[Dr.Abhi]

Yesterday I went for Mahindra Quanto test drive. Having gone through Team BHP official review, my motive was just to check the exact driving experience which was quite good. While coming back, I was thinking how much stress must be on 1.5 ltr engine which has to haul 1.7 ton atleast and I was apprehensive about long term reliability of the engine. Then I thought Renault's Duster engine is also 1.5 liter which is still in higher state of tune (110BHP) but the difference is it has to move much less weight, app. 300kg.
So, the question is,
-Does my suspicion holds any ground or am I thinking too much?
-If there is really any difference, then which engine is less stressed (more long time reliable)
1. Mahindra mCR100 producing 98 bhp @ 3750 rpm and 250 NM @1600 to 2800 N-M hauling 1.65 ton weight
2. Renault 1.5 dci 110 producing 110 PS @ 4000 rpm and 240 N-M @1750 rpm moving 1.3 ton weight

[narayan]

I think the CC capacity Vs the weight of the vehicle alone may not be a factor. The engine construction/layout/internals/materials used will impact this.

[ACM]

Your question is valid but the factors making up reliability are not just the stress on the engine but also the quality / manufacturing to precision of the internal components and the integration of the same with the transmission. Also the level of turbo charging and the impact of the pressures maintained on associated components will impact the life of the engine and finally also on the gearing that will impact the level of stress / rpm of the engine for each gear and speed.

The renault engine is proven and would in general possibly be manufactured to more exact specifications but then it is always easy to generalize against an Indian manufacturing effort.

Would bet on the renault in this case but there is no exact simple way of knowing so and the stress on the engine is not a sufficent parameter when manufacturers are different. Though we could use that consideration for two vehicles of the same manufacturer to some extent.

[StarrySky]

In this case, the Mahindra engine is a new engine whereas the Renault engine is a proven workhorse. The Mahindra engine may prove to be just as reliable as the Renault engine in the long run. But, if today I had to bet on the engine reliability, I would bet on the Renault - known devil and all.

In the case of Quanto, 3 pots are generating 1500 CC and a power of 100 BHP.

In the case of verito, 4 Pots are generating 1468CC (As far as i remember)

Obviously Each pot is contributing more in case of Quanto. Also Quanto has a Twin Turbo as discussed earlier. I think Verito has Naturally aspirated engine so the power is around 67 BHP. Guru's Please correct if required.

I wouldn't touch Quanto. The drive has left a bad impression in my mind. and yes, i prefer to buy a Verito if i had to buy something from Mahindra.

[MHG]

Shouldn't you also consider the number of cylinders in each engine ? The Renault dCi 110 engine is a 4-cylinder engine hence capable of being revved higher than the 3-cylinder Mahindra mCR100. And yes when you have a loaded Quanto versus a loaded Duster, the dCi has a lot lesser weight to pull further adding to its stress bearing levels.

But then we're looking at car engines (which are designed to last for atleast 2-4 lakh kilometers) and not bike engines which have much shorter lives. For practical purposes you needn't compare the two engines the way you are comparing them.

If its the cars you are trying to differentiate, then obviously the Duster is any day a better car than the Quanto.

And purely based on the engines, if you asked me to pick one of the two to plonk into a speculative car I'm planning to build and market, I'd actually prefer the Quanto's engine because it seems like the one that costs lesser to manufacture and maintain and also has a higher fuel efficiency thanks to being a 3-cylinder and has a slightly higher torque that is spread over a wide band of 1600 to 2800 RPM that results in better driving characteristics inside city.

[dhanushs]

Hi,

If the 'stress' you mean is the torque to weight ratio, then we can get it my doing some simple math.

Other than that, the 'stress' you have mentioned will only make the vehicle go/accelerate slower. It will not reduce the engine life, as engine life is depended on numerous other parameters, like quality of materials used, the design process, manufacturing precision,tuning, etc..etc...

But, I think I get an idea of what you are saying.. IMO, an engine is stressed when its tuned to deliver more power than it is designed for and the driver utilizing all the power. For example, put in a tuning box in a 1.3 DDiS and bump up the power to 120-130bhp (is it possible? ) and the driver utilizing all this power by mad acceleration all the time - That would be stressing the engine IMO.

As the crank, con rods are not designed to handle such stresses and would give away..

In this case, about the newer engine... Only time will tell how stressed, or rather reliable the engine is.

[srh]

A whole thread to discuss something that cannot be quantified in any manner except by an expert with good diagnostic tools!! Why speculate and pass uninformed judgements?

Does anyone know the exact material used in the engines? Does anyone know the dimensions of the parts? Does anyone know the force/ acceleration/ jerk produced? etc.......

[Ashley Nair]

Anyway, engines with higher displacement and lower power output ( mostly used in vehicles intended to be pure workhorses) seem to last infinitely. For example, I have seen Qualis and Bolero engines(MDI 3200) last upto 5,00000 kms before rebuild.This is in spite of the fact that, these vehicles are subjected to rough use and the engines remain ill-cared.
On the other hand 1.3 multijet on Swift seems to have a maximum engine life of 200000 kms.
Gurus, please explain the technicality in this aspect

[anandpadhye]

Originally Posted by Ashley Nair

On the other hand 1.3 multijet on Swift seems to have a maximum engine life of 200000 kms.

Where did you get this from?
No Swift diesel has survived beyond 2 lakh km???

[Ashley Nair]

You should have noticed that I used the word "seem" which roughly translates into "approximate" or "generally". Still my question remains unanswered

[CrAzY dRiVeR]

Originally Posted by anandpadhye

Where did you get this from?
No Swift diesel has survived beyond 2 lakh km???

Originally Posted by Ashley Nair

You should have noticed that I used the word "seem" which roughly translates into "approximate" or "generally". Still my question remains unanswered

How many Swift engines have failed around 2L kms mark? Even though you have used the word 'seems' there should be few cases of failure to make you feel that the engine can take only 2L kms of abuse?

Here is a case of 3.15L kms
http://www.team-bhp.com/forum/long-t...ounting-4.html

Another 2L kms with no major issues (But sold unfortunately)
http://www.team-bhp.com/forum/long-t...-pg-3-a-9.html

[vinodv001]

We may need more technical info to comment about the stress on the engine. cubic capacity, power and weight alone may not be sufficient.

Originally Posted by gemi_kk

I think Verito has Naturally aspirated engine so the power is around 67 BHP. Guru's Please correct if required.

Verito/ Logan uses a Turbocharger and Intercooler.

[Dr.Abhi]

Renault engines are reliable that we know but Mahindra engines are also quite sturdy.
Reliability of an engine or a car as a whole can only be proved with time but I want to know a generalised assumption (brands apart) based on the facts whether turbocharging and that too of different orders (Twin scrolls, VGT), intercoolers, number of valves have what effect on the engine's long time reliability plus the weight, engine has to always haul, power and torque produced in what rpm range.
Are there any thumb rules regarding all these or the early owners of these cars will pave way for the prospective customers say after atleast 6 months?

[tsk1979]

Mod Note : This thread really has no conclusive answer. Thread closed.

Engine stress is dependent on the RPM it runs at. The weight causes stress on components like drivetrain etc.,
Since both are low rpm (2000rpm peak torque engines) there would not be much of a difference.

That said the 1.5 liter renault engine is proven. the mCr is not. However, taxi market has lapped up this product, and long term reliability will be known soon.
I saw atleast 10 brand new vehicles being driven from Srinagar to Leh(newly bought). Within a year you would know is it as reliable and long lasting as the other Mahindra engines