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Old 19th October 2014, 21:01   #1
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Default Thar CRDe: Improving its low-end torque

The purpose of this thread is to inquire into what Thar CRDe owners are doing to improve engine performance. In my case I am particularly interested in increasing low end grunt. My Thar is maddeningly slow from a standing start and is a "dog" on steep slopes at low speed. Living at the front range of the Himalayas, I need power to boogie up the steep slopes filled with switchbacks, switchbacks which often do not allow you to reach mid-range speeds where the Thar's motor and turbo come into their strength. It is irritating to have to drop down into first gear to get around these hill curves. I suspect it is some very poor programming of the ECU that is the primary culprit.

What after market chips are you guys using? Any dramatic results? What else have you guys tried? E.G. blanking out the EGR? Tweaking the fuel pump?

My Invader's MDI3200tc with 4:88 crown gears waltzes up these steep slopes without breaking a sweat in 2nd gear with power to spare. My Thar too often requires 1st gear and a fervent prayer.
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Old 19th October 2014, 21:15   #2
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Default re: Thar CRDe: Improving its low-end torque

Quote:
Originally Posted by DirtyDan View Post
The purpose of this thread is to inquire into what Thar CRDe owners are doing to improve engine performance. In my case I am particularly interested in increasing low end grunt. My Thar is maddeningly slow from a standing start and is a "dog" on steep slopes at low speed. Living at the front range of the Himalayas, I need power to boogie up the steep slopes filled with switchbacks, switchbacks which often do not allow you to reach mid-range speeds where the Thar's motor and turbo come into their strength. It is irritating to have to drop down into first gear to get around these hill curves. I suspect it is some very poor programming of the ECU that is the primary culprit.

What after market chips are you guys using? Any dramatic results? What else have you guys tried? E.G. blanking out the EGR? Tweaking the fuel pump?

My Invader's MDI3200tc with 4:88 crown gears waltzes up these steep slopes without breaking a sweat in 2nd gear with power to spare. My Thar too often requires 1st gear and a fervent prayer.
Its not poor programming, this is the basic characteristic of a Common Rail engine. I havent come across any common rail engine, that has excellent low end torque,

I would recommend that you find someone who can remap the ECU for low end torque, tuning boxes/chips will not help in your case.

Last edited by GTO : 21st October 2014 at 17:38. Reason: Typo
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Old 19th October 2014, 22:55   #3
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Default re: Thar CRDe: Improving its low-end torque

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Originally Posted by akshay4587 View Post
Its not poor programming, this is the basic characteristic of a Common Rail engine.
I havent come across any common rail engine, the has excellent low end torque,
i would recommend that you find someone who can remap the ECU for low end torque, tuning boxes/chips will not help in your case.
I have owned several other common rail engines and they have all performed much better than my Thar. In fact, a common rail should be BETTER, not worse, than older fuel delivery systems. The "rail" of the common rail is very close to the injectors and is at greater pressure. These two facts should and do make for a more responsive motor but not so in the case of the Thar CRDe. This is part of the reason for the design of the common rail, in fact, responsiveness, along with fuel economy and clean burning and quieter operation.

Besides having poor low end response the motor does not "kick down", go to idle, when you take your foot off the throttle in any gear. Instead the vehicle (motor) wants to remain at a higher RPM and this is dangerous. You take your foot off the throttle and the vehicle lurches forward. You have to depress the clutch to get the "kick down" and go to a lower gear quickly to avoid a runaway. This is another example of Mahindra lack of testing and/or pure chintz and cheapness. It is also dangerous and I am a bit surprised that this got passed CMRV. This same irksome problem is not just my Thar, other owners report the same thing.

Last edited by DirtyDan : 19th October 2014 at 23:05.
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Old 20th October 2014, 13:01   #4
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Default re: Thar CRDe: Improving its low-end torque

I believe this EXACTLY is the basic difference between the DI Thar engine and the CRDE Thar engine. The DI engine has good torque available even at idling.


247 Nm @1800-2000 RPM for CRDe (quite high up in revs)
182.5 Nm @ 1500 - 1800 rpm for TDI engine (at lower revs, and my extrapolation is value higher than crd at near idling)
(btw have a look at TATA Sumo engine: 250Nm @ 1000 - 2000 rpm!!!)
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Old 20th October 2014, 15:06   #5
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Default Re: Thar CRDe: Improving its low-end torque

Hey DirtyDan,

Not sure of the final drive ratios of the Thar. What is the OEM? Is going a li'l shorter an option?

Any possible exhaust mods to increase back pressure?
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Old 20th October 2014, 15:13   #6
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Default Re: Thar CRDe: Improving its low-end torque

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Originally Posted by GTO View Post
Hey DirtyDan,

Not sure of the final drive ratios of the Thar. What is the OEM? Is going a li'l shorter an option?

Any possible exhaust mods to increase back pressure?

Hi GTO,

The Thar CRDe is using a 4.3:1 (43/10) Differential Ratio.

The next lower diff-ratio is 4.55:1 (41/9).

But changing the front will become quite a task, since the entire IFS live axle has to be disassembled, and the diff-tube, removed from the chassis to change the diff-ratio.

Regards,

Arka
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Old 20th October 2014, 15:18   #7
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Try Dieseltronics piggy ecu it will help you a bit.
My friend has a remapped Thar with 140bhp on tap and low end torque is quite good too.
A Dieseltronic piggyback will cost you around 20,000 and a remap will cost you roughly about 25-30k.
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Old 20th October 2014, 16:23   #8
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Default Re: Thar CRDe: Improving its low-end torque

Do not go for chips. Doing uphill stretches already puts the engine in stress with coolant temp max permissible level. Most of these chips cause engine to run hotter. In normal plains driving, you call in the extra power only while accleration and not cruising. Hills are a different matter.

My suggestion is to alter driving style.
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Old 20th October 2014, 16:51   #9
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Driving style or gearing ratios. If use is hilly terrain then changing final drive is clean option. Remaps without turbo gate boost settings also being done is really not possible
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Old 20th October 2014, 17:34   #10
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Default Re: Thar CRDe: Improving its low-end torque

For short drives on the hill say 15 to 20 min the problem can be solved by engaging in 4th gear Low ratio.

However long periods of driving on sealed tarmac with 4WD Low engaged will cause problems its not sand under the wheels.

In sand I frequently kept my SWB Prado in 4th gear low when the terrain was constantly crossing sand dunes shifting to 3rd gear if required or 2nd on steep decents.But the Indian hill terrain is different.

I keep telling that the Thar is a compromise vehicle of sorts never a serious off roader or workhorse of the hills like those old Land Rovers, the odd Jonga or even the Jeep CJ3B which used to perform superbly on hills tarmac or gravel track in 2nd gear in 2WD.

Last edited by desertfox : 20th October 2014 at 17:38.
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Old 20th October 2014, 17:55   #11
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Default Re: Thar CRDe: Improving its low-end torque

Akshay I used to have a Scorpio 2.6 it would easily shoot up hills in 2nd.
My Thar now requires me to cut down to 1st almost always.
The guys who changed the 2.6 engine to a 2.5 screwed up by making the engine oversquare.
Who puts an oversquare engine in an off roader? Oh I forgot its the geniuses at M&M.

I too am really considering a chip or a remap.

I have done 25k KMs and reckon my 1 and 2 gear shyncros are getting worn out and rough with the constant downshifting.
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Old 20th October 2014, 18:08   #12
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Default Re: Thar CRDe: Improving its low-end torque

Quote:
Originally Posted by GTO View Post
Hey DirtyDan,

Not sure of the final drive ratios of the Thar. What is the OEM? Is going a li'l shorter an option?

Any possible exhaust mods to increase back pressure?
Quote:
Originally Posted by ex670c View Post
Hi GTO,

The Thar CRDe is using a 4.3:1 (43/10) Differential Ratio.

The next lower diff-ratio is 4.55:1 (41/9).

But changing the front will become quite a task, since the entire IFS live axle has to be disassembled, and the diff-tube, removed from the chassis to change the diff-ratio.

Regards,

Arka
Arka is right on the OEM diff ratio. 4.55:1 is available but so close to the OEM
4:30 that I don't think it is worth the trouble.

One also has to be concerned with the ECU when modifying this vehicle, don't want to start a psychotic ECU episode.
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Old 20th October 2014, 20:21   #13
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Default Re: Thar CRDe: Improving its low-end torque

First order of the day would be to fit a boost gauge in the two vehicles you are comparing, and log the boost for road speed-gradient combinations. Only then can you take an informed decision.

In turboengines, even a slight change of gearing can have a major effect. Not because of the extra torque due to the gearing, but because the lower gearing can cause the turbo to cut in for your given road speed.

Regards
Sutripta
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Old 21st October 2014, 07:50   #14
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Default Re: Thar CRDe: Improving its low-end torque

Sutripta
Are you suggesting a lower second gear or a lower diff ratio.
Is it possible to lower 2nd gear?

Dan
Thank you for opening this thread.
I hope some good advice comes because of it.
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Old 21st October 2014, 10:16   #15
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Default Re: Thar CRDe: Improving its low-end torque

Hi Dan,

Did you consider Thar DI before buying the CRDE and if yes what made you choose CRDE?

I know my question does not help you but it will be good to know your point of view.

Regards
Rohit
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