Tee Koo Posted September 12, 2005 Share Posted September 12, 2005 What are the differences between EA82 and EA82T pistons? How about rods? Quote Link to comment Share on other sites More sharing options...
rallyrx Posted September 12, 2005 Share Posted September 12, 2005 i belive it's just compresion. I was going to put N/A pistons in my Turbo. it changes somthing like from 7 to 9 but i'm no subaru god or anything so chances are i may be wrong Quote Link to comment Share on other sites More sharing options...
Turbone Posted September 12, 2005 Share Posted September 12, 2005 The EA82T pistons are dished and produce a compression ratio of 7.7:1 The EA82 SPFI compression ratio is 9.5:1 The EA82 NA compression ratio is 9.0:1 Quote Link to comment Share on other sites More sharing options...
Snowman Posted September 13, 2005 Share Posted September 13, 2005 The rods, pins, crank, etc are all the same. Quote Link to comment Share on other sites More sharing options...
Tee Koo Posted September 13, 2005 Author Share Posted September 13, 2005 Thank you for your help! So is the piston the only thing that makes the difference between the compression, or is there also differences between the volume of the head's chamber? And what kind of power would N/A engine's pistons handle? Are they as durable as turbo's pistons? Quote Link to comment Share on other sites More sharing options...
Ross Posted September 13, 2005 Share Posted September 13, 2005 Thank you for your help! So is the piston the only thing that makes the difference between the compression, or is there also differences between the volume of the head's chamber? And what kind of power would N/A engine's pistons handle? Are they as durable as turbo's pistons? Yes, it is only the pistons that change the compression ratio - the head makes no difference. The N/A pistons should be just as strong as the turbo ones. Quote Link to comment Share on other sites More sharing options...
Tee Koo Posted September 13, 2005 Author Share Posted September 13, 2005 Yes, it is only the pistons that change the compression ratio - the head makes no difference. The N/A pistons should be just as strong as the turbo ones. OK, thank you! Quote Link to comment Share on other sites More sharing options...
oddcomp Posted September 13, 2005 Share Posted September 13, 2005 jumping on this thread anyone happen to know how much you would need machined off the piston dome to produce about ohh.. 8or8.5:1 compression? Quote Link to comment Share on other sites More sharing options...
JWX Posted September 13, 2005 Share Posted September 13, 2005 just get new pistons Quote Link to comment Share on other sites More sharing options...
oddcomp Posted September 13, 2005 Share Posted September 13, 2005 hmm know where i can get new pistons built to specs for cheap?? versus the potential to have stock spfi pistons milled down a smidge to achieve my goal for little money? Quote Link to comment Share on other sites More sharing options...
JWX Posted September 13, 2005 Share Posted September 13, 2005 it just won't last very long is all I'd add to the turbo ones before I milled off teh SPFI ones Quote Link to comment Share on other sites More sharing options...
Turbone Posted September 13, 2005 Share Posted September 13, 2005 The idea is to mill the turbo pistons to gain a little more comp, as compared to refitting with SPFI pistons. I think it might compramise the ring integrity if they were milled tho. 9.5:1 comp on SPFI pistons is alot for a turbo, altho theres a few running the setup. But its a interesting idea there Oddcomp. Quote Link to comment Share on other sites More sharing options...
Ross Posted September 13, 2005 Share Posted September 13, 2005 If you want to lower the compression, you could try taking some material out of the head. There should be plenty before you hit the water jacket, you might want to try it on an old one first though. Quote Link to comment Share on other sites More sharing options...
Turbone Posted September 13, 2005 Share Posted September 13, 2005 If you take material from the head surface, wouldnt this increase the comp ratio? Quote Link to comment Share on other sites More sharing options...
Ross Posted September 13, 2005 Share Posted September 13, 2005 I'm not talking about planing material off the whole surface, just increasing the volume of the chamber where the valves and spark plugs sit. A die grinder does the trick - i've seen it done on a chevy 8 before. Quote Link to comment Share on other sites More sharing options...
Snowman Posted September 14, 2005 Share Posted September 14, 2005 What about EA81 pistons? Those have a compression ratio of 8.7:1. I don't know if that is created by making the pistons a different height or if it's from head design. Anybody know? Quote Link to comment Share on other sites More sharing options...
oddcomp Posted September 14, 2005 Share Posted September 14, 2005 i think some people are as confused as i am as to what i meant... usally if you mill the whole head surface the comp goes up if you increase the "bowl" in the head to a larger volume usually from porting and polishing ect then your cr goes down if you take your turbo pistons wich are a dished type of setup and you mill down the ridge around the dish they become flat top pistons and since there is less "stuff" in the combustion chamber you lower the cr that way also now going on the theory that the spfi/carb pistons retain the same wrist pin location and ring land locations they are just a taller piston resulting in higher cr so you have extra material then you could safely mill those downa few thousandth of a inch or so and take pistons built for 9. something to something and reduce it to 8. something to something cr so now we end up with a increase in compression for turbo motors but not a huge giant make things go boom type of increase going from 7. something to 9. somthing also i suspect the things going boom due to hi cr in a turbo motor is mostly related to fueling issue's that the stock ecu just can't compensate for .. but thats for another thread feel free for anyone to correct me if i was wrong on any of my points Quote Link to comment Share on other sites More sharing options...
wrw166 Posted September 14, 2005 Share Posted September 14, 2005 +++++++++++++++? How about using thick head gsk? +++++++++++++++ Quote Link to comment Share on other sites More sharing options...
Ross Posted September 14, 2005 Share Posted September 14, 2005 Not a great solution, any of the above methods would be much more reliable. Quote Link to comment Share on other sites More sharing options...
kingbobdole Posted September 14, 2005 Share Posted September 14, 2005 I'm pretty sure that the CARBBED EA82 is 8.5:1 compression..... Quote Link to comment Share on other sites More sharing options...
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