Brake or Downshift?
01-07-10, 07:56 PM
#18
Driver
Join Date: Jul 2008
Location: CA
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While going downhill and slowing I also downshift and rarely brake (unless I am racing). That way when I accelerate again I am in the right gear. So I am indeed saving the brakes and perhaps the front tires a little too. I figure if I can space out changing the brakes/rotors/etc then that's good savings. And I never anticipate having to change the gearbox... I always believed that the gear box takes a much harder hit while shifting at red line when the engine is at 400HP, not while gently downshifting. As pointed out, the blip is also supposed to lessen the stress.
I have a hard time believing that this would be a destructive approach. But if one can explain with details...
I have a hard time believing that this would be a destructive approach. But if one can explain with details...
01-07-10, 08:49 PM
#19
Interesting... thx for the feedback.
Obviously more usage means more wear... if you don't drive the car you don't ever have to replace the brakes!
I'm more concerned with whether the manual mode F is supposed to be driven this way, and whether it would introduce unintended strain on the tranny to manually downshift when slowing down. Otherwise, what you guys are suggesting is that we should always let the computer auto-downshift even in manual mode, and that there is really no use for the downshift paddle unless you are trying to hold a certain gear for power or for going downhill.
Also, doesn't the same wear/tear logic apply to upshifting? Are we suggesting that driving in manual mode period will strain this tranny? Otherwise, can someone explain the mechanical differences for this tranny that makes downshifting more straining than an upshift?
Obviously more usage means more wear... if you don't drive the car you don't ever have to replace the brakes!
I'm more concerned with whether the manual mode F is supposed to be driven this way, and whether it would introduce unintended strain on the tranny to manually downshift when slowing down. Otherwise, what you guys are suggesting is that we should always let the computer auto-downshift even in manual mode, and that there is really no use for the downshift paddle unless you are trying to hold a certain gear for power or for going downhill.
Also, doesn't the same wear/tear logic apply to upshifting? Are we suggesting that driving in manual mode period will strain this tranny? Otherwise, can someone explain the mechanical differences for this tranny that makes downshifting more straining than an upshift?
I understand downshifting manually to ensure proper gear selection on a track or race situation but unless you're better than the car at smoothly rev matching each downshift the potential for additional wear is not worth it. I do a few track days in one of my other cars (manual transmission) and I rev match then. When I drive the same car on the street in "normal" situations I put the car in neutral, take my foot off the gas and let the brakes do what they were intended to do......slow down and stop the car.
Manual mode if used agressively and consistently to upshift (read bringing the car to redline in every gear etc.) can lead to premature transmission failure along with other things. As I said before these are not race cars. Race cars are usually well maintained and torn down and rebuilt regularly to deal with the conditions they are subjected to. In the end we are all free to do as we please with our cars and our money, I choose to let the car handle the downshifts for me. Oddly this is my first car with a automatic, so I'm used to doing my own shifting.
01-08-10, 03:04 AM
#20
Lexus Test Driver
You know you can save your brakes.....
.....by braking harder for a shorter amount of time and not those long, drawn out, brakes to a gentle stop.
Last edited by jkeifer3; 01-09-10 at 05:36 AM.
01-08-10, 07:21 AM
#21
In a nutshell the computer that controls the engine and transmission was designed to do exactly what you (the OP) is trying to replicate manually.The automatic transmisson in the IS F and twin clutches in other cars allow you to shift faster than a person using a conventional manual transmission. Unless you are a highly skilled driver the smoothness of your manual downshifting is not likely to match what the powertrain engineers at Toyota were able to come up with.
I understand downshifting manually to ensure proper gear selection on a track or race situation but unless you're better than the car at smoothly rev matching each downshift the potential for additional wear is not worth it. I do a few track days in one of my other cars (manual transmission) and I rev match then. When I drive the same car on the street in "normal" situations I put the car in neutral, take my foot off the gas and let the brakes do what they were intended to do......slow down and stop the car.
Manual mode if used agressively and consistently to upshift (read bringing the car to redline in every gear etc.) can lead to premature transmission failure along with other things. As I said before these are not race cars. Race cars are usually well maintained and torn down and rebuilt regularly to deal with the conditions they are subjected to. In the end we are all free to do as we please with our cars and our money, I choose to let the car handle the downshifts for me. Oddly this is my first car with a automatic, so I'm used to doing my own shifting.
I understand downshifting manually to ensure proper gear selection on a track or race situation but unless you're better than the car at smoothly rev matching each downshift the potential for additional wear is not worth it. I do a few track days in one of my other cars (manual transmission) and I rev match then. When I drive the same car on the street in "normal" situations I put the car in neutral, take my foot off the gas and let the brakes do what they were intended to do......slow down and stop the car.
Manual mode if used agressively and consistently to upshift (read bringing the car to redline in every gear etc.) can lead to premature transmission failure along with other things. As I said before these are not race cars. Race cars are usually well maintained and torn down and rebuilt regularly to deal with the conditions they are subjected to. In the end we are all free to do as we please with our cars and our money, I choose to let the car handle the downshifts for me. Oddly this is my first car with a automatic, so I'm used to doing my own shifting.
01-08-10, 08:41 AM
#22
On the IS F I'd let the transmission and ECU do what it was designed for under normal driving conditions. In a "race" situation where you want to ensure that the car is in a lower gear needed for acceleration you would manually downshift the car.
01-09-10, 02:14 AM
#24
Okay from what I understand when throttle blipping you only effectively use it if you are braking hard enough for the engine and transmission to freely come down
Besides do you know how much fun it is to brake hard and blip two gears
If you are having the engine brake IMO you're not only wear/tearing the car at an accelerated rate on the wrong parts but you're also missing out on a much more raw experience.
Besides do you know how much fun it is to brake hard and blip two gears
If you are having the engine brake IMO you're not only wear/tearing the car at an accelerated rate on the wrong parts but you're also missing out on a much more raw experience.
