backinbrat Posted January 7, 2007 Share Posted January 7, 2007 alright there everyone, ive got the engine out of my suby, tis an EA81, 1988 UK model, im assumeing its exactly the same as everyone elses! lol right, so im looking at doing some performance work on it, the main reason was to basically refresh it, as after 19 years of use, its pretty carboned, crapped and just generally used, lol, it has been maintained, i can tell, theres always been plenty of oil in it, theres always been antifreeze in it, no cracks, no nasty noises, so i think its a good block to be working on, i just want to upgrade it a bit. i was looking at these mods for it -balanced bottom end -shave the heads (anyone know whats the best for rally application compression wise and stuff, i can get 98 octane at the pumps if that helps) -do a good bit of porting and polishing -possibly performance camshafts, valve springs, and lifters obviously all new rings and shells and some low friction assembly lube -are stainless valves worth it? or is it just as good to clean up the valves and make them oober smooth? theres also all the other bits and bobs -dual carbs, maybe -advancing the timing, i heard something around the 12 degree mark is good, am i right in saying that? correct me on any of this if im wrong! -silicone HT leads, some new NGK's, and ive got a new performance coil -ive also heard of lightend flywheels, and they can be done whilst having the bottom end balanced, so ive heard, also on a thread about these ive heard that they will -NOT reduce torque -NOT change the torque curve for the worse (WILL look better) -make it easier to stall -make your clutch easier to overheat (You are lightening your heat sink) -NOT change your gearing -NOT make it harder to accelerate up hill all that true? lol remind me if ive left something obvious out which is a performance tweak/mod all this is probably edging towards £700, thats probs about $1400 US, and to be honest, here in england, it aint to bader price, things are f**ing expensive over here, or they end up being so when shipped, lol my eventual aim for at least one of my trucks is sort of a rally spec machine, and to just plop a EA82 in (which are quite hard to find here) and i dont want the hastle of bloody ECU's and such, i just dont want the hassle, the same with EJ's but with these its the price! woo! maybe when im older and have the money though! give us your thoughts and opinions, please, no argueing! ive seen it happan enough times on other threads! ideally i wouldnt mind some useful info out of this anyone also know what sort of power i might be putting out at the end of it all? im sorta guessin the 110-120 mark, and hopefully more torque, im not worried bout any of this 'seems like lost torque crap' ill just buy a performance clutch, lol once again, things that are to put into consideration -98 octane pump fuel is no problem to get hold of, can get higher -this is more focused towards rally application, im getting the tyres and wheels, and having a stripped out race interior, bucket seats, 4 point race harness etc -everyday 'driveabilty' is not really much of a bother (how smooth it runs blah blah) basically i want it noisey, fast (for what it is) unforgiving and harsh oh, and whilst were at is, dose anyone know why rally cars pop and bang when changing gears and stuff, as far as i no tis the turbo, but, i have heard km1 escorts and such doing the same, well thats what i would like mine to do LMAO! hope you all had a good christmas and have a fun filled 2007! soz for the long post, keeps ya entertained though! thanks for bothing to read to! Quote Link to comment Share on other sites More sharing options...
Ross Posted January 8, 2007 Share Posted January 8, 2007 Hey, sounds like you're on the right track, apart from maybe shaving heads.... you can't really reduce their height by much without having to modify or make a new intake manifold... You can put pistons for other engines (I think ea71 pistons will give you higher comp?) in to do the same. Definitely do the cam, thats one of the cheapest bits to do.... "Port" the intake manifold gaskets a bit to match the holes in the head and intake manifold. Should go well.... Keep in mind that the ea81 flywheel is resonably light to start off with.... Thought of finding some ea81t heads etc for it? I rebuilt one last year for my 83 wagon, they are a nice wee engine once you've got them sorted... Quote Link to comment Share on other sites More sharing options...
Phizinza Posted January 8, 2007 Share Posted January 8, 2007 Keep in mind that the ea81 flywheel is resonably light to start off with.... Don't mean to be rude, but compared to what??? Have you got the 200mm clutch or the 225mm one? The 225mm one has a slightly lighter flywheel, but still much heavier then something you would find on an italian car.. If I was doing something other then just adding a weber I would probably either go for GD's SPFI EA81 kit or build something myself with MS. If you want to stick with carbs have a look at making (maybe modifying) custom intake manifolds, one for each head so the carbs are directly ontop. This gets rid of two 90degree bends the air has to take. I had an idea about cutting the old manifold up and welding a new alloy pipe to it then making a alloy block to fit a weber or something to go ontop of that pipe, but it would be a lot of work (sorry for the poor explination, I gotta go now so...) Quote Link to comment Share on other sites More sharing options...
Subaru_Mechanic Posted January 8, 2007 Share Posted January 8, 2007 Do your carb! jet it and get all the mods you can done to that thing. i have a EA71 with a carb (duh) and i took it apart and jetted it and WOW! the thing was mean. Ex :(sunny summer day) I was in enumclaw stopped waiting to cross on to 244th and there was a chevy 1500 low rider on the other side waitig to cross on to the road where i was. the guy sees me and revs his engine making his truck sink on one side like a muscle car does, so i do it back, i started with little revs and then the final high with the crackle at the peak...(bwam bwam bwaaaambaaaa) so out came this deep loud roar (cut pipe just under my seat) and the guy opens his eyes and starts laughing thinking its just loud. (traffic is passing this whole time) altho my (79 brat:cool: ) EA71 wouldnt shake my car it did make the front end lift up... well the traffic stops and he starts to rev up his big V8, before he even had the chance to move my well tuned quick responce EA71 reved up faster then lightning and i popped that clutch the front end lifted up high and barely started moving, before i got to 8 mph i was in secong gear revin 5k, i hit third gear at he finally started to pass me leaving that big truck breathin my victory smoke...:cool: there are more times but are lenghty stories. lol but yea i recomend the carb job. its will somke ur tires off:headbang: Quote Link to comment Share on other sites More sharing options...
Ross Posted January 8, 2007 Share Posted January 8, 2007 Don't mean to be rude, but compared to what??? For starters an ea82, and many other passenger vehicles. There is a slight difference in purpose between an engine for an italian supercar and one for a japanese passenger car..... Lightening your flywheel can turn the engine into a pig without giving any huge benefit.... Quote Link to comment Share on other sites More sharing options...
Phizinza Posted January 8, 2007 Share Posted January 8, 2007 There is a slight difference in purpose between an engine for an italian supercar and one for a japanese passenger car.. I don't think he wants a japanese passenger car. I think he wants a power house rally machine (which I don't think a EA81 can really do, but it's fun to try, right?) I'm not talking italian supercars. I'm talking Fiat sedans... I'm not quite sure what you ment about the EA82 flywheel, as the flywheel in both my 89 Brumby and my Brothers 83 wagon are the same as the EA82 one. Here in Australia in 85 the Brumby's (only EA81 here in production from 85 onwards) used the 225mm clutch. So I can only guess that in other countries the EA81's only came with 200mm clutches and the 225mm type flywheel is lighter. But other wise I don't see a difference from a 225mm EA81 flywheel to a 225mm EA81 flywheel. Quote Link to comment Share on other sites More sharing options...
Ross Posted January 9, 2007 Share Posted January 9, 2007 I don't think he wants a japanese passenger car. Who does? but thats what we've got, not matter how hard you try! The ea81/ea82 comparison was just something i heard.... haven't compared them myself.... Quote Link to comment Share on other sites More sharing options...
Phizinza Posted January 9, 2007 Share Posted January 9, 2007 Who does? but thats what we've got, not matter how hard you try! The ea81/ea82 comparison was just something i heard.... haven't compared them myself.... Ok, cool. I understand now. The Brat is a pretty stupid japanese passenger car though, hey.. Only thing going for it is a little less weight and it's looks. Quote Link to comment Share on other sites More sharing options...
86BRATMAN Posted January 9, 2007 Share Posted January 9, 2007 heres a method i've seen talked about and considered if i were to keep the ea81 in my brat.... step 1. pistons) ea71 1600 series engines us the same bore size as the ea81, they have a bigger compression area, i'm not sure how much bigger or anything but i know putting these in the ea81 would raise compression, the ea71 have a comp ratio of 9.0:1 comprared the the ea81's 8.7:1, they use the same wrist pin height, so a swap of this wouldn't be too hard for someone with the proper tools and knowledge of how the motor comes apart step 2, cam) the small aircraft industry uses the ea81 for a lot of applications, there are many companies that offer cam regrinds of your stock cam, a list of some of these can be found on www.subarubrat.com, depending on what grind you go with(how much material they remove) you would need to have your heads shaved by the same amount so that your stock push rods would be the right length... one company for instance offers a regrind that removes .040" from the cam to make the new lobes, your heads would need to be decked the same amount step 3, heads) simple, have them decked, it'll further raise compression, also a port job could be done at the same time, but keep in mind the power band you want to operate in, the larger the port job the higher in the band your power curve is moved step 4, feed it) take into consideration all that you have already done here and either re jet your existing carb or look around for an upgrade... if you can find a 2wd ea81 laying around somewhere that carb caomes stock with better jetting than the 4wd does, also get the distributor from said 2wd car as they have a better advance curve built into them sorry its a little lengthy, hope it makes some sense Quote Link to comment Share on other sites More sharing options...
mikeshoup Posted January 9, 2007 Share Posted January 9, 2007 heres a method i've seen talked about and considered if i were to keep the ea81 in my brat.... step 1. pistons) ea71 1600 series engines us the same bore size as the ea81, they have a bigger compression area, i'm not sure how much bigger or anything but i know putting these in the ea81 would raise compression, the ea71 have a comp ratio of 9.0:1 comprared the the ea81's 8.7:1, they use the same wrist pin height, so a swap of this wouldn't be too hard for someone with the proper tools and knowledge of how the motor comes apart Easier, is to find some EA82 pistons. An EA82 might be easier to find then an EA71. Then you have choice of 9:1 pistons, or 9.5:1 pistons. Same bore, same wristpin height, etc as an EA81 piston. step 4, feed it) take into consideration all that you have already done here and either re jet your existing carb or look around for an upgrade... if you can find a 2wd ea81 laying around somewhere that carb caomes stock with better jetting than the 4wd does, also get the distributor from said 2wd car as they have a better advance curve built into them These are mostly myths. On the carb, the Jetting is almost the same. The secondary for the 2WD MT and AT, and 4WD AT is 145, whereas the jet 4WD MT has a 140. The other difference is the 2WD has a primary air bleed of 60, and the 4WD has one of 70. I don't see either of those making a huge difference at all. The advance curve on the disty though is not different. That's a myth. The FSM even shows the same exact advance curves for the two of them. Quote Link to comment Share on other sites More sharing options...
Phizinza Posted January 9, 2007 Share Posted January 9, 2007 Easier, is to find some EA82 pistons. An EA82 might be easier to find then an EA71. Then you have choice of 9:1 pistons, or 9.5:1 pistons. Same bore, same wristpin height, etc as an EA81 piston. I'm not 100% sure, but doesn't the EA82 run the same pistons as the EA81. It's the EA82 SPFI that has the more compression ratio. Standard EA81 compression in my FSM says 9.0 to 1. Which is the same as the EA82 specs. We didn't get EA82 SPFI here in Australia so I'm not too sure you see. I've heard the EA71 pistons are higher then 9 to 1, but not as good as SPFI EA82 ones. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 9, 2007 Share Posted January 9, 2007 Why don't you do some searches? This has all been covered, beat down, and discussed to death. By me, and lots of other folks that have already built hi-po EA81's and actually know what they are talking about :-\ 50% of the info given here is wrong, and half of the remaining 50% is incomplete at best. GD Quote Link to comment Share on other sites More sharing options...
Subaru_Mechanic Posted January 9, 2007 Share Posted January 9, 2007 actions are better then words. i suggest you do it and see. just from my carb job i went from okay acceleration and puttin around to roastin tires and hittin 90 mph easy.... Quote Link to comment Share on other sites More sharing options...
backinbrat Posted January 9, 2007 Author Share Posted January 9, 2007 this is some sound advise, the SPFI pistons are best for compression, EA71's are better than standard EA81 though, yes? the carbs need to be more focused on it also seems that the EA81 is not the greatest engine on earth, BUT its what i have, and something simple that i can work with, this is really the first time ive stripped a car engine this far, ive done mowers and stuff (yes, laugh all you want!) and i know how it all works, i would probably move on to ECU's and all that later on in life, i just wanna see if i can get this old kid stripped, cleaned, tuned, gasketed, and all back together again! tis a shame that the EA81 aint the best engine for high performance, but thats the way it goes and for EA81T parts, dont go there, ive NEVER seen one in real life, and i doubt i will, the closet thing is the gaske set ive got which says 'EA81(T)' lmao! as for this EA71 with the carb job, sounds like a mighty difference it has made, i got probs another say 7hp at a guess from doin that coathanger thing! lol, was getting 60 at a push across the field, after the mod, it was nearin 70! WOOOOOOOOO! Quote Link to comment Share on other sites More sharing options...
SakoTGrimes Posted January 10, 2007 Share Posted January 10, 2007 Won't be nearly as fun, but it would be much simpler and probably cheaper to just install an EJ from a wrecked Legacy or Impreza Quote Link to comment Share on other sites More sharing options...
Phizinza Posted January 11, 2007 Share Posted January 11, 2007 this is some sound advise, the SPFI pistons are best for compression, EA71's are better than standard EA81 though, yes? I believe the EA71 pistons are slightly better then standard EA81 pistons for compression. Quote Link to comment Share on other sites More sharing options...
86BRATMAN Posted January 12, 2007 Share Posted January 12, 2007 Easier, is to find some EA82 pistons. An EA82 might be easier to find then an EA71. Then you have choice of 9:1 pistons, or 9.5:1 pistons. Same bore, same wristpin height, etc as an EA81 piston. These are mostly myths. On the carb, the Jetting is almost the same. The secondary for the 2WD MT and AT, and 4WD AT is 145, whereas the jet 4WD MT has a 140. The other difference is the 2WD has a primary air bleed of 60, and the 4WD has one of 70. I don't see either of those making a huge difference at all. The advance curve on the disty though is not different. That's a myth. The FSM even shows the same exact advance curves for the two of them. thanks for the info, i was going by my mechanic and his things he told dad a few years back when i had my white brat, we swapped carbs and distributors from my brother's wrecked car and it seemed to make a good difference, but my parts could have just been in bad shape Quote Link to comment Share on other sites More sharing options...
Phizinza Posted January 12, 2007 Share Posted January 12, 2007 but my parts could have just been in bad shape That's a very good point to bring up... A lot of gutlessness is blamed on it being a old design. But I believe (from expierence) that most of the time you can get a good 10 to 20hp out of an old engine with a complete rebuild of all the things that wear down. New disty points, springs, weights, rotor, cap. New carb or carb rebuild, new air filter. New bearings, seals everywhere. New valve seats, maybe even valves. You get the point.. By brother got a wrecked 82 wagon, it's engine looked very much rebuilt. It had 170PSI in all four cyliders. And I reckon it is cranking out 80hp with the stock EA82 carb. It's very close match to a mates EA82 with a weber. Just lacking in the torque department. Quote Link to comment Share on other sites More sharing options...
BoostedBalls Posted January 13, 2007 Share Posted January 13, 2007 all this is probably edging towards £700, thats probs about $1400 US, and to be honest, here in england, it aint to bader price, things are f**ing expensive over here, or they end up being so when shipped, lol Wow, For that kind of dough, I would drop in a turbo long block with a blowthrough carb setup, or even a drawthrough. Either way, the Side draft delorto loves the turbo. See what 200hp feels like in that little car. Quote Link to comment Share on other sites More sharing options...
82bratavenger Posted March 10, 2007 Share Posted March 10, 2007 I would do as GD has suggested and run some searches of the forums and see what is already there. I am currently in my second year of auto tech classes and the 16+ years I have been working on vehicles is now starting to make sence. GeneralDisorder knows what he is talking about and is based on experience and study. Just my 2 cents. Take others ideas and do your own research. Quote Link to comment Share on other sites More sharing options...
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