My 2.2L Build Thread (300+ hp)
#26
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Keep in mind mine is a sedan and weighs a little more, but from other cobalt reviews I've never heard of a weight under 2900. Hell most reviews put it at around 2990-3000 for the SS.
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really? good to know man thanks.
they are forged, what about them exactly makes them bad for boost applications??
I think they would have to be good for at least 350hp....at least
sure boost is different than NA, but you're just forcing air in, as far as the forces acting on a piston, I dont think 300hp NA is really different than 300hp FI
I may be wrong, what would fail on them?
they are forged, what about them exactly makes them bad for boost applications??
I think they would have to be good for at least 350hp....at least
sure boost is different than NA, but you're just forcing air in, as far as the forces acting on a piston, I dont think 300hp NA is really different than 300hp FI
I may be wrong, what would fail on them?
The compression ratio from the factory will be different for naturally aspirated engines and boosted engines. For example, a stock Honda S2000 has a compression ratio of 11.1:1, whereas a turbocharged Subaru Impreza WRX has a compression ratio of 8.0:1.
There are numerous factors that affect the maximum allowable compression ratio. There is no single correct answer for every application. Generally, compression ratio should be set as high as feasible without encountering detonation at the maximum load condition. Compression ratio that is too low will result in an engine that is a bit sluggish in off-boost operation. However, if it is too high this can lead to serious knock-related engine problems.
Factors that influence the compression ratio include: fuel anti-knock properties (octane rating), boost pressure, intake air temperature, combustion chamber design, ignition timing, valve events, and exhaust backpressure. Many modern normally-aspirated engines have well-designed combustion chambers that, with appropriate tuning, will allow modest boost levels with no change to compression ratio. For higher power targets with more boost , compression ratio should be adjusted to compensate.
There are a handful of ways to reduce compression ratio, some better than others. Least desirable is adding a spacer between the block and the head. These spacers reduce the amount a "quench" designed into an engine's combustion chambers, and can alter cam timing as well. Spacers are, however, relatively simple and inexpensive.
A better option, if more expensive and time-consuming to install, is to use lower-compression pistons. These will have no adverse effects on cam timing or the head's ability to seal, and allow proper quench regions in the combustion chambers.
There are numerous factors that affect the maximum allowable compression ratio. There is no single correct answer for every application. Generally, compression ratio should be set as high as feasible without encountering detonation at the maximum load condition. Compression ratio that is too low will result in an engine that is a bit sluggish in off-boost operation. However, if it is too high this can lead to serious knock-related engine problems.
Factors that influence the compression ratio include: fuel anti-knock properties (octane rating), boost pressure, intake air temperature, combustion chamber design, ignition timing, valve events, and exhaust backpressure. Many modern normally-aspirated engines have well-designed combustion chambers that, with appropriate tuning, will allow modest boost levels with no change to compression ratio. For higher power targets with more boost , compression ratio should be adjusted to compensate.
There are a handful of ways to reduce compression ratio, some better than others. Least desirable is adding a spacer between the block and the head. These spacers reduce the amount a "quench" designed into an engine's combustion chambers, and can alter cam timing as well. Spacers are, however, relatively simple and inexpensive.
A better option, if more expensive and time-consuming to install, is to use lower-compression pistons. These will have no adverse effects on cam timing or the head's ability to seal, and allow proper quench regions in the combustion chambers.
http://www.turbobygarrett.com/turbob...ech102.html?#d
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Lower compression ratios are safer because you are less likely to detonate.
The reason why he's going with a higher compression is because it will produce more power, but I hope he understands the risks involved with this. I've seen a couple of people detonate at much lower compressions. Our NA engines do NOT like boost, they aren't built for boost, and many times things break.
The reason why he's going with a higher compression is because it will produce more power, but I hope he understands the risks involved with this. I've seen a couple of people detonate at much lower compressions. Our NA engines do NOT like boost, they aren't built for boost, and many times things break.
#29
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yea I understand what I am attempting to do, I just need a good tune, I think trifecta will be able to help me out just fine
I dont think I could count on the M62 to make enough boost (reliably) if I went with the 8.9:1 compression. What do you guys think? I am rebuilding it with ceramic bearings and a new coupler, I'll be using dual pass and the ZZP heat exchanger, I was going to use a 2.8" pulley, but I guess I could use a 2.7 and go with 8.9:1, I dont know about going with a pulley smaller than 2.7 though, even with an improved M62
I see now what that guy meant about the pistons, just because they were high comp, not because the pistons themselves cant take it
what do you guys think? I have debated over the low comp/high boost or high comp/low boost for a while, I had a long conversation with my dad, we agreed I would probably be happier with higher comp, from what I understand, throttle response would be better, I wouldnt have to beat up AND HEAT UP the M62 either, but tuning might be easier with lower compression and I could maybe still make around 300hp
I dont think I could count on the M62 to make enough boost (reliably) if I went with the 8.9:1 compression. What do you guys think? I am rebuilding it with ceramic bearings and a new coupler, I'll be using dual pass and the ZZP heat exchanger, I was going to use a 2.8" pulley, but I guess I could use a 2.7 and go with 8.9:1, I dont know about going with a pulley smaller than 2.7 though, even with an improved M62
I see now what that guy meant about the pistons, just because they were high comp, not because the pistons themselves cant take it
what do you guys think? I have debated over the low comp/high boost or high comp/low boost for a while, I had a long conversation with my dad, we agreed I would probably be happier with higher comp, from what I understand, throttle response would be better, I wouldnt have to beat up AND HEAT UP the M62 either, but tuning might be easier with lower compression and I could maybe still make around 300hp
#32
nop, never wondered why 10:1 wisecos are 50gr lighter than the 8.9 ones ?
they are a LOT less reinforced than the 8.9 boost ones, perfectly engineered for NA applications, but not for boost... of course they will still work better than stock items...
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well im going for the 300whp as well....currently working on mine...i have all the stock **** out...and im currently installing all the new ****...check my sig so you can get an idea of what im doing
#36
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I wouldnt judge Alanoo on post count.
The Wiseco pistons are very lightweight pieces, youre unlikely to find another piston that weighs less, even much smaller Honda pistons (~81mm vs 86mm) weigh more in many cases.
To be sure the Wiseco pistons are very high quality, and will outlast stock under almost any circumstances, but if you are looking to boost at 10:1 you may want to search around for pistons better suited to that application.
Just because two engine(NA vs boost) make 300hp doesnt mean the loads on the pistons are the same.
The Wiseco pistons are very lightweight pieces, youre unlikely to find another piston that weighs less, even much smaller Honda pistons (~81mm vs 86mm) weigh more in many cases.
To be sure the Wiseco pistons are very high quality, and will outlast stock under almost any circumstances, but if you are looking to boost at 10:1 you may want to search around for pistons better suited to that application.
Just because two engine(NA vs boost) make 300hp doesnt mean the loads on the pistons are the same.
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He is correct. I almost bought a set of 10:1 JE Pistons from someone here on the board but i ended up calling JE with the job number and they told me that the pistons were NA only and could NOT support boost. He said they were good for about 250-300hp NA and if they saw boost, they wouldnt last very long. JE Makes some good pistons and i would imagine as good quality as wiseco is, they probably follow the same guidelines. Custom pistons from wiseco are only $125 each, so it would cost you $500 for a set of 10:1 FI pistons. When you blow your engine you tend to be VERY picky and precise about what you buy and let me tell you, its worth spending the little extra time calling wiseco and finding out the truth then just assuming.
#39
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good info, thats why I started this thread.
I may just use the 8.9:1 pistons, but I'm not sure, might just get custom 10:1 pistons like you guys had mentioned.
I have another question, Does anyone know for sure on here, whether or not using the LSJ alternator on my engine will prevent me from having to cut one of the ribs off of my belt???
I can buy an alt and bracket right now, maybe Maven knows
I may just use the 8.9:1 pistons, but I'm not sure, might just get custom 10:1 pistons like you guys had mentioned.
I have another question, Does anyone know for sure on here, whether or not using the LSJ alternator on my engine will prevent me from having to cut one of the ribs off of my belt???
I can buy an alt and bracket right now, maybe Maven knows
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ok, so If I just cut off one rib on the belt I dont need to replace those pulleys then??
thats what the 2.4 and 2.2 guys did that have supercharged their cars
thats what the 2.4 and 2.2 guys did that have supercharged their cars
#46
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thats my worry
another question, I was planning on using 60# injectors, will these be fine, I know they should be enough, I dont know if 42# would be enough or as easy to tune with
AND almost forgot, what should I do about my fuel pump, I have read previously that I will need a better fuel pump supplying fuel from the tank, should I just get some kind of a booster? what are guys using? inline pumps or replacing the stock one completely?
another question, I was planning on using 60# injectors, will these be fine, I know they should be enough, I dont know if 42# would be enough or as easy to tune with
AND almost forgot, what should I do about my fuel pump, I have read previously that I will need a better fuel pump supplying fuel from the tank, should I just get some kind of a booster? what are guys using? inline pumps or replacing the stock one completely?
Last edited by brandon2.2; 10-18-2008 at 12:53 AM.
#48
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the stock L61 idler is a non ribbed pulley....unless im reversing the names
http://www.gminsidenews.com/ECOTEC20L.jpg
You have the crank pulley, then the idler pulley, then the tensioner pulley, then the alternator pulley, then the blower pulley, then the AC compressor pulley
http://www.speedmafia.com/images/2-2...2012499679.jpg
the l61 has the crank pulley, the idler pulley, the alternator pulley, and the AC pulley
To run the LSJ belt with 1 rib cut off, you need the LSJ tensioner, and the LSJ idler
To run the LSJ belt with all 6 ribs, you need the LSJ tensioner, the LSJ idler, the LSJ crank, the LSJ AC pulley, and the LSJ alternator pulley
Maven, i know ur an uber expert...but its my understanding the tensioner pulley is the one adding tension (makes sense), and the idler pulley is the one that adds no tension, and serves no purpose other than to route the belt in that direction
if the above is true, then both ecotecs have an idler pulley...wouldnt they?
#50
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Maven, i know ur an uber expert...but its my understanding the tensioner pulley is the one adding tension (makes sense), and the idler pulley is the one that adds no tension, and serves no purpose other than to route the belt in that direction
if the above is true, then both ecotecs have an idler pulley...wouldnt they?
Maven, i know ur an uber expert...but its my understanding the tensioner pulley is the one adding tension (makes sense), and the idler pulley is the one that adds no tension, and serves no purpose other than to route the belt in that direction
if the above is true, then both ecotecs have an idler pulley...wouldnt they?
L61s only have a tensioner, they dont have an idler.
All the pulleys have a purpose, they dont use extra ones because its a waste of money(so no idler on NA/turbo engines)check out my mad artisism and these bitching diagrams