Tb48 vs Td42 Engine

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Crazy-Wheels
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Tb48 vs Td42 Engine

Post by Crazy-Wheels »

Which is the best engine between Tb48 and Td42, just asking out of curiosity :think:

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Re: Tb48 vs Td42 Engine

Post by hugejp »

Time to get the popcorn!!! :rolling:

I have both & I wouldn't sell either of them & truly can't choose a favourite.
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Re: Tb48 vs Td42 Engine

Post by Peter Connan »

This is like asking whether an lion or a hyena is the best predator.

Hyenas have a much better kill ratio, but they cannot take care of buffalo. Nothing but lion can do that.

If you compare the engines in their original guise (IE both non-turbo), the TB48 will be more powerful and have more torque at any speed, but it will use more fuel. The TD may last longer, but I think that has more to do with how they are likely be used than with the engines themselves. The TD will require more maintenance but that maintenance will be slightly easier to perform, and for small problems it will probably be easier to find a mechanic that will be able to fix it.

If you compare a normally aspirated TB48 with a turbo-charged TD42, then the exact specification of the TD becomes the determining factor. If we are looking at the TD42T as sold in South Africa (it was only ever sold locally with a very low pressure turbo, really more an altitude compensator) and not modified, then I think the same applies. The TB48 will still have more torque at all RPM's.

If the TD42 has the high-pressure Australian spec, the UD40 lorry spec or an aftermarket/modified turbo setup (which I think is the most common basis for comparison, although it is to my mind an unfair comparison), then it depends very much on what has been done to the TD. Let's assume a fairly typical setup comprising standard compression ratio, a 10mm pump and boost of around 1 bar, then the TD will have considerably more torque between about 1600 and 2500rpm, which is exactly the rev range you are likely to cruise in. That means you get a more relaxed cruise, with fewer gear changes and better towing ability but still better fuel consumption and little change in reliability, assuming you control the engine based on temperatures. A TD42 with anything over about 0.5-0.8 bar boost becomes an engine that you need to drive with an eye on the temperatures, and if you don't you WILL break it before very long.
However, it will also still be more economical. The TB48 will probably still have a bit more maximum power at high RPM's and will have a flatter torque curve.

If you compare a boosted TD42 to a boosted TB48, the TB48 is once again in the lead with regard to both torque and power, potentially by a massive margin, but it will also be more expensive to get there.
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Re: Tb48 vs Td42 Engine

Post by hugejp »

:goodpost:

Well said Peter.

Both my TB48 & TD42 have been slightly modified. They both have pro's and con's, but again I couldn't choose a favourite.
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Re: Tb48 vs Td42 Engine

Post by graham1 »

I used to have both, but recently sold the td42.
My td42 was quite heavily modified, big pump, balanced etc, so it made very big power, and the cherry on top was that it just would not get hot.
All that said, I still sold it rather than my 4.8.
My 4.8 is way way down on power compared to that td42, but, I just love the silky smoothness of it.
I guess I’m just more of a petrol guy than a diesel guy.

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Re: Tb48 vs Td42 Engine

Post by hugejp »

@Graham1

That sounds strange to me, have you compared your 4.8's power output to any other standard 4.8?
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Re: Tb48 vs Td42 Engine

Post by graham1 »

hugejp wrote:
16 Dec 2020 17:53
@Graham1

That sounds strange to me, have you compared your 4.8's power output to any other standard 4.8?
I might have exaggerated a bit, but I think there was definitely a lot more torque than the 4.8.
I must compare mine to someone’s though, this is the second time it’s been mentioned, other times was on a discussion where I mentioned I battle to get 140 with the 4.8

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Re: Tb48 vs Td42 Engine

Post by Peter Connan »

Graham, you can get some idea of what the relative power and torque outputs could/should be by looking at the table about half-way down the page here:

viewtopic.php?f=61&t=8542&start=40

This is the results of the forum dyno day we held last year. Note that there were only two TB48's there that day, being Christo Boegman's factory-standard GRX (Auto box) and Alex Roux's Skilpad, which is internally standard but running on a completely different ECU, a non-standard exhaust and intake and through a manual box. It should be noted that the dyno operator was having trouble with the GRX's gearbox. The moment he floored it, the box would change down, and thus the results are lower than they should be in reality.

However, even Alex's TB48 was down on torque on a couple of the TD42's, but not on power as the torque is available higher in the rev range. Add to that, my TD42 quite easily gets to 140. A 4.8 should do it without breaking a sweat.

But basically the message I am trying to put across is that all these engines have advantages and disadvantages. First pick the job, then pick the engine. For long-distance touring, the TD42 (or perhaps the later ZD30) is king. As a dune warrior, the TB48 still has the upper hand. For technical rock-crawling, it becomes a matter of taste. The petrol engines actually have more torque at the applicable RPM's, but they do not have the anti-stall characteristics of the TD42, and thus they require more driver input, but I would still argue that they are slightly more capable, just because you are not sort-of forced to crawl at one fixed speed like the TD42 does, but the TD42 has more than enough torque for most situations and you can sort-of leave it to do it's own thing while you concentrate on the line and it just keeps chugging.
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Re: Tb48 vs Td42 Engine

Post by hugejp »

I can assure you that when my 4.8 was still standard I could effortlessly cruise AT & way over 140km/h & still be very far from the red line.
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Re: Tb48 vs Td42 Engine

Post by hugejp »

hugejp wrote:
16 Dec 2020 20:29
I can assure you that when my 4.8 was still standard I could effortlessly cruise AT & way over 140km/h & still be very far from the red line.
That is until my wife noticed!!! & then the cruise control would become my friend :rolling:
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