Is it worthwhile to convert an LT35 from an AHD (102 hp) to an AUH (158 hp) engine?

Hello,

I'm not sure where else to ask, so I'm asking here.

I'm considering upgrading the engine in our beloved campervan, which is based on the LT35 (2nd generation), from the current 102 horsepower turbodiesel to a more powerful one. For example, the AUH (158 hp) common rail engine, which was installed in the 2nd generation LT starting in 2003.

"Does anyone recognize this engine?" / "Is it good/reliable" (e.g., does it have gears instead of a timing belt? 4 cylinders instead of 5 cylinders?) or what other engine would be "better" / potentially more powerful / generally conceivable?


Okay, let's assume the engine fits in the available space. How about the transmission, clutch, dual-mass flywheel, etc., in terms of how they would connect to the existing driveshaft-based drivetrain? "Should the transmission, clutch, dual-mass flywheel, etc., all be replaced with 'new' components that are suitable for the more powerful engine?"

"I'm confident I can handle the purely mechanical modifications / that shouldn't be a problem. But what about the "initialization" or "start-up" of the engine?" Can I use VCDS (which I have) to adjust or configure "everything necessary," for example, according to the original repair manual like Erwin?

"I imagine I would need to acquire the following: engine, all related components (including sensors), engine control unit, transmission, clutch, and dual-mass flywheel."

Would the TÜV (German technical inspection agency) approve this, and if so, how much would it cost? Or does he, for example, also want to see a more powerful braking system?

Questions upon questions...

I would really like to talk to someone who has real expertise in this area (my number is 015754099963 or d.jamaer@gmx.net). (I'm not completely helpless myself; for example, I once installed a new engine in a T4 (including replacing the timing belt and dynamic adjustment, etc.)).

Or "award" would also be possible: those who want less than 10,000 € (including all necessary components / attachments for it) might be in the running...

Actually, a separate topic: As an alternative to a conversion, there's a chip tuning offer for around €400, which promises an extra 30 horsepower and 50 Nm of torque, from a tuner with a reportedly good reputation (at least that's what they say about him in the T4 forum). Could this be a (temporary) solution? (Mileage: 150,000 km, new fuel injectors)

As I said, making phone calls (e.g., Please send your number to my email, and I will call you. Alternatively, you can also send me a quote.

Or, if you have any other suggestions, please provide links/addresses/providers/forums where I might find better assistance with this question.


Thank you for your help in advance.


Best regards, Daniel Jamaer.
Tel: 015754099963
d.jamaer@gmx.net

Hello,

Quote:

"Does" anyone know this engine? / Is it "good/durable" (e.g., gears instead of a timing belt? 4 cylinders instead of 5 cylinders?) or which other engine would be "better" / potentially more powerful / generally conceivable?

Yes, that is an MWM engine that was originally designed for the South American market.

Just because it has brow ridges doesn't mean it's more durable. These motors sometimes suffer from the problem that the wheel mounts become brittle, and the wheel housing is located on the clutch side, which means the motor needs to be removed for repairs.
Another disadvantage: very few mechanics are familiar with this engine, and even friendly dealerships often aren't (based on my experience).

Quote:

I am confident that I can handle a purely mechanical conversion / that shouldn't be a problem. But what about the "initialization" of the engine? Can I use VCDS (which I have) to configure or set "everything necessary," such as settings from the original repair manual, similar to what's available through Erwin? (No, you don't need a credit card for that; see the error database.)

The AHD has an MSA15, while the AUH has a rather exotic version of the EDC15C. I'm not sure if it will be compatible with the other control units (ABS, instrument cluster, etc.).

Quote:

Actually, a separate topic: as an alternative to the conversion: a chip tuning offer for approximately €400 = 30 horsepower & 50 Nm more from a tuner with a demonstrably good reputation (at least that's what they say about him in the T4 forum). Would something like that be a (temporary) solution in principle? (Mileage: 150,000 km, new fuel injectors)

Certainly the simpler solution. "By now, every tuner should be able to increase the performance and make the AHD more durable and smoke-free."

I also think that the renovation would be too expensive for what you would get in return.
As an alternative to the 30 horsepower chip tuning, there's a 150 horsepower option with larger injectors.
I suspect that the AHC is the longitudinal version of the ACV. Then, the 216 injectors from the AXG engine, with a tuning of 150 horsepower, would be a good fit. I've been using them with great pleasure in my T4 for a long time. It won't cost you more than just a chip.

Tagessuppe wrote:

Then the 216 injectors from AXG, with a tuning of 150 horsepower, would provide.

AHY.
AXG engines, like many other TDI engines, did not receive injectors due to the conversion to Euro 3 standards. The VAG/Bosch part numbers clearly indicate this. The DSLA150P764 are only used in the DHK that are listed for the AHY.

Regarding the project: The only potential advantage would be its possible legality. You can get the 5-cylinder engine for about half the cost (5000€), and it will definitely provide more power than the 2.8-liter engine, but of course, it won't be legal.

Don't you mean the AXL? My records show that AHY and AXG are listed with 216 nozzles.
The AXL, on the other hand, is an AXG engine equipped with ACV nozzles and ACV performance to achieve better emission values in the Syncro.
To achieve the 150 horsepower in the AXG engine, at least a larger high-pressure component would have been necessary, and to my knowledge, this component is also identical to that used in the AHY engine.

Tagessuppe wrote:

Then, the 216 injectors from AXG, with a tuning of 150 horsepower, would provide.

"In agreement" or "in coordination." Do you mean that I should just screw these 216 injectors into the AHD and then it will be good = I will have 150 horsepower?

1.) I'm familiar with the AXG from my T4. While it also has the MSA 15, I strongly suspect that it uses completely different calibration maps compared to the MSA 15 in the AHD.

"To my knowledge, the components such as pistons, etc., in the AXG engine are different – more robustly designed – compared to the ACV or AHD engines, due to the higher power output (only the engine block is the same). Where would the air come from (to allow for more fuel through larger injectors), especially since the ACV and AHD engines do not have a VTG turbocharger (as far as I know)." Increasing the boost pressure through tuning is certainly limited (due to the non-VTG turbocharger).

Are you saying that all you have to do is install these 216 injectors into the AHD, then a "tuner" makes "some" adjustments/tuning, and in the end, I'll have a "long-lasting" 150 horsepower engine (based on the AHD)?

I can't really picture it (leaving aside what the transmission, clutch, and dual-mass flywheel have to say about it...).

My other idea was to install a complete AXG engine with all its accessories in my LT35, if it would fit. Then I would also need the AXG MSA 15 engine control unit, right? (Because, as I understand it, the AHD MSA 15 wouldn't work with the AXG, would it?)

Unfortunately, I haven't made much progress yet, but thank you all for your help so far.

You wrote that you might chip it to 130 horsepower, but would you have more concerns if it were chipped to 150 horsepower? I don't understand the logic behind this way of thinking!
As I mentioned, I've been using this combination for 150,000 km in our T4, which now has 400,000 km on the odometer. A genuine AHY conversion with VTG loader and front linkage is available.
"Tuning" means that someone who is knowledgeable about the subject will adjust the engine for you, specifically setting it up to work with 216-sized injectors.
You also don't need a different MSG if you adjust the performance for larger nozzles. You leave the rest as it is!

If you have any concerns, just let it go.

Tagessuppe wrote:

You wrote that you might chip it to 130 horsepower, but would you have greater concerns if it were chipped to 150 horsepower? I don't understand the logic behind this way of thinking!

All the chip tuners I contacted say that you can safely extract 30 horsepower, but you shouldn't go beyond that.

Tagessuppe wrote:

A genuine AHY conversion with VTG loader and front linkage is ready. "Tuning" means that someone who is knowledgeable about the subject will adjust the engine to work optimally with 216-size injectors.

Sorry, maybe I'm just too clueless: Are you now driving an ACV engine into which you simply screwed in 216 injectors and adjusted the settings? Or did you essentially create an AHY/AXG engine by modifying your ACV engine by screwing in 216 injectors, using AHY components, an auxiliary radiator, and adjusting the settings?

Tagessuppe wrote:

If you have any reservations, just let me know!

I just want to know what is conceivable/feasible/realistic.

fouzek wrote:

Consider installing a more powerful engine than the existing 102 hp turbodiesel into our beloved camper van, which is based on the LT35 (2nd generation).

Before anyone suggests a +50% tuning or similar, it's important to understand your specific needs and goals better.

What is your motivation for seeking more power?
A) Acceleration sprints.
B) Consumption reduction.
C) Higher top speed on flat ground.
D) Higher speeds when going uphill.

Based on the WoMo structure, I suspect options C and D, meaning that the additional capacity will not be called upon in the short term, but rather utilized in the medium to long term.

Therefore, tuning WoMos presents a unique challenge, as the engine is often operated at its performance limit continuously (unlike in passenger cars). For this reason, the mileage is usually lower.

Without having any knowledge of engines, I suspect that achieving a sustained +50% performance increase is not possible simply through software and nozzle modifications.
I suspect that, at the very least, the cooling system and turbocharger will need to be modified if the enjoyment is to be long-lasting.

Quote:

All the chip tuners I contacted say that you can safely extract 30 horsepower, but you shouldn't go beyond that.

"More than 130 horsepower isn't achievable with 205 injectors. Anything more would result in excessively long injection times. As mentioned, this applies to the original injectors!" That doesn't mean that the engine/transmission are designed for 130 horsepower.

Quote:

Sorry, maybe I'm just too clueless: Are you now driving an ACV engine into which you simply screwed in 216 injectors and adjusted the settings? Or did you essentially create an AHY/AXG engine by modifying your ACV engine by screwing in 216 injectors, using AHY components, an auxiliary radiator, and adjusting the settings?

I got 150 horsepower out of an ACV engine with AHY/AXG injectors (216), and I've been running them for a long time without any problems. With the planned AXG engine conversion to VTG components and a front-mounted LLK (likely referring to a small radiator), I meant that I will then aim to achieve the performance of a chipped AHY/AXG engine by using an ACV engine block, transmission, and clutch.

Quote:

I just want to know what is conceivable/feasible/realistic here...

Realistically, you can achieve around 150 horsepower with relatively little effort and maintain reliable performance. In the LT, it is generally observed that more full-throttle driving occurs due to the weight and the drag coefficient, but I am confident that there is a sensible driver behind the wheel .

I'm familiar with the gear-driven MWM engine, and not in a good way. It's a rough-running engine that, even after a repair, never quite worked properly again, especially after being used in a VW.
Nobody knows him at the VW workshop, so stay away.

guste100 wrote:

Based on the WoMo structure, I suspect options C and D, meaning that the additional capacity will not be called upon in the short term, but rather used for medium- to long-term needs.

Okay, here's the translation:

"Yes, that's correct."

Tagessuppe wrote:

I got 150 horsepower out of an ACV engine with AHY/AXG injectors (216)

.

I wouldn't have thought (I have little to no knowledge), that something like this would be possible or realistic with the existing ACV Turbo (which is not a VTG turbo) and the significantly smaller intercooler compared to the AHY/AXG engines.

Here's a quote from /viewtopic.php?t=3063, for example.

Increasing boost pressures, especially in the Pmax range, require a significantly higher power demand from the turbocharger to force additional air through the compressor's bottlenecks.
Increasing the turbocharger's boost pressure to provide more power to the loader can only be achieved by increasing the exhaust back pressure (by further closing the wastegate/variable geometry turbine, or by not opening it sufficiently with increased fuel injection). In other words, from the exhaust side, increasing the boost pressure acts like a partial blockage, which is not conducive to achieving the desired increase in engine power.
Conclusion: When increasing the boost pressure in the Pmax range of modern TDIs, the standard turbocharger sometimes only works against the increased exhaust backpressure it itself creates. This significantly increases the stress on the materials (exhaust and intake air temperatures, turbocharger speeds), while the actual increase in air mass is relatively small.
Therefore, higher injection quantities are converted into less additional power when compared to an engine equipped with a suitably larger turbocharger.
So, if chip tuning aims for the next higher factory performance level, the fuel injection amount must be significantly increased beyond the corresponding factory setting in order to achieve the normal performance of the more powerful factory engine. After the tuning, a significant amount of horsepower is lost due to excessive friction around the (now undersized) turbocharger. For example: /viewtopic.php?t=11885
In the mid-RPM range, the TDI turbochargers, on the other hand, have significantly greater reserves, which many tuners exploit to achieve substantial torque increases – much to the detriment of the clutch, transmission, and drive shafts.

I'm also familiar with the 4-cylinder South American engine from my professional experience. It was installed in many Kühl-LT vehicles and caused more problems than joy for owners, especially when they were young. I would advise against it.

Hi,

For a campervan, where wind resistance and hills are likely to be the biggest challenges, and where people tend to drive at high speeds, I wouldn't necessarily recommend maximizing power output.

However, the difference in engine displacement between the two engines, from 2.5 liters to 2.8 liters, isn't that significant. Therefore, the most important factor for a long engine life will be proper engine cooling. I would therefore keep an eye on this (measurements are available through the existing sensors) and only moderately increase the power output. New and larger fuel injectors help achieve the increased power output without excessive exhaust temperatures.

For a standard ACV with the larger injectors, I would consider 125 horsepower and a torque curve that is gentle on the clutch and transmission to be very durable.

The ACV engine can be tuned to approximately 133 horsepower using software, but the turbocharger is then at its limit. Therefore, it's better to opt for slightly less power and lower boost pressure. The engine code "AHD" doesn't mean anything to me right now; I would need to compare it in more detail.
It's no use if the camper van turns into an overheated, smoky mess otherwise...

Best regards, Rainer.

- The LT has rear-wheel drive, right? Is it possible to install a different rear axle?
- What is the engine speed at cruising speed? High, very high, or rather, not at all?
- Could a change in translation achieve a faster speed?

That would then compromise acceleration and climbing ability.