[DirtyDan]

Originally Posted by Sutripta

Normally, when does a turbo glow red hot?

Regards
Sutripta

Dunno...I think maybe it had better not "glow"! There is a lot of stuff about exhaust temperatures and damage to turbos out on Google. I don't pretend to know the particulars right now. I may pursue this kw more later.

Sometimes these "box" companies also sell enhanced intercoolers to keep temperatures down. To date my research has been aimed at finding companies with good reputations in this area and trusting them.

[dhanushs]

DD, yes more diesel does mean faster spinning of turbo and higher exhaust gas temp. However, I think the Thar engine and turbo is pretty rugged.

Engine: most of the so called off-road modifications block the air flow to the radiator. (Bumper, winch, insect guard, AC condensor, AC fan, roots horns, light force lights etc.. Etc.)I've seen vehicles with all of these, revving and revving trying to cover an obstacle and not heating up. And yes, they were running a tuning chip too.

Turbo: I'm running the thar crde turbo in my SD25. I had severe overheating problems with my engine in the initial stages, and used to run at close to 100 degrees. However my turbo hasn't given up till now. Now it's functioning smoothly.

So I guess a mild tuning chip to aid low end should do the trick for you.

Not ones like these.

[Sutripta]

Originally Posted by DirtyDan

Dunno... I may pursue this kw more later.

Till such time then!

Sometimes these "box" companies also sell enhanced intercoolers to keep temperatures down.

'Temperatures down' of what?

And your thoughts on 'AFR'?

Regards
Sutripta

[DirtyDan]

Originally Posted by Sutripta

Till such time then!


'Temperatures down' of what?

And your thoughts on 'AFR'?

Regards
Sutripta

I am interested in getting more low end grunt out of my Thar and getting up hills in much better fashion than I do now. If you have some thoughts on intercoolers and AFR that you might think are germain, please feel free to share them with us. You know quite a bit about thermodynamics, intercoolers, AFR. I can't imagine why you are asking me for information you already have.

[ringoism]

Originally Posted by prabhuav

I agree that mahindra lost the plot on the 2.5 compared to the 2.6

Yeah, have driven both those over the Lahaul-Spiti terrain (from Manali, as far as Darcha/Udaipur/Tabo), and all our drivers of those two vehicles agree that 2.6 is FAR superior in terms of turbo lag. On the other hand, the MDI3200T is even better. I mentioned somewhere earlier how I was having trouble even in the 2.6 Scorpio staying ahead of a lowly M&M Bolero pickup (albeit unladen) on the switchbacks back side of Rohtang. And this past week personally spent some time behind the wheel of a friend's brand-new Bolero 4x4 LX with the MDI-T (gov't spec with PS). The horsepower (62, vs. about twice that) is obviously not there at higher speeds - there's no surge of power anywhere to be found - but there's also basically no lag / dead spots at all - you'd hardly know you were driving a turbo, even with the Bolero's pretty high gearing (1500rpm in 5th gear @80kmph?!); and there's comparatively much less need for gear-changes in normal hill driving. Dan knows this already (keep forgetting his Invader has the MDI-T instead of the old XD3P); so posting this for the benefit of other readers.

Originally Posted by DirtyDan

Would you believe, Jeep in North America used to offer 5.0L V8 motors, 200 hp, in similar jeeps

A local airport where I grew up had one of those 304 V8 Jeeps. Ultimately, it had to be permanently parked and left to rust, on account of the various teenaged staff who had been wont to go out and (on official airport business, of course) pull wheelies with it.

Originally Posted by DirtyDan

It is my good fortune to be able to buy another CRDe or a Di or maybe a Bolero Camper for trekking. I am hoping something more suitable breaks into the market for early 2015, something not Mahindra, something not Tata either.

Would be great if something like that suddenly appears. If not:
If you can handle the mandatory commercial vehicle registration (Rs. 8,000/year), a little more length to park, and a relatively firm ride, IMO you can't go wrong with the Camper. Dozens of them running around Manali and doing regular Rohtang service, and owners absolutely love them. Might've been a year and a half or two ago when the showroom here quoted 5.5 lakhs (or was it less?) for a new one w/ 4x4 (about the same as a Thar DI). Can't see anything to complain about there. They come with a 5-speed now (NGT520, I presume?) and the rugged old cast-iron Dana (T18) transfer cases, allegedly manage as much as 12-14kmpl locally, and are pretty bulletproof. Had one along in June for support / extra passengers when we rode the bikes to Leh in June. Bit rough riding, but not so bad with the long-wheelbase and probably a lot more controlled than something like the over-cushy Scorpios, etc.

You might finally have to figure what's going to cost you more - trading in the Crde Thar at some loss in favor of something a bit better suited to your purposes, or fooling around with aftermarket stuff for the Crde that MIGHT make it what you want it to be reliably (or not).

Just my 2cents. Living/driving up here daily, I do understand the nature of your dilemma.

-Eric

[Sutripta]

Originally Posted by DirtyDan

I am interested in getting more low end grunt out of my Thar and getting up hills in much better fashion than I do now. If you have some thoughts on intercoolers and AFR that you might think are germain, please feel free to share them with us. You know quite a bit about thermodynamics, intercoolers, AFR.

I think you introduced discussion about AFR and intercoolers in this thread, so was asking you about how these affect anything (in our context).

I can't imagine why you are asking me for information you already have.

I get the feeling that the you are convinced that almost anything not done by the manufacturer will badly damage the vehicle. In that context, us saying anything is an exercise in futility. You have to do your own homework, and come up with your own 'aha' moment. And since IMO, AFR and intercoolers have no part to play in the context of our discussion, I was hoping to save you some time!
But then again I might be totally wrong. And if in your studies you have come across information which links these to our topic, I'd love to know about it.

Regards
Sutripta

[ringoism]

Originally Posted by DirtyDan

Sometimes these "box" companies also sell enhanced intercoolers to keep temperatures down.

BTW, intercoolers cool down (specifically) the compressed intake charge after exiting the turbo, so that boost pressures can be increased (the old basic PV=nRT thermodynamic formula - i.e., temps go up/down proportionate to pressures and vice-versa) and engines can create more power. And all else being equal, more power output might generally tend to increase exhaust system temps rather than lower them. Your Crde already has an intercooler, of course - if someone's offering a bigger one, it's only to allow for increased boost, not to cool the engine / turbo.

Re: the cheapest / easiest way to make more low-end torque with the Crde, I always wondered whether turbo sizing was the real issue. The old adage here: "Horsepower sells cars, torque wins races" (or in this case, climbs hills). M&M and every other company need to make customers feel they're getting something more for their extra money, and nobody's satisfied with marginally higher hp numbers. Thar DI: 62bhp, Crde: 120 or whatever. Makes the extra couple lakhs seem worth it, right? (well, for us, wrong - but for 90% of the posers out there, it works). Anyway, they need a big turbo to make big horsepower. And a big turbo (relative to engine size) is not good for lag / low-speed boost. You could spend 30,000 on a re-map / box, etc that might be trying to make the engine do what it's not really designed to. I dunno.

I'm not particularly experienced here, but here's one thing: I had an old 280ZX (Nissan) Turbo that came with a T-3 turbo unit and no intercooler; that was good for 180bhp from the factory. Turbo was bad when I got the car, so figured I'd upgrade when I replaced it. Turbo specialist made me one with a larger T-4 (compressor side) unit with turbine vanes suited to midrange power (this was an otherwise stock engine), special floating center bearing, etc. The BIG change happened, however, when I put in an intercooler and cranked the boost up to at least double the stock 7psi. Based on the huge cut in quarter-mile times, I'm guessing the output was now at least 250bhp. But the lag was a LOT more. So part of the trouble, at least, was the increased volume in the intake plumbing. Intercooler and related plumbing = more volume. And more volume = more time to compress it to the specified boost level. As a street-driven sea-level car, the vastly increased power was for me well worth the lag in that case. But that car would've lasted about a day around Manali (besides the lag, it probably would've broken in half, what with the flexi T-top and rusty unitbody structure). Anyway, at one point I temporarily had the intercooler off again for some reason and the boost pressure back to stock, and was amazed how little lag there was...

Might've mentioned it in another thread somewhere, but I'm kind of thinking that a Thar with a smaller, quicker-spooling turbo would work out better. Electronic controls (ECU's) cannot create boost. That's exclusively a function of turbine profiles on both exhaust and intake sides of the compressor, etc. A purely mechanical question, though fooling with ECU's and stuff might be able to give a little better off-boost (pre-boost) response, etc. Other thing is, in conjunction with a smaller turbo, I do wonder whether one might lose the intercooler entirely, reducing intake-system volumes, and modify the wastegate to correspondingly reduce the boost pressures. Peak horsepower would have to be a lot less, but if my own experience (albeit with a very different machine) is any indication, it'd reduce the lag considerably.

A rebuilt / good used MDI turbo unit - if indeed they're smaller - might cost under 15,000 outright. Not sure if it'd be a bolt-on or what other issues might be there. These are uncharted waters, so a little risky and I'm not recommending it in your case - but wish someone out there would try it and see.

-Eric

[DirtyDan]

Originally Posted by ringoism

Might've mentioned it in another thread somewhere, but I'm kind of thinking that a Thar with a smaller, quicker-spooling turbo would work out better. [b]Electronic controls (ECU's) cannot create boost. That's exclusively a function of turbine profiles on both exhaust and intake sides of the compressor, etc.

Yeah, Erik, you may be right about the Thar's turbo being too big for low end performance but maybe I can still glean something via ECU tweaking. The aftermarket box boys pick up some power partly because they are not restricted to government rules about emissions, fuel average etc. They can think outside the...er,...box, so to speak. In some cases maybe they just program better parameters. They also claim to get info from sensors many more times per unit of time compared to OEM boxes, making them more responsive, they say.

Over the last 25 years or so I have had five 4x4 trucks and I have tried to be a savvy consumer. For all of these trucks I bought aftermarket chips, ECUs, tuned exhausts, intercoolers and the results were mild to dramatic improvements on performance that could be felt in the seat of my pants, no gages needed. My last 2 trucks were Ford SuperDutys with 7.3L and 6.0L diesel engines. Both of these 7000lbs monster trucks could lay rubber in 1st and 2nd gear and they also got respectable fuel average. I asked trusted 4x4 shops, watched videos of "independent testers" doing dynanometer tests, heat tests, on aftermarket chips and ECUs, I read many threads on Ford diesel forums and I tried to make a semi-informed decision.

The latest Ford SuperDuty trucks have two turbos one small, one large. The small one provides instant-on low speed torque, the big one kicks in later. This ain't going to happen in India anytime soon, I think. Maybe in high end stuff.

I think Arka and Behram should merge and produce revamped, rebuilt MM550s and reworked Thars. Thars returned to something like a semblance of what B.D. had in mind. I think they would make money hand over fist.

I await 2015. Maybe something new will pop up on the market making modification of my Thar unnecessary.

[Sutripta]

Originally Posted by ringoism

Re: the cheapest / easiest way to make more low-end torque with the Crde, I always wondered whether turbo sizing was the real issue.

In the context of this thread, a smaller turbo would certainly help, at the cost of ultimate power. Some of that power can be reclaimed with a VGT. In the Indian context this modification would figure as being complex (= expensive).

My gut feel: If blocking EGR does not help, then reprogram ECU. That with lowered gearing (even if slightly) will go a long way towards making the Thar drivable in the hills.

For more than gut feel, one needs instrumented data. One (easily obtained) data I'd love to see is boost/ road speed for the Thar and its competition.

When one is struggling for torque up a slope at very low speeds, does the Thar smoke?

Regards
Sutripta

[ringoism]

Originally Posted by DirtyDan

In some cases maybe they just program better parameters.

Over the last 25 years or so I have had five 4x4 trucks and I have tried to be a savvy consumer. For all of these trucks I bought aftermarket chips, ECUs, tuned exhausts, intercoolers and the results were mild to dramatic improvements on performance that could be felt in the seat of my pants, no gages needed.

Sutripta likes instruments But maybe the only instrument needed in your case would've been a tape measure; i.e., to check the lengths of the patches of burned rubber on the pavement, before and after each modification.

I've seen some of the Super Duty forums, etc. Lots of guys modding these and other diesel trucks over there. So there's a much larger knowledge / experience base, on account of the much higher demand in N. America for these kinds of things. So everything's easier.

I suppose I could retract my earlier statement a bit, that electronics can't create boost: Indeed, it's true that turbos make boost. On the other hand, one could go back a step further and say that it's exhaust gases that spin turbos. So maybe if an ECU can be programmed to dump more fuel at lower rpm's, or advance the timing to create more cylinder pressure, etc, etc, it would have the effect of creating more exhaust flow/pressure to spin the turbo up earlier? Quite possible, I guess. Also the bit about intercoolers. Of course, one would be free to add a larger one and just keep boost pressure the same - which would cool the intake charge coming into the cylinder and reduce cylinder head temperatures. Wouldn't add any power in itself, and might create more lag due to the greater volume, but might have its place.

Sorry for speaking too much too soon and thinking too little (was going over all this in my mind as I sanded and wire-wheeled the Marshal's body and floor pan today...).

-Eric

[Sutripta]

Originally Posted by ringoism

Sutripta likes instruments

Very very true! Knowledge is power!

But maybe the only instrument needed in your case would've been a tape measure; i.e., to check the lengths of the patches of burned rubber on the pavement, before and after each modification.

Burning rubber when there is no torque?

Gutfeel time again: The issue is not lag, but that there is an rpm band between idle and turbo coming on song, which corresponds to actual practically needed road speeds. In this rpm band, there will be no boost, no matter how long one waits.

Not unique to the Thar.

Regards
Sutripta

[prabhuav]

We have remapped a thar to do two things.
climb up a 30" tall ramp at idle
Rev cleanly to 4800 rpm.
?

[Sutripta]

^^^
Who is 'we'?

Regards
Sutripta

[SPIKE ARRESTOR]

Prabhuav, please do share what you have done. Would be interesting to know.

Cheers
Spike

[Samurai]

Originally Posted by prabhuav

We have remapped a thar to do two things.
climb up a 30" tall ramp at idle
Rev cleanly to 4800 rpm.
?

Are you referring to Pradeep's Jeep which attended the RFC this year?

This is from BODA annual OTR 2012 report, but it was done in 4L.

Originally Posted by Samurai

Then we come across this incline.



It shouldn’t be a big deal for Thar, but Pradeep says he can do it without touching the accelerator pedal. And he does it. He says it is because of some mods he has done. Don’t remember the mods anymore.