Thor Forums

[Chance]

Originally Posted by Oneilkeys

I cannot believe that "the engine doesn't brake at all". That just does not make sense. For some reason that I do not understand, it may not brake as well..... With the 5 Spd on 10% grades it would sometimes downshift two gears and run the rpm up over 4000 - almost too much braking. I wish I could go try mine out, but it will have to wait until this summer.

I agree; not "braking at all" doesn't make sense to me either.

Having said that, there is an explanation that does make sense to me based on my experiences driving in the mountains.

With a fully-loaded 14,500-pound RV, the V10 would easily go towards 5,000 RPM on steep downhills which forced me to occasionally apply the brakes. By comparison, the same V10 in my van provides much more engine braking -- mostly because the van weighs a lot less.

What's happening is that as engines have gotten a lot more powerful for their size (displacement), manufacturers have made motorhomes larger and heavier, so that the engine can't provide as much braking relative to vehicle mass.

One way to provide more engine braking in order to hold a slower steady speed is to first slow down a lot in order to engage a lower transmission gear. On some steep descents I found that starting out around 50 MPH there wasn't enough engine braking to keep the motorhome from accelerating downhill unless I used the brakes. However, on the same grade if I slowed to 30 MPH to access a lower gear, the engine could prevent the MH from speeding up.