[satishfaction]

I have got a Matiz (SD - 2000 make) recently. The first thing I have done is change the stock tyres from 145/13" to 155/13" (both with 70 profile - Swapped from my 2001 Santro as I am selling it off). Now I am facing an issue of under steering. I am not very sure whether the issue was there before the tyre change or not but the under steer is really bad. I was about to crash into a road divider when I took a turn at 60KMPH. Is this a common thing with Matiz? (I seriously hope it is not!) Please advice. Also, the pick up is really bad, especially with the AC ON. Any quick and low cost ways to enhance the pick up at low speeds??

Looking for your advice!

[Su-47]

Matiz's low-end torque isn't too great anyway. On top of it you have put a tyre which is bigger. As expected, this has brought down the performance.

Some quick suggestions:
-- Clean air filter or get a new one. Isn't pretty inexpensive.
-- Get injector nozzles checked.
-- If there isn't much life left in the tyres, get new ones. Expensive suggestion, isnt it
-- For the understeer: Get you steering checked. I have never seen anything of this sort. My matiz (non-PS) steering is pretty precise.
-- BTW, does the understeer only occur on one side or is it both sides. If it does so only on one side, it might be an alignment issue or may be because of tyres with uneven wear (one is new, other in jaded) on the front wheels.

[Su-47]

Originally Posted by Su-47

-- Clean air filter or get a new one. Isn't pretty inexpensive.

Meant: Is pretty inexpensive.

[Kinetik]

matiz doesnt understeer that badly.. especially with the strut braces which come standard on it..like sukhoi mentioned get the tyres checked/rotated/replaced.. and alignment done...

[Shan2nu]

The Matiz is a very good handler if you ask me. i've followed a Matiz in my Vtec, entering a corner at close to 110kmph.

I was shocked to see the car hold on so well, to it's line.

I've a feeling you've got suspension related issues. FWD cars are prone to understeer but not at 60kmph and definately not on a Matiz.

Shan2nu

[rahul_intlad]

As a matiz owner I too can say that have never faced understeer issues,

I face a similar problem but I think it is oversteer[I am really getting confused between oversteer and understeer]I feel since I have upsized the tyres on my matiz to the same old santro specifications[A Team-bhp member has already said that following problem caused due to wrong upsizing].

The problem I face is the moment I hit a pothole at speeds of say 60kmph + the car just veers sideways completely without me doing anything with the steering[real scary nearly hitting divider], and a car which is supposed to go straight turns towards the side automatically.

[Shan2nu]

The problem I face is the moment I hit a pothole at speeds of say 60kmph + the car just veers sideways completely without me doing anything with the steering[real scary nearly hitting divider],

Have u upgraded to newer alloys as well? If so, then get the wheel offset checked....if not, then try reducing the tyre pressure a lil.

Shan2nu

[rahul_intlad]

Originally Posted by Shan2nu

Have u upgraded to newer alloys as well? .....

Nope OE steel rims.

[Kinetik]

rahul, check ur sterring rack is there any noise ? and is there a play between you turning the steering wheel and the wheels actually turning like a dead zone.

[Shan2nu]

Oh yes, totally forgot about tie rod problems, get that checked as well.

Shan2nu

[satishfaction]

Originally Posted by Shan2nu

The Matiz is a very good handler if you ask me. i've followed a Matiz in my Vtec, entering a corner at close to 110kmph.

I was shocked to see the car hold on so well, to it's line.

I've a feeling you've got suspension related issues. FWD cars are prone to understeer but not at 60kmph and definately not on a Matiz.

Shan2nu

Su-47 & Shant2nu..
I wish you are right.. I have got the suspension changed immediately (as it was pretty bad - Only the springs / shock absorbers). Also, got the air filter cleaned and injectors cleaned. But, the problem is still on (Mine is a non powered steering). I have been experimenting alot about how to do away with the problem (inexpensive wasy and the only solution I found is that I switch to a lower gear (third in most cases) at a tight corner and I am able to hold the baby in place?? Now I am able to make a turn even at 80 KMPH. I know that I am missing out on some physics/auto mechanics but would be delighted to get enlightened!
Yes, when I know the roads too well, I add up a slight handbreak action and see the car drift away (not the typical Tokyo drift but good enough to make you smile!). The only problem is that hand break locks up and I am unable to set the car in normal motion with out loosing speed after the corner. I guess I need more practice!!
Also, I think that the best way to practice this drifting thing is at a round about (deserted one with less friction, rainy days / smoother gravel) and keep going round and round at 2nd or 3rd gear with continuous hand break adjustment. What say pros??

[Speedme]

Hey as a Matiz owner myself also (SG-2000) i have not faced this problems while negotiating curves at 100+ on stock tyres.

I would go with Kinetic, that you should get your steering rack checked.

[Shan2nu]

Maybe it's just your driving style that makes the car understeer. Like you mentioned, using the right gear is important as far as cornering goes.

Try this for a change. Fill the front tyre with 2 psi more air than the rear ones. That did a good deal to the way the Vtec took corners. Since these are FF cars, the front tyres experience a lot more tyre flex while braking (due to weight distribution and weight transfer), increasing the psi will make the sidewalls stiffer and help corner with better stability.

Shan2nu

[satishfaction]

Originally Posted by Speedme

Hey as a Matiz owner myself also (SG-2000) i have not faced this problems while negotiating curves at 100+ on stock tyres.

Speedme,
To start with.. It is a WOW.. 100 KPMH+ on turns.. U started to make me feel like a child:(
Guys, Is it normal that people can take turns in India at 100+?? To make it more clear, let us say I am driving on a straight city road, at a junction I need to go left and then take a left at the same speed. Spare me on my ignorance and driving capabilities but is it casual to make such turns at such speeds??

Coming back to the main topic, got the steering rack checked.. It seems to be totally normal.

[satishfaction]

Originally Posted by Shan2nu

Maybe it's just your driving style that makes the car understeer.
Try this for a change. Fill the front tyre with 2 psi more air than the rear ones.
Shan2nu

I guess you are right.. May be I am throwing the car into the car rather than driving it into the corner.. Can you recommend at what best speeds you can take a turn (left or right) with out loosing balance.. I know it is very subjective but I guess a right turn (total 90 degrees) cant be done beyond certain speeds in a composed manner..
Yes, I will alter the tyre pressure as u suggested this time! Thanks for the advice!
U r expert voice on speeds at which we take turns (new thread?) will be good to read