2nd Gen Non-Engine/Transmission After 3.54 to 4.10 conversion

[Bart]

I brought my rig to work this morning. I'm still running 55 mph (like before) but the boost and exhaust gas temps are both down quite a bite. Obviously, the truck is more responsive and when I'm all locked up at 55 I'm thinking "I haven't shifted into o. d. yet". But I have. The higher rpms will take some getting used to. I hope that Josh (my partner in this swap) is as happy with his truck as I am mine. I do realize that I'm somewhat of an oddity, because I can just sit in the slow lane and watch the world "fly" by. I was getting 16 average on my rig before on a long trip with my 10'6" cab over, It will be interesting to see the improvement (I hope) in fuel mileage.

 

[bkroupa]

I went the other way & picked up a solid 1. 5 mpg empty. My TT towing mileage was not affected at all, but I have a 5 speed, 33" tall tire & SRW

 

[Regcabguy]

I brought my rig to work this morning. I'm still running 55 mph (like before) but the boost and exhaust gas temps are both down quite a bite. Obviously, the truck is more responsive and when I'm all locked up at 55 I'm thinking "I haven't shifted into o. d. yet". But I have. The higher rpms will take some getting used to. I hope that Josh (my partner in this swap) is as happy with his truck as I am mine. I do realize that I'm somewhat of an oddity, because I can just sit in the slow lane and watch the world "fly" by. I was getting 16 average on my rig before on a long trip with my 10'6" cab over, It will be interesting to see the improvement (I hope) in fuel mileage.

I almost went 4. 10's but settled for 3. 73's from stock 3. 54's. With my camper and 285's and mods it's a good compromise. If I went to 35's,4. 10's would be the way to go. If you go to an "E" rated Toyo 285 or BFG it might be a perfect combo.

 

[RDelissen]

don't count on a mileage increase. It'd be more likely to see a decrease with the lower axle gears (given the same size tires), but you'll have more fun driving your rig and towing

 

[hdtrukn]

Increase ? Maybe, Maybe not!

If you drive at 55 or 60 your RPM was to low with the 3. 54.

I run a little faster, but if I stay at 60 mph, I'm at 600 degree's and turning 2000rpm.

Of course I am running stock 215/85/16 tires.

With 35's your RPM may still be alittle low.

Just my thoughts.

Scott

 

[surfbeetle]

I just went from 4. 10 to 3. 54. Empty running 75mph I got 22mpg going down I-5 from Sacramento to San Diego. The same trip with the 4. 10s I got 18 if I was lucky. Now I can get 700 miles in a tank of fuel. My only issue is that I have the 5 speed, I have to be careful of the going too slow in fifth and causing problems with the fifth gear nut.

 

[jkidd]

Brake specific horsepower

Tdr has a few older articles about Brake specific horsepower.

24v is most efficient at 2000rpms as far as power per amount of fuel.

12 valve was a few hundred lower.

 

[nps]

The RPMs at which the motor is most efficient does not necessarily translate into the speed at which the vehicle gets the best MPG. Many other factors involved with MPG; most obvious is wind resistance at higher speeds.

 

[CurtisM]

Sounds like I will be geting some 4:10's for my truck once I put in a new coverter and trans I think I'll need the extra grunt since my truck has 35 bf's on it