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Discussion Starter #1 (Edited)
Chevy just officially showed the new Chevy HHR (PT Cruiser competitor) based off the Cobalt platform. There are two versions, LS and LT. The LS uses the 2.2L ECOTEC, but the 1LT and 2LT have the 2.4L VVT as an option and base. The official GM Media press release gives some information about the engine however.

Engines: Ecotec 2.2L I-4
Displacement (cu in / cc): 134 / 2189
Compression ratio: 10:1
Horsepower (hp / kw @ rpm): 140 / 104 @ 5400
Torque (lb-ft / Nm @ rpm): 150 / 207 @ 4000
Maximum engine speed (rpm): 6500

Engines: Ecotec 2.4L I-4
Displacement (cu in / cc): 145.5 / 2384
Compression ratio: 10.5:1
Horsepower (hp / kw @ rpm): 170 / 127 @ 6000
Torque (lb-ft / Nm @ rpm): 170 / 235 @ 4400
Maximum engine speed (rpm): 6500


I've highlighted the information that I found fairly interesting. I've added the 2.2L non VVT ECOTEC for comparison too. Also the older Twin-Cam 2.4L engine ran at 9.5:1 compression making 150HP. Until now we didn't know the new engines compression ratio, or at what RPM the HP and Torque was available.

From this information you can see where the power increase has come from. The extra 0.2L and the 0.5:1 compression increase, plus VVT moved the ECOTEC from the 140HP/150 lb-ft to the 170HP/170 lb-ft range. However the 2.4L engine has to go higher into the revs to get this power too though.

With a stock compression ratio of 10.5:1 I'm betting we're not going to end up getting a GM Performance Parts Supercharger addon kit :(
 

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Yep, I have serious doubts about a simple bolt-on S/C kit with that kind of CR. If there's a kit at all, it would have to come with at least a thicker head gasket (but that's a band-aid) or dished pistons.
 

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Good information! That is an awfully high compression ratio to be adding a bolt on supercharger to, but they may still have a low pressure solution in mind. What I am wondering is how that will affect a potential factory supercharger/turbocharger on the VVT engine? I know they can drop the compression down, but they will have to drop it a lot to use a decent amount of boost!

I’m also curious to see what the power band looks like. Whether most of that power shows up throughout, or whether it is a fairly peaky engine. Based on the displacement I would not expect it to be very peaky, but you never know.
 

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Discussion Starter #6
DreamerDave said:
Any word on if they specify regular or premium gas? With that compression ratio, it could go either way.
Since this engine is going to become part of the econo vehicle line of GM I'm betting it's only 87 octane gas. I don't think many people would buy a 91+ octane using low end car unless it was producing a good bit more then 170HP.
 

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brentil said:
With a stock compression ratio of 10.5:1 I'm betting we're not going to end up getting a GM Performance Parts Supercharger addon kit :(
Maybe have to use Premium gas too. That would suck. :(
 

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Man that horsepower peak rpm and max rpm are close. Wonder where the rev limiter will be set.

Would love to see a horsepower/torque curve. I too am hoping for a flat 'stroker' profile on this engine, the opposite of the Honda S2000.
 

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with the computer monitoring preignition you probably could use a lower grade of gas, but you wouldn't get the best performance. I'd love to see the hp/tq curve also- i'm hoping the VVT will give us good power down low without running out of breath at higher rpm
 

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Discussion Starter #12 (Edited)
Woo-Hoo TCL, I had totally forgotten about that PDF. Let me go update my FAQ post with this info.

That PDF actually also gives the compression ratio as 10.6:1 too.
 

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Discussion Starter #13
Variable Valve Timing helps deliver 90 percent of the peak torque at as low as 2400 rpm

So in essence 153 ft-lbs is available at 2400 rpm.
That's more then what my current car produces at peak using 93 octane. :D
 

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brentil said:
Variable Valve Timing helps deliver 90 percent of the peak torque at as low as 2400 rpm

So in essence 153 ft-lbs is available at 2400 rpm.
That's more then what my current car produces at peak using 93 octane. :D
Those are figures I like to see! That torque figure at 2400 RPM is better than the max torque of half of the cars I have ever owned! :nonod I think I will be happy with that! :yesnod
 

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I need to see Dyno Specs :smile
 

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Discussion Starter #16
Rickady88GT said:
I need to see Dyno Specs :smile
Unfortunately since GM pulled the 2.4 ECOTEC from being a Cobalt engine for now, we lost that chance of seeing graphs. We wont get any public dyno graphs until the Solstice is available, and an owner takes it to get pulled.

Since I've never been to a dyno before, does anyone know how much it costs to get three pulls done to do a baseline value?
 

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Discussion Starter #18
The thing is the 2.0L ECOTEC engine was designed to be boosted. So it's compression ratio has been decreased from 10.0:1 to 9.5:1. However the new 2.4L according to what we've found has a compression ratio of 10.6:1 making it fairly unfriendly to boosting in its current state without a lot of work being done to the system to ensure it stays safe.
 

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brentil said:
Variable Valve Timing helps deliver 90 percent of the peak torque at as low as 2400 rpm

So in essence 153 ft-lbs is available at 2400 rpm.
...
The original Honda S2000 had a peak torque rating of 153 ft lbs at 7500 rpm. The 2004 models make 162 ft lbs at 6500 rpm. This is one reason I have the Solstice rated above the S2000 on my potential buy list. I don't want to be forced to downshift every time I need to make a quick move in traffic.
 

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brentil said:
Since I've never been to a dyno before, does anyone know how much it costs to get three pulls done to do a baseline value?
A friend of mine owns Thunder Racing, if I remember right Geoff told me that it's about 100 dollars.
 
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