Team-BHP (https://www.team-bhp.com/forum/)

-   4x4 Technical (https://www.team-bhp.com/forum/4x4-technical/)

-   -   Thar CRDe: Improving its low-end torque (https://www.team-bhp.com/forum/4x4-technical/156710-thar-crde-improving-its-low-end-torque-9.html)

I have done EGR blanking for three CRDe engines.

Just as a heads up to everyone trying this mod, the oil seperator has conked within 5000kms of doing this each time.
As a result it begins to ooze oil into the air cleaner intake, which fills up in the intercooler.
My hunch is that the crankcase pressure increases as the Turbo gets more exhaust gas and thus provides more psi inlet pressure which the seperator cannot handle.

I have disconnected the oil seperator breather from the air cleaner intake, blocked the small oil seperator inlet into air cleaner and then added a long pipe from the oil seperator breather to drip out any excess oil (like old crankcase breather pipes).

Just see this video @ 6:00, these guys have fitted Scorpio SZ CRDE "Torque Monster" in the Thar

https://youtu.be/VIDC8W3qatI?t=360

Mahindra should have this from the first day of the launch. Putting an oversquare short stroke engine in an offroad vehicle with dead cow like low end grunt, Bean counters surely at work. please:

Stock this old Scorpio motor is rated at 116 BHP. Not much of a gain over the existing 105 bhp OEM Thar motor. And there are easy ways of modding the existing Thar motor discussed above in this thread.

My guess is that my 2018 slightly tweaked OEM Thar will blow the doors off Khan's Scorpio SZ CRDe relic Thar. And I bet I paid a whole lot less for my engine mods than the plonking of this old Scorpio SZ CRDe cost.

Yet another "Moga Special Edition", methinks. Generally speaking, and I do mean generally, not specifically, Moga shops do not enjoy good reputations.

The original 2.6L Scorpio motor was neutered slightly to meet export regulations for the Thar. It wasn't strictly a bean counter thing.

And what, may I ask, is an "oversquare short stroke engine"?

The point is not about Moga shop reliability, its about why the Thar lacks bottom end torque compared to other vehicles in Mahindra stable which donot ! Its the Oversquare engine. I still remember Late Behram telling in one of his posts on the forum about SZ CRDE Scorpio engine's might. I still donot know what engine was in his V521 Prototype Thar.

To give you a better perspective, I have driven:

1. Scorpio SZ Crde on a steep incline, midway hill start in 1st gear 2wd. It moves ahead without the touching accelerator pedal, just normal clutch release. Did the same in 2nd gear, bit of acceleration needed but it moves.

Bore 94mm X Stroke 94mm Square engine. Torque band starting from RPMs 1200 upwards.


2. Friend's Thar OCT 2018 stock on same steep incline, midway hill start in 1st gear 2wd. It stalls, I had to use clutch slippage + accelerator push to make it move. Bore 94mm X Stroke 90mm Oversquare engine. Majority of Torque only available at RPMs above 1800

3. Bolero Camper 2017 MDI3200TC on same steep incline, midway hill start in 1st gear 2wd. It moves ahead with a surge without touching the accelerator pedal, just normal clutch release. Did the same in 2nd gear, moves ahead without accelerator being touched. Bore 88.9mm X Stroke 101.6mm Undersquare engine.

4. My Thar MAY 2018 "ECM REMAPPED" on same steep incline, midway hill start in 1st gear 2wd. It moves ahead without touching the accelerator with gentle clutch release. Bore 94mm X Stroke 90mm Oversquare engine. Torque band in this case as per my experience starts from 1500 RPM onwards

Oversquare engine has shorter Stroke travel length than Bore diameter dimensions . Good for high RPM, translates to highway cruising. Lacks bottom end Grunt severely. The reason the THAR suffers.

Square engine has same Stroke travel length and Bore diameter dimensions. Balanced recipe gives wider torque band. Scorpio SZ CRDE has this advantage.

Undersquare engine has larger Stroke travel length than Bore diameter. Torque concentration is at lower end of RPM band. MDI3200TC the torque band starts from almost Idling to 1800 RPM. This is what is required in offroading and load hauling. Tata 407 3.0L engine for example has 230NM torque availability at 1000 -2000 band. The large stroke travel needs heavy crank and flywheel which actually leverages into large amount of momentum thus advantageous for offroad vehicles, pickup, Trucks.



Ford Endeavour, Safari /Scorpio 2.2, Fortuner, Gurkha all of these vehicles have undersquare engines.

On Hills, MDI3200TC wins like anything. This engine just keeps on pulling ahead. The final drive ratio of Thar, Scorpio is 4:31 and Camper is 4:27. Still camper wins. Our forum member Ringoism [He has Marshal With MDI3200] knows what I am talking about.

Read these posts please:
First

Second

Okay, bore and stroke by their older names. I had an Invader 4x4 with 4:88 crown gears that I put in
it and a stock MDI3200TC. It flew up the big hills here and embarrassed some people in Scorpios and Dusters. Even Fortuners had to work to stay ahead of me. I know Ringo from his posts here on this subject. Both my 2013 and late 2018 Thars handle the mountains okay, now that I have..updated...them. Not great, but okay, e.g. on the Manali/Leh road.

I believe Behram's test bed had a 2.6L and he probably knew some tricks to make it fly.

Are you aware of the new Mercedes powered 140bhp Gurkhas? Undersquare? Overpriced?

When my struggling Thar on inclined road + Traffic jam was overtaken by a Bolero Pickup loaded with cement bags on Markanda-Shimla Road, I was shell shocked and after that only my enlightenment started about the MDI3200TC lol:

Even I tend to believe that only, otherwise the way he use to go gaga over that vehicle's prowess, was only possible with SZ2600 CRDE... :D


Both FM2.2 CR [Gurkha Extreme]and FM2.6 CR [Gurkha Explorer/Expedition/Traveller] engines are Undersquare long stroke travel length engines. These engines are famous for low-end grunt.

Gurkha is way overpriced, yes. Has horrible finish on the dashboard which has RPM meter between AC vents lol: , nodoubt an after thought jugaad job, No power windows/central locking on the vehicle which now costs in excess of 12.7 Lac Ex-showroom.

Some of its positive points are:

1. Front and Rear manually locking differentials.
2. Rigid front axle.
3. Coil spring suspension for comfort.
4. Undersquare Engine for Natural low-end grunt.
5. 5 Door option available.

Mahindra has just released the Bolero Camper ZX loaded with all basic creature comforts like central locking/AC/PS/Power windows/Cushioned seats/Console/New Dashboard but unfortunately it doesn't have 4WD option yet.:Frustrati


PS: These videos show the Thar vs Gurkha Low end grunt capability and crawling nature.

https://www.youtube.com/watch?v=8mHACYW_0qs

https://www.youtube.com/watch?v=hXZU4Qckx6k

Been quite some time since you posted this but just came across it.

Any chance that, a Catch Can which can handle changes in pressure, will do the job?

something like this - https://www.westernfilters.net.au/provent-kits/

There are quite a few videos on YouTube showing how effective these are, especially in SUV's. Maybe this helps?!

I have a 2013 Thar and a 2018 Thar. 30,000km ago I unplugged the Air Mass Sensor and blocked the EGR on the 2013. I have had no trouble with the oil separator, PCV, air filter or anything else. Not yet, anyway. I unplugged the Air Mass Sensor and blocked the EGR on my 2018 Thar 12,000km ago. No problems also, yet.

I don't know the definitive answer to this. From all the pro/con chatter on the web about this, I am not at all sure ANYBODY has a definitive universal answer that is valid for all diesel engines. One fellow mentioned that regardless of blocking the EGR or installing an oil catch can, your vehicle usage habits may have more effect on the intake system than any other factor. He said that if you continually go on short low speed trips wherein the Thar does not come up to full operating temperature a few times a day, the oil separator and intake system will tend to get dirty and gunked up pretty fast. He said the best remedy and maintenance is to take out the vehicle and run it a little hard and fast once in awhile and get it hot. Blow out the gunk, so to speak.

All I can say is that I intend to keep a close eye on this potential problem. The wonderful gain in horsepower makes me willing to experiment a bit with this. I will be going for oil changes soon on both Thars and I will ask my pretty savvy mech to have a long look at my PCV, oil separator, air filter and the whole intake system and see if there is anything amiss.

Hi DD,

How has been the experience by far on both the Thars after disconnecting the air mass sensor and EGR?, considering it’s been a while since you have got it done.

What exactly did you do with the air mass sensor, did you just disconnected the wire from the sensor or removed the wiring completely. Any impact on the FE after removing the air mass sensor? (:uncontrol:uncontrol I know it’s a silly question to ask to people who stay in the hills)

Both Thars are running fine with the "fix" still in place. My 2013 Thar has 42,000 K on the fix and my 2018 Thar has 21,000 K on the fix. No problems at all. No oil leak in the air intake or anything like that.

I just unplugged the air mass sensor wire and taped it to a nearby overhead support strut with electrical tape. I can easily hook it back up if I have to. I blocked the EGR with a little piece of sheet metal easily fashioned by the mechanic in ten minutes with just a pair of tin snips. Works great. Whole business cost me 300 rupees.

The power gain is simply amazing and gratifying. No change in FE. Member Danushes suggested trying this. He is a mech engineer. His picture is now on my piano.

Thanks for giving the feedback, have you tried or any idea of removing the catcon aids in additional low end torque.

Yes his 521 had the 2.6 CRDe engine and it ran on a different map, god knows how many ECUs were slaughtered during the testing. Being a product engineer he surely had a few tricks up his sleeve to enhance the performance. Probably it had an upgraded turbo, different gear ratio and god knows what else. It’s no short than a riddle to solve.

Below is a photo(posted on another thread) probably with his 521 as the engine bay looks similar to that of production Thar, if you watch closely SZ CRDe is embossed on the engine, which means it’s a 2.6 CRDe.

Now being a CRDe owner and looking for torque below 1600rpm, happened upon this old thread again...

Personally I believe the prohibitions against 2 Low are somewhat overstated. Even with a heavy full-steel LWB body like the Marshal I use 2Low very, very often (almost daily to get into my parking, if truth be told) and we've had the car almost 11 years now, and no axle or cross-joint or other rear drivetrain problems ever. And the car has a LOT (probably lakhs) of miles done.

The reason is that there's a distinction that needs to be recognized between theoretical torque which COULD be applied to those axles and the actual torque that normally WOULD be in situations you'd want to use 2Low.

The torque load comes from the RESISTANCE to rotational motion, essentially.

If you have a loaded Getaway with wide tyres and want to pull a trailer-load full of cement sacks up a dry, clean, grippy concrete slab set at a 45-degree angle, and you rev up that CRDe into boost range and pop the clutch in 2Low (assuming manual hubs), well, yeah, you may very well break something. For that matter in that scenario you might even break something in 4Low, just not as readily, because right, the front drivetrain is helping and thus reducing the total on the rear.

Thing is, we are almost never in situations where we have that much resistance to movement, i.e., that much grip or load, or where it's that steep, or where we're popping the clutch in the boost range.

Take an old CJ3b with a light engine up front, NDMS tyres, and a driver who isn't going to pop the clutch or crawl at much more than idle speed, and regardless of surface, I am pretty sure nothing will ever break - because there's so little resistance to that rotational movement,hence very little actual torsional load applied to the axles/ splines or whatever else.

Manufacturers know that some percentage of owners will do dumb /ignorant things for which they don't feel like paying out on warranty claims, I don't blame them for making recommendations that will as much as possible eliminate costs to them.

@Samurai, it's an absolutely valid point that in cases in 4Low where traction is lost on one end and still very good on the other, you can have the same forces applied to that grippy end as in 2Low.

I'd be a lot more concerned about using 4Low and experiencing bad windup. Which is what would happen in my parking, where I need to tuen the steering to full-lock on pavement, reverse through a shallow drain and up a steep slope. My wife manages this in 2Low with aplomb, incidentally, as per my instructions.

For eleven years now. And twelve of marriage, and no serious mishaps in either realm as yet. lol:

-Eric.

Reviving this old thread

I own a 2019 Thar CRDe with roughly 70k Kms on the ODO, for the initial 3 years of my ownership period had struggled with the slow low end torque issue in the CRDe. In city driving and in ghats it used to get frustrating at times. Easiest solution was to drive with a heavy foot however the resultant effect was it used to take a hit on the FE.

Finally after evaluating different options, took the plunge and got the ECU remapped with Stage 1 software update from T8 performance, Bangalore in Jan-2023.

Have driven the Thar for 16k+ Kms post remap in the last 6 months, this includes a 4000 Kms Himalayan mountain drive. The CRDe is now much more responsive even with a slight rap on the throttle, earlier one had to juggle continuously between 2nd/3rd on the ghats and once you loose momentum it was a time taking affair to regain the same. However, it now cruises on the ghats comfortably in 3rd gear and you can keep juggling between 3rd/4th all day long. On highway drives earlier it used to cruise at 80kmph/2000rpm, there’s a slight bump in this with speeds ranging at 85-90kmph at 2000rpm.

So for me the Stage 1 remap has worked fine for me, it has overcome the shortcomings of the slow low end torque and has further enhanced highway cruising.

FE efficiency has remain unchanged however if you floor the pedal, it does take a hit.

More details can be found on my ownership thread here:

https://www.team-bhp.com/forum/test-...km-update.html

Suggest you look at post numbers 65,66 and 78 in this thread. The suggestion to unplug the air mass sensor and block the EGR was given by Danushs...he is a mechanical engineer by trade and a real motorhead by temperment. I have two Thars. I have blocked the EGR and unplugged the air mass sensor on both. The result was amazing. I have driven a combined 70,000 km with this modification with absolutely no ill effect.
A pale yelow engine light came on located on the dash but that only means the air mass sensor is not functioning...the light is not distracting in the least. Try it. You can do it easily and if you don't like the results you can easily return things to normal.

There is definitely no risk of engine damage here, previous model pre-electronic Scorpio CRDe's with identical engine minus sensors all ran richer/leaner all the time depending on altitude and weather conditions, mechanical pump had no good way of compensating, and it smoked bad at high altitude, which is exactly how a CRDe Mahindra with MAF disconnected running on default open-loop fuel curves would probably run!!!!

And I might add that despite this these old pre-sensor ~2001-2004 series 1 Scorps are STILL the vehicle of choice for taxi duty in places like Zanskar, Ladakh. Even at 13,000+ft, they run brilliantly , and last basicallly forever. Have heard of these early models with 300,000+kms still running well.

Btw more diesel (rich) = more cylinder wall lubrication, diesel is inherently slippery, unlike petrol which is more of a solvent. That's a big part of the reason old diesels almost always lasted longer than older petrol engines. No longevity issues with heavier fuel metering here in these hills or anywhere. Quite the contrary.

All this said:. I tried disconnecting the MAF in the Getaway today for the first time. Definitely a noticeable improvement.

Stock mapping seems to provide just about zero torque till you're in the boost, then it pulls fine. So you end up giving lots of accerator and revving and "half-clutching" all the time trying to get into the boost range so you can get started on inclines. Which is hard on clutches for sure, besides just being a pain.

Whereas with MAF disconnected, I found boost comes no earlier BUT engine actually pulls ok BEFORE turbo is spooled / boost builds. My test-drive was limited, will try and more fully assess but I think it's safe to say that the stock mapping was somewhat defective.

Xylo of similar vintage which used almost identical CRDe engine (but the 2.5) pulls much better down low. Someone said that Xylo's mapping was done by AVL/Bosch whereas the Thar/Scorp was done in-house. Maybe so.

All this suggests that these engines should respond well to a good remap / tuning box done by a competent party.

I'd rather not have MAF disconnected especially if FE could be affected. In a typical year I drive at wildly varying altitudes anywhere from a couple hundred meters to 17,000+ft. So some measure of compensation seems appropriate and without a MAF no way to do that.

Might do the switchable resistor thing in the MAF wiring that some in the VAG and other international forums have had good success with. Still not as good as a solid remap or tuning box but would be vastly cheaper and would help a lot in those times when some extra grunt was specially required.

-Eric

PS having just noticed post #124 it reminded me of another quirk in the Getaway: Without touching the accelerator and simply letting out the clutch smoothly, ECU feeds fuel in and you can feel that forward surge as it attempts to maintain minimum engine speed. HOWEVER, touch the accelerator even slightly, and all bets are off, things get very sluggish and till you get into boost nothing much is going to happen... Again this points to programming/mapping issues, not bore or stroke or turbo size etc. Engine simply not being given enough fuel off-idle at low revs.