To downshift or not...?

[Oren09]

Doesn't that tear up your transmission?

[Zanzer]

anyone ever do clutch-less shifts? up or down? i do both when im board lol...

I used to do it in my 2.3 turbo Cougar XR-7 all the time and I do it in my Mustang every now and then but the T45 transmission is a little more picky about RPM's. I haven't tried it in my Festy yet....but I've thought about it :mrgreen:

I HAD to learn how to do it because I kept popping clutch cables and got tired of towing it home. When a cable would break I'd kill the engine at stoplights and then crank it in 1st gear to get her going and then just upshift from there. When it came time to slow down I'd just put it in neutral and coast down.

I only use this method for upshifts.



Oren - If done correctly you can't even tell you aren't using the clutch

[sasquatch]

its easy when the have syncros i didnt feel or hear anything bad when i did it... (exept when i fricked up lol) but i wouldnt do it that offten lol... its only when i got bored...

[JohnGunn]

What they said.

Except for this little tidbit:

I read recently that for best mpgs, you should let the car coast down in whatever gear you are in because putting it in neutral tells the ECU to give the engine a little gas to keep it running with no load. When you leave it in gear, the centrifigal force turns the engine and uses less fuel to keep it running. Take it out of gear before the engine starts to lug, then you come to a stop.

Now, if I'm wrong, or wrong for Festiva ECU mapping, someone please tell me. As I said, I just read it in one place and haven't confirmed this. It makes some sense, though.

Karl

I think you're wrong on this, Karl. When you set your idle speed by turning the idle speed adjusting screw you are setting the amount of air that will bypass the throttle valve when it is closed. The only way to control the size of that opening is through the adjusting screw. Once set, it is always open by that amount, not just at idle, but at all times whether the engine is running or not.

The computer can not reduce fuel use below that at which the car's idle is set. The only thing the computer can to that affects idle speed is to increase it when a load on the engine causes the idle speed to fall below the set level.

You can easily test this. Next time you go down a fairly long hill shift to neutral and watch your tach. (This only works if you have one of those.) It will immediately fall to your normal idle speed and remain there. I have a 1 mile coast down the bridge leading from San Diego to Coronado, and I always take advantage of the free ride.

John Gunn
Coronado, CA

[Evil D]

I've always been of the opinion that it was a waste to downshift unless you really need extra help slowing down...but you're basically just dumping fuel for no reason and slowing the car down with the engine/trans. I can't help myself though, most of the time i catch myself rev matching and dropping down a gear going into the apex :lol:

[wybnrml]

If done correctly you can't even tell you aren't using the clutch

Yeah if you do it right it fells like you used a clutch. I used to do it in my 4 speed Festiva all the time, up and down, that is how I drove that one. Once you get used to the car you can shift without the clutch and it shifts like butter.

[bhazard]

I've always been of the opinion that it was a waste to downshift unless you really need extra help slowing down...but you're basically just dumping fuel for no reason and slowing the car down with the engine/trans. I can't help myself though, most of the time i catch myself rev matching and dropping down a gear going into the apex :lol:

Except, like I said in my above post, over a certain rpm the ecu cuts fuel to the engine. If it was dumping in fuel while engine braking you would have black smoke and fouled plugs.

[easywind]

Most of you are thinking about mpg and in doing so you lose control of your car. When you coast, you have absolutely no control. You should ride your car exactly like you would ride a motorcycle.
What if you're coasting and someone cuts in front of you?????
You can't save enough gas to make this practice worthwhile.

[stevewl1164]

I slow down gradually leaving it in as high a gear as possible...right before stopping I put it in neutral and leave it there until the light changes...then I am in fifth gear by 45!

[JPT]

anyone ever do clutch-less shifts? up or down? i do both when im board lol...

Doesn't that tear up your transmission?

See below

Two words. rev matching.

[Festiva_tunner]

anyone ever do clutch-less shifts? up or down? i do both when im board lol...

I usually do 3 4 5 when I do a lot of times I go straight to 5 from 3.

I downshift all the time all the way to second then to first once I'm just about stopped. Its a habit from driving trucks. Engine braking is no harder on the trans then hard shifting unless your going too low too fast. But coasting is the least stressful unless your holding in the clutch then your throwout bearing is still under a load

[bhazard]

Most of you are thinking about mpg and in doing so you lose control of your car. When you coast, you have absolutely no control. You should ride your car exactly like you would ride a motorcycle.
What if you're coasting and someone cuts in front of you?????
You can't save enough gas to make this practice worthwhile.

Dude what are you talking about. Neutral coasting? You still have brakes, and if you've done a brake swap, plenty of them. Second of all for people like me 95% of your driving is two lane roads with low traffic.

If youre talking about engine braking then not only do you have your brakes but also the engine helping you slow down.

All you gotta do is pay attention to whats going on around you.

[getnpsi]

Take a part time job delivering pizzas. When your income is DIRECTLY affected by the way you drive, you teach yourself how to save money and your car. Coast in neutral uphill, coast downhill over 1600rpm in whatever gear. This will turn off your injectors and use less fuel than coasting downhill in neutral. Time your traffic lights and blow by the guy who sped up to just stop at the red. You might be going under 20mph for 1/8 mile but when it hits green you are in 3rd gear and never stopped.

[drddan]

anyone ever do clutch-less shifts? up or down? i do both when im board lol...

All the time. (also known as speed shifting) Been doing this forever on all the sticks i've owned. Doesnt hurt tranny one bit, unless racing and miss the gear! I have broken trannys this way, but i was in my 450 hp Camaro.
Poor tranny!

[JohnGunn]

Coast in neutral uphill, coast downhill over 1600rpm in whatever gear. This will turn off your injectors and use less fuel than coasting downhill in neutral. Time your traffic lights and blow by the guy who sped up to just stop at the red. You might be going under 20mph for 1/8 mile but when it hits green you are in 3rd gear and never stopped.

I agree completely with the importance of timing in making your driving efficient, but the part about coasting downhill over 1600rpm turning off your injectors is news to me. Are you sure this applies to Festivas? In my above post I stated that the idle speed is adjusted by a screw which sets the amount of air allowed to bypass the closed throttle. If you shift to neutral and the engine speed drops to 700 rpm that amount of air will be sucked into the engine for every intake cycle of every cylinder. Since the engine must rotate twice to service all four cylinders, that means at 700 rpm there will be 1400 intake cycles per minute. At 1600 rpm that will be 3200 intake cycles per minute. So, assuming the decent down this hill takes the same amount of time for both cases, there will be 128% more air drawn into the engine at 1600 rpm than at 700.

The action of the injectors is controlled by the computer in response to both the output of the oxygen sensor and the amount of air coming into the engine as measured by the Vane Air Sensor. It injects enough fuel to balance the amount of air that is passing through the engine. If 128% more air is passing through the engine, it would seem to me that it would take 128% more fuel to create the fuel/air ratio that the computer is programmed to maintain.

Of course, this is all theoretical. And to really test this would require one of those systems which can provide instantaneous readings of mpg. And, since we're dealing with Festivas here, it would have to be installed on a stock Festiva. If the source of your statement is from actual readings from such a setup, I will have to defer to you in this matter. If, on the other hand, it is based on pure theoretical speculation, by you or anyone else, then I would need to hear the basis of that speculation before questioning my own.

Do you think you could possibly be wrong on this?

John Gunn
Coronado, CA