The perception of improvement

[Petrus]

Following from the various sceptical observations concerning results of individual modifications, a pondering to provide perspective.

A reasonable assertion is that the average non too sensitive mortal driver will perceive a 5% difference.

To make that more real:
a red line of 7.000 rpm shifting to 7.350 rpm
stopping distance from 100 to 95 meters which is a car´s length
50 kilo from a 1000 kg car
7 hp more on top of 140
Just about anyone but the most insenstive wíll notice those.

Taking it a step further:
Asuming that the car´s polar moment of inertia is 800 kgm then 5% is 40 kgm which is 10 kilo off the extreme end of the car; p.e. the front crash bar + washer bottle or replacing the OEM muffler by a lightweigh alu one.
Ditto spare wheel + tool roll in the front bucket or not.
Most wíll notice that.

Ergo:
Even though the car weighs >1000 kilos and a say 10 to 20 kg delete only 1 - 2% of that, which will be difficult to perceive by even the most sensitive driver, the efféct depends of whére the change is made.
Taking 5 kilo off the flywheel is 0.5% of the car´s mass but boy is it noticeable in the way the engine revs. even takes off or stalls :cool:
On the other hand a full vs empt tank is near 40 kg yet is has nó perceivable effect on the way the car steers.

Moral of the tale:
Empty the frump, delete the crash bars front/rear, swap in a washer fluid bag, change the lardy OEM cat/muffler for lightweight and even the most insensitive driver WíLL notice that the car is more agile, hass less initial understeer and is more sensitive at speed.
Even the most sensitive will hardly notice the above in the perfórmance difference.

[Nvy]

I can notice +/- 1 passenger in my two cars - the two and Mazda 6. Mainly in acceleration, in the mazda it is visible on the revs too. More weight and it needs more revs to accelerate, its very apparent when going up hill.

[1979scotte]

In a stock power 2 a passenger or luggage is noticeable without a doubt.
Not so once you've added a few pony's.
Notice nothing in my focus estate tdci. Imagine there is so much torque I'd need a trailer before it would matter.

[Dev]

  It really depends on your goals based on practicality which also includes safety items for you and your passengers.
 Most people will never go this far because there is a limit before it becomes a perceived stripped junker or kit car that no longer has any semblance to a road going car to be taken seriously.
 I take the approach of removing and then adding back something of light weight or higher quality. If there is a chance something can go wrong I will not entertain a part if its not going to have near Toyota reliability.   A good friend of mine went though hell last year at great expense  by buying a light weight flywheel where the aluminum separated from the steel ring gear which is a known issue.
 
There are somethings that are for off road applications that has consequences. I admit that I have taken somethings too far particularly a urethane passenger mount which made the car shift great but It was unbearable so I reversed course so I can hear music again.

 The only modification I felt that made the greatest and most dramatic difference was the dampers and next a great set of tires. It never got old continues to be fun to drive.
  Most of these other things are generally not as perceivable or you will eventually get over it looking for more power where that quest never ends especially if you do all the small stuff.
 Happiness also comes from having a mostly complete car with good paint and upkeep by being a custodian while its in your care. 



 

[Petrus]

It really depends on your goals based on practicality which also includes safety items for you and your passengers.

This thread is about what one is likely to precieve or not. That is all.