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

[lokka]

Ok guys ive heard all sorts of storys on this subject and would like to know what the owners of 4bd1's have to say about turboing a N/A 4bd1

I knnow theres huge bennifits on fitting a turbo to a deso id just like to know what others think i have a 4bd1 with only 150 k on it and would like to fit it to a rangie with a turbo and intercooler either air to air or water to air ..

I dont want to run huge boost just the right amount to suite the set up i use i know im not going to get the same HP figures of a V8 but i also wont have the drinking habbit of one ....

Im planing on running the original LT95 which came with the doner stage1 the engin came from and std raito's in the diffs and a set of 33in tyres as ive read on other threads on here that this type of combo is about the best set up what do others think ...

Cheers

Chris

[JDNSW]

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

[Bigbjorn]

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.

[Larns]

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.

[EchiDna]

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...

[JDNSW]

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

[EchiDna]

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!

[JDNSW]

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

[rovercare]

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;)

[JDNSW]

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

Well, yes. The piston temperature will depend largely on how much fuel is burnt, but will generally be higher with higher intake pressure, simply because the fuel is burnt more effectively. And since the whole idea of pressurising the engine is to increase the power, as a general rule the maximum fuel delivery WILL be increased. But as you are pointing out, the problems will only arise when you actually use the increased power.

John

[rovercare]

Well, yes. The piston temperature will depend largely on how much fuel is burnt, but will generally be higher with higher intake pressure, simply because the fuel is burnt more effectively. And since the whole idea of pressurising the engine is to increase the power, as a general rule the maximum fuel delivery WILL be increased. But as you are pointing out, the problems will only arise when you actually use the increased power.

John

Hence, with a pyrometer, and sensible fuelling (EGT temps) its doubtful to effect longevity, go overboard and you motor croaks

[JDNSW]

Hence, with a pyrometer, and sensible fuelling (EGT temps) its doubtful to effect longevity, go overboard and you motor croaks

Agreed, although unless the EGT temperature is continuously monitored and used to control maximum fuelling, the risk will always be there - on that real hot day when you call on it to do its utmost. But as I said at hte start of this thread - there is quite a margin of safety, you just have to be aware that you are cutting a bit into it.

John

[Bigbjorn]

No point in putting a turbocharger onto a naturally aspirated engine without increasing fuel availability, unless the engine was already over fuelled and insufficient air was being supplied to burn the available fuel.

[rovercare]

No point in putting a turbocharger onto a naturally aspirated engine without increasing fuel availability, unless the engine was already over fuelled and insufficient air was being supplied to burn the available fuel.

That's exactly right, no gains to be made, even at 25psi with no extra fuelling, there won't be any issue's

'tis the fuel that creates heat

[Blknight.aus]

I agree with rovercare and a few others with this one...

If you turbo the suzi without messing with the fuel pump other than to do the timing of it your not going to have any problems, it will seem to run cleaner and in the right circumstnaces it will run cooler as its running leaner (more air, relatively less fuel) depending on how you set the turbo up you'll get a slightly sharper respones or a longer flatter torque curve.

Its messing with the pump that gets you in the end. If you do a lot of messing with the pump then you need to do the rest properly to deal with it.

Ive seen a burnt piston in a suzi (3.6 not 3.9) that was caused by a poorly set up pump/injector that was letting one pot work a lot harder than his buddies and it paid the consequences.

[rovercare]

I agree with rovercare and a few others with this one...



Do you feel dirty? like you need a shower:D

(tongue in cheek:angel:)

[Blknight.aus]

no mate, check your tag line for the reason why :cool:


although 25 PSI might cause some valve float and might put the inlet manifold gasket at risk. :P

[andrew e]

I have only heard of 1 4bd1 having problems because of an aftermarket turbo, and the owner claimed to have the piston skirts end up in the sump when he got the motor. The car was a yellow rangie 4 door in western syd, very nice car too.

Its strange, when my fueling was increased to suit the turbo, there has been no difference with my egts. Hottest so far has been 450, (550 is meant to be the safe limit) however i have not overloaded and pushed it hard yet.

Andy

[Bush65]

... with my egts. Hottest so far has been 450, (550 is meant to be the safe limit)...

Andy
My workshop manual states 750*C for the BD1-T. Measured at the inlet of the turbo.

The 4BD1-T has oil cooling for the pistons as JD mentioned. They also have alfin pistons, but I have heard that later 4BD1 also have these.

So I wouldn't like egt as high as 750* in a 4BD1, but would be feel comfortable with 650* for short periods.

When you see the egt climbing to around 650*, backing off a little or going down a gear will usually drop it.

[lokka]

I agree with rovercare and a few others with this one...

If you turbo the suzi without messing with the fuel pump other than to do the timing of it your not going to have any problems, it will seem to run cleaner and in the right circumstnaces it will run cooler as its running leaner (more air, relatively less fuel) depending on how you set the turbo up you'll get a slightly sharper respones or a longer flatter torque curve.

Its messing with the pump that gets you in the end. If you do a lot of messing with the pump then you need to do the rest properly to deal with it.

Ive seen a burnt piston in a suzi (3.6 not 3.9) that was caused by a poorly set up pump/injector that was letting one pot work a lot harder than his buddies and it paid the consequences.


So dose this mean i can alter the pump a little to gain some more horses providing i use a EGT gauge and try keep my EGT's down ..

I also want to run as big a cooler as i can even if i have to make my own i dont care as long as it dose its job im happy

[justinc]

My workshop manual states 750*C for the BD1-T. Measured at the inlet of the turbo.

The 4BD1-T has oil cooling for the pistons as JD mentioned. They also have alfin pistons, but I have heard that later 4BD1 also have these.

So I wouldn't like egt as high as 750* in a 4BD1, but would be feel comfortable with 650* for short periods.

When you see the egt climbing to around 650*, backing off a little or going down a gear will usually drop it.

Far out, When I was running 650 I ruined 3 ZF autos and had traction issues in the wet...I had to wind it back to stop breaking things. I just towed a van west and back, hottest EGT's into a headwind on a 35deg day was 470 and thatr was for about 3 hours straight at 90kmh. Returned lousy fuel economy that time, down from the usual 22 to 23 mpg to 19.5.:o:mad: I hate wind.

I agree, driving to the EGT gauge is very important when working hard, towing into strong winds in high-ish ambient temps will push them up high as quick as.

For the record, at 480,000km this engine used 1 litre of oil for the 9000km trip.

JC

[Blknight.aus]

So dose this mean i can alter the pump a little to gain some more horses providing i use a EGT gauge and try keep my EGT's down ..

I also want to run as big a cooler as i can even if i have to make my own i dont care as long as it dose its job im happy

If your going to add and EGT gauge you can mess with the pump all you like so long as you dont push too much past 600deg c for the EGT before the turbo

But I would advise initially just to give you a baseline on how well the turbo is going to work for you just giving it a touch on the timing (like the timing on a dizzy) and get it sweet without the intercooler and limit your boost to say 6-7psi via the wastegate settings.

Then youve got the turbo you want on the exhaust manifold and youve got an idea about how you want to make it best work with your driving style and can put some time into rethinking your cooling system, induction system and intercooler setup once youve got that sweet you can then think about giving the wastegate and FIP a proper touch up.

Theres a lot of variables that you can fiddle with endlessly and while It may take a while to do it this way your only really adressing one variable at a time and IMHO it stops little problems at one point snowballing into the next and giving you headaches. The other benifit of it is you get to do it piecemeal so if something else goes west your not left with a big problem to get it back on the road should something else tax the finance.

[rovercare]

Far out, When I was running 650 I ruined 3 ZF autos and had traction issues in the wet...I had to wind it back to stop breaking things. I just towed a van west and back, hottest EGT's into a headwind on a 35deg day was 470 and thatr was for about 3 hours straight at 90kmh. Returned lousy fuel economy that time, down from the usual 22 to 23 mpg to 19.5.:o:mad: I hate wind.

I agree, driving to the EGT gauge is very important when working hard, towing into strong winds in high-ish ambient temps will push them up high as quick as.

For the record, at 480,000km this engine used 1 litre of oil for the 9000km trip.

JC

Obviously didn't get a chance to drop in and pic this gearbag up:eek:

[Dougal]

If your going to add and EGT gauge you can mess with the pump all you like so long as you dont push too much past 600deg c for the EGT before the turbo


600 pre turbo is a fairly big safety margin. Not that that's a bad thing.
My 4BD1T would only do 550 deg preturbo at around 2500rpm with 15psi (intake temps 130-150 deg C). But at 3500rpm the EGT's would climb to 700, I couldn't get a stable intake temp reading in those conditions.

This on a 4BD1T with a 1/4 turn on the fuel screw which at the time had suspect rings. Haven't tried it lately.

[Blknight.aus]

mate the safety margin is there for if you turbo a 4bdI without upgrading the guts... I picked it as thats the hottest Ive ever managed to get a 4bdI and even then IT was borderline outright abuse/NFW type treatment.

[rar110]

I can't wait to do this.

I hope Dave your still up Qld in 6mths or so. Is it true the gunbuggys have a 4bd1T?

Unfortunately I can't see me having the bits before cooma next year. If I get to go it would be good to do the trip in a turbo motor.

[Blknight.aus]

nope gunbuggies (as the adjies have em) are NA with the lower geared tcase.

I'll be lurking here for about oh 6 years I guess.