C.J.

I was just curious to see how many of you guys out there who drive the 6-speed cars. Downshift them when coming to a stop? I do quite often, always rpm matching. Anybody seen any negative effects on their cars from this?

777

iTrader: (21)

i do it occasionally but not very often...the only thing i can see is clutch wear (even if you do rev-match) and higher gas consumption...shouldn't neccasarily be a bad thing

txhorns281

iTrader: (12)

it's good in some cases, but it should be obvious that it adds to the "wear and tear" list...

BlueSix

If you are of the gas (decelerating, downshifting to slow) your fuel economy is not decreased with increased RMP's.

Here's something to think about when downshifting to slow down.....which is cheaper to replace, a clutch or brake pads? That's why i don't downshift to slow down.

777

iTrader: (21)

good point, are you sure about the gas part...that almost doesn't even make sense...is this just your theory or is there a place i can read about it

BlueSix

When an engine is not under load (i.e. decelerating, or engine braking) fuel is barely comsumed. In my GTO i have an instantaneous fuel consumption gauge (it's a pretty pimp feature, you should see how bad accelerating is on gas mileage), when i'm in and gear, and get completely of the gas, the instantaneous mileage goes to 99.9 mpg. It will do this regardless of vehicle speed or engine RPM. 4000 rpm in second gear under no load, 99.9 mpg; 2000 rpm in 6th under no load, 99.9 mpg. first gear casually accelerating, 3 mpg. 6th gear accelerating from say 65 up to 70, it will drop from about 25 to 10, then level out when i go back to cruising. I could take a 40 mile trip down the mountain my uncle lives on, and only use 1 gallon of gas (40 mile trip), but i will use 3-4 gallons to get back up that same mountain.

777

iTrader: (21)

very interesting...thanks for the info

NBM2k2SS

iTrader: (2)

I normally just keep it in the gear that I am in untill I almost come to a stop then I push the clutch in and put it in neutral, I only downshift when I want people to hear me

98Z-6Speed

I always have downshifted manual cars, thats how I was taught and I thought thats the way the cars were designed. In an auto your car downshifts for you to help save the brakes. I have never replaced a clutch in the three manuals I have owned or done any transmission work. 110,000 miles, 89,000 miles and 48,000 miles on each. I have only had to have the brake pads replaced on the 110,000 car, the other two no brake work.

LSWannabe

I have to believe, to some extent, that rev-matching while downshifting will consume more fuel than if you dont down shift at all. You have to use gas to rev-match, I dont think it's revving on air alone.

BlueSix

the ammount of fuel consumed by rev matching while not placing a load on the engine would not even be noticed....we are talking less than 1/100th of 1 mpg. It might drop you from 20.01 mpg to 20.00.

LSWannabe

So you're saying that, to some extent, that it DOES consume more fuel. I KNEW IT!!!!

BlueSix

bastards.

txhorns281

iTrader: (12)

depending on your DFCO (Deceleration fuel cutoff) setting is whether or not your fuel consumption is conserved or expended... engine load keeps the motor vacuum but with the TB shut, the lack of airflow is matched with reduced fuel so that deceleration occurs while in gear... With that said... this "load" is primarily transfered to the drivetrain and therefore reduces the lifetime of associated parts...

z98

Nope.

The only auto I've been in that had any compression breaking (without manually shifting) was a 4:1 geared 4x4 with 3.73 gears.

So no, it doesn't.

No. The TB is closed, no fuel is being added except what would usually be added at idle.

And engine braking wears your engine faster, shouldn't be hard on the clutch at all.

I for one will get some use out of those big *** brake disks I have.

SSCoulter

iTrader: (4)

I do it every once in a while just to hear the Loud Mouth.

99FormulaM6

iTrader: (21)

i do it sometimes if i need to slow down in a hurry

LSWannabe

When you're approaching a stop you let off the gas, hit the clutch and move the shifter to a lower gear. You then must press the accelerator(open the TB) to make the engine rev to match the RPM that it will be operating at when you engage the clutch for the lower gear. This will consume more gas than if you merely decelerate in neutral (clutch depressed).

There's no way that it will slow you faster than your brakes. Unless perhaps you are doing something bad, very bad.

99FormulaM6

iTrader: (21)

well i guess i wont do it anymore. lol. if these people on here are downshifting to help save the brakes, how would downshifting when already on the brakes not help you to slow quicker?

hothugger99

bout the only downshifting i do is going down in gears while the clutch pedal is to the floor. the clutch cost more than brakes, along with more time consuming. sometimes i do shift through the gears without the clutch, its very easy on the camaro m6.