330 hp Caterpillar Power?

[wmiii]

We've just taken our 1st trip in our, new to us, 2003 National Tradewinds 375LE, powered with a 330 hp Caterpillar diesel, I think 3126.
All the way North bound on I-75, we did fine, pulling our Honda CRV, running between 60 and 65. (Except for Atlanta)
I was surprised when we got into the hills before Chattanooga by the way we lost some speed but not too bad.

We took Hwy 111 Northwest across Waldens Ridge and we were down to 38 mph going up the mountain. The engine brake worked great going down the other side. We turned North on Hey 127 and when we climbed the Cumberland Plateau, once again, down to 36-38mph.


We bought this Diesel coach to take a trip out West and into the mountains out there. If we have trouble with these East Tennessee hills, what am I going to encounter out there?

Is this just the way these are or do I have an issue??

Thanks,

Wm Mayberry
2003 National Tradewinds 375LE
2011 Honda CRV

KOA Crossville, TN

[zproud]

I have a cat c7 330, don't know if all is the same for yours.

Need to check when the power comes on for yours for my c7 its 1900 to 2400 rpm . You need to be in the correct gear to keep it in the power range.

Empty my weight is 25,000 I have no problem pulling 5 % grade at 70

I am new to this coach, loaded with my trailer iam 33,000 no pulls on hills yet, slight hills and flat no problems keeping up with the flow of traffic

The normal checks, fuel filters, fuel preasure, air cleaner , turbo boost, air leaks

Wishing u the best

[Mr_D]

OP, you have an exhaust brake not an engine brake. You don't get an engine brake till the C-9.

[rgrpm]

Sounds like what I went thru, Plugged fuel filter, algae in fuel tank and plugged filter up. I also had a bad injector so was really down on power. That engine when right should be able to maintain your speed without any loss.

[Bigd9]

On my C7 330 HP Cat, I loose some speed on steep hill climbs, but I expected that. Going out west over the Rocky Mountains I lost some speed up hill, but I expected that. I just put her into cruise, and let the computer downshift the transmission when she thought it best sat back and enjoyed the scenery. BTW, what is a steep hill anyway? 1%?, 2%?, 3%?, 6%, 10%

My engine is consistent and she just purrs along. If she suddenly lost some pazazz then I would worry.

If you are concerned, take it to a Cat dealer who can perform a dyno test on your engine. You might be surprised at how much HP and torque actually reaches the rear wheels. Or you could race me up Jellico Mountain on I-75 North of Knoxville, Tn and see who makes it to the top first

[smsawle]

I had a 2007 Tuscany with a C7 Cat rated at 350 hp. We went over Loveland pass out of Denver with no tow. We were in the mid 30s. If you have a 330 that will do 5% grades at 70, you have one of the strongest 330s out there. I have gone to a 2018 36' Winnebago with a V10 and it is stronger than my 350 Cat. Don't get me wrong,it drinks when you work it. All filters were new when I climbed Loveland. It was the hardest pull we had on our 5000+ mile trip. Also, I have been driving trucks for the last 50 years.

[Outbound]

I had a 330 Cat in my 2001 Safari Zanzibar, no way would it run 60 or 70 over 6% pulls with any distance like the Siskyou's in California/Oregon, 38/40 is about as good as it gets towing a vehicle or car trailer, it did much better not towing. It was a great motor but you can get only so much out of 330 hp, I did have the local truck shop install a chip which bumped it to about 375 hp.

[vito.a]

wm I'm sorry you're disappointed.
What is the torque rating on your Cat 3126, and what is the combined gross weight of your motorhome and CRV?
I suspect you just do not have enough torque to pull the weight.

Sometimes you can get a run at the hills by downshifting to 5th prior to the hill and getting the engine into the upper RPM range.
You are really not going to like climbing through the Rocky Mountains on a hot day.

[wmiii]

I believe I saw 6% for the grade.
But still somewhat surprised.
Wm

Sent from my SM-G930V using iRV2 - RV Forum mobile app

[Outbound]

wmiii, I would not worry about the speed you mentioned, your 330 cat will get you over west coast hills without a problem, there are not many times you will drop below 38/40 mph, sounds like your rig is right on the money, my 330 always got me home.

[Tony Lee]

Read this https://www.rvtechlibrary.com/engine...erformance.pdf

That way you will realize that driving motorhomes is a bit like fishing. Every second one you meet is full of BS.

If you are also new to driving heavy vehicles then google "Snub Braking" and get yourself familiar with what will keep you and your coach in one piece.

[FIRE UP]

Originally Posted by wmiii

I believe I saw 6% for the grade.
But still somewhat surprised.
Wm

Sent from my SM-G930V using iRV2 - RV Forum mobile app

wm,
Don't be too surprised at your performance. Every single motorhome will perform differently on a given grade, even two coaches built right behind each other on the assembly line. Weight, tire pressure, ambient temp, toad, and more will make differences. What one coach owner "says" he climbs grades at, quite possibly is gonna be different than the next guy. Being that your coach IS an '03, yes, you do have a 3126. The C-7 was not introduced until late (later OCT) of '03 and, all coaches with that C-7 were labeled as 2004.

The 3126 and the C-7 are very close to the same engine. Both are 330HP and 860 ft.lbs. of torque. The C-7 did/does have (3) versions, 300, 330 and 350 HP versions. All of them have 860 ft. lbs. of torque. As for your 3126, yes, it too has 860 ft. lbs. of torque. Now, it's been suggested that you take your coach to a CAT shop with a dyno to see just how well it runs, up against the specs it's supposed to run at. Well, yes you can do that if, you think it's lacking in any particular area of performance.

A 330HP diesel is a good engine. It's got plenty of power for about 98% of anyone's running around and towing. But, up against some grades, yep, it's gonna slow down, it's a given. You stated this was your first trip in your new-to-you coach. Well, this trip should have given you a good basis to judge your coach on. You've learned what it will do, with a given set of circumstances.

I don't know if you've done any maintenance on any section of it. Namely the oil and filter, fuel filters, air filter, etc. Those are paramount for making sure it runs at top notch performance. Correct tire pressure vs the ACTUAL weight you're carrying is also important. This is not, repeat NOT, in accordance with the weight/spec sticker that should be on the wall, just to the left of the driver. You WEIGH your coach and then go to the tire pressure chart online, that is put out by the tire manufacture of your tires.

I don't know how much diesel driving experience you have but, I'm not in total agreement with BigD9 on this one. We do think fairly alike and I'm sure he'd agree but, letting that Allison think on it's own when traversing grades or, approaching them, might not be the best of choices. The Allison is an outstanding trans, no doubt about that but, a competent diesel RV driver knows his/her coach and, just when it's time to downshift, for a given approach to a given situation. And that, can make one heck of a difference in speed up the potential grade vs letting the Alison make the decision for you.


If you and your better half are otherwise totally happy with this coach, its layout, condition, floorplan, size, and more, then negotiating grades is but a small part in the total picture here. And by the way, you're not alone in your situation. While some may boast of ricky-racer grade climbing, there will PLENTY of others that you'll be cruising right alongside or even passing, on many of the grades in this country. Keeping your engine in the best operating condition, it's radiator and CAC clean of debris, proper and timely maintenance and, proper technique in driving tactics, are all top priorities for dependability and efficiency which, leads to fun and enjoyable trips. Good luck.
Scott

[wmiii]

Originally Posted by rgrpm

Sounds like what I went thru, Plugged fuel filter, algae in fuel tank and plugged filter up. I also had a bad injector so was really down on power. That engine when right should be able to maintain your speed without any loss.

Before we left, I had a complete service done by the Catepillar service center in Sarasota. They changed all the filters and fluids.
I'll add some injector cleaner and see if that makes any difference as we travel on.

Wm

[Ivylog]

Just because it’s in the East does not mean it isn’t steep...usually not very long. 6% is going to slow you down and a general rule is 1HP for every 100lbs of weight will give you OK performance.