Towing with an Airstream Classic?

[Jenniflow]

This thread is really surprising and I'm now wondering about my engine.

I read the manufacturer recommendations and thought I was pushing it when I towed my 2800 lb Mini 4 wheels down with my 1986 345 classic. It has the average 454. I compensated for the "extra" weight by keeping all the tanks low in volume while I was on the road. I also turn out to have had a nonfunctioning rear fuel pump.


It always felt to me that I was really pushing the li
It for my coach with this arrangement. Am I or was I missing something? We're on the verge of buying another Toad and would love to have more options than this experience suggested that I have!

[bkahler]

Originally Posted by Jenniflow

Am I or was I missing something? We're on the verge of buying another Toad and would love to have more options than this experience suggested that I have!

I upgraded the hitch on our 310 based on the information I found in the following link as well as other posts on the forum. If the hitch upgrade is done right you shouldn't have much to worry about. Also keep in mind I tow a 14' flatbed trailer with a race car on it and Robfike tows a 24' enclosed trailer with his 345.

345 hitch upgrades

[Jenniflow]

Sorry if I'm still missing something but just humor me here for a minute: I've read the other threads people have referred to here but it seems that we're talking about coaches of all kinds of sizes from which it's hard to conclude much, generally.

I was driving a 345 which is 3.5 feet longer than a 310 with (isn't it?) the same Chevy 454 engine. So it seems to me that with a bigger coach I'm going to have less available power to tow and that's why it felt like a lot when I was towing a 2800 lb Mini. I understand Keyair's engine is more powerful, although I'm not familiar with it, so he might be able to expect more. So are people really saying that a 454 can easily move a 345 MH and, in addition, another 4-5K lbs as long as the hitch is upgraded?

When I towed my Mini with my 454 I had a Banks system and Blue Ox hitch installed, and I used a Break Buddy. I was certainly a ready customer for a hitch upgrade but at the time, no one in either of the Airstream service centers I dealt with suggested I do anything more.

So my question is, are people saying that even a 345 with a regular 454 engine can tow an additional 4-5K as long as it has an upgraded hitch? If so, that suggests to me that the I wasn't getting the power I should have from my engine, even though they went over the engine and transmission and pronounced them good. No compression problems. Well, but the rear fuel pump wasn't working, which they apparently didn't catch. Could that account for it entirely?

Or are we comparing apples and oranges?

[Smartstream]

It's interesting seeing this discussion going back and forth. Some people don't have enough power unless they can do 75 mph fully loaded on a 9% grade. Others are less demanding. I was looking at the Chevrolet Motorhome P-30 Chassis Service Manual and they have a towing capacity chart. The 454 with a 4.56 rear axle has a GCWR of 19,000 lbs. With the 4L80E trans it goes to 20,000.

The interesting thing is the 6.2 diesel which has a similar power rating to the Isuzu diesel I have, Rates the GCWR at 13,500 lbs. Airstream says my GVWR is 14,500 so I'm already 1,000 over factory spec.

There is a footnote that allows a trailer to be 25% overweight if you do not exceed 25 mph. I guess being 1,000 overweight I'm not allowed to exceed 25 mph.

Cheers, Dan

[Jenniflow]

Vewwwwy intewesting, Dan. Thanks for that info. I don't have that manual on hand but I will look up to see what I have.

I agree it's also probably a matter of expectations. I'm one of those people who wants to start with the basic understanding and manufacturer's recommendations and THEN decide on what liberties to take. I've certainly wished at time that I had a diesel pusher but that's obviously not in the cards for this Moho, or as I fondly call her, the motyho.

[bkahler]

Originally Posted by Jenniflow

So my question is, are people saying that even a 345 with a regular 454 engine can tow an additional 4-5K as long as it has an upgraded hitch? If so, that suggests to me that the I wasn't getting the power I should have from my engine, even though they went over the engine and transmission and pronounced them good. No compression problems. Well, but the rear fuel pump wasn't working, which they apparently didn't catch. Could that account for it entirely?

Or are we comparing apples and oranges?

Kinda sorta maybe

You can do various things to the 454 (or any engine) to improve performance. To me first and foremost help the engine to breath better which means installing a good exhaust system with headers. Next improve the air intake by ensuring you're getting your intake air from the front of the motorhome with an appropriate hose. I don't know if or when Airstream actually added a hose from the carburetor to the front but the 345 I'm dismantling does have one and the Banks system on our 310 added one as well.

Here is a true story. We had a 1983 27' Winnebago with a 454 and were making a trip along I-40 heading east. Being a flat faced motorhome the Winnebago mileage just plain sucked. I was checking mileage after every stop (and we were making a lot) the average was 5.5 mpg. At the 3rd fuel stop I decided to add a means of getting air from the front of the motorhome into the carburetor. We stopped at a Walmart and bought a 4" aluminum dryer hose. Installed it and found on the next stop that our mileage had gone up to 6.5 mpg. And this was while also now driving through the hills and grades of central Tennessee. The average stayed above 6 and even reached 7 a time or two after that.

That is just an example what improved breathing can do. The Winnebago did not have headers and and I firmly believe that if it did the mileage would have been in the 7+ range constantly.

The other thing better breathing does is provide a little more get up and go. Not mind blowing but it sure doesn't hurt.

So to answer your question I believe that if you don't expect jack rabbit starts and use the cruise when possible you might be surprised at how well the old 454 will run. Especially if it breaths better. A better cam, TBI and various other mods would definitely help as well.

We tow at 70 mph with our 310 pulling a 14' 3500 lb trailer and still get 8 to 10 depending on road and weather conditions. We loose a little in the hills but not enough to bother me. Besides in hills I'd rather go just a bit little slower

Brad

[gunner]

When I purchased my 345 motorhome the electric rear fuel pump was not working ( found this out after I got home ). I drove it from Florida to Ohio and I had half the power I should have had, it lost power going up hills and I had to back off the gas pedal or the carburator would run out of fuel and it would backfire. I even took the carburator apart at midnight at a truck stop thinking that was the problem. This confirms that not having the electric fuel pump operational will cause you to loose up to 50% of the engine power. I upgraded my hitch and pull a Jeep Wrangler 4 down and don't even know it is back there.

[gunner]

bkahler, please advise where the extended air cleaner hose picks up the clean air and is it affected during heavy rains. There is not much room to put the hose out the front between the cruise control and the airconditioner compressor.

[Mike Leary]

Originally Posted by Smartstream

I guess being 1,000 overweight I'm not allowed to exceed 25 mph.

Cheers, Dan

I thought you said you lost some weight recently.

[Jenniflow]

Bkahler and gunner, your stories really start to explain more of this picture. I thought the Banks system would help a lot but it didn't help as much as I expected and the intake and especially the fuel pump could explain why. We've got the coach in the shop right now getting the rear fuel pump replaced and now I'm really looking forward to seeing the difference. I will report back. Thanks!

[bkahler]

Originally Posted by gunner

bkahler, please advise where the extended air cleaner hose picks up the clean air and is it affected during heavy rains. There is not much room to put the hose out the front between the cruise control and the airconditioner compressor.

I'll try and snap a few pictures of the air intake on the 345 when I get hope this evening. We have never had any issue with heavy rains.

Brad

[Keyair]

Good feelback and discussion peeps!

My 454 has the Banks kit.
Someone replaced the Carb with an Edelbrock, and the stock airfilter base would not fit.
It had a pancake filter on it. I bet that pancake killed some power/economy by sucking hot, less dense air in.
Even so, I had no problem with power when I needed it on inclines on the freeway, and even pulled up over the continental divide at about 10,000'.
Best economy was nearly 8.5mpg on one leg.
I now have the Banks intake top and a unchopped stock lower restored and ready for when I swap the Quadrajet back on.


As Brad suggested, I will be extending the snorkle intake with a piece of trunking to maximising the cold air drawn in!

The plan is to also swap the stock cast iron intake at the same time with an Edelbrock Performer..
I am told this will add power/torque too..
Here is the rebuilt carb sitting on the intake..


My only concern is the under-doghouse clearance.... but I have a plan....

[bkahler]

Originally Posted by gunner

bkahler, please advise where the extended air cleaner hose picks up the clean air and is it affected during heavy rains. There is not much room to put the hose out the front between the cruise control and the airconditioner compressor.

Here are some pics of the 1986 345 air feed hose from the front of the motorhome to the carburetor air filter inlet. This particular setup has a flat plate in front of the opening which I suppose is designed to keep water out.

On our 310 with the banks inlet it doesn't have that blocking the opening.

On our old winnebago I didn't use anything to block the opening either and never had a moisture problem.

Brad

[crazeevw]

The set-up on my Banks is a bit different. Too dark right now to get any pix, but will post tomorrow.
Thanks, Derek

[gunner]

Originally Posted by bkahler

Here are some pics of the 1986 345 air feed hose from the front of the motorhome to the carburetor air filter inlet. This particular setup has a flat plate in front of the opening which I suppose is designed to keep water out.

On our 310 with the banks inlet it doesn't have that blocking the opening.

On our old winnebago I didn't use anything to block the opening either and never had a moisture problem.

Brad

Attachment 165255Attachment 165256Attachment 165257Attachment 165258

Thanks for the pictures I will have to see what kind of clearances I have for routing a hose to the front.

[Keyair]

Thank too for those pics Brad...
I could not figure out where the snorkle of the filter went... I did not know it was going under the battery isolator bracket!

[bkahler]

Originally Posted by Keyair

Thank too for those pics Brad...
I could not figure out where the snorkle of the filter went... I did not know it was going under the battery isolator bracket!

Glad they helped.

Here are a couple of pictures of the Banks intake funnel on our 310. I don't care for the opening in the fitting on the right side and I'm assuming it was put there by Banks to keep moisture out of the carburetor. Personally I would prefer the ram air effect if it was blocked off. If any I would just make a very small hole for moisture to drain out of.

Brad

[crazeevw]

here's what I have on my '89. Brad, the photo you have of the inlet with plate directly in front of it, looks very similar, except there is an additional hose, going directly in front of the grill.
Seems they are similar, except for installer positioned my air intake a bit differently. Almost wondering if a rubber flap on back side of grill inlet wouldn't help with a more 'ram-air' effect? Realize there is the need of no water coming into carb, but that sort of travel of the incoming air, would that much rain get into the carb?
Thanks, Derek

[bkahler]

Derek,

Interesting differences in the air intake that Banks supplied. Ours was probably installed back in 86 when the motorhome was new so that might explain the difference between your arrangement and ours. Of course I'm referring to our 345.


Our 310 is the one that is like yours although it doesn't have the box where the hoses connect. Our hose comes straight from the carburetor to the front of the grille.

I do like your rubber flap idea. That would force more air towards the carburetor while still allowing the flap to open slightly to drain moisture off.

Brad

[crazeevw]

Brad,
My guess for a rubber flap, I'm going to need to readjust the grill intake to look more like yours, since the 'dump' area for excess air is pointed downward......just my thought.
Thanks, Derek