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Making your Automatic car dance to your tune October 27, 2007

Posted by Ragesh G R in Physics and Maths, Uncategorized.
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The most common complaint and comment about an Automatic tranmission car, is that “You have less control over it, there is less involvement, compared to a manual transmission car”. Agreed, you can’t dictate the car to change to any gear that you please when you have an automatic transmission, but from my experience, I can tell you, if you know your know your car well enough, and if you are able to feel what it is doing, you can make even an automatic transmission car do whatever you please (well almost!).

First of all it’s possible due to the fact that most engine management system of today’s cars are intelligent and are based on a feedback system. The car does n’t just do pre-programmed actions irrespective of anything anymore, but on the contrary, listens to the driver input, tries to gauge the intention of the driver and tries to act accordingly, producing wonderful results almost always.

Next is your talent, how much you know your car and can undestand what it’s trying to tell you.

Downshifting in an Automatic car

Apart from the obvious manual change to”L” or “2”, the modern day cars downshift when you floor the throttle (full(open) throttle), provided the current revs of the engine can accomodate a higher rev as a result of a downshift. Imagine, you are cruising along at a rather relaxing speed of 70 km/hr in Overdrive(highest gear), when you need to pass a lorry in front of you, and an intersection is approaching, so it’s a case of now or never. But since you are in Overdrive, obviously you may not have enough acceleration to complete the overtaking manoeuvre before the intersection. No probs! You just floor the throttle, the car immediately shifts down to the previous(lower) gear, u get a jolt of acceleration, the next thing you know is you have passed the lorry at a speed of 90 km/hr. No more waiting for the speed to build up and no more nervous times during a pass

Warning: Do not ease the throttle(i.e., always keep it in full throttle) in the middle of the overtaking manoeuvre or else the car will upshift and lose acceleration and phew! you don’t want that to happen. So keep it floored till you have completed the overtaking.

Upshifting in an Automatic car

Now it’s not as straightforward as the downshift because here you have got to do all the work. The secret lies in judging if the rev (engine speed) is appropriate for an upshift and playing with the throttle. Generally, an automatic car upshifts to a higher gear in the start-middle of the rev band appropriate to the next higher gear. But sometimes we need power. So to prevent an upshift untill all the revs (max revs) at the current gear is utilised and you get maximum acceleration, floor the throttle and don’t ease it until it upshifts. But sometimes at higher speeds, not letting the car upshift will sometimes keep you in a low speed gear when you want speed and not torque. For that, just ease the throttle when you want an upshift. The engine management system(EMS) senses that since you are no longer in full throttle, you don’t the need the acceleration and torque and can upshift. Once it has shifted up, you can get back on the throttle (but not full throttle, else it might downshift again), and drive away. The beauty here is you can upshift almosy whenever you want to (i.e., at whatever rev you want to) by easing the throttle. But there is a limit to it. You can use this easing the throttle to upshift only when you are in the right rev band. If you ease the throttle too early (before the rev band of the next higher gear), the car will not upshift and you will just slow down, and if you don’t ease the throttle at all, it might not shift untill it hits the red line which might be unnecessary sometimes. It’s a delecate balance between speed and torque, and it’s a wonderful feeling when you get it just right.

When the driver sensitive EMS of the car, and your feel for the car work in tandom, you can make it dance to your tunes. It’s sometimes more challenging than a manual car because, there are no explicit levers to do anything, you are just overriding the car by thinking from it’s perspective.

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Comments»

1. Vasu - December 2, 2007

I agree with you regarding making the best out of auto cars. Also bear in mind that the mileage what you get out of your car also heavily depends upon your driving style. In general, autocars are not popular in India because of the stigma of bad mileage. In fact the mileage of an automatic car can be made “almost same” as that of a manual car, if you observe certain “best practices” while driving it.

The main thing that you should avoid is “flooring the accelerator”. This may be against what you have mentioned in your post. So the change that is required is more about driving style than any secret technique. Use the gas pedal as less as possible, and avoid having to use brake pedal by using good judgement of the road conditions. This does not mean driving at a snails pace. This is even worse for auto cars. Understand which speed the car is more comfortable at and try to maintain it. For a car like Santro it should be about 60-80 kmph on highways. Anything more is a strain and the proportion of fuel required to maintain that speed increases exponentially. Not sure if your car has a tachometer. If it is there, it will help you understand the “heartbeat” of the car better.

This best practice are also applicable to manual cars. I used to tell my friends who ask how do I get very high mileage for my cars, I will say simply “use only accelerator”. Use clutch and brakes only when absolutely required. It means not to keep it pressed all the time like some call taxis, sumos etc do. It is about intelligent use of accelerator pedal. It gives good mileage, good longevitiy for your car and peace of mind.

2. Ragesh G R - December 2, 2007

@Vasu: Of course, you have a valid point there. What my post concentrated on was the driving and performance part; and what you said was about the fuel economy part. Both are valid. It depends what you need from the car. You cant use “acceleratore only – no flooring technique” if you need to urgently pass a vehicle or if you have some urgency. And I understand the heartbeat of the car without the techometer.

3. Malachi - January 11, 2008

When i floor my car it revs the first gear to the max before it shifts then its a jurk into the second gear and everything is fine why is my car slow at shifting from 0-60 it also does it when i drive at speeds of 70-100 and floor it it will rev high before shifting. Is my transmission slipping or is it normal for overdrive to kick in late. I have a 1997 Ford Crown Victoria. My car will shift perfect when the pedal is not floored.

What do you think is the problem?
Can I fix It myself?

4. Ragesh G R - January 11, 2008

@Malachi: There is no problem.Thats obvious: An automatic car is designed like that. When you floor, the computer senses that u need power and acceleration, hence keeps the lowest possible gear till it exhausts almost all available revs. If you do not want to delay your shift, then do not floor, if you are soft on the throttle, up shift will happen much earlier. The harder you are on the throttle, the later the car will up shift. This is normal. In fact it’s a very useful feature of an automatic car that it shifts according to the severity of the throttle input.

5. garrett sala - March 4, 2008

1997 grand marquis cold air & dual exhaust. when racing off the line how would i get the most acceleration? if i mash the throttle my tires just spin. if i take off with less throttle and then mash it as soon as it hits second i feel a drop in power. is there a way to play with the throttle so that i wont lose as much power when the tranny shifts while im racing? ive heard that if you let up for a second and then floor it again it will shift. any suggestion?

6. Ragesh G R - March 6, 2008

Your first quetion, well try pumping the throttle rather than flooring and flooding the engine at low speeds, and
your second question, well, the clutch needs to disengage when it shifts, so a little drop in power is inevitable.

7. Malachi - October 26, 2008

Hello i was wondering if you knew why the dashboard/meter fuse would keep blowing everytime you put it into gear and then into park. None of the meters work the gas speed or indicator lights work until fuse id replaced but then it blows again. i have a 2001 crown victoria

8. sujith - October 21, 2010

hi i would like to modify my 2 door zen…like body kits and skirts will you be able to do…also i have a picture of another zen.i wish my car to look same as the other car.If you can do it please let me know.
thank you

9. Ashu - February 29, 2012

Can anyone gives me the contact details of the persons who can modify cars for physically handicap persons in Jammu.It would be a great help for me.

Please help me guys…

anilsuthar - September 22, 2012

@ashu Pl contact Mr.Rajesh Sharma (09414070083)& he is from Jaipur, Rajsthan. He was modifing cars for disabled at all over India and charging very nominal price in comparison to other car modifiers all over India…

Mob. 9416236663
Azad nagar hissar

10. Ramni Uppal - March 29, 2012

Hi! I have a cruze automatic.Sometimes on turns when I try to pickup at a pace it gives a jurk and sometimes I feel it is normal. This also happens at high speeds sometimes.What could be the reason.

11. Haridwar - July 18, 2015

I have a zen lx car model no.2001,I would like
to have hand drive setting for it .My mobile no. is 8948803232.Please reply reply back on my gmail account.


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