Chevy Sonic 1.4L Engine Torque Curve

[ChevySonic113]

Does anybody know the torgue curve for the 1.4L Turbo engine when it is mated to the six speed automatic transmission. I know that it develops 148 lb. ft. of torque at 1,850 RPMs. I also know that it will maintain the 148 lb. ft. number into the 4,000 RPM range, but at what point in that 4,000 range does it start to drop off (i.e., it starts running out of twisting force)?

I read about this in one of the car magazine reviews last year, but cannot find it now. The discussion was centered around the six speed manual and why it was a wasted effort to take the engine into its higher RPM range.

That same discussion would also apply to the engine mated to the automatic.

Help!

 

[2013sonicblk rs]

I have heard about 5000 to 5200 rpm makes a good shift point auto or stick really seems to run out of steam after that

 

[ChrisJ]

Does anybody know the torgue curve for the 1.4L Turbo engine when it is mated to the six speed automatic transmission. I know that it develops 148 lb. ft. of torque at 1,850 RPMs. I also know that it will maintain the 148 lb. ft. number into the 4,000 RPM range, but at what point in that 4,000 range does it start to drop off (i.e., it starts running out of twisting force)?

I read about this in one of the car magazine reviews last year, but cannot find it now. The discussion was centered around the six speed manual and why it was a wasted effort to take the engine into its higher RPM range.

That same discussion would also apply to the engine mated to the automatic.

Help!

I constantly use 5th and 6th gear on my commute. Every gear ends up being the sweet spot often so I do not see it being a waste. The car was designed to be fun yet achieve impressive MPG numbers and that is exactly what it does.

 

[sx sonic]

There have been a few dyno charts scattered around the forum of stock and tuned 1.4t's. Unfournately they are hard to find and some of the links have disappeared.

Stock this engine starts falling off the power curve at around 5200 RPM. Tuned and with some intake plenum porting this engine continues to pull all the way to redline.

Not sure why having six speeds would be a waste. What would be different with a 5sp or heck even a 3sp? The extra gears aren't there for "2 fast 2 furious" driving. They simply allow a very tall final drive in top gear (read best mpg) and have even ratios between 1st and 6th (read even rpm drops between shifts).

IMHO a 5sp would be great in this car. Taller 1st gear, taller 2nd, 3 & 4th about the same ration and a Dth gear way taller than our current 6th gear. But the typical turn key driver would have complaints and questions about the tall 1st gear and huge jump to 5th because they don't understand the functional rationale behind it.
Hence why we have a 6sp

 

[$ub$onic]

I will say in mine I wish it had a 6 speed. She is spinning a little fast at 70-75

 

[Eric Smit]

it's close to full torque from 2000-5000 RPMs.

 

[Swordsmith]

You're reading the point backwards, it isn't that the six speeds are a waste, but rather that you should shift into higher gears sooner, because it's supposedly a waste to run up to the top rpm in each gear before shifting.

I don't necessarily agree, but that's the opposite of saying you want fewer gears.

While there have been some charts posted, the fact is once you start modding the car, all bets are off on those charts anyway, ideally what you'd want is to make your own chart for the car you're driving.

There is certainly something to the idea itself; you don't want to shift too early and lose power by dropping into the low torque end, but you also don't want to shift late if you drop out of your high torque range by doing so. Where (and even if) that happens, though, is based on your tune and other mods; some are even looking at moving the rev limiter up to 7000 because they aren't seeing torque fall off at all and are just hitting the built in hard line.

All things being equal you'd be better off staying in first all the way to 200mph, if your engine could rev that high and keep building torque.

 

[vmaxed]

Does anybody know the torgue curve for the 1.4L Turbo engine when it is mated to the six speed automatic transmission. I know that it develops 148 lb. ft. of torque at 1,850 RPMs. I also know that it will maintain the 148 lb. ft. number into the 4,000 RPM range, but at what point in that 4,000 range does it start to drop off (i.e., it starts running out of twisting force)?

I read about this in one of the car magazine reviews last year, but cannot find it now. The discussion was centered around the six speed manual and why it was a wasted effort to take the engine into its higher RPM range.

That same discussion would also apply to the engine mated to the automatic.

Help!

Here is a dyno chart from Vtune.

 

[ChrisJ]

Isn't hard to find a stock one.
They are at gmpowertrain.com

Regardless of torque you have peaked hp or close to it until about 6K looks like.

 

[Macehammer]

You're reading the point backwards, it isn't that the six speeds are a waste, but rather that you should shift into higher gears sooner, because it's supposedly a waste to run up to the top rpm in each gear before shifting.

I don't necessarily agree, but that's the opposite of saying you want fewer gears.

While there have been some charts posted, the fact is once you start modding the car, all bets are off on those charts anyway, ideally what you'd want is to make your own chart for the car you're driving.

There is certainly something to the idea itself; you don't want to shift too early and lose power by dropping into the low torque end, but you also don't want to shift late if you drop out of your high torque range by doing so. Where (and even if) that happens, though, is based on your tune and other mods; some are even looking at moving the rev limiter up to 7000 because they aren't seeing torque fall off at all and are just hitting the built in hard line.

All things being equal you'd be better off staying in first all the way to 200mph, if your engine could rev that high and keep building torque.

Swordsmith, and everyone else.

Your last comment is insanity, and no one should ever try that. And from an fuel efficiency perspective it makes absolutely no sense.

 

[Eric Smit]

I think you do want to shift early. I haven't gone over 1500 RPMs on this tank yet except for my 55 mph highway drive, and my MPG is looking great. you'll see when I post it.

 

[$ub$onic]

My mounts shake at 1500 rpm. I avoid it

 

[ChrisJ]

My mounts shake at 1500 rpm. I avoid it

That's cause you have a 1.8.

I often run at 1000-1500rpm with the 1.4.

 

[$ub$onic]

Must be nice run that low

 

[ChrisJ]

Must be nice run that low

The 1.4 at 1200rpm

Dumbo Casey Jr I Think I Can - YouTube

 

[sx sonic]

Short shifter for life.

There are several reasons why short shifting improves MPG

1. BSFC (brake specific fuel consumption) is better in the low RPM range
2. Friction. As the rpms go up so does internal friction and windage loses. These require power to overcome, power that could have been used to propel you down tthe road.

Those are the biggest reasons, BSFC is really intriguing and i something I recommened researching.

 

[ChevySonic113]

Thank you "2013sonicblk rs" and "sx sonic". I am glad to know that 5,200 RPM is the top RPM for this engine's torque output before it starts dropping off. For the automatic transimission equipped cars, this is a good/broad torque curve (148 lb. ft. from 1,850 RPMs to 5,200 RPMs) in any gear.

FYI: Therefore, going beyond 5,200 RPMs in any gear means that the engine is getting beyond its useful power range and therefore its time to think about upshifting to the next higher gear.

I am a new member to this forum. I am glad I joined.

 

[Eric Smit]

For a stock car, it might be good to shift at 5200. If you grind out the intake runners, you're good to redline.

 

[ChrisJ]

For a stock car, it might be good to shift at 5200. If you grind out the intake runners, you're good to redline.

If you look at the stock power curve shifting at 6k should be perfect as you want to stay in your peak area which is 5 to 6K. Yea, torque starts dropping off but it makes up for it with rpm. Shifting at 5200 would result in a pretty big drop in power when you go into the next gear.

 

[River_Rat]

I agree with Chris on this one. also, what is important is the horsepower in the destination gear. if you shift too soon then you are missing out on available horsepower at the bottom of the next gear.

that being said, I personally don't redline all that often because I don't have a racecar.