I have a 1984 Barth with a 454 engine and at 60 mph the tach reads 3000 rpm and the engine tends to get noisy at this speed. Can anything be changed maybe in the rearend to offset this without changing overall performance.
Steve W

Might try a Gear Vendors over/underdrive. It cuts my rpm from 3000 to 2400 on my 1984 Barth.

Another quick thought.....Gear Vendors will give you a rebuilt unit for $800 with your exchange core. What happens is if you push the unit to hard in reverse, it will knock out the reverse band in the Gear Vendors....your coach will not back up at all. It happened to me. If you can pickup a core (that someone thinks is bad), you can get a rebuilt unit from the factory.

quote:

Can anything be changed maybe in the rearend to offset this

YES

quote:

without changing overall performance

NO

A Gearvendors aux tranny will make a difference.....For me, this worked:
http://barthmobile.com/eve/for...1087061/m/1073998957

Thoroughly crunch the numbers if you're considering a rear end gear ratio change - for every
plus, there's a negative

Thanks for everybodys info but surprised that the mileage didn't go up with the overdrive unit. Noticed on my 84 Barth with the 454 that it is the belt driven cooling fan that gets louder with rpm. Has anybody tried taking off this fan and converting it to all electric???
Steve& Cassie

quote:

Originally posted by Cassie and Steve:
Noticed on my 84 Barth with the 454 that it is the belt driven cooling fan that gets louder with rpm.

The OEM fan is designed to slip a fair amount when the engine is not too hot, and engage almost fully when the it senses really hot air coming through the radiator. An RV with a good cooling system and fan clutch will be very noisy on cold start-up, then quiet down in a block or three. Things will stay quiet until the engine heats up, either in slow traffic or hot hills. The stock temp gage will be approaching the middle mark when the fan starts to roar. If you want to test yours, drive it around to warm it up, then park it and let it idle with a newspaper blocking the front of the radiator. Watch your temp gauge and listen for the roar before the needle reaches the middle mark. They do die with age, and require replacement after a few years. I use only GM parts.

quote:

Has anybody tried taking off this fan and converting it to all electric???
Steve& Cassie

Hot rodders do it, off-roaders do it, my Vette LT1/4 engine has electric only, but the fan sellers do not recommend it for heavy loads. Or, at least, the last time I checked.

There is no reason why it wouldn't work, but it would take some development and testing to get it right. I would start with a pair of two-speed electric fans out of a 3.8L V6 found in Ford Taurus and Lincoln Mark VIII’s made between 1990 and 1995. (model 8C607). They do 3000 CFM on high. These work pretty well on off road vehicles, so might be worth trying on a MH.

On my Oshkosh Chassis - I have a Dana Hypoid Drive HD80 with a 5.13 ratio.

If it was on a John Deere Chassis, I would have had an option of the 4.63 or a 5.12 ratio.

My engine's peak HP of 230 is stated to be at 3,600 rpm's

my peak torque is 390 ft-lbs at 2200 rpm's.

If I get ambitious, I might change my ratio to the 4.63... but, I haven't crunched numbers nor do I know if my rear end housing is capable of that size.

Current tires size for me is 225/70R19.5 - I could also go with a 245 profile too.

Anyone want to crunch the numbers to show my current engine rpm's at 70 mph & how tire size and ratios will change cruising speed and performance?

Bill, I don't think your wheels would accept 245 metric tires. most wheels are 6" and the separation would not allow the wider tires without contact. Been thru this. I went with 225 tires "G" load rating and settled for a loss of 60 engine RPMs at 60-70 MPH.

I had steel wires made for the 245 with proper separation and were 7" wide as opposed to 6" which I think you have. They are heavy! Didn't use them.

I have 4.1:1 rear