so after doing some small repairs, and a thousand of these "head swaps" for some customers, ive started getting curious if anybody has done the 2.7 pistons etc, into an IX block. im curious because, i do have a turbo, and would like to maximize the benefit of a lower compression ETA/seta setup. im currently at 7psi on a stock HG, and engine w/ 107k... if its possible to change out the internals in the IX block with those of the eta/seta, i think i might give it a go, but i dont want to invest the time if it cannot be done.. anybody hear or bear witness to a stock for stock piston/rod/crank swap? anybody see or bear any personal witness to turbo comparison to SETA pistons vs. ETA? my spare IX engine with a blown ring in cyl. #2 will be put on the stand in short time for some real work. im not looking to maximize power, the boost range will probably bump up to 8 - 10 after doing a complete rebuilt and some better head studs... but im looking for a safe, reliable, fun setup.
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no, nobody on the face of the earth. ;)
but really... while the block and oil pump are different, you can do anything to an ix block that you can do to any other M20.
IMO, though, you're better off rebuilding a 2.5 and boosting that, than piecing together a stroker from junkyard parts - go find some dyno charts for 2.7 "strokers", for the most part (there are exceptions) you make about the same power as an M20B25 only the torque curve gets shifted lower. The compression is lower but the M20B25 already has a pretty nice ratio for boost. -
well, my current turbo in the ix actually is just installed on what was a clean b25 and run only at 5 - 7psi. it ran like this for years, and blew a piston ring in cyl #2.. i do believe it has something to do with the higher compression. now that the cars in my possesion, the results im hoping to achieve are for lower torque curve so that my turbo wont be only effective in the higher rpms like it is currently. this isnt for much tracking and racing, but more to enjoy as my daily, and perhaps the occasional autocross events. i dont have the intentions of driving this car very hard at all, thats what my RWD is for :)
being said this build will be done responsible, and though i do understand its very common and almost "amateur" as it is for being a "stroker", this is about as wild as ill be going with this motor. ive considered custom pistons, or cams, or both.. nando again, you have me completely inspired to follow your footsteps, but i dont think it will work out this way for me.. just looking to work with what ive got.
the ETA pistons, rods, and crank also arent just out of any unknown engine. i do have a very clean block with a known 110k on it also, but if alls installed in the ix block, will definitely be getting professionally cleaned thru and through, all re-installed with new rings, bearings, freeze plugs, seals etc... i only wish to lower the compression so i can still utilize stock headgasket and not be afraid to bump up my psi roughly <5lbs. a head resurface with a higher RA rating than whats needed to go with a MLS gasket will have me feeling confident enough.Comment
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[/SIGPIC]"we are so totally screwed!"Comment
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it broke a ring land at only 5-7 psi? how was it being tuned? was it still using Motronic? 8.8:1 isn't really "high" compression, it's almost ideal for boost using efficient parts and good tuning. being a "low boost" setup my gut feeling is it was never tuned and that's why it broke.Originally posted by imwhyteyo View Post
a turbo only being effective at high RPMs probably means it's either the wrong turbo, it's old and not efficient, or it's not setup correctly (wastegate issues, boost leaks, etc). Going from 2.5 to 2.7 with lower compression isn't going to help that significantly. the shape of the torque curve between the two isn't so different that you're going to reach boost 1500rpm sooner or something.
well, sometimes you just gotta do what you gotta do. :)being said this build will be done responsible, and though i do understand its very common and almost "amateur" as it is for being a "stroker", this is about as wild as ill be going with this motor. ive considered custom pistons, or cams, or both.. nando again, you have me completely inspired to follow your footsteps, but i dont think it will work out this way for me.. just looking to work with what ive got.
the ETA pistons, rods, and crank also arent just out of any unknown engine. i do have a very clean block with a known 110k on it also, but if alls installed in the ix block, will definitely be getting professionally cleaned thru and through, all re-installed with new rings, bearings, freeze plugs, seals etc... i only wish to lower the compression so i can still utilize stock headgasket and not be afraid to bump up my psi roughly <5lbs. a head resurface with a higher RA rating than whats needed to go with a MLS gasket will have me feeling confident enough.
the gasket isn't what failed the engine before so I'm not sure why you want to lower compression so you can use a stock gasket, when you can already use the stock gasket and a decent amount of boost. really, 8.8:1 isn't so high that your engine will explode just because of that one fact. There are lots of boosted stock M20B25s out there. I think some crazy swedes built one to something like 800hp (ok, the internals were all stock, and the rest was well.. crazy swede stuff).
my point is more that you will want to pay attention to the tuning because that is most likely the reason the previous motor had trouble, not because of the mild compression ratio. this applies whether you are building a 2.5 with stock compression or a 2.7 frankenmotor. it will still pop if it's not tuned even if the CR is half a point lower than it was before.
fortunately for you there are tons of inexpensive tuning options that didn't exist 5-10 years ago when "low boost" setups with an ebay chip and a RRFPR were popular!Comment
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I try ....Originally posted by nando View Postthanks for your potent contribution to this thread!
[/SIGPIC]"we are so totally screwed!"Comment
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