Is my U295 ISL400 in good health?

Topic: Is my U295 ISL400 in good health? (Read 1192 times) previous topic - next topic

Is my U295 ISL400 in good health?

June 22, 2018, 08:22:00 pm

We just drove highway 22 over 8400' Teton Pass from Jackson WY to Victor ID. Much of the grade is 10%.

Is a top speed of 25mph in 2nd gear normal?

I'm used to SoCal grades at lower elevations, like the Grapevine or Cajon Pass, holding at 45mph.

No check engine light, do I don't think it's in limp home mode for any reason.

Re: Is my U295 ISL400 in good health?

Reply #1 – June 22, 2018, 08:36:36 pm

How much does the coach weigh currently, and we're you blowing smoke? Do you have a boost guage? Might have a simple turbo leak, or loose clamp.

Re: Is my U295 ISL400 in good health?

Reply #2 – June 22, 2018, 08:45:34 pm

Around 33000 pounds with a 4500 pound toad. Only have factory instrumentation at the moment.

Re: Is my U295 ISL400 in good health?

Reply #3 – June 22, 2018, 08:51:03 pm

Do you know at what rpm your motor torque peaks at? May just be in the wrong gear.

Re: Is my U295 ISL400 in good health?

Reply #4 – June 22, 2018, 09:01:37 pm

Quote from: Tom Lang – June 22, 2018, 08:22:00 pm

We just drove highway 22 over 8400' Teton Pass from Jackson WY to Victor ID. Much of the grade is 10%. Is a top speed of 25mph in 2nd gear normal?

We've driven that road with a much lighter Airstream coach, I could walk faster than the speed we pulled it. If all your gauges looked normal, and, which has been mentioned, no smoke that would indicate a turbo problem, I'd say, you 'dun good!

Re: Is my U295 ISL400 in good health?

Reply #5 – June 22, 2018, 09:13:03 pm

No smoke, no check engine lights or bells. I suspect it'd just the nature of a nominal 400hp engine dealing with a 10% grade at 8400 feet and a combined weight of around 39000 pounds.

I do have a vmspc which I just hooked up after years of non use ( my preferred setup with a windows tablet I'd on the fritz, but I still have my previous setup with an elderly windows notebook). I hooked it up to use on the rest of my trip, and it shows no error codes.

Re: Is my U295 ISL400 in good health?

Reply #6 – June 22, 2018, 09:35:20 pm

Quote from: Tom Lang – June 22, 2018, 08:22:00 pm

We just drove highway 22 over 8400' Teton Pass from Jackson WY to Victor ID. Much of the grade is 10%.

Is a top speed of 25mph in 2nd gear normal?

I'm used to SoCal grades at lower elevations, like the Grapevine or Cajon Pass, holding at 45mph.

No check engine light, do I don't think it's in limp home mode for any reason.

2nd and 3rd sounds right. Only way to get back into 3rd (upshift) while climbing is to lift off the throttle about 1/4 to 1/2 way for a few seconds.

Re: Is my U295 ISL400 in good health?

Reply #7 – June 22, 2018, 09:37:27 pm

Probably nothing to loose sleep over, I made the mistake of shifting down too early going up cajon pass below the engines sweet spot, once there you just have to wait there and enjoy the view.

Re: Is my U295 ISL400 in good health?

Reply #8 – June 22, 2018, 10:00:16 pm

I was upset when we got this coach; there was not a set of boost/pyrometer gauges, which I lived by in the 20 years of 'climbing the high roads'. Research, (and this forum) taught me that, as long as the original FT design had not been 'souped-up', there was no need. So far, it's been proven right. I still like analog gauges, I have no plans to hook-up any stuff a lot of you think is important. That being said, if you live by gauge readings, you better think about a upgrade. I re-did both our SOBs and this coach is about ready for a complete gauge/sender re-do, as well.

I swear by this bunch: ISSPRO.com - Quality Gauges, Tachometers, Speedometers and more!

Re: Is my U295 ISL400 in good health?

Reply #9 – June 22, 2018, 10:16:32 pm

Quote from: Tom Lang – June 22, 2018, 08:45:34 pm

Only have factory instrumentation at the moment.

Tom, you should have a engine data display under the backup monitor or radio (I forget exactly which) that gives different information
by scrolling with the up & down arrows. Boost pressure is one.

Re: Is my U295 ISL400 in good health?

Reply #10 – June 22, 2018, 10:23:04 pm

phred as you have learned keep the 300 cat spinning at full revs(2,950 rpm. 60 in 3rd is full revs.

Coach gets 8mpg wide open fourth. 10 at 70.

More horsepower than torque. Make use you have correct matching belts that are fresh.

It's a v8 not a I6 with a torque

Re: Is my U295 ISL400 in good health?

Reply #11 – June 22, 2018, 10:24:01 pm

It is. I just now set it for percent of max power. I don't know how much boost is right.

Re: Is my U295 ISL400 in good health?

Reply #12 – June 22, 2018, 10:32:42 pm

Tom,

Your 8400 feet may be more like 12,000 feet density altitude that your body, engine, radiator, etc sees in the summer. 25 mph in second gear is nothing to sneeze about so keep the rpm up without going to full throttle and sit back and relax. High density altitude will also mean higher EGTs so keep this in mind. This is what the higher rpm and partial throttle will help keep at bay.

To calculate density altitude, use the formula at this link: density altitude calculator

As an example, if you are at 8400 feet, 84 degrees outside, average altimeter setting of 29.92 and a dew point of 60 degrees, you and your coach will think it's 12,077 feet. Changing the dew point even if you don't know it won't make that much difference. Windy: Wind map & weather forecast (also known as Windyty) will calculate the density altitude if you have airports selected in the preferences and click on a nearby airport.

The most you can hope for even with a waste gate turbo is keeping sea level horsepower to about 7500 feet. After that, it drops off rapidly. And your radiator and radiator fan don't get to take advantage of the turbo so they won't be nearly as efficient.

In three days, we will be up in the Sierra's and with the heat wave, our 9000 foot passes will be much higher plus with our four speed Allison, I'm sure we will be in first gear with the heater on when climbing one or two of them.

This is the kind of thing you risk when buying a used coach no matter who has done the maintenance or if it was parked inside. Was the last owner fat, dumb and happy when it came to mountain climbing in hot weather? It can take a toll.

Pierce

Re: Is my U295 ISL400 in good health?

Reply #13 – June 22, 2018, 11:43:18 pm

Just saying a boost guage at the engine inlet may give you warning about abnormal leaks in the charge air cooler or associated hoses, clogged air filter, or an exhaust leak prior to turbo. Even runnig on the flats. Just another tool of prevention or risk assement

Re: Is my U295 ISL400 in good health?

Reply #14 – June 23, 2018, 12:04:58 am

Tom, as you know we're doing similar mountains. I'm driving our 34' ISC 350 with my VMSpc as my gauge. I'm trying to keep 50-60% engine load and turbo boost under 20. Temps on engine, tranny and retarder under 200.

For us that means 2nd gear to 30 mph (about 2200 RPM) climbing the highest ascents. When possible 3rd gear to about 40 mph (also about 2200 rpm). When ever ascent brings 3rd gear down under 1700 rpm downshift to second.

As we climbed 64 from Page to Grand Canyon temps under 200 the entire way. Pulled over when possible to let faster traffic get by and enjoyed the ride and was also able to enjoy the view. Average speed over the 132 Miles was about 35 mph.

I'm learning to like looking out the window and not worrying!

Re: Is my U295 ISL400 in good health?

Reply #15 – June 23, 2018, 12:44:21 am

Randy,

Yes, very similar. I've learned 2nd gear in the 20's, 3rd gear in the 30's, and 4'th gear in the 40's to mid 50's tends to keep rpms in range, mostly around 1700, no higher than 2200. And my coolant temps have stayed below 200 all day.

And I got my old pc and vmspc working for the remaining two months of this trip.

Now I'm wishing for paddle shifters.

Re: Is my U295 ISL400 in good health?

Reply #16 – June 23, 2018, 04:41:18 am

Um correct if I am wrong, but I have always heard and practiced that diesels prefer to be run fully loaded but that may just be the two strokes. Four strokes may be different.

Re: Is my U295 ISL400 in good health?

Reply #17 – June 23, 2018, 10:17:11 am

Quote from: Old phart phred – June 23, 2018, 04:41:18 am

Um correct if I am wrong, but I have always heard and practiced that diesels prefer to be run fully loaded but that may just be the two strokes. Four strokes may be different.

You can get away with it in a 2 stroke as the EGTs run about 150 cooler, all four valves in the head are exhaust so head temps are pretty even across the combustion chamber and they use a huge amount of air. They have lots of low end torque and the lower RPM range seems to be ideal for best fuel mileage. My GM 4107 with it's 8V-71 had it's fuel cut off at 1800 RPM and Greyhound geared it so it slept on the highway. 10.3 mpg w/toad in the Rockies was the worst I ever got. The same 2 cylinder version used in railroad generators many years ago was famous for it's economy and generated 20Kw at 1200 RPM. With the same 8V-71 in a fire truck, our fuel cut off was 2300 to 2400 RPM depending on the individual truck and we never let it get below 1700 RPM. They didn't get such good mileage.

Like many turbo CATs, the 6V-92 has an aftercooler, not an intercooler (CAC) like Cummins. It is under the turbo and cooled by the engine coolant. As coolant temps go up, the aftercooler is less efficient and EGTs can also go up plus the engine is less efficient. The aftercooler is one of the reasons there is nothing on the outside of a Detroit, no injection lines/pump or hoses leading to an intercooler.

So, in my experience with all diesels including dozens of four stroke OM617s, the more throttle you use, the more heat you produce and if the temps are high, higher RPM with less throttle circulates coolant better to keep temps uniform in the engine plus since a diesel has no throttle butterfly, more air passes through the engine at higher RPM. The ECU in our electronic engines keeps some of the villains away but you still have to stay on top of it. The mechanical engines require a little more skill as a heavy foot injects more fuel and produces more heat so an eye in the mirror is necessary to watch for black smoke.

The Cummins B engine or 5.9 liter has a B50 life of 350,000 miles. This means the average 5.9 will need an overhaul at 350K. Some will need it sooner but some can go three times the miles. It just depends on how it is treated including maintenance, hot weather driving including heat soak on shut down.

Here is a quote from another forum for the ISX 650 engine. This is an example of Cummins perhaps pushing the new engine a little too much HP rating for non-professional drivers and poor driving habits bringing the any problem to the surface. His turbo failure (and perhaps other failures) may have been caused by incorrect driving habits such as heat soak after shutdown.

Quote: Bought it Feb 19th, went to the GS rally in Phoenix. On the way back we got 40 miles from home the engine blew up. Estimate is right at $29,000 to fix and we only drove it 3,000 miles or so, as is sale and didn't have time to purchase a service contract. The engine ate the valves in #6, which took out 5 and 4. This is the second failure for this with this engine. Engine failed at 19,032 and was rebuilt under warranty. About 1,000 miles later the turbo went out again, and now the third engine failure at about 44,000 miles. Cummins admits there is a problem with the ISX 650's and the have new heads and valves in the supply line.

So, with all diesels, lighter loads and higher RPM go with higher temps on the instrument panel for a engine that will beat the B-50 rating every time.

Pierce

Re: Is my U295 ISL400 in good health?

Reply #18 – June 23, 2018, 02:35:52 pm

Quote from: Tom Lang – June 22, 2018, 09:13:03 pm

I suspect it'd just the nature of a nominal 400hp engine dealing with a 10% grade at 8400 feet and a combined weight of around 39000 pounds.

Exactly right. You're 97.5 lbs/hp with your 400 hp engine. I'm 96.5 lbs/hp with my 300 hp engine. (I watch the weight carefully.)
Performance sounds comparable to mine. I like to pick a gear that allows around 2100 rpm then back off the throttle a bit and let the resonator sing. The only time pedal is on floor is charging downhills in anticipation of a climb.

Re: Is my U295 ISL400 in good health?

Reply #19 – June 23, 2018, 06:03:56 pm

I have just realized that my perception of coach performance is skewed by the fact that my first coach is only 73 lbs/hp and is only 8' wide and only 9'4" tall

Re: Is my U295 ISL400 in good health?

Reply #20 – June 23, 2018, 11:45:33 pm

Mine goes way faster than it should .

Re: Is my U295 ISL400 in good health?

Reply #21 – June 24, 2018, 12:06:47 am

Sold a lot of 250 cat and especially the 300 ORED's.

phred I remember taking the original owner on a demo ride in your coach.

He was driving along and commented that the coach was slightly noisy.

Told him to look down at the speedo.

"OMG we are going 85 mph."

Told him this was the best running rv I knew about.

He grinned and said "no" that his pace arrow 26' was faster .

I politely disagreed.

Then he walked me over to his trade in.

Coach had a duetz 6 cylinder 700 cu in air cooled German Diesel engine under the hood.

Might have been a stick shift.

I,took it for a drive. He was correct. His WAS faster.

Long ago story

Re: Is my U295 ISL400 in good health?

Reply #22 – June 24, 2018, 12:47:33 am

My biggest regret buying this hot rod coach, which I had no idea at the time that it was a hot rod, is not meeting caflashbob who was probably less than 30 miles away before I left CA. Yes he called me on the phone, but at the time I had not discovered it was Charlie White's coach. Bob filled me in on a lot of little details. That is totally Priceless. I owe Bob a very nice dinner.

Re: Is my U295 ISL400 in good health?

Reply #23 – June 24, 2018, 01:04:26 am

If I had the opportunity to drive it again the deja vu would have been interesting. Plus the ability to check its condition now might have been helpful, maybe someday down the road.... I will earn my dinner

Re: Is my U295 ISL400 in good health?

Reply #24 – June 24, 2018, 04:20:17 pm

She must be in good health. Just took some 6% grades at altitude. Maintained 60mph. Turbo boost peaked at 23psi, and vmspc claimed 100% load and up to 400hp depending on rpm.

She even passed some lesser RVs on the grades.

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