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Hi folks,

I recently purchased a 2012 Chevy Cruze Eco. This is my first vehicle with a manual gearbox. One problem I'm having is determining at what RPM & speeds I can downshift. It seems like I can downshift 4 -> 3 between 15-20 mph with no jerks a I do it but I'm too nervous to test the other gears because of transmission and engine damage. Does anyone have a table or guidelines for what RPM & speeds it is safe to downshift to for each gear? I tried searching the forums but could not find any table or guidelines for downshifting for this model.

I would greatly appreciate it.

Thanks!
 

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I very rarely downshift to 2nd and never to 1st. The ratios just don't allow it without over-reving the engine.
 

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Firstly, welcome to stickshift-dom. :D IMHO you'll only drive a stick shift really well when you learn to drive by feel, not numbers. Each different hill, light, passing maneuver, etc. will call for a different combination of engine speed vs. gear position. Knowing where your car produces power, when you need it, and how much of it you need will begat a mastery of driving it. Now, as engines go the Cruze 1.4 has a pretty dynamic? power curve - no power below 1,800 RPM, peak torque (that firm, positive force that gets you up a hill) around 2,500 RPM, and horsepower up above 4,000 RPM.

Your Eco is geared differently than my 1LT, but not so drastically that none of what I can relate as a 1LT driver won't apply to learning your Eco.

When you say downshift, I assume you're referring to clutch-braking or compression braking - downshifting and letting the clutch out which in turn spins the engine up and assists in slowing the car. Yes? In that respect, X2 on what blancmange said - Cruze's first and second gear ratios are slow enough that it's really not effective to use them to clutch-brake. For the other gears, it gets back into a matter of the dynamic of "what you need in what circumstance". If I'm having some fun and rolling up on a 35MPH curve at 65 and want to keep as much speed as possible through the curve, having been in 5th beforehand I'll go to 4th (which spins the engine up in the 4,000 RPM range at 65) and either pull through the curve in fourth or, if I want to get even more aggressive, go down again to 3rd after the halfway point in the curve. At that point let's say I'm down around 45 MPH so the engine is perfectly positioned around 3,500 RPM? to spool back up fast, be well up into the meaty horsepower range, and pull back through 5K or so as I come out of the curve and go back into fourth or fifth.

In normal driving I rarely engine-brake - at most I'll bring the engine speed up to meet whichever gear I've downshifted into, but if I'm going to be coming to a near-complete stop I just put the clutch down and coast all the way to a stop. Several of my friends make a habit of downshifting in all circumstances, but my own idea is that it's cheaper to replace brakes than clutches and motor mounts which both take more abuse when clutch-braking.

Unless you've already gotten the memo about the lube in your manual transmission, make sure it has Amsoil synchromesh fluid in it. I use the standard stuff, but many use their 75-90 grade with just as much success. I've made enough boo-boos over my car's 93,000 miles (and taught my wife to drive stick on it) that if it was terribly fragile something would've happened, so don't be unduly afraid you're going to break it. Of course, don't just slip your foot off the clutch all at once - that would break even the best transmission. But within reason I don't think the M32 is terribly weak. Launching at 3,500 RPM>6,000 before shifting out of first, hammering second and actually getting the tires to bark a little in the process hasn't torn it up - not constantly, but probably a dozen times over its lifetime.

Above all, learning to interpret the car's feedback and adjust accordingly is what will make you the best driver.
 

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You can safely downshift to 1st gear once your engine speed in 2nd is 2,000 RPM or lower. I tend to downshift to keep my car in DFCO as long as possible.
 

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Downshifting as a way of engine braking? I do it sometimes but not usually. If the light is expected to change to green, I might do it to be ready to go again. If I'm descending a long grade and need braking, then definitely. Should always be safe if the RPMs in the next higher gear are well below 1/2 way to redline. For me, driving around here where it's pretty flat, I mainly use it well below even that. As a way to ensure I don't overheat my brakes in mountain driving, I'd be a little more aggressive.

Don't ride the clutch. Holding the pedal for long periods wears on the release bearing. When you're coasting down to a stop, leave it in gear until the engine approaches idle speed, then declutch, put it in neutral, take your foot off. Don't put it into 1st to start up again until the light is about to turn green.

Rev match on downshifting. When downshifting, rest your foot on or blip the gas pedal to increase engine revs to match the speed for the new gear. Saves wear on the synchro rings and other components. You'll notice the transmission gives less resistance to downshifting when you do this. Doesn't have to be perfect; you'll get the feel for it as you gain experience.

Enjoy your new car!

Edit: Agree with Camcruise. Don't want to or need to watch the tach when you get used to it. Should always be watching the road, anyway.

It's been a struggle for me to get used to the torque/power behavior of the Gen2 1.4T. Some of it is the computer 2nd-guessing my throttle inputs, I'm sure. This is my first throttle-by-wire car. I wonder if the turbo wastegate was initally a little sticky, too. Or something. Hopefully we'll all come to an agreement soon.
 

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I would recommend you go by feel. A manual tranny is all about feel. The Cruze has one of the easiest manual trannies to drive. The more you drive it, the more you will know when it is the right speed to downshift or not. The only gear you can really go wrong with is 1st because if you try to go into 1st at a too high rpm, it will grind a bit. It is best to be at a stop or nearly at a stop to go into first.

I have been driving mine for a long time, but still not perfect at downshift and getting that "perfect shift". So don't beat yourself up...enjoy it and just trying to improve as you go.
 
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You'll get a feel for it with time. Rev matching will help smooth downshifts. Bump the throttle with your brake foot to what you think is an appropriate RPM (you'll learn with time), let go, and change gear.

I would never do a 2-1 downshift unless you're nearly stopped. Very hard on the synchros. 2nd is useful for holding speed back on long, very slow hills.

Like someone else, slowing to a stop I'd generally just clutch in. Less wear on the clutch disc
 

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My 2ct would be to downshift into neutral, and only shift into gear when you're about to accelerate.
You can lessen the jerky shifts, by gently adding some throttle.
I do this on my manual- automatic from time to time, when I am cruising in neutral, at about 50mph, I bring it to 2k RPM, or as close as possible.
The engine usually revmatches quite easily. Most of the time the revs around that speed are 2.25k RPM.

Engine braking?
I would rather wear out the brakepads, than the clutch.
You can engine brake, between 2 and 4k Rpm Just fine.
But the reduced brake friction may cause you to be too gentle on the brakes which over time causes glazing on the pads, as well as increased clutch wear.

Just stay in gear until rpms are below 1.5k RPM, and then just go to neutral.
May the jerk be small on you!
 

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Put your car in first gear, rev up to 2,000 rpm, read your speedometer, and either memorize the speed or write it down. Do this for all the gears, sixth will be roughly around 60 mph.

From here, its all ratio, divide any rpm by 2,000, get a quotient, multiply this times the speed you got at 2,000 rpm. Can make your own table.

Ha, can't even count the number of vehicles I owned before getting an AT, every vehicle prior to 1949 had an MT. 30 Olds, Buick, and Ford did not have synchros, had to double clutch these things.

With the Cruze, can put it in first gear at 80 mph, but you sure don't want to release the clutch.

Can't even buy an MT car anymore unless you get the base model, what's with America. Ha, in Italy and other countries, if you want to rent an AT vehicle, have to do this three months in advance and pay $$$$ extra.

What turned us against buying a 2011 Eco with an MT, could not get a spare tire unless you purchased it with an AT. What idiot marketing guy came up with this? Like GM a heck of a lot better when it was ran by engineers, but going way back to the 60's.
 

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The "no spare tire in the eco 6M" was an engineering decision, to lose as much weight as possible to get the EPA 42 MPG.

The "no spare tire in the LS" was a beancounter decision.
 
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