TB42S (Carb) aftermarket EFI options

[symmetry4wd]

Good morning all,

I think t some point the thought crosses all of our minds:

"Should I do an engine conversion", "how do I get more power from my engine", "I need more power", "should I turbocharge my engine" etc etc

I'm no stranger to engine conversions, or fiddling and modifying cars, so naturally when I got the GQ, my mind went places.

After thinking about engine conversions, VK45, TB48, TD42 etc, the costs involved are pretty astronomical, like more than what I paid for the vehicle. and because the car is my daily, it has to be done in one shot. So R100k+ engine conversions are not really on the cards. I also know from experience, the teething issues with conversions and trying to get them reliable and done well is a massive task, or expensive. Plus the fact that whatever you think the budget is for the conversion, you can quite often double that to get a more realistic cost.

I always like the idea of keeping an engine that was meant for and came with the chassis, better documentation and oem parts/support. Thought about TD42's but again the price put me off, and Petrol can be less of a hassle than diesel in terms of engine.
I then started to like my TB42 more and more, very well suited to the GQ, and has good off-road engine characteristics. I guess my only gripes would be on-road performance, while not bad, for the engine capacity and fuel consumption, it leaves a bit to be desired.
Ideally, if we could more easily get the fuel injected TB42's locally, that would be perfect, and I wouldn't look any further into other options, that would be perfect for me, as a base to build from.

Ideally, I think a low boost turbocharged, standard compression TB42 would tick all the boxes for me. Not after major power, just a bit more.
The TB42's are nice robust and under tuned engines, so from my searching, a bit of boost and a power upgrade is now big issue for them, you can quite effectively double the power output.

If there was a way to efficiently and effectively turbo the carb TB42 I would look at that, but it doesn't seen at all like a viable or reliable option.
I then looked at converting the carb to EFI to be able to turbocharge down the line.
You could go the route of a TB42E EFI engine conversion, or getting all the EFI components from a TB42E and transferring them to the TB42S carb, documented here and other places: https://www.patrol4x4.com/threads/tb42- ... ost-929899
This is an option, but requires quite a bit of wiring, and re-making looms etc, or using old 25+ year old parts, which may not end up in a nice reliable conversion, and could have quite a few headaches like an engine conversion. Or if replacing all the wear and tear items, it can end up extremely costly.

This then got me looking more at "universal" carb to EFI conversion kits:

Holley Terminator, Sniper ETC
FiTech
Edlebrock
MSD
EZ-EFI

(basically a whole lot of American companies given all their old carb v8's etc)

Have any of you looked into these EFI conversion kits, or have any useful information, or seen it done on a TB42 anywhere?
What are your thoughts?


My thinking would be to take the first step converting the TB42 to EFI, then can build up turbo components over time after that, which also means I wouldn't have to fork out R100k+ for an engine conversion in one go.
It would maybe be around R30k+- to do an EFI conversion, then maybe another R50k down the line to turbo.

I even thought maybe a "cheap" TB45 conversion, then turbo that down the line, but it seems the TB42 is better suited to boost, and again at least came in the GQ chassis.

[Peter Connan]

Personal opinion again (but backed up by two different engine conversions into the same GQ):

The Nikki carb is pretty good as carbs go. An indication of that is the difference in power output between the carburetor and fuel injection versions of the TB45: 142kw vs 138kW.
Even comparing the 126Kw of the TB42 carby with the fuel-injected TB45: 126kW vs 146kW. There is a difference but not enough to make it worth while unless the current engine needs work anyway.

Fitting the intake manifold from the TB45 onto the TB42 is also not really an option. Possible but quite difficult because the bolting pattern is completely different and the thermostat housing is part of the manifold on a TB42 but not on a TB45. I believe any fuel injection system using that just replaces the carb (single-point EFI) is likely to be less efficient than the TB45's system.

So either sell the GQ and buy a GU, or leave it as it is, or put a TD42 or a TB48 in it.

Either of the last two will cost you more than you can buy a GQ for.

I strongly recommend leaving well enough alone, especially if you intend touring to remote locations.

[symmetry4wd]

Found thi video, interesting:


@peter connan

I hear you,

I wouldn't want the conversion to EFI, just for the sake of EFI, or expecting much greater efficiency, the main purpose would be to allow for a turbo setup.

From all the forums etc, most people say there really isn't much of a difference in power or economy between the carb or EFI TB42. Or much of of a difference between the TB42 and TB45.

I wouldn't look at a fitting a TB45 intake manifold and EFI system onto a TB42, but rather the overseas/import TB42 intake manifold and EFI system. All the components would have to be imported though.

Do you have a link to your build of your GQ by any chance, would love to see what you have done to your GQ over it's lifespan, I'm sure there is some good information there for me to expand my knowledge/

What engine conversions have you done on your GQ?

My thought's/options that I am currently thinking of are:

Leave the TB42 as is
TB42 OEM EFI Conversion
TB42 aftermarket EFI Conversion
TB45 engine conversion

I appreciate your advice and recommendations

[jakeslouw]

I'd consider an RD28 Turbo. Seriously.

Sent from my SM-A032F using Tapatalk

[Peter Connan]

I'd consider an RD28 Turbo. Seriously.

Sent from my SM-A032F using Tapatalk

If it was only a touring car, it could be a good option.
But the smaller diesels don't work well on the trails, unless you also reduce the low-range gearing as part of the change.

Andreas, unfortunately it's not all in a single thread but multiple threads scattered all over the place.
The first change was brought on by a cracked head (due mostly to lacking maintenence prior to my ownership but also to my trying to be clever instead of just replacing the radiator and viscous right away) resulting in many overheating episodes. At the time I was offered a TB45 for less than a new head, so went with that. Because I have an aversion to aftermarket electronics I fitted the TB42's carb and distributor (quite a challenge).

However unknown to me that engine had been internally modified, bad workmanship causing a failure in the lubrication system which ruined the engine. I rebuilt it but still had oil pressure issues, so I put a TD42 in.

[jakeslouw]

If it was only a touring car, it could be a good option.
But the smaller diesels don't work well on the trails, unless you also reduce the low-range gearing as part of the change.

Beg to differ.

[Peter Connan]

Yes they are great in sand and mud.
I am by default talking about rock crawling.
My apologies.

[symmetry4wd]

I'd consider an RD28 Turbo. Seriously.

Sent from my SM-A032F using Tapatalk

If it was only a touring car, it could be a good option.
But the smaller diesels don't work well on the trails, unless you also reduce the low-range gearing as part of the change.

Andreas, unfortunately it's not all in a single thread but multiple threads scattered all over the place.
The first change was brought on by a cracked head (due mostly to lacking maintenance prior to my ownership but also to my trying to be clever instead of just replacing the radiator and viscous right away) resulting in many overheating episodes. At the time I was offered a TB45 for less than a new head, so went with that. Because I have an aversion to aftermarket electronics I fitted the TB42's carb and distributor (quite a challenge).

However unknown to me that engine had been internally modified, bad workmanship causing a failure in the lubrication system which ruined the engine. I rebuilt it but still had oil pressure issues, so I put a TD42 in.

That sounds like quite a rollercoaster of engines!
Is your TD42 you have now a factory turbo TD or NA TD? Do the NA TD's ever come up for sale locally?

@jakeslouw
I have thought about the RD28, the experiences I hear from people is very 50/50 when it comes to reliability. The argument is often said, if you are thinking of going RD28, why not just go TD42. I think there is generally more support both aftermarket and oem for the TD engines, as well as a knowledge base and community support. Nothing against the RD, just doesn't seem right to for me.
What's the support locally for the RD? (not say the TD's or TB's is good, I just can't imagine the RD being great).

I must say, after having an NA Petrol 4x4 now, I quite like the characteristics, and less worrying about EGT's and overheating.
I much prefer the slower more technical, crawling 4x4ing, and having a turbo diesel can be difficult in those situations (also one of the reasons I'm not a huge fan of the carb, stalling in bad situations and having to try start the engine again)

[Tinus lotz]

Look at petrus 4.5 gq ....works well

[Peter Connan]

Current engine started life in a GQ, thus normally-aspirated but it was the vaunted "silvertop" so the pistons were turbo-ready and there are oil squirters in the block. Engine had over 400k km on, but the pistons, crank and bearings were still good. I did have to re-sleeve it and replace the head.

It is fitted with the turbo from the altitude-compensated bakkie but with the EGR blanked off and the wastegate linkage disconnected. I also later replaced the fuel pump with an 11mm one (standard is 10mm), but to be honest that made little difference on this little turbo. Max boost is just less than 1 Bar. It was dyno'd once (when it still had the 10mm pump) at 410Nm and 103kW at the wheels.

Comparing the TD42 with the TB42:
at very low revs (anything under 1200), the TB has more torque. I don't know how much because I have never seen a dyno result that starts under 1500rpm, but I don't think it's a huge amount. However, the diesel's fuel pump has a built-in mechanism that strives to keep the revs steady at idle. As a result, it can seem as if the diesel has more torque, because you can usually just leave the throttle alone and the car will crawl over most obstacles, whereas the TB has to be driven almost all the time. So off road, there are pros and cons to both, but in terms of ultimate ability the TB wins for me. I also found the Nikki carb to be very tolerant of angles and seldom had any trouble re-starting after a stall.

On the road the TD is a very clear winner. At 120 it is running pretty much at maximum torque, and that torque is enough that one very seldom needs to gear down. I can do hills in 5th that I used to have to gear down to 3rd. And economy is better.

Having said all that though, the TB48 is a very strong contender. A bit less torque but more power and similar fuel consumption than the TD, and no turbo to nurse. The only disadvantage to me is that one needs an aftermarket management system. I am a bit allergic to those having seen too many expire in wet conditions but if enough care is taken they can be very reliable. However that would also be necessary if you injected the TB42.