[ananthkamath]

Originally Posted by Rtech

It's more an inherant problem due to the way it was designed and the basic suspension geometry, which can only really be altered by changing certain mounting points etc. (again, can't say without a proper study).

I know someone who was personally involved in the development of the Scorpio, and they tried everything they could to get rid of this problem, but with every change, the improved one thing but made something else worse. The fundamental problem lies in the overall design.

You may in fact be right. I think we should do more research into this before jumping in with two feet. I am thinking the tradeoff lies in ride quality. But cant say anything without checking things out first.
We need to get in touch with this gentleman from Mahindra. He may be able to help us out.

By the way, is there any data which can show us how many Scorpios have crashed due to its handling problem? Even indicative data is sufficient to get a reasonable idea.

People have said the handling is scary. Ok, lets be specific. I'll write my own experiences first, then you guys can add yours:

1) The roll angle is alarming at high speeds. This gives the FEELING that its going to tip over. However, I have not heard anything like this happening. Could anyone shed light on this?

2) The front is too soft and the rear is too hard. Even a small mid-corner bump is enough to shift the back end a few inches outwards..meanwhile the front continues to roll... This causes the "oversteering" feeling in my opinion. Thats why I suggested stiffening the front and softening the back.

MPower & other suspension experts, we need your help on this one....

[drifter]

From personal experience...

The rear is very skittish...and yeah like mentioned during hard cornering, it gets easily unsettled by even small bumps. The front is fine by my standards...but it does roll a lot...

Coming to the brakes...it comes equipped with LSPV...but even after that the rear wheels tend to lock up quite often...which is why it doesnt brake in a straight line...

For me the brakes are the most scary part. Those need to be sorted out more than anything else.

Drifter

[Steeroid]

Originally Posted by ananthkamath

You may in fact be right. I think we should do more research into this before jumping in with two feet.

Yalla habeebie - after all that talk about making things happen am a bit disappointed at that statement.

[veyron1]

well i get around 9 in city, so if i was to buy a fuel efficient muv i'd rather go in for a fuel efficient tavera.

hey, i wasn't critisizing the scorpio, manson; i like the car, but i wouldn't consider it an SUV, that's all....

and usually people don't buy vehicles for the main purpose that it serves, how many safari,sierra,etc owners go offrroading?

agreed, most don't; but some do....again, i'm only saying that the coin has two sides- only suggesting that the 4x4 option of the scorpio isn't as much value for money as the safari, as the latter offers much better capabilities and comfort...

look guys, i didn't say the scorpio was a below average car- i will never say that about any machine; all cars have their pluses and minuses, and one should accept it for what it is.


as for the suspension, there's pretty much nothing you can do, as the chassis has limited capabilites to accomodate extensive suspension mods. stiffening the front and softening the rear aren't the solutions, as it might not give the desired results; as it is, the chassis has more-than-required flex (which is a srict no-no for cars, and are abundant in SUVs, like safari and endeavour). speaking from personal experience, the scorpio's suspension is not sorted well enough to match it's brilliant engine, as taking turns at over 130 kmph is extremely hairy, and every once in a while, you can feel the rear inner wheel losing contact with the tarmac.

the only solution could be to convert the rear suspension to a multi-link setup with coil springs and chassis links to the suspension arms, which is next to impossible; the other solution is to extend the wheelbase by cutting and and lengthening the chassis long-members, along with cab extension, and stiffening it up with arc-type cross members- now this is possible, and DC has done a semi-good job with a "long-wheelbase" scorpio; although i haven't personally seen or driven this particular scorpio, i have heard good reports about it...

with regards to the brakes, the problem is that they are over-servoed, and the brake-fluid boils up at the slightest hint of overload; due to this, the brakes fade with constant use, making it ineffective; the possible solution is- to get an entirely new brake-setup, including larger dia sleeve master cylinder and a smaller dia booster, along with a larger brake-fluid reservoir, that will help in keeping the hydraulics cool(due to more quantity of cooler brake fluid)...

[ananthkamath]

Steeroid, no need to be disappointed. I was merely refering to my ignorance regarding the new info given by Rtech. Doesnt mean I am backing out.

Veyron, how do you know the chassis has flex? In any case, none of us here are even remotely qualified to talk about whether the chassis has "more-than-required" flex. So lets not get into generalizing here. If you indeed have numbers for stiffness then share it with us. Opinions of technical parameters don't quite work out unless you are hinting at stiffening the chassis as an experiment towards our goal.

Contrary to popular belief, flex is built into the chassis. For race cars its different though; its undesirable to have flex because it makes it impossible to tune the suspension accurately. I am not picking out something from the net, here. I speak from first-hand accounts from the old Formula Indian racers.

Yes I know converting to a multi-link would, in theory, be better. The problem however is to make the existing setup better, which is a real challenge.

Your solution to the braking problem. It may be just an issue of correcting brake bias. If you increase the size of the master cylinder then it may muck up everything else because it reduces peak velocity in the lines. This results in spongy feel and may in fact INCREASE the braking times. We want to make it stop in the same time, but in a straight line and without locking up. A better brake fluid may be the answer...can anyone enlighten us as to what fluid is used presently...DOT 3 or 4?

[ananthkamath]

I've attached a copy of my letter to Mr. Roy Sujan of Mahindra (R&D?) :
************************************************** ******
Sub: Reg: Scorpio suspension upgrade kit from Team-BHP.com

Respected Sir,

My name is Ananth Kamath, & I am writing on behalf of Team-BHP.com, India's biggest online community of auto enthusiasts. I am a mechanical engineer by profession and have worked as Member- Prodn. Engg. with TVS Motor in the recent past.

Recently, the handling characteristics of the Scorpio have become the object of torrid discussion in our Forum, and I am sure the same has been debated vehemently in other forums also. (The link for the relevant thread at Team-BHP is attached at the bottom of this page.)

We understand that the people at Mahindra have done their best to rectify this problem and that customer satisfaction is your #1 priority. However, it is also true that your product has to cater to a wide variety of customers and hence is a reflection of this "general" approach required to develop any mass-produced product.

It is this fact which leads us enthusiasts to concieve of an aftermarket suspension upgrade kit for the Scorpio, which will improve high-speed vehicle behavior at some expense of low-speed ride quality. This will naturally narrow the focus of the Scorpio as a product, but that is true of any aftermarket upgrade.

We understand that while we cannot match the collective engineering skill & facilities of your R&D team, there are, among us, professional suspension-development engineers as well as people who have had practical experience with automobiles; this, allied with our large member base, can generate enough ideas to make a project like this (theoretically) possible.

We therefore request your help in this project, beginning, first and foremost, with your opinion on whether or not it is possible to develop such a product as mentioned above. In this connection, I would like to invite you to be a part of the 3000-strong Team-BHP community.

Thank you for your time.


Awaiting your early reply,

Thanks & Warm Regards,
Ananth Kamath
For www.team-bhp.com


Link discussing Mahindra Scorpio:
http://www.team-bhp.com/forum/showthread.php?t=7897
************************************************** ***

[veyron1]

Veyron, how do you know the chassis has flex? In any case, none of us here are even remotely qualified to talk about whether the chassis has "more-than-required" flex.

every car's chassis, be it road-going or race-prepped, has flex. and no, i do not have the "numbers" here to quote the chassis dynamics of the scorpio; but then, no one knows about the numbers except,maybe, the design team at mahindra R&D; and since no one here, according to you, is qualified enough to talk about chassis dynamics and chassis engineering, we ARE, talking in a generalised sense...

the chassis flex has to do with vertical loads,available traction, centre of gravity,etc. all of which result in the net cornering efficiency, that puts the chassis flex into the picture. for example, if a car has available traction of 700 units and has a vertical load of 500 units, the car's cornering efficiency stands at 140%, or the car would exert a force of 1.40 G's while cornering (theoretically), and would exert a certain amount of force on the chassis, causing it to flex.

so, i was GENERALLY ASSUMING, that since the scorpio has a high centre of gravity, is top-heavy, and puts a lot of load on it's tyres while cornering, it has high chassis flex; and when compared to it's rivals, more so...

Your solution to the braking problem. It may be just an issue of correcting brake bias. If you increase the size of the master cylinder then it may muck up everything else because it reduces peak velocity in the lines.

the scorpio's brakes are not as effective as they are supposed to be, hence my solution. and no, brake biasing alone won't solve the problem, as the problem here is not of the rear locking up or the front being over-responsive; it is a question of lack of bite, hence my suggestion for a larger dia master cylinder; and pray tell, how the heck would a larger master cylinder reduce peak velocity in brake lines?? from what i know, in hydraulics, the pistons work thus;
if a piston is 2 inches (5.08 cm) in diameter (1-inch / 2.54 cm radius), and another piston is 6 inches (15.24 cm) in diameter (3-inch / 7.62 cm radius). The area of the two pistons is Pi * r*r. The area of the first piston is therefore 3.14, while the area of the second piston is 28.26. The second piston is nine times larger than the first piston. This means that any force applied to the first piston will come out nine times greater on the second piston, and vice versa. So, if you apply a 100-kg downward force to the first piston, a 900-kg upward force will appear on the second. The only catch is that you will have to depress the first piston 9 inches (22.86 cm) to raise the second piston 1 inch (2.54 cm).

therefore, an increase in the dia size of the master cylinder would actually increase the hydraulic pressure, with the only catch being that the piston would have to travel lesser distance; hence the smaller dia booster & a larger reservoir...

[merve_extreme]

Why does everyone associate 4x4's with excellent offroading potential.Even the multi-pulti priced BMW X5,Canyne ,Tuson and what else ....will get stuck where our Maruti Gypsy(a.k.a Suzuki samurai) will carry on.there is more to off-roading than mere 4x4(though it is essential).

From what i understand the main problem of the Scorpio is its handling at high speeds.But do we ever reach such high speeds on our cramped roads.Even driving one on the highway at 120-140kmph will be stable enough in a straight like,only when u take turns at 80kmph + will it start to get nervous(which increases with speed),but does anyone really take tight corners(or slightly tighter ones) at those speed in normal day to day driving cycle(atleast 90% of the people don't,those who do don't buy a SUV/MUV).

And about the crampness in the rear,even the Octavia is cramped than many c+ segemnt cars but its sells well.Most indian's(men) are between 5.5 to 5.8 feet in height and i dont think they will feel to cramped in a Scorpio(the jump seats are used mostly in taxi's only).think about those who travel in chauffeur driven zen's,santro's and esteems.

So the scorpio is good for most indians and i think the base model is still cheap(appx 7 lacs Ex-showroom in mumbai,SLX CRDe is 8.5 lacs) enough for it to be VFM.

[ananthkamath]

Originally Posted by veyron1

end since no one here, according to you, is qualified enough to talk about chassis dynamics and chassis engineering, we ARE, talking in a generalised sense...

If you go back and read my post, you will notice that I never said any such thing. I said we are not qualified to talk about whether the chassis has "more-than-required" flex...simply because we do not know what is the "required" flex in the first place, since that data is calculated based on the same vertical loads, the same available traction that you talk about. Guess what? We dont know jack about any of the forces. I am talking specific values here.

I am not questioning your or anybody else's technical ability, I am simply saying that when you don't know the base parameters, you cannot judge the end result and say it is too much or too less.

Originally Posted by veyron1

the chassis flex has to do with vertical loads,available traction, centre of gravity,etc. all of which result in the net cornering efficiency, that puts the chassis flex into the picture. for example, if a car has available traction of 700 units and has a vertical load of 500 units, the car's cornering efficiency stands at 140%, or the car would exert a force of 1.40 G's while cornering (theoretically), and would exert a certain amount of force on the chassis, causing it to flex.

You may be right on whatever you said. But look at this from a holistic viewpoint. We are not looking for a stiffer chassis here. The chassis is serving its purpose pretty well. Look at the task at hand: improving the handling characteristics of the Scorpio. If you think stiffening the chassis will help, then tell us why you do.

All I said earlier was to stiffen the front and soften the rear. Now since you are a specialist in generalized vehicle dynamics and chassis engineering, pray tell me what effect a 20 N/mm increase in front spring rate and a 15 N/mm decrease in rear spring rate would have on the torsional stiffness of the chassis? Cant predict, right? Thats why we have CATIA and ANSYS.

Originally Posted by veyron1

so, i was GENERALLY ASSUMING, that since the scorpio has a high centre of gravity, is top-heavy, and puts a lot of load on it's tyres while cornering, it has high chassis flex; and when compared to it's rivals, more so...

Again you are comparing vehicles solely based on seat of the pants evaluations. These differences in loads and centre of gravity that you talk about with gay abandon, are more often than not talked about in grams and mm, boy you really must be tapped into the cosmos to even MAKE out such small differences....Tell me how many millions of miles might you have done in the Scorpio and its rivals to be able to make out such differences.

Originally Posted by veyron1

if a piston is 2 inches (5.08 cm) in diameter (1-inch / 2.54 cm radius), and another piston is 6 inches (15.24 cm) in diameter (3-inch / 7.62 cm radius). The area of the two pistons is Pi * r*r. The area of the first piston is therefore 3.14, while the area of the second piston is 28.26. The second piston is nine times larger than the first piston. This means that any force applied to the first piston will come out nine times greater on the second piston, and vice versa. So, if you apply a 100-kg downward force to the first piston, a 900-kg upward force will appear on the second. The only catch is that you will have to depress the first piston 9 inches (22.86 cm) to raise the second piston 1 inch (2.54 cm).

therefore, an increase in the dia size of the master cylinder would actually increase the hydraulic pressure, with the only catch being that the piston would have to travel lesser distance; hence the smaller dia booster & a larger reservoir...

Impressive. But consider this: The equation for force applied on the piston is -

F = (Wa/A)

where W- force exerted at the slave cylinder.
a- area of the piston
A - area of the slave cylinder.

Since A is constant in our case, the equation is F = K (Wa).

Keeping 'a' constant, if you increase F, W increases. Meaning, press harder if you want to stop faster.

Keeping W constant, if 'a' is increased, F increases. Meaning, if you install a larger diameter master cylinder, you increase pedal force for the same braking force. And if you add a SMALLER booster, all you are doing is further increasing the pedal force. All this math crap means, in effect, what I said earlier:

Originally Posted by ananthkamath

This results in spongy feel and may in fact INCREASE the braking times.

Go read your hydraulics textbook again, this formula is given right underneath the theory that you explained to me. If you want to indulge in mathematical mud-slinging, I am all game for it. This is the stuff that I do everyday. Yet, something tells me that nothing comes of protracted debate.

We are trying to solve practical problems here, not indulging in one-upmanship as to who knows the most theory or who does the best guessing. Again I am not judging you for your theoretical knowledge or approach. I understand you want to share what you know like the rest of us here. But please refrain from making any judgments regarding technical issues. Thats even worse than judging subjective things like styling.

No offence meant or taken.

Ananth

[BUSA]

Greatgoing Ananthkamth! Just hope that Mahindra do take a positive step forward! I love the scorpio but i am not happy with some of its problems and was just highlight and not degrading the car!

Ok guys I don’t want to show Scorpio as a bad car. I just wanted to highlight its faults which are being overlooked! Infact I would have loved to buy a Scorpio intil I came to know how many faults this vehicle! Why buy a car which cant be safe even 100!

@ Manson i said the front looks good but the rear styling is not so good!

Atleast be near to perfection or try to touch it!

Guys please dont pounce on me for being underage! Look at dadude driving at 140 and he being youger then me

[veyron1]

Originally posted by ananthkamath

Now since you are a specialist in generalized vehicle dynamics and chassis engineering

did i ever say i was...??

Originally posted by ananthkamath

Again you are comparing vehicles solely based on seat of the pants evaluations. These differences in loads and centre of gravity that you talk about with gay abandon, are more often than not talked about in grams and mm, boy you really must be tapped into the cosmos to even MAKE out such small differences....Tell me how many millions of miles might you have done in the Scorpio and its rivals to be able to make out such differences.

the differences in loads of the vehicles that we are talking about here, are in kgs; again, not getting into specifics, since i do not know the exact numbers(in your words "we do not know jack about the specifics/forces"). all these parameters are taken into "general" consideration while you drive, which is why i made my "general" opinion clear; although i haven't driven the scorpio or the safari or the endeavour for millions of miles, i have driven them for thousands at least (since i used to own a safari myself and my relatives had the others); which is why i made the assumptions- and you don't need to be tapped into the cosmos for that. just try taking the same curves at the same speeds in the safari, scorpio, and the endeavour, and you can actually feel the suspension and the chassis dynamics. agreed, chassis flex is too complicated a calculation to be figured out by guesses or even by the human mind on it's own, but in the real world, you have to go by trial and error basis, and precision science and maths doesn't always work.

Originally posted by ananthkamath

If you want to indulge in mathematical mud-slinging, I am all game for it. This is the stuff that I do everyday.

i'm sorry, i am not a proffessionally qualified mechanical engineer, only a humble comp. engg. student. i do not practice maths and formulae everyday, so i can't debate with anyone on the specifics and "mathematical mud slinging". the little knowledge that i have, i have gained through experience and long years of automobile passion...

Originally posted by ananthkamath

We are trying to solve practical problems here, not indulging in one-upmanship as to who knows the most theory or who does the best guessing.

right, so let's get to the point then- i believe you didn't read my earlier post;

Originally posted by veyron1

the other solution is to extend the wheelbase by cutting and and lengthening the chassis long-members, along with cab extension, and stiffening it up with arc-type cross members- now this is possible, and DC has done a semi-great job with a "long-wheelbase" scorpio; although i haven't personally seen or driven this particular scorpio, i have heard good reports about it...

what i meant by that, was that the "good reports" suggested that the LWB scorpio had none of it's predecessor's weak handling....

Originally posted by ananthkamath

I understand you want to share what you know like the rest of us here. But please refrain from making any judgments regarding technical issues. Thats even worse than judging subjective things like styling.

the same as you are; and no, i am not making any "judgements" on technical issues, only opinionating on the same. i am not rigid to my concepts, and am very willing to correct myself when wrong, hence the word "opinion".

look, you are missing the point of my posts by a country mile;one cannot have expertise in all the VAST areas realted to automobiles; just like a scientist can't have the knowledge of a tuner or a race driver, and vice-versa; a scientist believes in theory and achieving results by complex calcns. et.al, whereas the others believe in practical results via real-world knowledge and trial & error methods.

i was only putting forward my opinions based on real-world experiences; i can't state the specifics or scentific data like proffessionals...


No offence meant or taken...

[Steeroid]

Originally Posted by BUSA

Guys please dont pounce on me for being underage! Look at dadude driving at 140 and he being youger then me

One guy exhibiting irresponsible behaviour does not give everyone else the license to act similarly. If you HAVE to imitate, pick a slightly better role-model.

[devarshi84]

scorpio according to me is the best ever attempt made by an Idian manufacturer after tata safari in the suv market.

But that certainly doesnt mean that its the best product ever. What mahindra aimed with the scorpio was an MUV that looks sporty and carries a family of 7-8 in comfort. It has succeeded completely in doing that. Coming up from the old jeeps that mahindra manufactured this vehicle is an excellent development.

I am also happy that mahindra is constantly upgrading this car. But now the game has moved on and so should mahindra. Scorpio has lived its age to be precise as it debuted at a later point of time in its life.

Mahindra now need to bring in a new car.

Hats off to the scorpio for being a good vehicle but its old now.

[dadudeonfire]

Originally Posted by BUSA

Guys please dont pounce on me for being underage! Look at dadude driving at 140 and he being youger then me

hey dude...why cant u just say sorry and finish off the matter...man..how kiddish you could get...hhahahaah ...people blame you for something and like a five year old kid you say "even that guy did it ...look at him nooooo"

[devarshi84]

scorpio was actually in competition to the old qualis, sumo and old safari.

now that the innova, tavera and new safari are out mahindra should either ditch the scorpio platform and make a new car or update the scorpio like tata made the DICOR.