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Topic: What HP?? (Read 1875 times) previous topic - next topic

What HP??

The manual for our coach says it has a 8.2 Liter turbo charged Detroit Diesel 250 horsepower. Our coach is a 1989 36' on an Oshkosh Truck chassis.

Not really big. Not really heavy. Not a lot of storage room to load it up with stuff to increase the weight. I have seen other FT coaches-with a variety of engines, bet it Cat, Cummins or DD listed at 250HP in the wider, taller, newer coaches that their owners say they cruise at or above 65 MPH. At 65 MPH our tach indicates we are starting to exceed 2500 RPM. Are the newer coaches running at max RPM to hold 65 MPH? Does 6 speed trans account for dif?

Our coach seems underpowered and does not hold speed on most hills. Even towing our 96 Geo. Normal? Something wrong? Mileage averages between 8.6 and 12 MPG. (headwind--no headwind)

Any way to tune engine?

Re: What HP??

Reply #1 –
Yep, HP,If your happy, all is well.  For me no such thing as too much HP, I like the ability to run like my hair is ablaze sometimes.
Now for what is needed, depends on two things, need & want.  I feel the 2500 rpm at 65 mph is too much and more like the old days with small engines. 
Today it is more like 1350 rpm @ 65 mph area on my setup. and driving 75 mph is just a matter of foot position and fuel burn, why the need for cruise control and a good mph readout,  do I want and need ? sometimes.  ;D

Re: What HP??

Reply #2 –
The 8.2 is a high reving, low torque engine. It's governed at 3100. The 250 hp 3208 cat probably has twice the torque of the 8.2 and runs at a much lower RPM. I was told by more than one diesel mechanic not to tweek them as the durability would be severely reduced.

Re: What HP??

Reply #3 –
Hello Nitehawk,
The 8.2l Detroit is actually a good engine despite what lots of folks say. 380k miles on my '83 ored proves that. In your coach Oshkosh actually installed a 210 hp version of the 8.2 on the V-815 chassis. This engine can be safely tuned to 250 h.p and with addition of an after cooler 300 h.p. the rear axle ratio will also limit your top speed. The chassis you have is equipped with a 4:33:1 That will also allow the speed drop on hills. Your rig was designed for economy and comfort not really speed or lots of power. This is an adequate engine and with proper care a very dependable engine. The torque spec stock setting is 442 where as the 3208 is 650 but if you turn yours up you can achieve equal torque. If you want to pursue this contact expertdiesel.com as they are the premier builder for 8.2l Detroits. Don't be discouraged and enjoy your beautiful coach. I hope this helps.

Re: What HP??

Reply #4 –
Thanks James, thanks all.
I am really not discouraged but just curious, as there is rarely any discussion re the older engines/coaches such as ours. So, I wondered if the performance is where it is supposed to be, or if we may have a problem starting to raise its ugly head.

We do enjoy cruising at 56 MPH (per our GPS) as it lets us really relax and enjoy the scenery we are passing thru. We try to take a different route coming and going to a destination and also try to take the less traveled, less traffic roads that are normally driven at lower speeds.
We have been blessed with eyes to see, health to go places, beautiful places to experience, and a magical vehicle to take us places.
We love our '89 GV and, just like parents with small children, care that it is kept in the best possible condition--HAPPY!!

Re: What HP??

Reply #6 –
nitehawk,

My earlier post wasn't meant to be discouraging. You won't pass a lot of people going up hills and you won't be cruising down the freeway at 80, but you shouldn't have problems either. I traveled for 7 years in my  89 gv with the 8.2 and never had any engine problems.  The only problem I had with it was It blew out the high pressure hydraulic  line at the brake pedal a couple of times. If yours has air brakes that won't be a problem either. 

Re: What HP??

Reply #7 –
Randy, no air brakes. There is a small electric motor mounted on the side of the brake reservoir that apparently provides "boost".

Re: What HP??

Reply #8 –
That motor is to provide enough boost to stop in case of engine shutdown. make sure it is working properly. I was an idiot and ran mine out of fuel once and the electric motor didn't come on like it was supposed to. Fortunatly I was on the freeway with no traffic and was able to coast to a stop. All the pressure with both feet on the pedal seemed to have virtualy no effect.
 

Re: What HP??

Reply #9 –
Randy is correct on the reason for that motor. I had to replace mine on the old \GV we had 93 with oshkosh as I found out it was not working by exactly the same reason--no brakes when engine shut off once while driving--scary.
John H