a steady 54MPH (admittedly with the pedal matted in 4th gear running against the 3500RPM governor). It isn't a long hill by any stretch (about 1/2 mile), but it's steep (and, due to the RIDOT being run by morons, has 2 lanes with no climbing lane). | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A |
Johnny, you "cheated" by not playing by the normal rules. Most of us are stuck with a heavy big coach conversion. You have a neat, light weight shorty Ford ex schoolie chassis. You did an outstanding job rebuilding your big 460 Ford to work with your application, resulting in a vehicle with a good power to weight ratio, resulting in good hill climbing ability. For us to successfully compete with your power to weight ratios, we would have to spend $thousands$ of bucks. I in paticular would have to spend $10 grand or ssoooo just on the Cummins, not counting driveline or radiator upgrades. | ||
| Johnny (63.159.192.4)
Rating: N/A |
Mine isn't a shorty--where'd you get that idea? It's a 24-seat, 71-passenger, 40' B-700. It even has 10-lug 22.5" wheels. I figure I'll be running ~30-32K GCVW fully converted with a toad, & I have ~325-350HP. | ||
| Bradd B. Smith (Bbsrtbusproject) (216.18.141.206)
Rating: N/A |
Henry, hardly any of us are rich, but almost all of us are nuts! | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.164.175.14)
Rating: N/A |
Boy Howdy on That! |