2011 Chevrolet Cruze: Hot Weather MPG Part 2

It just proves what a bad decision to put this engine in a mid priced compact sedan. Why would anyone want to go through all that crap? Why not just put in a nice NA engine that runs fine on 87 ALL the time and call it a day? Stupid Stupid Stupid.

premium is recommended for the Regal, I would think that is why Erin used it.

this makes me a happy camper, my car is doing 26.5 atm, 150 miles in. Probably 70% highway 30% city.

stov, the Regal kind of disproves your argument, if the turbo mills were built for the EPA test and no real world.....how did it beat it's EPA numbers? Just sayin' no arguing or being defensive I don't think.

Now you have to drive the Cruze to Vegas and back on 91 octane, to confirm the hypothesis. Darn the luck.

Very, very, interesting. It's a shame JKav couldn't have done Le Mans updates for Straightline. That would've been very cool. Ah, well, something to keep in mind.

In any case, that's a great explanation, and just the sort of thing that makes the LTRTB great. Looking forward to JKav's sciency graphs and things.

I do agree that the EPA's silly fuel economy shenanigans seem to lead to carmakers trying to "beat" or "game" the system, rather than trying to make truly efficient cars. What this leads to is a car that does well in the EPA tests and looks great on paper, but doesn't work as efficiently in the real world. Part of this is the silly CAFE regs. Vice versa you have the Regal, which does poorly in EPA testing, but on Erin's road trip got better than rated highway mileage. I do believe that cars need to become more efficient, but the government setting arbitrary and mandatory targets is not the way to do it.

On another point, I wonder whether VW's 1.4L TSI engine suffers the same problems, or if this is just a GM engineering issue. If the same problem does affect the VW engine, that could explain why it's only offered in Europe (no desert climes, the hottest is probably the SoCal-like weather in southern Espana) and we still get the old inline 5 in cars like the Golf and Jetta. Anyone have any ideas on this?

"Why not just put in a nice NA engine that runs fine on 87 ALL the time and call it a day?"

+1.

Instead of offering both the 1.8 and 1.4T I think it would've been better if Chevy was focusing on just the 1.8L and made it class-leading in both performance and fuel economy.

@ dracy

I think the EPA tests are set up in a way that is rather unrealistic. I mean, the Cruze is set up to get great EPA numbers (because EPA mileage is a great selling point). On the other hand, you said that the Regal's gearing means that EPA tests will rarely hit sixth gear (where the fuel econ benefits are). So that means that the test is unfair to the Regal and it performs poorly. OTOH, the Cruze doesn't perform as well as the EPA says it should in the real world. Whereas the Regal outperforms EPA estimates.

Silly EPA people...

Oh, and I wonder what sort of movies were sold at the "Original Truck Driver's Movie Store."
Not G-rated I imagine. Or even PG13...

"stov, the Regal kind of disproves your argument, if the turbo mills were built for the EPA test and no real world.....how did it beat it's EPA numbers? Just sayin' no arguing or being defensive I don't think."

In a way, yes it does but what it also demonstrated is that in these conditions, a small turbocharged engine can probably only make the sticker numbers with 91 octane. So you save money by running an engine like this on 91 octane versus 87, but you'd save even more money on an engine that could run fine and meet or exceed the sticker numbers on 87 octane regardless of the weather.

Many enthusiasts (myself included) don't mind putting premium in our performance machines, but the average car owner buying a car like this to commute in (particularly one with such anemic engine performance anyway) might not be too keen to go for premium gas.

@ stovt

Hell, many won't even know to put premium in to get the sticker mileage. Unleaded is unleaded, right?

The technical explanation makes perfect sense to me. If I use 89 octane in my S60, it will not take full throttle without obvious ECU intervention when the ambient temperature is over 100°F. It runs fine on 89 in the winter, but even then I still get better gas mileage with 91.

So which one was the Cruze using while performing the EPA test, 87, 89, 91 or 93? Can we get an answer for that? Does anyone know?

"Many enthusiasts (myself included) don't mind putting premium in our performance machines, but the average car owner buying a car like this to commute in (particularly one with such anemic engine performance anyway) might not be too keen to go for premium gas."

+1000

GM has come so far in the past few years but this just shows that they arent quite there yet. An economy car needs to run on 87 and run well on it, ALL OF THE TIME. So I have to look at the weather report before I go get gas in my Cruze?? Give me a break.

"In a way, yes it does but what it also demonstrated is that in these conditions, a small turbocharged engine can probably only make the sticker numbers with 91 octane. So you save money by running an engine like this on 91 octane versus 87, but you'd save even more money on an engine that could run fine and meet or exceed the sticker numbers on 87 octane regardless of the weather."

Just pointing out, the Regal, at a 70+ mile an hour average speed in very high temps with the a/c running the whole time and some traffic out paced it's EPA numbers. You make it sound like the car just barely met it's numbers under ideal conditions. It beat them regardless of the conditions.

The Cruze fell pretty far short, running on the recommended fuel too. No engine runs the same in all conditions, humidity, altitude, temperature, and fuel were always factors for fuel economy. And most cars don't beat there EPA numbers anyway.

Louis, I would think EPA would use the recommended/required fuel right?

@stovt001

Even http://www.fueleconomy.gov/feg/why_differ.shtml says YMMV and says "EPA ratings are a useful tool for comparing the fuel economies of different vehicles but may not accurately predict the average MPG you will get..."

I suspect most people don't realize this nor know what goes into the tests.

Can you imagine the vitriol some of these posts would have caused just a few days ago? Good lord!

I think intercooler location plays a role as well. From what I can tell perusing the Cruze forums, the intercooler is placed _between_ the AC condensor and the radiator. This sounds like a recipe for thermal problems in hot climates where the AC is running non-stop. You're preheating the air before it gets to the intercooler, which is pretty small to begin with. I guess if you're putting AC performance before engine performance, that's fine, but given the charge air temps associated with little turbos pushing big airflow (relatively), it seems like a mistake to me. I still prefer this to a side mount setup with ducted airflow, but a true front mount is usually best (unless you want to do a V-mount - tasty).

I can't find any info on the Regal IC location, but if its like the old Cobalt SS setup which uses a similar engine, its a true front mount which would handle heat much better.

Yeah, I think it's safe to say the midget Ecotec was a fail, Ecotastrophe, catastroTec, etc...most reviews have called this engine/tranny the lowpoint of an otherwise nice vehicle.

You know what's scary here: GM had a similar problem with the LLY Duramax. I wonder if the same high temp testing people did the 1.4T. Intercooler between the A/C condenser and radiator, just like the Cruze. Hey, don't want to lose that cold A/C! As intake temps heat up, power drops off, and the variable vane turbo does its thing to really get that compressor going. This heats the air more and the closed loop system just starts a bit of a runaway. This was what the LLY did in extreme conditions. Not so good when towing.

They have since licked those problems (circa 2004-2005), but sheesh.

kev, the only problem I have ever really seen with the Duramax was fuel injectors.

But that's one of the reasons GM is now getting more vigilant with tracking ECM changes. The Duramax was one of the first engines to get it I think. Guys would chip the trucks, then be all surprised when the extra 200HP they just added and the various drag races with every Mustang they could find would blow head gaskets and/or pop injectors.

then you uninstall it and get it covered under warranty B-)

I know, we did it.

Someone on here told me about the GM ECMs tracking the last 10 tunes. Vince at Trifecta told me about it also and has a loophole for it but there is always a risk of course.

This engine makes a great business case for GM. It is cheap to make and plays the EPA game very well. The biggest automakers are the best at playing the game that is why so many people hate them. Ususally you see these manufactuers ostracize some of the enthusiasts to get bigger sales. I don't think there is anything wrong with this strategy.

I'm really not sure why so many people hate on the little cruze. It is a handsome little machine, and it was made to woo the average consumer not the enthusiast.

If you must buy a four door sedan with enthusiast flair its obvious this car wasn't created for you.

And for the record every car doesn't have to be for enthusiasts.

I hate Hybrids, but I'm beginning to understand their appeal in a 100% logical way. I just hope they don't smother the enthusiasts.

So, don't go anywhere with 110 degree weather... Got it!

"GM also has a tendency to overbuild their transmissions, ESPECIALLY in their performance cars"

I dont know about that....Go back and look at the horrible problems IL had with its LT Silverado's transmission (had it in the shop several times then it finally crapped out and had to be towed) ....then the LT Camaro was out of service for almost a month with a failed trans (had to be rebuilt).

SO I am not sold on GM transmissions being "overbuilt"

Nice picture of the Cruze. The exterior styling of this car is really growing on me, especially dressed up in white. I prefer classic designs like this more than some of the overstyled designs we're seeing these days (e.g., Sonata).

In my personal experience they are, vince from trifecta performance agrees. Take it how you want.

I think GM still makes pretty decent RWD automatics. My wife's old 528i had one as does her X3 truck. At 116K it's still going strong, although I'll note that I change the ATF twice as often as the service schedule calls for.

Regal recommends premium, Cruze does not.

If Cruze had a NA V6 or V8 it wouldnt have this issue as others have noted. Can't understand what GM was thinking.

Camaro's manual is built by Tremec, not GM.

Being a Phoenix native, I know all about the desert heat. The only turbo I want is on a diesel. The heat just kills performance on boosted gas engines. I agree with others here about have an NA engine that runs on 87 for an econo box. 91 for a performance vehicle, no problem.

dracy, the 4L60E as used in the V8 trucks and SUVs was one of the worst transmissions ever from a reliability standpoint - far exceeding the Honda 5AT debacle IMO. From about 2002-2005 they had a massive failure rate due to weak input sprags and sun gears. I know, our Tahoe's failed at 37,000 miles stranding us 500 miles from home. To GM's credit, they covered about 90% of the cost, hotel and rental car even though we were officially out of warranty. Unfortunately, it failed again at 55,000 miles on our Tahoe and we had to eat it - I went with a performance build. Sad thing is, the truck was totally stock and we didn't even tow with it. If you visit some of the truck and SUV forums, some informal surveys were done and 30-40% of owners were having some issue.

We've owned GM trucks for decades (and many GM cars up until the mid-80s), and our joke was that the body and interior may fall off around you, but the engine and transmission would run forever. After the Tahoe experience, we don't say that anymore.

"Regal recommends premium, Cruze does not."

Thanks, if that's the case then Chevy would've used 87 for the EPA testing.

Does EPA actually reveal which grade of fuel was used during the test? The reason I am asking is because it looks to me that the 1.4T was optimized for 91, not 87. So if Chevy used 91 for EPA testing but doesn't even recommend it then the owners would never get the optimized performance out of the car they purchased.

Cars are tested by EPA with recommended fuel. OBviously Cruze runs on regular due to the fact that its an inexpensive car and all competitors run on regular.

A turbo engine may have issues in heat, a NA engine will choke at altitude. Each design has deficiencies and perhaps turbo equipped cars arent ideal if you live in the deserts of NV or AZ.

Church, I'll give you that. but I didn't know they put the E in the tahoe, I thought it was the H like the impala ss.

Knock on wood, all of our 4L60's have held up.

My friend's s10 blew up his 4l60E but he is also lifted 10 inches and riding on 39's

Just kidding I'm mis informed :)

4L80 was the answer I was looking for but the impy still had the 60

What year was your tahoe?

4L80-E was reserved for 3/4 ton and up platforms. It was a good trans, though. Refined shifts, durable for heavy use.

The sad thing about the 4L60/65/70-Es in trucks is that they failed WITH torque management control. The design was never meant for heavy vehicles with a lot of power. It even started to become a bit of a debacle when the LT1s were introduced to the B-bodies in 94. Meanwhile, my 93 Caprice 9C1 has the hydraulic varient, the 4L60, and that car has 265k. Shifts a little soft at WOT, but you know what, that's exactly how it shifted at 113k when I bought it 10 years ago. I haven't been easy on it either. But the throttle body V8 isn't really giving it a huge challenge, either, and I think that's the whole point.

It's obvious GM made a conscious decision to use this engine to get exceptional fuel economy (42 mpg highway IS exceptional for a non-hybrid, non-diesel) at the expense of driveability under certain circumstances. It's not a design flaw, nor is it ignorant engineering. GM's engineers do the same hot weather testing other automakers do; they undoubtedly encountered this same problem. Even the engineer Dan spoke with admitted that they were aware of the problem, and that a solution is to run higher octane. Big deal.

I think we need to consider that ALL turbo 4's or current turbo engines in general don't have the heat traits of the Cruze's engine so let's not put all of them in the same category.

What I don't understand is how this engine has this trait given all the testing that goes into the development of the drivtrains in various climate types and temperatures. I know that most Cruze owners probably won't experience this but I see no excuse for the oversite. It seems this drivetrain has potential it just needs a bit more refinement and development.

Insideline, I'd like to see other turbocharged vehicles from various brands cover the same trip with similar temps to see who has better execution in terms of driving in high temperature climates.

I'd also like to see a fuel economy comparison between all the compacts like the Civic, Cruze 1.4t, Mazda3, Corolla, Elantra and Focus. I know MotorTrend or Car&Driver recently did that test and found the Civic to be the most efficient in the real world and the quickest in various acceleration test yet the car got blasted here because its drivetrain is inferior and doesn't have the latest technology like DI or a 6at. Those here who blasted the car fail to understand Honda's philosophy of doing the same or more with less.

The torque management made things worse for those trannies so I've heard, my impala went 120k with torque management removed via power programmer.very hard shifts but they were fast.

green point, this car isn't rated for 42 mpg, the eco is.

B-bodies had no torque management. But they were heavy cars, with really tight torque converters (something like 1300rpm stall!) and 3.08 gears (or worse), plus a wide 1-2 ratio spread means the trans has a tough life.

You can increase the line pressure via PCM calibration, though. I did that in my Fleetwood (LT1, 4L60-E) when I had it, but I never got it to feel right, so I put it all back to stock.

Well I'm batting 1000 aren't I

The lt1 made plenty of torque though, it only red lined around 5500.

We had a jeep wrangler with a zz4, turbo 350 3500 stall speed riding on 36 inch fun countries

That was a monster in 4 lo

someone from Phoenix said that turbocharged cars are known for these kinds of issues and he wouldnt buy one unless it was a diesel. It sounds like this performance/efficiency loss is endemic to turbocharged vehicles with small engines when temps are very high. One thing is for sure, you can expect to see more turbos in the future, not less. Ford is working on a 1.6L turbo to replace some of its NA larger fours.

I had a hyper tech programmer, also allowed me to change fan temps, shift points, speed limiter (bye bye lol), standard stuff really. My mom's Trinity is cool, it has a full range of telemetry along with tuning, I don't think my trifecta will have that.

"green point, this car isn't rated for 42 mpg, the eco is."

I know. (I assume you meant me). Do you think the Eco won't suffer from the same cooling problems as the non-Eco 1.4T?

Yea, auto correct is to blame for that.

and I suppose it would, but when you said "this car"I was all like "hold up"

This cruze is rated for 36 if I remember the op correctly

We had a 2002, which, unfortunately, got totalled a few months back with only 68k miles on the odo. Despite the issues with the trans, we were really attached to it, so we replaced it with a pristine 2003 model that had already had some upgrades done to the trans. It also has the factory 3.73 with a locker at the rear vs. the open 3.08 we had on the old truck. This would seem to make life a lot easier on the trans (not to mention it is much quicker, with no measurable fuel economy penalty to date).

Back to the Cruze though, someone mentioned that all turbo cars have issues in high heat. I say, anecdotally, not so. My EvoX, even with the stock intercooler pushing a lot more power than stock, had no issues in Phoenix or Las Vegas in the middle of summer. A little slower? Sure, hot air makes less power. But even with the AC on full, leaving the line wasn't a chore.

Its a heavy car with a small engine, plus a turbo for those that need more performance occasionally. This means that if you take it easy you will get exceptional MPG, but the moment you step on the gas to pass that semi then your MPG dives as the turbo kicks on.. so if you slow down you will come out ahead, if you drive at a higher performance level then you would have been better off with a different car.

GM tailored the engine/turbo size for the EPA cycles (its a cynical belief, perhaps not), but those cycles are not that pansy, they use 0.2g acceleration.. so its fairly brisk. I think its the appropriate choice for this car.

if you need a bit higher octane but dont want premium, try blending in some E85, start around 20%.

"church123 says:
Back to the Cruze though, someone mentioned that all turbo cars have issues in high heat. I say, anecdotally, not so. My EvoX, even with the stock intercooler pushing a lot more power than stock, had no issues in Phoenix or Las Vegas in the middle of summer. A little slower? Sure, hot air makes less power. But even with the AC on full, leaving the line wasn't a chore."

Is it safe to assume you weren't running 87 octane?

"I had a hyper tech programmer"

I have TunerCat. Yeah I need a laptop but I can change....well, everything. Still haven't put HP Tuners for the CTS-V in the budget though...

If they would redesign it with direct injection, I presume they could really put a dent in getting rid of this issue.

No froggersjc, but I was running about 28 psi of boost compared to the 14 psi on the Cruze, producing about 3x the hp, with a lower compression engine, in an AWD car that weighed nearly 3600 lbs. So, if anything, you'd expect the Evo to suffer even more. But you know what? It has a big, honkin intercooler sitting right out in front of _everything_ to get as much airflow as possible. Point being, it isn't a turbo thing, it's a design choice thing. And the GM guys chose to prioritize something else over charge cooling - not a good idea on a turbo car.

What are the chances of somebody in the aftermarket business bringing out a Cruze intercooler relocation kit. If it is as reported, between the A/C condenser and the radiator, you are royally screwed in hot weather.

As for turbos in NV an AZ, there are ideal for the mountainous terrain provided they have enough space under the hood to avoid heatsoak. My S60 gets away with it, probably because it is the LPT 205hp motor so it is pretty understressed. On the higher performance motors I am not so sure. It will be interesting to see how the new long-term S60 deals with the ride to Las Vegas. Let's hope Edmunds do a run soon while it is nice and stupid hot in the Mohave.

My '07 GTI has the intercooler between the radiator and ac condenser. I have only had to put 87 octane in it a couple of times, but it had no problems coping with the 100+° heat at that time. It did feel slightly less peppy, so I decided premium was the way to go unless we run out of gas in Charlotte again. I was still fairly impressed as my car has a fairly high pressure turbo and a crazy high 10.3:1 compression ratio. I expected much more power reduction.

If GM added DI to the 1.4T that would cool the cylinders and stop the detonation issue in the desert. But that costs money and money is tight in this segment... the LTZ could absorb it but maybe not the LT1 which is alot less. It's one thing to have a turbo/intercooler OR DI, but both is expensive and complex for this price segment.

For 80% of buyers who live in more moderate climates it's not an issue... for those rare occasion they see over 100F they can just use premium... but most buyers don't know this.. and this is the problem. It can't be good for the engine to have detonation and retarded firing... can't be good for the cat.. unburnt fuel. This is asking for warranty issues... GM should think about this. You can see why Toyota & Honda rarely offer a turbo. Those brands r all about consistency and no brainer operation/ownership.

What to do? I think they chose to go with the 1.4T mainly for the manuel ECO model because they knew w it's lighter weight, LRR tires, less drag and manual tranny that it would be able to a achieve over 40 mpg, but most people don't buy a manual & it's doubtful that a car this heavy could acheive 40 or higher with a torque converter in the real world.

They should continue offering that engine in the Eco manual, but for the LT/LTZ/LS it would probably be better to offer a 2.0DI N/A... like the Focus which weighs about the same. Make that the standard engine. It would probably only get no more than 26/38 w auto though but at least it'd be more consistent. The LT is practically a small mid-size sedan in terms of weight & size. They can just take the turbo intercooler off the Regal turbo's 2.0TGDI if GM cannot swing DI for the 1.4T or better yet DI on a 1.6T.

Perhaps GM should send a notice to owners of the 1.4T explaining the heat issue and premium gas. Most drivers have no clue.

"Perhaps GM should send a notice to owners of the 1.4T explaining the heat issue and premium gas. Most drivers have no clue."

Even worse, most owners do not know that the ECU will take a while to realise that you have just filled up with premium. So, GM inform the owners of the issue who slap in a tank of 91 then complain 100 yards down the road that they still have the "problem".

Sorry to say that GM have been caught with their pants around their ankles on this one. I personally like turbo motors, but on this occasion it looks like GM have been unable to engineer a way out of the marketing corner that 87 octane puts them in. Short of DI or a relocated IC, they are screwed.

I don't think they are screwed, for this issue to come up you need to be up to running temperature in 100+ degree weather and then stop, turn the engine off, then start it again within 15 minutes. Not terribly unlikely when running errands but even still seems like a minor inconvenience than a serious design issue. If we get turbo failures from the ic placement then we have a problem but it would seem the engine is protecting itself.

Can IL replicate this and then do some basic acceleration tests so we know how much it truly affects the car?

"It can't be good for the engine to have detonation and retarded firing... can't be good for the cat.. unburnt fuel."

Well the high temps just cause the fuel to burn faster/sooner, so it's not really an efficiency problem (directly), so much as a power problem. Indirectly, fuel enrichment is very likely, which leads to poor economy. I know GM had a so-called "cat protect" mode on cars way back in the 90s that ran open loop and rich AFRs when the PCM calculated high catalyst temps.

"Even worse, most owners do not know that the ECU will take a while to realise that you have just filled up with premium. So, GM inform the owners of the issue who slap in a tank of 91 then complain 100 yards down the road that they still have the "problem"."

As far as I've determined, GM octane detection works via a fillup of 5 gallons or greater. That resets the learned octane timing and re-evaluates the fuel. An ethanol sensor, imo, can only help the situation, providing some accurate feedback on what's in the tank, with regard to spark timing optimization.

My original point is still valid. Why should any owner have to worry about any of this? Wrong engine for this car....how much evidence does anybody need to figure this out?

As far as I can tell, the problem with the Cruze is literally NOTHING that a larger or reconfigured intercooler could not fix (and a reprogrammed transmission).

Does it not surprise anyone that some continual improvement would be needed on relatively novel drivetrain choice such as this? Sure, Chevy could have put in a V6, lived with a 22/30mpg rating and called it a day. But the 90's called and wanted their drivetrain back. It's friggin called evolution, guys. Deal with it.

dracy69 said:

"I don't think they are screwed, for this issue to come up you need to be up to running temperature in 100+ degree weather and then stop, turn the engine off, then start it again within 15 minutes. Not terribly unlikely when running errands but even still seems like a minor inconvenience than a serious design issue."

You perfectly describe running errands in Las Vegas or Phoenix on a July afternoon. I have had heatsoak in this city in NA cars with biggish engines and it takes a VERY noticeable toll on initial acceleration. Consider this setup in the Cruze.

So, I go to exit a strip mall that has no traffic light onto one of the city's major surface streets with an alleged limit of 45 MPH. I see what looks like a good sized gap, goose the Cruze running on 87 octane and.... very little happens. That scenario can quickly become rather more than a "minor inconvenience".

they used the turbo so that with the extra fuel package they could get 42mpg, something that hyundai, ford etc cant touch...

"they used the turbo so that with the extra fuel package they could get 42mpg, something that hyundai, ford etc cant touch..."

Assuming you take the EPA numbers as anywhere close to real, which I don't.

It would also help the Cruze if it didn't weigh so freaking much.

And, despite GM's cool technical explanation - it still doesn't change the fact that the car doesn't perform well in very hot conditions. There is no reason for a "modern" car to have a deficiency like that. Especially since it is possible for well over half of the country to have a week of days that hot (or close to that hot) a year - if a customer is not aware of this issue then how can they be prepared when their car might not perform safely?