[tjf0288]

So as far as I know there is no deffinate thread that states differences and pros/cons to either engine. Does anyone have any deffinate information for a complete 4BT vs 6BT thread? Obviously there is a 2 cylinder difference but what about stuff like average MPG, HP/TQ numbers and such. Before I commit money to any one engine/vehicle I'd like to make sure I get the right one for me!

-TJ

 

[JimmieD]

That's asking a lot really. The 6BT was used from '89 to present in Dodges, and earlier in other applications. There have been dozens of versions with at least 4 different injection pumps, various heads, computers, injectors, intakes, exhausts, intercooled/non-intercooled etc. with dozens of power ratings. Hard to compare apples to oranges!

Personally I'd say the best comparison is still to look at similar versions, as in VE injection pumped, and intercooled/non-intercooled and see how the numbers fall out. You'll be pretty close on power ratings if you divide by 6, multiply by 4 to compare power ratings, then calculate for weight differences and engine room clearances. For a swap, with the power available in a 4BT that's built right, I don't think they can be beat, especially considering a HUGE difference in mileage.

 

[BobS]

This was discussed a few times on the Yahoo 4BT Forums side. The key factors in selecting generally come down to size & weight, room available under the hood, drivetrain to be used, availability of the engine and transmission you intend to use, costs of required modifications to do the installation, and your intended use of the converted vehicle.

If you have a Ranger, S-10, Dakota, or Toyota it would be much easier to install a 4BT due to size and weight. 6BT's have been installed in these trucks with moderate to heavy modifications.

If you have a full size 1/2 Ton or larger Ford, Chevy or Dodge a 4BT or 6BT is a some what common modification. The cons to a 4BT in this case is usually based on your intentions and where you live. For example if you have a full size crew cab truck and want to tow a 10,000 pound trailer in Montana the 4BT probably is not a good idea.

Costs of the 4BT are generally higher than a complete running 6BT engine if you buy a "donor truck" complete. 6BT's donor trucks in the Northeast and Great Lakes regions are getting more plentiful each year due to vehicle rust. You can end up with everything you need from a donor vehicle for the same price as a 4BT pull out engine with just an engine adapter attached.

Power and mileage are determined by many factors. You can reasonably increase the power of the 4BT to be somewhat compatible with the lower powered 6BT's but your fuel mileage will generally be closer to that of the 6BT's in the same power range. You can also retune a 6BT for a bit less torque on the drive line for slightly little better fuel mileage.

And the BIGGEST overall factor is to make sure your modified vehicle will be street legal after you complete it. There could be nothing worse than spending thousands of dollars along with hundreds of hours of work to find out you now own a high priced lawn ornament.