Slow acceleration

[ken&ellen]

Most of my trips have involved interstate routes with highway speeds,but this last trip to New York involved stop and go traffic on Rt 13 through Virginia, Maryland, & Delaware. In many cases I would have to stop at another signal prior to reaching 40 MPH. I was towing my Jeep Liberty and did not have any problems maintaining 65+ MPH on the Jersey Turnpike nor the NY State Thruway. To use drag strip terminology it seems slow out of the hole! My '91 Liberty has the 8v92 DD and the Allison 4 speed, which were serviced within the last 3000 miles. All gauges were in the green, air filter is clean, oil level was right on, tire pressure was good, and fuel milage was in the 5 mpg range. Maybe it is too much to expect, but it seem as though I should be accelerating quicker. Your thoughts....ole wise POG members. Ken

[Ben]

Clogged fuel filters could be a cause. All it takes a one tank of bad fuel. That's why some people never fill up when a fuel truck is at the station since filling the station's tanks can kick up all the gunk that is at the bottom of the tanks and allow you to pump some of it into your coach's tank.

[Chris and Debbie Yates]

My 95 Royale also has an 8v92 and I find the turbo comes onstream much slower if I am running the busair, this obviously makes the bus slow off the line but it doesn't seem to make too much difference at highway speeds.
Just my 10 cents worth.

Cheers,

Chris

[Joe Cannarozzi]

Try running the dash blower fan on a higher speed, it will make you think you are going faster! Or get somebody else to drive and enjoy, at the rear. I got a feeling your bus runs fine. As they say, it is what it is.

[Jon Wehrenberg]

K and E,

There are some simple things you can check quickly. Do you get full turbo boost when the engine is running above about 1500 and you floor it? If not, or if it is slow coming up look carefully around the manifolds and the inlets to the turbo for leaks, cracks, bad gaskets, etc. Sooting is the thing to look for.

If that is OK, you are dealing with "density altitude" issues. As the summer air heats up, it is less dense, and is the equivalent of operating the bus at a higher altitude. If the bus is sluggish until about 1500 and then gets responsive your engine is probably OK, it just thinks it is operating at 4000 feet or more.

You should have know that, right? Or don't Mooneys have those issues.

[Ray Davis]

It's interesting you mention that. When I was in Salt Lake City, before the air conditioning meltdown, the bus felt very sluggish when accellerating from a dead stop. I thought at the time perhaps it's altitude, as SLC is up in the 5000 foot area.

[ken&ellen]

Jon, Jon, Jon, Density altitude effects all aircraft. My Mooney had a Ram Air system above 5000 ft, but that did not help with take off issues during the dog daze of summer. I am sure that Jerry will say his Doc Killer does not suffer the effects of density altitude, but to some extent all lose some performance. It is a very good point; however since the trip home was in 90 degree heat with very high humidity. Thanks for your insight. Ken

[Jon Wehrenberg]

You shouldn't have tweaked Winchester. Now he will wake up and want to respond about your accurate description of his flying machine.

Do check for exhaust leaks however, but I suspect it is an air density issue.

[rfoster]

Jon: Glad to see on the board again- The high temps have an adverse impact on the performance - My mpg fell off on my last run to Nashville (600 miles round trip) at 100 degrees from 7.82 to 7.37 mpg. Do you think the temps are the problem, I have looked at everything from tire pressure, wheel bearings, brake drag, air cleaner, fuel filter, etc that I can think of. I did run the OTR air all the way. No good answer other than diesel fuel cost more now and am enjoying it less.

Bling the crap out of em Jon!

[Jon Wehrenberg]

Roger,

Your MPG should improve in the summer and decline in the winter. It is just the way things are because the winter air being more dense will require more fuel. The pilots on this forum can look at the performance charts and see clearly that this is the case.

But do not forget other factors. Are you towing? Are you running in more hilly terrain? Do you have a headwind or tailwind? Is your speed the same? Did you get some biodiesel?

I reset my DD Pro Driver at every oil change so the mileage is spread over a 5000 mile range. That tends to average out minor trip variations. I am now averaging 8.3 on this last 1400 miles (to OSH), but I did not tow, so I expect when I do tow, I will pull it down. If we go to FL via Atlanta and we don't go through the mountains I see about a .5 MPG difference from when we run through the mountains.

I think your range is normal.

[Jerry Winchester]

Where was Ken when I was parked next to all the mini Mooney's?

One of the guys that flew in with us told me yesterday before we left that he was going to rethink his whole camping strategy. He said, "Hey, I look like a Mooney guy camping; little bitty tent, SpongeBob folding chairs, and a beach towel for an awning." He had been down to Camp JW where we had the 10' tall tent, full sized awning, generator, chairs, table, Go-PED, ice chest, fan, etc. Of course, you couldn't haul that in a Mooney cuz you couldn't get it in there and still have room to fly it, so density altitude for them was no issue.

Yep, I have to do a MangoMike and work for a couple of days, but when I get caught up, the crap will fly. The photos from OSH will add enough color to keep us whacking Jon until Santa Fe.

And there were exactly two P-210's there. And he pointed them out at every opportunity.

[Jon Wehrenberg]

There were only 2 P210s there because their owners usually don't go back-packing. If we can't do it first class we don't do it.

Hence, Casa del Liberty.

[win42]

7.82, 8.3 mpg. If I ever got that kind of mileage I would shoot up a flare. More like 5 or less towing, 6 not towing. Where I mostly run in CA and OR it is hilly but?
Maybe I need a crash course in accelerator operation. The coach gets serviced on a regular basis. When parked It is started and ran for thirty minutes minimum every month between trips, I'm sure that has some bearing on avg. mileage. Secrets please I need secrets. Maybe I need big tires on the back and little bitty ones on the front so I can travel down hill all the time. Only thing saving my bacon is my Chevron and Exon stock increases.

[mike kerley]

Win42, I'm with you . I get excited when I check in "close" to 6 mpg.

That only happens when I catch a good tail wind for an extended period.

With an 8V92, I think we should learn to expect 5 to 6 (speed makes a very small difference on mine) and accept it. Keep the filters clean, shop for the fuel on line and enjoy the moment.

Mike

[Jon Wehrenberg]

Apples and oranges guys. I recorded every gallon of fuel every put into my 8V92 (I do it for my current bus too) and I averaged 5.6 for the 15 years I ran the coach. That is not a number based on one or two tankfulls, but on annual totals for fuel and miles. It is not as accurate as the figures for the current coach which comes from the Detroit Diesel Pro Driver because the old coach totals include generator operation. I had no way to isolate that fuel use.

The Series 60 by design is a more efficient engine, hence the ability to deliver better mileage (not skewed by generator usage) with a 4000 pound heavier coach. The fuel savings alone is not a sufficient justification to get a newer coach, but it is a major consideration.

[win42]

Mike
Thanks I guess I'm not alone. A friend of mine told me he drove a truck with a 8V92 in it and he was unhappy with it's performance as he was trying to finess his driving. The truck owner told him the only way to drive an 8V92 is to go out in the morning put your hand in the door jamb, slam the door hard on it, get in and drive it pissed off the rest of the day. He said it worked.
I wonder if there isn't a little creative mileage calculating going on. Well I can't imagine !!

[Joe Cannarozzi]

Look at the brite side, this makes for easy fuel calculations, 6mpg divided by 3 dollars a gallon and wala 50cents a mile! You also will be pleased to know that when your only getting 5.5 nursing it down the road at 62 or 63 that gives you the luxury of just going ahead and stepping it up to 70 or 75 with reletivly little difference, so hammer down! Our 86 has 3.31 rear end ratio and it doesnt hit the big hole til 61 mph, you gotta run 65 to keep it from downshifting the grades and I think it loves 72,73.

[Jon Wehrenberg]

Listen up folks. Joe is a real driver and he speaks volumes.

My old 8V92 was geared low and although Jerry breaks my chops about 62 MPH that was the sweet spot. It was 1800 RPM and I still had a few MPH available if needed. If I drove 70 I was screwed because my top speed was about 72. You get hung out to dry if you can't go faster than you are running sometimes.

I drive slow now because I never have to kick off the cruise control, my MPG is good, and despite the ball breaking I have to endure from Jealous Jerry, on long runs I will often see the same guys go smoking by me.....about three or four times a day. I don't have a job so I don't have to hurry.

[Joe Cannarozzi]

Let only the wind and the weather be our governer!

[Ray Davis]

Given this thread was about acceleration, I wonder if we're going to have that issuse going to SF. According my research here, SF sits at 7000 feet, which means we're going to do some climbing.

Anyone know if there are any steep grades (downgrades) on the road to/from CA to Santa Fe? I'm not sure that my jake brake is working (it might with the temporary mod suggested by Country Coach until I get the logic board fixed), but I just don't know. So, I'm always a bit hesitant in mountain driving.

Hopefully things will be all fixed before October. Fingers crossed.

[win42]

Ray
You may want to go to googleearth.com and have a look. I'm crossing upper NV on hwy 50, one night at Ely,NV the next night at Moab UT and the next day into SF NM. There will be hills. I would do what I could to get the jake fixed. Adj your brakes before leaving home. You'll be fine, take it easy in the hills and gear down.
Harry

[Just Plain Jeff]

On the front page of this site is an article entitled, "High Altitude Touring." That may be of some help?

[Joe Cannarozzi]

On the front page of what site? Is there anything in there on bridge weight limits? Hmmmmmm.

[Just Plain Jeff]

The article is here: http://www.prevostownersgroup.com/hihgaltitudetouring.html

If you are driving off the interstate system, there is a book call Next Exit, which is highly recommended. Further, it's good to get a Trucker's Atlas, as there is a section with non-conforming bridge heights by state.

This is particularly useful when going into unknown territory; especially east of the Mississippi.

[rfoster]

Photo of DD display for you veiwing pleasure:

[IMG]http://i52.photobucket.com/albums/g31/parkwayautoofbristol/CIMG0478.jpg

[Ben]

Does anyone know if the DD ProDriver panel (the thing shown in the last post) can be added to a coach that doesn't have it.

I'd love to know my MPG and other info... I run my generator too much to be able to tell from my fuel usage.

[Jerry Winchester]

Ben,

I have seen several of them for sale (new) on eBay in the last month, so there are some cheap(er) ones out there. I can't think they are hard to install. It is just a remote readout of the DDEC system.

Jon,

I like the 69.9 MPH figure since I still get to run with the cruise on, everyone passes me and the driving is less stressful. And I still get 5.6 mpg. When I bought my first tank of $3.00 diesel, I threw the notebook away and just enjoyed the ride. I would rather not fret over the $ per mile and just ease down the road with the King of Bling getting smaller in the mirror.

You fly to Oshkosh for the same reason a dog licks his nuts :eek:

[Ben]

Jon, are they usually listed as Detroit Diesel ProDrivers on ebay, or is there something else I should be searching for?

[Ray Davis]

I would do what I could to get the jake fixed. Adj your brakes before leaving home.

Harry,

Yep, that is my intention. Unfortunately, it's a Country Coach logic board problem, and CC wasn't able to see me for 5-6 months. I'm flying a mechanic out here (hopefully in two weeks), and he's going over these issues before I leave for Santa Fe. I really, really wan the jake working.

-ray

[win42]

Ray
For you it's a nice two day run up to the CC factory in Oregon. If I were you I would make the trip and camp on their door step and run customers off until they decided to fix your coach permanently. A call to the Better Business Bureau is also in order. Oregon is beautiful this time of year. Have you tried to get the name of the electronics people that designed and built their bords?
Hope you get it resolved.
Harry

[Ray Davis]

I thought of that, but I'm still working, and can't easily take the time off to camp out (I took the time off to come to POG2!!).

I've got a mechanic who is familiar with the systems coming down next weekend. It's costing me far less to fly him down, and house him for a couple of days, than it would to drive 2000 miles round trip!

I'm hoping I get everything solved when he comes.

-ray

[dalej]

Ray, what route are you taking to Santa Fe? you won't need any brake assist if you stay on the southern route, (I-40). You will steadily be going up and won't notice that your at 5000 feet. And then when you arrive we can all gather round and work to solve you problem (s). Wouldn't that be nice if all of use could gather twice a year and fix all of our busses.

[Coloradobus]

Ray for the most part, 1-40 is flatter than I-70. But you will go up heading into Flagstaff, which means you'll go down going home. Flastaff on is just rolling to flat.
There are some short hills in eastern Arizona, but they are only a couple of miles long.
You will have a 10 mile downhill heading into Albuquerque. And if you are planning to get fuel at the Flying J, that exit ramp is part of the downhill geography.
Then there is a long pull about 15 miles south of Sanfa Fe. This means you will go down it leaving, but its about 2 miles long.

A NOTE ABOUT DIESEL. SANTA FE IS SLIM TO NONE WHEN IT COMES TO TRUCKSTOP TYPE DIESEL STATIONS. THE CASINOS ALONG I-25 HEADING NORTH TOWARD SANTA FE HAVE IT. THERE IS A FUEL STOP NEAR THE CAMPGROUND, ITS A BULK TYPE TRUCKING FUEL STATION, WE HAVE USED IT BEFORE. TO BE ON THE SAFE SIDE, THOSE TRAVELLING THRU ALBUQUERQUE, FUEL THERE.

[Ray Davis]

Thanks guys for the suggestion. I had assumed I'd go I-40, so that seems the best way. There will potentially be 5 coaches heading in from Southern CA, so we'll be in good company, should there be any issues.

Most of the group will be coming back, but I'm heading down after this rally to Kerrville Texas for the DataStorm Users Group rally the week following. I'm actually getting three weeks off, and on the road in the bus!! Woohoo! :D

The group is expecting to leave Monday morning (the 9th), and stop Monday evening, Tuesday evening and then arrive early on Wednesday. If anyone has suggestions as to where to stop along the I-40 route, let me know. The total trip is around 850 miles, so I'm thinking we'd put in around 300+ on Monday and Tuesday, and then the remainder on Wednesday morning.

Thanks,
Ray

[dalej]

Ray for some reason I thought you were coming from the east, sorry. That hill west side of Flag is your only big hill, it will be a good idea to have jake along on the way home! It your not pulling any trailer weight then you'll be fine.