Thread: Pro's and Con's of Turboing A N/A 4BD1

The 4BD1 actually produces near enough to the same power as does the V8 in the form used in the Stage 1 and 110! And a lot better torque figures. But nothing like the power of the V8 in other applications. Turbocharging the engine is a simple and relatively inexpensive way of increasing power substantially with little increase in mass. The downside is that (without incorporating the differences in the -T version, which brings in a whole new dimmension of cost and complication) you are using up some of the admittedly ample durability and safety margins (how much depends on how much boost you use!), and have all the maintenance problems of running a non-standard engine - but you are doing this anyway in putting it in a Rangerover.
A number of people here have run turboed 4BD1s without reporting problems, although some have cautioned that you should keep an eye on exhaust temperatures.

As a different option - have you considered diesel gas? This involves less change to the engine installation for similar power increases, but as combustion efficiency is increased stress on the engine is likely to be less for the same power, and the cost is probably around the same. Downside is you have to find somewhere to put the tank(s).

John

Given that motor manufacturing is a cost concious business, and manufacturers generally don't do radical modifications for the sheer sake of change, I suggest that the considerable differences between the naturally aspirated and pressurised versions of the 4B & 6B series Isuzus are necessary from the points of durability, reliability, and performance. An engine man very familiar with the engine family tells me that there are barely two parts the same when comparing the two systems.

Originally Posted by Brian Hjelm

Given that motor manufacturing is a cost concious business, and manufacturers generally don't do radical modifications for the sheer sake of change, I suggest that the considerable differences between the naturally aspirated and pressurised versions of the 4B & 6B series Isuzus are necessary from the points of durability, reliability, and performance. An engine man very familiar with the engine family tells me that there are barely two parts the same when comparing the two systems.

Very true

Without sounding like too much of a hipocrite, mine seems to have handled the turbo alright. But you do feel a very flat area due to not having the right cam.

Originally Posted by Larns

Very true

Without sounding like too much of a hipocrite, mine seems to have handled the turbo alright. But you do feel a very flat area due to not having the right cam.

I don't disagree, however don't forget the 4BD1 was never intended for running a little truck like a 110 - it was engineered and built for moving fully laden trucks...


my turboed formerly N/A motor aint missed a beat thus far...

Originally Posted by EchiDna

I don't disagree, however don't forget the 4BD1 was never intended for running a little truck like a 110 - it was engineered and built for moving fully laden trucks...


my turboed formerly N/A motor aint missed a beat thus far...

It was designed for moving heavily laden trucks - but on reasonable roads at reasonable speeds, where there is a bit of air cooling for example. I doubt the extreme service in a truck, pulling hard in hot weather in hilly country is any harder on the engine than in a Landrover overloaded with expedition gear pulling hard all day in second gear through sandhills with an air temperature over forty. But if it spends its days commuting on freeways, or even driving to the shops, then the Landrover installation will have an easier life.

John

Originally Posted by JDNSW

It was designed for moving heavily laden trucks - but on reasonable roads at reasonable speeds, where there is a bit of air cooling for example. I doubt the extreme service in a truck, pulling hard in hot weather in hilly country is any harder on the engine than in a Landrover overloaded with expedition gear pulling hard all day in second gear through sandhills with an air temperature over forty. But if it spends its days commuting on freeways, or even driving to the shops, then the Landrover installation will have an easier life.

John

you are right JD, but just to split hairs further - the frequency with which you do those sandhill trips in 40+ degree heat also comes into the equation... most will do that kind of extended trip 1-2 times a year at most, so the hard work for the motor would occur in that time period of (lets say) 8-10 weeks a year, or 20% of the time... even if the wear is accelearated to 5 x normal levels, it's still gonna be a long time between rebuilds!

Originally Posted by EchiDna

you are right JD, but just to split hairs further - the frequency with which you do those sandhill trips in 40+ degree heat also comes into the equation... most will do that kind of extended trip 1-2 times a year at most, so the hard work for the motor would occur in that time period of (lets say) 8-10 weeks a year, or 20% of the time... even if the wear is accelearated to 5 x normal levels, it's still gonna be a long time between rebuilds!

The downside is likely to be not increased wear, but the increased probability of failures such as melted pistons on that once a year trip. Remember that the turbo version has oil jets onto the pistons, not to reduce wear, but to keep piston temperatures down. But of course, the probability of this sort of problem is very much dependent on how much extra boost you give it, and how much you use the extra available power. A mild boost is unlikely to give any problems. Same as "chipping" a Td5.

John

Originally Posted by JDNSW

The downside is likely to be not increased wear, but the increased probability of failures such as melted pistons on that once a year trip. Remember that the turbo version has oil jets onto the pistons, not to reduce wear, but to keep piston temperatures down. But of course, the probability of this sort of problem is very much dependent on how much extra boost you give it, and how much you use the extra available power. A mild boost is unlikely to give any problems. Same as "chipping" a Td5.

John

Doesn't have a lot to do with the boost really, its how much fuel you tip in with the boost