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Discussion Starter #1
No this is not another SRT post. I happen to come accross this at
http://www.caranddriver.com/idealbb/view.asp?topicID=60226&pageNo=1&num=20

I really like the Cobalt too. Much better looking both inside and out than the SRT-4 IMO. It may be a few tenths slower in the quarter mile, but thats nothing a few mods woudn't fix

Ion Relines have been putting down between 200-210 HP at the wheels, which is very impressive to say the least. The engine is also still making power when it hits the rev limiter, so there is even more potential if the limiter can be raised with an aftermarket chip.

Heres the link to a dyno graph that an owner posted on redlineforums.com:

http://www.cs-servers.com/ion/dyno1.jpg
Is there any way to get the hp peak before readline instead of right at redline. All the other cars that I've had the hp actually starts to go down around redline. If you shift at the right time you actually keep the optimal hp within your shift point instead of shifting at the peak and working your way back up.
I think if there was a way to reach peak 500rpm earlier it would have even better performance.
Will the lack of limiter make this better or will we just kill the engine?
Any oppinion?
 

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geokots said:
No this is not another SRT post. I happen to come accross this at
http://www.caranddriver.com/idealbb/view.asp?topicID=60226&pageNo=1&num=20



Is there any way to get the hp peak before readline instead of right at redline. All the other cars that I've had the hp actually starts to go down around redline. If you shift at the right time you actually keep the optimal hp within your shift point instead of shifting at the peak and working your way back up.
I think if there was a way to reach peak 500rpm earlier it would have even better performance.
Will the lack of limiter make this better or will we just kill the engine?
Any oppinion?
What really needs to be done, is to raise the rev limiter to about 7,000 rpms. They're cutting it off early for some god awful reason, probably durability concerns or something. Someone just needs to hack the shit outta the ECU module.
 

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Discussion Starter #3
Wouldn't that potentailly kill the engine? Redline is not just a random number that is picked. Even if we elliminated the limited I still wouldn't want to exceed redline.
 

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geokots said:
Wouldn't that potentailly kill the engine? Redline is not just a random number that is picked. Even if we elliminated the limited I still wouldn't want to exceed redline.
The redline is a number that someone comes up with based on numerous factors. It's not always a decision based on pure engineering either. With an engine like ours, and the quality of the rotating assembly, the oil-jet piston cooling, balanced rotating assembly, and all the other steps taken to build this engine like a rock, a 7,000 rpm redline is nothing. If you look at the race prepped Ecotecs, the only real change is to a higher strength connecting rod. That's to make HUGE horsepower. When you look at the hp graphs, the ones that show the engine building power right up to redline, it's almost proof that the engine can handle more revs. Usually the redline is determined by the power band, once the power stops building there's no reason to rev higher. The engine is built around those parameters. If you build a small block chevy and it makes it's horsepower peak at 5,800 rpms, then there's no reason to build any of the other components to go past 6,000 or maybe 6,250 rpms. So once you've matched the components to the rev range, you're effectively locking in the redline. No reason to spend money on rods and valve springs that can hit 8,000 rpms when you're never going to see it. Am I making sense here, or just rambiling? I guess what I'm saying is that you never REALLY know what the engine as a whole is capable of RPM-wise. The same small block that I have in my Camaro can be turned into a 9,000 rpm beat with a few key changes.
 

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Discussion Starter #5
That makes sense. I didn't think of it that way. Even though I kenew that redline was typically set for just past the peak hp for some reason I was thinking only about durability (maybe because I always feel like I'm over reving it).

Then why the hell would Saturn do this to us. If the hp on the graphs is typical to our cars then why short-change us on power. Until I see the HP start to go down there is no way knowing where the "true" peak is plus there's the performance issue that I started this post with.

Does the Cobalt SS have the same limiter setting? BTW what is the limiter set at... isn't it 6800?
 

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6000rpm is ridiculous for a H.O. 4-banger. I'm wondering if it has to do with overspinning the supercharger. Does the ecotech have a long stroke?
 

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Hey, this comes from the VP of engineering in an interview done with him in a mag......He stated the redline was set at 6450 because that was what the engine speed was when doing durability testing. They don't specifically know if the engine in a daily driven RL could (read: or couldn't) handle the stresses of a higher set limiter. They didn't test it any higher, so that is where they stuck it!!
 

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there is also the fact of changing out pullies later. upping the redline AND changing pullies could be detrimental to the blower if exceeding the max rpm of the m62

you should be happy that the engine is still building power at redline instead of falling off like other cars...
 

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slt said:
6000rpm is ridiculous for a H.O. 4-banger. I'm wondering if it has to do with overspinning the supercharger. Does the ecotech have a long stroke?
I think it has a short stroke, I think the 2.0 is the same general block as the larger ecotecs, they shortened the stroke to 2.0 for the supercharged application. Does that make sense? Is a shorter stroke better for forced induction? I know it's better for high revving correct?
 

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Sp00ner said:
I think it has a short stroke, I think the 2.0 is the same general block as the larger ecotecs, they shortened the stroke to 2.0 for the supercharged application.
That's what I read somewhere...not too sure where though but I remember reading that.
 

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MrCleanY0 said:
That's what I read somewhere...not too sure where though but I remember reading that.
If I'm not mistaken, the shorter the stroke the slower the piston head moves at the same rpm. For example, an engine with a short stroke sitting next to an engine with the same displacement, but a longer stroke, will have the piston heads moving at a slower speed than the engine with the longer stroke. Since the longer stroke has to have the pistons moving faster than the shorter stroke to hit the same RPM levels. The slower piston speeds decrease the abuse that they would be subjected to at a higher piston speed, therefore increasing the durability of the shorter stroke over the longer stroke.

Somewhere I read about shorter strokes for forced induction vehicles too, something about the... shit.. I really don't remember...
 

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Discussion Starter #12
Sp00ner said:
If I'm not mistaken, the shorter the stroke the slower the piston head moves at the same rpm. For example, an engine with a short stroke sitting next to an engine with the same displacement, but a longer stroke, will have the piston heads moving at a slower speed than the engine with the longer stroke. Since the longer stroke has to have the pistons moving faster than the shorter stroke to hit the same RPM levels. The slower piston speeds decrease the abuse that they would be subjected to at a higher piston speed, therefore increasing the durability of the shorter stroke over the longer stroke.

Somewhere I read about shorter strokes for forced induction vehicles too, something about the... shit.. I really don't remember...
I'm not an authority on this but according to this Road and Track article is a long stroke (whatever that means)

http://www.roadandtrack.com/article.asp?section_id=6&article_id=1177&page_number=1

Although GM calls it an Ecotec, the Red Line's 2.0-liter engine is actually based on the aluminum long-block of the Saab 9-3, a twincam inline-4 with oil-cooled pistons and sodium-filled valves to help it cope with 12 psi of intercooled boost, courtesy of a large Eaton Roots-type blower normally used on GM's supercharged 3800 V-6
 

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Discussion Starter #13
Damn sorry I just realized that they called it a long block not long stroke.

Sorry about that.

Good article though
 

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Wow....You guys are confusing me.....They destroked and debored the 2.2 Ecotech to LOWER THE COMPRESSION RATIO!!! Too high of a compression ratio before you boost it will result in blowing off (literally) a head, or sending the piston through the side or bottom of an engine. This is litterally what will happen. The optimal compression ratio of an engine before SC/Turbo should be around 8.5-9.1:1. This allows an charge to be "forced" (hence: forced induction) into the cyclinder and raising the compression ratio (Compression Ratio= The volume of a cylinder at Bottom Dead Center vs. the volume of the same cyclinder at Top Dead Center). In other words how much fuel/air you are able to put into a cyclinder, and then how far that cyclinder can compress (crush) in distance to TDC. Now most cars fire Before Top Dead Center, like my '83 K-5 is set to 12 degrees BTDC ('Cause of the altitude). As I understand it, SC engines are even further retarded.
So you have this engine that has been destroked and debored, and that is to lower compression ratio. Let's move on to the "Balancing". Like the 3rd gen eclipses, the Ecotech has externally balanced "rods" (not the con rods, and if any Eclipse owners wanna help me out with this it would be great). This allows for any imperfections / inattention to details during the engine build process to be "sucked up" and allow the engine to operate. Keep in mind that the engine has to be balanced, other wise the thing would vibrate and tear itself apart.
Long stroke vs. short stroke......The less somthing has to go foward before it has to come back makes it faster than the one that has to travel a longer distance. In other words the shorter stroke it technically faster, although to debore and destroke the 2.2 to the 2.0sc it would be close to mm's in thickness, maybe even .001 of an 1".

And just an FYI.....Long block refers to an engins sans the accessories, and the intake and exhaust manifolds........

Just thought this would help clear things up!!!!
 

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Discussion Starter #16
Sp00ner said:
I'd be a little leary of that article as well. It was written long ago, and I didn't think that our block had anything to do with the Saab block. Plus, the blower is similar to the one in the GranPrix, but I think it's the size below isn't it?
I always thought that it was from the Saab. Even my delaer told me that (but they've been know to be on crack).
My car before the RL was the GP GTP (R.I.P.) and it does look the same but I think the pully is smaller on the RL. I think the RL has the same size as the one I changed it to.
 

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Discussion Starter #17
rip_vw32 said:
Wow....You guys are confusing me.....They destroked and debored the 2.2 Ecotech to LOWER THE COMPRESSION RATIO!!! Too high of a compression ratio .............................
My eyes just lost focus and I now have a headache.

I thought I knew nothing about this stuff before... but now.

Where's the Advil.
 

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rip_vw32 said:
Wow....You guys are confusing me.....They destroked and debored the 2.2 Ecotech to LOWER THE COMPRESSION RATIO!!! Too high of a compression ratio before you boost it will result in blowing off (literally) a head, or sending the piston through the side or bottom of an engine. This is litterally what will happen. The optimal compression ratio of an engine before SC/Turbo should be around 8.5-9.1:1. This allows an charge to be "forced" (hence: forced induction) into the cyclinder and raising the compression ratio (Compression Ratio= The volume of a cylinder at Bottom Dead Center vs. the volume of the same cyclinder at Top Dead Center). In other words how much fuel/air you are able to put into a cyclinder, and then how far that cyclinder can compress (crush) in distance to TDC. Now most cars fire Before Top Dead Center, like my '83 K-5 is set to 12 degrees BTDC ('Cause of the altitude). As I understand it, SC engines are even further retarded.
So you have this engine that has been destroked and debored, and that is to lower compression ratio. Let's move on to the "Balancing". Like the 3rd gen eclipses, the Ecotech has externally balanced "rods" (not the con rods, and if any Eclipse owners wanna help me out with this it would be great). This allows for any imperfections / inattention to details during the engine build process to be "sucked up" and allow the engine to operate. Keep in mind that the engine has to be balanced, other wise the thing would vibrate and tear itself apart.
Long stroke vs. short stroke......The less somthing has to go foward before it has to come back makes it faster than the one that has to travel a longer distance. In other words the shorter stroke it technically faster, although to debore and destroke the 2.2 to the 2.0sc it would be close to mm's in thickness, maybe even .001 of an 1".

And just an FYI.....Long block refers to an engins sans the accessories, and the intake and exhaust manifolds........

Just thought this would help clear things up!!!!
Wait, wait, wait..

A longer stroke has to go a longer distance in the same amount of time in a fixed RPM range. Right? So the longer rod has to be moving faster. The reciprocation (rpms) would be faster in the shorter rod if the pistion heads were travelling at the same speed, but we're talking a fixed rpm here.

Where did we start talking about the compression ratio? Or was that your explanation for the change in the larger ecotec to ours?

The bore is the same as the 2.2 at 86mm. The pistons just don't go up and down as far, that's where the reduction in displacement comes from. Plus, the pistons on the 2.0 are dished to lower the compression and have a different attachment point to the rod, since the pistons need to sit up higher on them.
 

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Yes.....if you "fix the rpm range", And after all that typing I was getting blurry eyed and needing Advil.....I did indeed get it backwards. The longer stroke gets it done slower....I am sorry. And yes the explanation was for the change in the Ecotech. Again I most humbly apologize.....
 
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