Tiffin Allegro Red 340 38 LL - POWER?

[retired long]

Originally Posted by BillW15237

I've got a deposit on a 2021 Tiffin Allegro Red 340 38 LL. It has 340 HP Cummins. A Tiffin service rep told me that if I tow my wife's Lincoln Nautilus Flat I may get down to 30 MPH going up long grades. We live in PGH and I want this to go back and forth to New Port Richey, FL so I will be in the mountains for 50% of trip.

Can anyone that may own this coach or one with pulling a Chrysler Pacificapower give me their opinion as to how it will perform? Thank you!

We have a 1999 Allegro bus with a 315-330 Cummins-Case tractor engine (505 cu inch)an on all hills including Fancy gap pulling a Chrysler Pacifica 4300lb plus dolly an few extras in car we are able to stay with loaded semis climbing hills.Even if able to gain small amount of speed it is better to just stay in lane an enjoy the senery.Having driiven semis for few years the hardest pull fromYork pa to San Francisco s the last 1000 feet climbing 322 north to State college Pa. I think it is a 7percent grade.Never did it with rv but sure it would do it.

[RV Driver]

Originally Posted by txwright

One thing I seldom see in these discussions is the simple option to disconnect...

This option is not available to everyone. My DW has Mild Cognitive Disorder and cannot drive. It would be a long walk back down the hill to go get the jeep!

With regard to Fancy Gap on I-77, we have the 400 HP ISL in our Mandalay coach. We're at 32,500 pounds, towing a 4,875 pound Jeep Grand Cherokee. In this video, I hit Fancy Gap at 65 mph and manually shift down early to keep the RPM up on the horsepower peak. Even so, we end up at 45-47 mph in 4th gear for most of the climb. My dash cam shows the speed, and I have added graphics that show what gear I'm in, the engine RPM and engine temperature on this climb.

https://www.youtube.com/watch?v=4LRAEVd1FJE

[rockriver]

rv, i see and read a bunch of folks... your video made it real simple... thanks.

[BillW15237]

Originally Posted by Wufpaq

Bill, I've got an Allegro RED 37 PA with the 360 HP Cummins. I flat tow a 5,000 lb Jeep Wrangler. My guess is my coach weighs about 5,000 lbs more than yours and I can safely say your 340 HP engine should be fine. I just went up I-77 heading to PA and easily made it up going 55-60 MPH. I-26 N into Asheville and US 421 N into Boone are more severe and my speed dropped to 40-45 MPH. I also recently completed a 6,000 mile trip (and flat-towed my Jeep) from NC to Bozeman, MT, down to Nevada and AZ and then back across the country on I-40 and NEVER had any speed issues while going over countess mountains (exceeding 6,000 feet too). I also average 8.3 MPH - I also don't go much over 65 MPH unless going downhill. To give you comfort as well on the quality of your coach, my only mechanical issue during the 6,000 mile trip was a loose passenger side mirror!

PS. I looked at the 340 but the 37 PA (which has a similar floor plan), had a much bigger bathroom and kitchen counters and was still accessible heading down the road for only $14k more at the time (2019).

Thank you, I appreciate all of the feedback!

[BillW15237]

Thank you all for your replies! The video was great as well.

[Chas P]

Anything under 400HP and you will have problems with mountains. I drive a 43 foot American Coach Tradition with a Cummins 425 HP and my toad is a 1/2 ton GMC Denali Seira. On steep grades I can hold 60 mph but that’s about it. In the mountains it will pull down to around 45 at best.

[bdersham]

Have a Winnebago Itasca Ellipse with 400hp Cummins towing 27 foot trailer at 11,000 pounds and never get down anywhere near that slow.

[RichKimball]

Originally Posted by SargeW

And don't worry, you can't "over boost" your turbo, there is a built in "waste gate" that will open and release excess boost pressure if it exceeds design limits.

I know that my Powerstroke 7.3 and my Cummins 5.9 turbos had a waste gate...but cannot find any reference to one on the VGT turbos used on the Cummins 6.7?

[GaryJoel]

I’ve got a 330HP Cat C7 … similar in power to your engine (maybe a little less torque) Flat Tow 3800 lbs.

Yes it’s slow going over steep climbs - but the objective is engine temp control - so a lower gear with higher RPMs using less throttle (less fuel explosion = cooler temp and higher RPMs means faster fan speed.

So on a step grade - 3rd gear and 35 mph is better on the engine.

Plan to go down hills in the same gear as you go up. Plan to be in lower gear before the crest of a steep downgrade.

[WinnieJurney]

We had a 34’ with a Cat 350HP. We rarely fell below 45 MPH while pulling grades. We pulled a Lincoln MKS, around 4500 pounds.
FYI to Sarge, boost is measured in bar or psi, torque is measured in ftlbs….

[Roadyacht1]

I had a Dutch Star 39000 gvwr towing a 4200 lb car and only a 250 Cummins. Went cost to coast twice, over smokies, Rockies, Sierras never a problem. When you are pulling up a steep grade was I going freeway speeds? No. But I was passing many trucks. It was a non-issue to me. I was always conscious not to lug the engine. Keep the R’s up and no problem.

[JTRNA]

Originally Posted by BillW15237

I've got a deposit on a 2021 Tiffin Allegro Red 340 38 LL. It has 340 HP Cummins. A Tiffin service rep told me that if I tow my wife's Lincoln Nautilus Flat I may get down to 30 MPH going up long grades. We live in PGH and I want this to go back and forth to New Port Richey, FL so I will be in the mountains for 50% of trip.

Can anyone that may own this coach or one with similar power give me their opinion as to how it will perform? Thank you!

We purchased the exact same coach and kept it for a half a season, in my opinion the 340 is under powered for that size and weight coach. My toad is either a Chevy Colorado or our 2019 4 door Jeep, going through the mountains of West Virginia it struggles to maintain 30-35 going up mountains.

We traded it for a 2015 Allegro Bus with the 450 Cummins, better fuel economy and not even a hiccup in the mountains.

[EdB Wingman]

I have a very similar setup. Live in Florida and head out every summer for New York and Colorado towing a 2018 F150 sometimes with golf cart or a motorcycle. Sorta slow up the major hills but nice and controlled going down. I have always been faster than the slowest truck. Just stay in your lane and let the transmission do its thing. We just got back on what I think would be your route. And after 25000 miles on the coach I averaged a bit more than 8.7 mpg via my scangauge keeping speeds@ 65 ish. At first I was worried about not enough power but figured trading it would cost me $50m in lost value. I am retired so another day on the road is no big deal.

[Bob and Lisa]

We RV out of Medford, Oregon and have to do at least two lonnng hard pulls to go in any direction... Surprisingly absent from the thread is that you are driving a diesel not a gas engine - you don't care about HP, RPMs or Boost - you only CARE about TORQUE when pulling a grade! Our Cummins 400ISL cruises down the flats at 1800 RPM for near peak HP, but the torque curve tops out at 1400RPM - so when you are climbing, you let the RPMs go DOWN to the 1400-1500RPM range for much better pulling as well as better fuel consumption. Check your engine owner's manual for the peak TORQUE specs of your particular engine...