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Motor Authority: GM Insiders Pushing For Chevrolet Cruze SS

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2011-chevrolet-cruze_100233873_t.gif With the death of Saturn and Pontiac, two of GM's best small, sporty cars are gone: the Solstice and Sky and their turbocharged GXP and Redline variants. The excellent Cobalt SS got the axe this year as well, leaving GM with only the HHR SS for its small-car, fun-to-drive segment. But the Cruze could step in to fill that gap. Speaking with Motor...

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I thought they only axed the Cobalt SS Sedan?

Yes, GM needs a Cruze SS. Even if the drivetrain is simply the same 2.0T as the Cobalt/HHR SS - drop it in, tune the suspension, brakes, etc, and give people a reason to continue to take GM performance seriously!

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I thought they only axed the Cobalt SS Sedan?

Yes, GM needs a Cruze SS. Even if the drivetrain is simply the same 2.0T as the Cobalt/HHR SS - drop it in, tune the suspension, brakes, etc, and give people a reason to continue to take GM performance seriously!

Yes these guys seem to be reporting incorrectly. Coupe SS is still there for 2010.

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Jeez, so I need to keep hacking away at this? Any Cruze SS needs to be a coupe. There is no excuse not to have a coupe at launch... ridiculous Kia had their Forte coupe at launch, and you can bet your bottom dollar Honda will have a Civic coupe ready same time as the new sedan... and Ford with their Focus, and on and on...

Some say GM needs to get the Cruze sedan "right" at launch, and then worry about alternative bodystyles. I say it makes them look weak in the engineering department when all these competitors are able to do multiple styles at the outset.

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Yes these guys seem to be reporting incorrectly. Coupe SS is still there for 2010.

The Cobalt SS and HHR SS are in the last year.

The Cruze needs to be a Coupe or hatch before it is an SS. The Cobalt Coupe SS was low Volume but the Sedan was very rare. Few people bought it. I don't know if better Marketing would help Sedan sales.

Don't get me wrong I would love to see this even as a sedan but when the Cobalt SS sedan sold under a 1000 units is it what they really need. I would rather hope for a coupe first and market the hell out of it.

Leave the turbo sedan to the Regal and the coupe to Chevy might be the smart move.

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Cobalt SS coupe did quite well, so I very much doubt that GM will waste that goodwill.

A Cruze SS coupe is a no-brainer.

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Cobalt SS coupe did quite well, so I very much doubt that GM will waste that goodwill.

A Cruze SS coupe is a no-brainer.

GM needs to really must do better than the Cobalt SS

2008 SS total 2,537 Turbo coupe and sedan. Note only 474 Turbo Sedans only.

2009 SS totsl 1,105 Coupe only.

HHR SS out sold it both years but was itself under 5,000 units both years too.

GM failed here mostly since they failed to really market this car. Also the old Cobalt body did not help either.

GM also needs to not offer any watered down performance car too. No FX and wing cars without the best engine. It would be ok to offer a plain car with the engine though.

Edited by hyperv6
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I'm with Ocn on this one...they need to have the different body styles available at launch. A performance model especially should be applied to something more than the sedan.

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Jeez, so I need to keep hacking away at this? Any Cruze SS needs to be a coupe. There is no excuse not to have a coupe at launch... ridiculous Kia had their Forte coupe at launch, and you can bet your bottom dollar Honda will have a Civic coupe ready same time as the new sedan... and Ford with their Focus, and on and on...

Some say GM needs to get the Cruze sedan "right" at launch, and then worry about alternative bodystyles. I say it makes them look weak in the engineering department when all these competitors are able to do multiple styles at the outset.

Those competitors haven't been through what GM has been through in the last year, the horror of bankruptcy, etc. They have bigger budgets and profits.

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I'm with Ocn on this one...they need to have the different body styles available at launch. A performance model especially should be applied to something more than the sedan.

It is a little late for at launch but in time we will see it.

The Marketing and pushing of the sedan is more important at the start since it will account for most of the sales. They do sell more Civic 4 doors as do the other companies sedans in this class. The boring buyers are the ones that buy the majority of these cars. Sad but true.

But they do need a coupe and it will need to be something special with the new Honda coupe coming. GM needs a CRX of it's own with LNF like power. GM needs a leader in all areas of performance. If they can do what they did with the Cobalt imagine what they can do with a new car. I do not expect Lutz to miss this one.

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I agree, I probably shoulded have said needed, which I still believe is true, but if the sedan does well, then hopefully when the coupe comes out the reputation will help the coupe...

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Dropping the LNF (260hp 2.0 DI Turbo) into the Cruze is a good idea. But it can be better.

IMHO, the LNF makes too much torque for a 3000 lbs class FWD car and has less than ideal turbo lag characteristics. An LSD helps, but it also reduces the turn in agility of the car. The right thing to do is to reduce the torque output of the engine while increasing the power output, improving engine response and increasing linearity.

We can do this by:-

  • Reducing maximum boost from 18.4 psi to 13.2 psi
  • Increasing static compression from 9.2:1 to 10.2:1
  • Switching to a more efficient ball-bearing twin scroll turbo (Eg. Honeywell GT2259RSD)
  • Switching from a high volume Air-to-air intercooler to a low volume air-to-water intercooler

The target ought to be:-

270hp @ 6300 rpm (up from 260hp @ 5300 rpm)

228lb-ft @ 2200~6200 (down from 260 lb-ft @ 2500~5200 rpm)

This will make the car handle better by reducing torque steer and reducing turbolag. Incidental to the changes instituting higher static compression and lower boost is increased cruise efficiency.

Edited by dwightlooi
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Dropping the LNF (260hp 2.0 DI Turbo) into the Cruze is a good idea. But it can be better.

IMHO, the LNF makes too much torque for a 3000 lbs class FWD car and has less than ideal turbo lag characteristics. An LSD helps, but it also reduces the turn in agility of the car. The right thing to do is to reduce the torque output of the engine while increasing the power output, improving engine response and increasing linearity.

We can do this by:-

  • Reducing maximum boost from 18.4 psi to 13.2 psi
  • Increasing static compression from 9.2:1 to 10.2:1
  • Switching to a more efficient ball-bearing twin scroll turbo (Eg. Honeywell GT2259RSD)
  • Switching from a high volume Air-to-air intercooler to a low volume air-to-water intercooler

The target ought to be:-

270hp @ 6300 rpm (up from 260hp @ 5300 rpm)

228lb-ft @ 2200~6200 (down from 260 lb-ft @ 2500~5200 rpm)

This will make the car handle better by reducing torque steer and reducing turbolag. Incidental to the changes instituting higher static compression and lower boost is increased cruise efficiency.

Might note the HHR SS LNF is only 222 lb-ft at 1650 RPM and 235 HP at 5900 RPM in first and second gear. It feel like it has no spirit. There is little to no lag but it just feel so very weak to the 5 speeds 260 HP and 260 lb-ft.

Just to note with my upgrade to the 315 lb ft. It feels like it has the spirit and the performance of the manual but still lag is no factor at I can climb over 20 PSI with little to no lag. just cracking the throttle I am at 17 with little pedal.

Also I have noticed the Auto even witht he extra perfromance is much better with torque steer than the manual. The Manual even with the stock 260 lb ft feels much more harsh.

I think GM Performance did a much better job on the Turbo upgrade kit than the drivetrain people did with the factory set up. I talk with Bill Duncan from GMPD and he filled me in on many of the changes and they were able to control the torque much better so the auto tranny will live and perform much better. They were able to match the performance of the 5 speed with the Upgrade kit and still keep the 5 year warranty intact with GM on the auto. Bill's a very hands on guy and a very sharpe engineer. I wish they would let him have a hand at the Cruze.

The end result is my upgrade ont he auto feels very V8 like with only a hint of torque steer on uneven surfaces at over 20 PSI, it feels to wonder. Under 20 PSI what torque steer? not an issue under 20 PSI. At my Alt I can see 24 PSI and the kit is set to peak at 27 PSI at higher Alt.

I don't disagree with anything you say for the most but as a daily driver of a LNF and also having drive the other versions it is not something that I think needs drastic measures. I almost think they could do most of it with computer torque management.

Or if you took your Idea I would have no issue with a little less torque but I would not drop it as far as you want. Other than the compression jump the stock HHR auto LNF is very similar to what you discribed and I would not want to return mine to that for any reason. After driving a lnf with out the upgrade again it felt like a V6 2010 Camaro vs mine that feels more like a 2010 SS Camaro.

just my impressions here nothing more. Please understand I am Not looking for a argument.

Edited by hyperv6
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Or if you took your Idea I would have no issue with a little less torque but I would not drop it as far as you want. Other than the compression jump the stock HHR auto LNF is very similar to what you discribed and I would not want to return mine to that for any reason. After driving a lnf with out the upgrade again it felt like a V6 2010 Camaro vs mine that feels more like a 2010 SS Camaro.

just my impressions here nothing more. Please understand I am Not looking for a argument.

(1) Most of it is opinion, so you wouldn't get an "argument" from me.

(2) What I was proposing however was based on the following:-

  • Lowering boost while increasing compression increases cruise economy.
  • Lowering boost while increasing compression reduces lag (especially part throttle lag).
  • Lowering boost while increasing compression reduces maximum torque which reduces torque steer.
  • Lowering boost to 0.9 bar puts you on a more efficient part of the turbo's compressor map* improving overall engine efficiency.
  • Reduced torque steer and overall torque loading may make an LSD unnecessary reducing cost and reducing LSD induced understeer.
  • Reducing pressurized volume further improves engine response.

(3) The objective being to create the most linear and most responsive 270hp possible from a smallest number of cylinders and displacement. Overall, I simply felt that this is a better interpretation of a small displacement forced-induction in a small front drive car.

* Compressor map of Honeywell-Garrett GT2259 turbo at various boost levels

map.gif

Edited by dwightlooi
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I'm going to get beat for it, but I think GM doesn't need to worry about an SS for the Cruze...at least for a while.

This money could be spent on REAL preformance cars...

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(1) Most of it is opinion, so you wouldn't get an "argument" from me.

(2) What I was proposing however was based on the following:-

  • Lowering boost while increasing compression increases cruise economy.
  • Lowering boost while increasing compression reduces lag (especially part throttle lag).
  • Lowering boost while increasing compression reduces maximum torque which reduces torque steer.
  • Lowering boost to 0.9 bar puts you on a more efficient part of the turbo's compressor map* improving overall engine efficiency.
  • Reduced torque steer and overall torque loading may make an LSD unnecessary reducing cost and reducing LSD induced understeer.
  • Reducing pressurized volume further improves engine response.

(3) The objective being to create the most linear and most responsive 270hp possible from a smallest number of cylinders and displacement. Overall, I simply felt that this is a better interpretation of a small displacement forced-induction in a small front drive car.

* Compressor map of Honeywell-Garrett GT2259 turbo at various boost levels

map.gif

On question. With the increase in Compression would the engine still be rated as Premium Recomended or would it be changed to Premium Required.

GM has moved to this Recomended rating to not scare off potential buyers who resist paying for the more expensive gas. To most of us here it we would use nothing less than 92 OCT but there are many in the the Chevy Value image that just refuses to pay the higher price.

I know the lower octane will kill off 20 HP in my GTP with the Series III. I have never run Regular in the SS but have heard it will do similar results. With my upgrade it is no longer an option.

In other words the Octane is an option GM and Chevy wants to offer to sell these to anyone who wants one no matter the fuel.

Would your idea still retain this octane option.

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I'm going to get beat for it, but I think GM doesn't need to worry about an SS for the Cruze...at least for a while.

This money could be spent on REAL preformance cars...

you mean the ones that no one can afford to buy in a depressed economy?

chevy might want to still be in a segment that has mazdaspeed 3 , wrx, and gti.

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On question. With the increase in Compression would the engine still be rated as Premium Recomended or would it be changed to Premium Required.

GM has moved to this Recomended rating to not scare off potential buyers who resist paying for the more expensive gas. To most of us here it we would use nothing less than 92 OCT but there are many in the the Chevy Value image that just refuses to pay the higher price.

I know the lower octane will kill off 20 HP in my GTP with the Series III. I have never run Regular in the SS but have heard it will do similar results. With my upgrade it is no longer an option.

In other words the Octane is an option GM and Chevy wants to offer to sell these to anyone who wants one no matter the fuel.

Would your idea still retain this octane option.

This is actually much easier to achieve on a turbocharged engine than in a normally aspirated one. A turbocharged powerplant's static compression -- no matter how high relative to other turbocharged engines -- is always pretty low.

10.2:1 is about 1.5 points lower than the LF1 3.0 V6 runs with 87 octane. In otherwords, if you want a "Premium Recommended, but Not Required" rating you can simply have the ECU turn down the boost when it hears the pings. 8~9 psi on 10.2:1 is definitely OK, perhaps even 10~12 psi.

Edited by dwightlooi
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Oh, BTW, just in case anyone cares to know how I pulled 270hp, 13.2 psi and 6300 rpm seemingly out of my butt... here's the math.

Let’s consider the LNF 2.0 liter DI-Turbo 4-potter running 18.4 (1.25 bar) psi of boost and making 260hp @ 5300 rpm.

Engine displacement = 122 cu-in

Air density @ 1 bar (sea level) = 1.2 kg/m3 = 1.2/27680 = 0.000043353 lb/in3

Mass air flow at 5300 rpm @ 1 bar = 122 x 0.5 x 5300 x 0.000043353 = 14.0 lb/min

Mass air flow at 5300 rpm @ 2.25 bar = 14.0 x 2.25 = 31.5 lb/min

A rough rule of thumb is that you get ~10 hp per ~1 lb/min of airflow. So this equates to about 315 (gross) hp assuming 100% volumetric efficiency and zero internal loss. We know that’s never the case in any engine. More likely a DOHC engine has a volumetric efficiency of around 95% and loses another 10~15% to mechanical losses. Take 17.5% off and 260 (net) hp is about right.

Now if we reduce the boost level to 0.9 bar…

Mass air flow at 5300 rpm @ 1.9 bar = 14.0 x 1.9 = 26.6 lb/min

That’s about 266 (gross) hp. Taking the same 17.5% off we end up with 219 (net) hp at 5300 rpm.

However, if we sustain 0.9 bar of boost through 6300 rpm…

Mass air flow at 6300 rpm @ 1 bar = 122 x 0.5 x 6300 x 0.000043353 = 16.7 lb/min

Mass air flow at 6300 rpm @ 1.9 bar = 16.7 x 1.9 = 31.7 lb/min

That’s about 317 (gross) hp. Taking, again, 17.5% off we end up with 262 (net) hp.

I peg it slightly higher at 270hp based on the notion that compressor and intercooler efficiency ought to be slightly better given the reduced charge heating at 13.2 psi vs 18.4 psi.

Edited by dwightlooi
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you mean the ones that no one can afford to buy in a depressed economy?

chevy might want to still be in a segment that has mazdaspeed 3 , wrx, and gti.

Reg, even those are getting hammered.....

There is a thing called aftermarket...might be a good thing for GM to push...

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Reg, even those are getting hammered.....

There is a thing called aftermarket...might be a good thing for GM to push...

GM has pushed the aftermaket well with the Camaro. It is like the old days where many MFG got a lot of lead time and GM offered many in house things.

I would like to see GM parts and GMPD offer more for the other performance lines. The problem is to get the bigger MFG interested you need to sell more than 2500 or more cars to make it worth their time. So until there are more sales it will be up to GMPD and parts offer things like Mini offers to customize there cars not only cosmetic but performance wise.

If there is a Cruze coupe it needs to be trendy and cool. Something the youth market will love to drive and be seen in. The failing of the Cobalt SS is the image of the car was a Cobalt with a wing. Nice car but it looks like grandma's Cobalt. With a fresh coupe they could change that image fast.

But the sad truth is until they learn to sell more cars the aftermarket will always be limited.

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dwightlooi, have you competitively driven a Cobalt SS/TC, or talked with anyone who has? There's one that's a regular at local autox events, bone stock except tires, and those that have driven it have said there is no turbo lag.

I'm going to get beat for it, but I think GM doesn't need to worry about an SS for the Cruze...at least for a while.

This money could be spent on REAL preformance cars...

You have some uppidy definition of "real" performance car? Last I checked a 1/4 mile time in the 13's was pretty darn fast for a factory car. Yes, it's not an all-out sports car, but it's capable of being built to be very competitive in drag or handling events, ESPECIALLY for the price. I would like to see some even more all-out performance trim levels, though - something to line up against the EVO and STI.

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dwightlooi, have you competitively driven a Cobalt SS/TC, or talked with anyone who has? There's one that's a regular at local autox events, bone stock except tires, and those that have driven it have said there is no turbo lag.

You have some uppidy definition of "real" performance car? Last I checked a 1/4 mile time in the 13's was pretty darn fast for a factory car. Yes, it's not an all-out sports car, but it's capable of being built to be very competitive in drag or handling events, ESPECIALLY for the price. I would like to see some even more all-out performance trim levels, though - something to line up against the EVO and STI.

Actaually, yes.

I've been to the track....the Balt still has balls, but no tech/style/updates.

And the aftermarket is not that cheap at the moment...a few grand would be a good start....at least for pure speed...

It does handle well when pushed though...

Don't get me wrong, the Balt SS is a good solid ride...and one of the better right out of the box....

But for the most part, the current tuner market is on the way out.....

Many people can't afford those pricey rides....they just "build" them up...

GM could make a killing in that market...

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dwightlooi, have you competitively driven a Cobalt SS/TC, or talked with anyone who has? There's one that's a regular at local autox events, bone stock except tires, and those that have driven it have said there is no turbo lag.

I have driven it, but not competitvely.

Every turbocharged car has turbo lag; not having turbo lag is impossible. It takes any compressor some time to bring the pressurized volume from vaccuum to 18 psi or whatever the prescribed boost level. The only question is whether it is objectionable, and that is highly subjective.

The Cobalt SS and Solstice GXP takes about 3/4 of a second to reach full boost from cruise power, a tad longer from decelerative vacuum. It's not bad, but it can be better.

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