Isl 400 - cummins

[logansrun]

Those of u that have one.....do u ever wish u had a few more horses, especially during those long 6 or 8 or 10% pulls.....& if u are in a long pull like that how many gears do u have to drop to keep bus rolling?????
Just curious
Thanks

[Skip426]

You're going to get a lot of feed back on this; From " What's yor hurry," to "how much do you want to spend " I'm at 300hp 860 ftlbs torque, 32000 lbs rolling and can pass loaded semi's on cruise control on the hills. All the H/P in the world will probably only get you to happy hour 1/2 hour early and up your fuel bill considerably so you can't afford to drink. So I'm the first of the "What's your hurry " crowd.

[logansrun]

Well Skip no hurry....but just got back from driving the hills in Ca., OR., & WA, & there were times I was into 3rd gear to maintain 30 mph....elderly 8.3 towing a Malibu...so I think its time to upgrade....maybe.....400 or even 500...don't like having to use 4 ways going uphill, that's 4 truckers pulling heavy loads!!!!!
Thanks

[rv rick]

I have an ISL in a 42' coach pulling a Buick. We have plenty of power and no problems keeping up with traffic or climbing hills or passes in the Rockies. Works great.

[Steve Ownby]

There are days and grades that make us all wish for, in the words of Tim the tool man Taylor, MORE POWER.

If your goal is to make the top as soon as possible then you will need to shift the Allison yourself. Hit the bottom of the grade carrying the max speed you are comfortable with. Keep your foot to the floor and as your rpm's fall, down shift with the goal of stabilizing your rpm's at no lower than a couple of hundred Rpm's below governed engine speed. This should also manage your engine temp. If your temp gets out of your comfort zone, then back out of the throttle and down shift again to keep rpm's up.

[Mr_D]

Of course I wanted more, that's why I put a Banks kit on the ISC 350. It used to have a max of 1050 ft lbs @ 1400 rpm, now I never get below that except at 2100 rpm and up. It's not so much the peak changes in HP and torque but the area between the old and new curves.

[Robi.1014]

My ISL needs 3rd gear and about 35 MPH to make some of the grades of I-8 going west from the Imperial Valley up to the top (Alpine)....and towing the Buick. I'm happy with that.

[YC1]

I have a 40 foot four slide very heavy DP. I wish it had ten gears instead of 6. It is a rear radiator model so I had the option to replace the fan with a two speed model or with a one speed model from Source Engineering which I did. There was an immediate increase in acceleration and mileage and a reduction of over 1/2 of the engine noise as measured with a db meter.

Two months ago I added a performance chip that added even more power and better mileage again. I don't know the exact hp increase but based on factory curves I suspect I have close to 475 hp now versus 400. Maybe more but won't know until I get it on a dyno. I topped the Grapvine in Southern Calif. at 52 mph this year versus last year at 35-40.

[drnitrous]

1500 hp drag car, 650 hp street car, both need more, but I am still really impressed with the ole ISL. Gets me where I'm going and accelerates well with a 32 foot tag trailer on the back. I guess I remember the days of pulling a 40 foot trailer with my 460 getting 6 mpg and taking a major run at the big hills, well, I still take a run at the hills, lol, but pretty happy with this as it stomps the guts out of my old 460 in mileage, weighs 25,000 lbs more and I don't have to pull over until I want to. Sure, if the ISL dies, I will transplant an ISX with the appropriate upgrades because then it will make sense. Until then, I will get there when I get there and enjoy the ride. I still pass most of the OTR truck guys on the grades, and that my friend makes me smile!!!! I wouldn't need any more engine if I wasn't pulling a trailer. Happy travels!!
B

[rorr1821]

Originally Posted by logansrun

Those of u that have one.....do u ever wish u had a few more horses, especially during those long 6 or 8 or 10% pulls.....& if u are in a long pull like that how many gears do u have to drop to keep bus rolling?????
Just curious
Thanks

I have owned 2 MH with the ISL engine. What year was your made? This engine has gone through changes in 2004, 2007 and 2010 that I know about. Also it has been offered in 400HP and 425HP. I also believe I saw offered with 450HP. I know my current ISL which was made after 2007 is 400HP but according to Cummins it could be changed to 425HP with a cost of around $700 since it is still under warranty. After warranty period the cost drops to around $300. Also if you have a rear radiator vs side radiator it makes a difference. Side radiators draw constant power from the engine as will a rear radiator with direct drive fan. The rear radiator fan can be changed and reprogrammed by Cummins with a clutch fan which uses much less engine power.

Why all the verb-age? I had a side radiator ISL in a 2004 Monaco Dynasty and I considered it a dog because the engine needed all the power it could get to climb big hills. I have an ISL 2007 version in a Monaco Diplomat with a rear radiator and clutch fan which goes like race car, not really but you get the point. The difference is night and day between the performance of the two MH with ISL engine. Also the DP gets an average 9+ MPG. The Dynasty was lucky to get in the 5 -6 range. Also the Dynasty weighted probably 10,000 more. So MH weight, type radiator,and year of the engine are factors when evaluating the ISL. But in my opinion that there are a lot of MH which have marginal power to weight ratio and when driven in high altitudes and hot climates they have problems.

[moisheh]

Lots of good advice in these posts. But also some possible errors. If you are in Oregon where there are those long climbs one does not go down the grade at a high speed. The proper method is to go down at a controlled speed. You find the speed at which you can slow down your unit 5 mph with a 3 second brake application. That speed is often the same speed that you would use to climb the grade. When you have slowed down allow the unit to gain 5 mph and repeat the procedure. This repeated brake application is called snubbing. Of course this all depends on the weight of your unit, whether you have an exhaust brake or an engine brake and the weight of your toad. If you hit the bottom of the grade and there is a long straight stretch you can put the pedal to the metal. But so long fuel mileage! I also do not think a side rad is less efficient than a rear rad. The side rad fans are hydraulic and they only operate when necessary. Our fan rarely runs.

[deSanford]

With my MP-8 and source fan I set my ISB 340 to cruise control at 55MPH and the TCM & ECM does everything automatically (maintains 55 up most hills). While I enjoy the view out the "I MAX" windshield. deSanford

[logansrun]

Thanks 4 the info.....I guess the size & weight of ur boots has a lot to do with how the trip progresses.....maybe u make do with what u got!!!!

[zmotorsports]

Originally Posted by drnitrous

1500 hp drag car, 650 hp street car, both need more, but I am still really impressed with the ole ISL. Gets me where I'm going and accelerates well with a 32 foot tag trailer on the back. I guess I remember the days of pulling a 40 foot trailer with my 460 getting 6 mpg and taking a major run at the big hills, well, I still take a run at the hills, lol, but pretty happy with this as it stomps the guts out of my old 460 in mileage, weighs 25,000 lbs more and I don't have to pull over until I want to. Sure, if the ISL dies, I will transplant an ISX with the appropriate upgrades because then it will make sense. Until then, I will get there when I get there and enjoy the ride. I still pass most of the OTR truck guys on the grades, and that my friend makes me smile!!!! I wouldn't need any more engine if I wasn't pulling a trailer. Happy travels!!
B

Just out of curiosity, how much does your trailer weigh? Fully loaded and headed to the track with car, tools and everything. How often do you tow your trailer, once a month, every weekend? I am just curious as I am always comparing other peoples' loads and coaches to my own and how happy or unhappy they are with the performance.

Thanks.

Mike.