Need advice: Engine & suspension modifications for my Tata Harrier

I have now given my car a Stage 1+ remap from one of the most reputed professional experts in India, which significantly increases the power and torque numbers.

BHPian Livnletcarsliv recently shared this with other enthusiasts.

I am in no second thought of letting go of my lemon Harrier 2019 model BS4 since I have decided to continue with it for as long as possible and take control of the maintenance with ASS (as long as it is under warranty period) and with an FNG, once the warranty expires (since I have access to a few professional FNG's in my place). Not letting go of course, primarily because of my financial constraints, my strong attitude that "I can fix anything as long as it is man-made" and finally it's a BS4 diesel (I know what is the demand for BS4 diesel cars due to its sheer simplicity and ease of maintenance compared to BS6).

I have now given my car a Stage 1+ remap from one of the most reputed professional experts in India, which significantly increases the power and torque numbers. In fact, we tried 2-3 variations of remap for the reasons mentioned below.

However, I am in a dilemma for a few things that I need our community's input for

  • There is a difference in acceleration and low-end pickup post remap. However, I see no difference in the top end. With the help of a larger turbo, the top end can be increased to a great extent. But my doubt is if I put a larger turbo, will the low-end not get affected? It's like this - stock turbo after remap - no difference in the top end and good difference in the low and mid-range. Larger turbo - no low end but increased performance in the mid and top range. How can this be solved?
  • Is it worth upgrading to a performance filter (like BMW, K&N, or anything else) to enhance anything in the top range without affecting the improved low and mid-range?
  • How effective are installing sway bars in a car like Harrier to improve handling and reduce rollover?
  • Will the upgrades like performance spark plugs, stiffened suspension (already harrier's suspension is on the stiffer side), 1 size bigger rims with better tyres (stock comes with 17" rims with Goodyear Wrangler tyres - 235/65/R17), do any improvement in the drivability, handling and performance? If yes, how significant is the change?

I don't want to go with a more aggressive tune (Stage 2 or more). I just want to extract the maximum out of the current stage 1+ with appropriate and reliable hardware upgrades for a significantly improved enthusiastic drive.

Here's what BHPian condor had to say on the matter:

We need low end response most of the time, since that is where the action is. Why do you want top-end response ? Do you want to go faster ?

IMO, skip the top-end changes also because the remap can be simpler by focussing on where most of the driving happens - i.e., low and mid-range. And you also say you dont want to with Stage 2

Trying a larger turbo can cause things to go awry. Let the current turbo do it's job.

2. No to performance filters. We have enough discussions that these are more placebo than actual action.

4. Sparkplugs ? These are for petrols. Not for your harrier.

4a. Ride is better on 16" rims, a little less on 17", lesser on 18". Also cost of tyres increases with increasing size. So here too, stick to 16" or max 17".

Here's wishing you the best with resolving the problems. Yes, BS4 gave the balance of simplicity with clean emissions. Try hold on to this as long as you can.

Here's what BHPian kosfactor had to say on the matter:

If the tuner has made it respond better at lower engine speeds, that in itself is an improvement . At this point if the car is running well, I would leave it as is but with Mods, there is often no end to the story.

I do not remember seeing a rear sway bar in the Safari, I would guess its the same in Harrier as well. The suspension set up may not need a sway bar in the rear, front end has it of course.

Since your tyres are perhaps a bit worn out, a new set of tyres along with an upsized alloy will certainly improve the road manners and looks too.

Here's what BHPian IshaanIan had to say on the matter:

A bigger turbo requires more energy to spool up thus you will get improved performance in the higher rpms but reduced drive-ability in the low rpms. Perhaps a twin turbo setup could be considered (one small and one large) if the internals can handle it and if there's enough space in the engine bay.

A high flow filter will not be able to filter out as many airborne impurities as your stock filter and in this day and age of excessive urban development and dusty road conditions in our country, I'd advise against it.

The Harrier already has a tall center of gravity IMO sway bars will reduce the progression of weight shift between maximum lean and a rollover (car could snap out of control giving you less time to react). So I would advise installing them with caution (check for different levels of rigidity and judge for yourself what works best) at the end of the day chassis flex is also an important quotient to grip especially in less than ideal traction conditions such as in the rain. Lowered suspension can be looked into though.

Bigger rims I would only recommend if you can find ones that are bigger than stock but weigh the same if not slightly lighter as otherwise with the bigger rims and larger tyres, you will be looking at increased rotating unsprung mass which will lead to steering inputs and throttle inputs feeling sluggish as the car will not feel as light on its feet anymore. Not to mention extra stresses on the suspension as well as the mounting points and all related hardware that may not be designed to cope with the greater load of rotating mass.

Read BHPian comments for more insights and information.

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