Ugh this stuff is a pain in the rear sometimes. So I have the 2.2L OHV in my 1997 cavalier. That means that the engine is NOT roller rocker, it is a stamped 1 piece jobbie. I saw that there are 1.6 ratio roller rockers on ebay and a few other places. Would I see any real performance improvement, and would these even be a straight bolt on in place of the stock ones?
1.6 SBC roller rocker conversion?
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If you got from say a 1.5 to a 1.6 rocker you will get more lift and duration. Your little 2.2 needs all the TQ it can use and adding duration will raise the TQ to a higher rpm so it might be more gutless.
Ah, I see. Well I figured it was something to look into. I don't need it to be even more gutless than it already is. I'm a fan of the 140lb/ft of torque which is pretty good considering it only puts out 120HP.
Higher ratio rocker arms also increase the ramp up rate of the cam, resulting in more power across the band.
I have very little experience replacing rocker arms, so I don't know how much is gained because the sliding surfaces are replaced with rolling ones. It must be enough, because around 2000 or so, every GM engine I worked on has a roller fulcrum.
I have very little experience replacing rocker arms, so I don't know how much is gained because the sliding surfaces are replaced with rolling ones. It must be enough, because around 2000 or so, every GM engine I worked on has a roller fulcrum.
I think it is a bad idea. I'm thinking the 2.2 has 1.6 ratio rockers. But even if it doesn't you don't have a MAF sensor and would probably need to tune the prom to see the gains. I don't think you'd gain much anyway. GM engineering tended to max the cylinder head flow for the factory lift so not much gains.
Roller rockers is just a good engineering move. John--Las Vegas
Not sure what they are called, but these are what I have
They went to roller rockers for the 1998 model year and later.
They went to roller rockers for the 1998 model year and later.
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Originally Posted By: mechanicx
I think it is a bad idea. I'm thinking the 2.2 has 1.6 ratio rockers. But even if it doesn't you don't have a MAF sensor and would probably need to tune the prom to see the gains. I don't think you'd gain much anyway. GM engineering tended to max the cylinder head flow for the factory lift so not much gains.
A speed density engine can still realize gains if the Volumetric Efficiency is increased.
Just look at how many are doing fine with performance exhaust systems added.
Also, it isn't like MAF equipped engines don't need tuning to get the most out of upgrades.
I think it is a bad idea. I'm thinking the 2.2 has 1.6 ratio rockers. But even if it doesn't you don't have a MAF sensor and would probably need to tune the prom to see the gains. I don't think you'd gain much anyway. GM engineering tended to max the cylinder head flow for the factory lift so not much gains.
A speed density engine can still realize gains if the Volumetric Efficiency is increased.
Just look at how many are doing fine with performance exhaust systems added.
Also, it isn't like MAF equipped engines don't need tuning to get the most out of upgrades.
Originally Posted By: artificialist
Originally Posted By: mechanicx
I think it is a bad idea. I'm thinking the 2.2 has 1.6 ratio rockers. But even if it doesn't you don't have a MAF sensor and would probably need to tune the prom to see the gains. I don't think you'd gain much anyway. GM engineering tended to max the cylinder head flow for the factory lift so not much gains.
A speed density engine can still realize gains if the Volumetric Efficiency is increased.
Just look at how many are doing fine with performance exhaust systems added.
Also, it isn't like MAF equipped engines don't need tuning to get the most out of upgrades.
True but speed density just goes to eprom calibration to calculate injector pulse width without actually measuring airflow, and is much more limited in compensating for increased VE than a MAF system. I think, not totally sure, the long term fuel trim will probably somewhat compensate at WOT too for the speed density sysstem though.
Originally Posted By: mechanicx
I think it is a bad idea. I'm thinking the 2.2 has 1.6 ratio rockers. But even if it doesn't you don't have a MAF sensor and would probably need to tune the prom to see the gains. I don't think you'd gain much anyway. GM engineering tended to max the cylinder head flow for the factory lift so not much gains.
A speed density engine can still realize gains if the Volumetric Efficiency is increased.
Just look at how many are doing fine with performance exhaust systems added.
Also, it isn't like MAF equipped engines don't need tuning to get the most out of upgrades.
True but speed density just goes to eprom calibration to calculate injector pulse width without actually measuring airflow, and is much more limited in compensating for increased VE than a MAF system. I think, not totally sure, the long term fuel trim will probably somewhat compensate at WOT too for the speed density sysstem though.
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Originally Posted By: Shannow
If an ECM can be designed to work OK given normal production engine variability, plus a couple hundred thousand miles of wear and tear, I don't think changing rockers is really going to overpower it.
Exactly. One of the VERY common Mustang upgrades was to put the 1.7 ratio roller rockers from the Cobra (they were cheap) on the stock HO engine.
If an ECM can be designed to work OK given normal production engine variability, plus a couple hundred thousand miles of wear and tear, I don't think changing rockers is really going to overpower it.
Exactly. One of the VERY common Mustang upgrades was to put the 1.7 ratio roller rockers from the Cobra (they were cheap) on the stock HO engine.
Ok so those kind of rocker arms are type SBC? I thought SBC was something else... Gah, nevermind. Anyway, would I see any real improvement going from those, to roller-tip and higher ratio ones? I mean noticeable enough (primarily in the mid range) to be worth the upgrade? Also, the car is not MAF equipped, all it has is an Intake Air Temperature Sensor.
If you want more power, just rub a few pennies together and buy this for your car.
http://cgi.ebay.com/ebaymotors/96-98-Cav...=item51900f27f4
http://cgi.ebay.com/ebaymotors/96-98-Cav...=item51900f27f4
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Originally Posted By: rudolphna
Ok so those kind of rocker arms are type SBC? I thought SBC was something else... Gah, nevermind. Anyway, would I see any real improvement going from those, to roller-tip and higher ratio ones? I mean noticeable enough (primarily in the mid range) to be worth the upgrade? Also, the car is not MAF equipped, all it has is an Intake Air Temperature Sensor.
SBC = Small Block Chevy
Ok so those kind of rocker arms are type SBC? I thought SBC was something else... Gah, nevermind. Anyway, would I see any real improvement going from those, to roller-tip and higher ratio ones? I mean noticeable enough (primarily in the mid range) to be worth the upgrade? Also, the car is not MAF equipped, all it has is an Intake Air Temperature Sensor.
SBC = Small Block Chevy
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