bobjr94 Posted February 20, 2008 Share Posted February 20, 2008 Since I just put in a 5 speed trans I may as well keep the ea81. I would like to know how has spfi and how did it effect power & mileage ? Im sure it will run better, or run better more consistently. But since I drive the brat 110 miles a day gaining a few mpg's would be well worth the swap. Quote Link to comment Share on other sites More sharing options...
carfreak85 Posted February 20, 2008 Share Posted February 20, 2008 Since I just put in a 5 speed trans I may as well keep the ea81. I would like to know how has spfi and how did it effect power & mileage ? Im sure it will run better, or run better more consistently. But since I drive the brat 110 miles a day gaining a few mpg's would be well worth the swap. Have you tried using the search function? :cool: Quote Link to comment Share on other sites More sharing options...
Pooparu Posted February 20, 2008 Share Posted February 20, 2008 I know that GeneralDisorder has done this in his BRAT. He also has done a write up on the swap (it's very good). Quote Link to comment Share on other sites More sharing options...
bobjr94 Posted February 21, 2008 Author Share Posted February 21, 2008 I tried searching but didnt see anyone with before / after mileage. I was looking for someone who actually has done it. Ill ask GD about his swap then. Most spfi threads I found end up with people arguing about just putting on a weber vs an fi swap and if they are going to do a FI swap put in a ej motor. Quote Link to comment Share on other sites More sharing options...
kingbobdole Posted February 21, 2008 Share Posted February 21, 2008 I did it to my lifted BRAT.... I had a REALLY CRAPPY and Rigged carb before(not my own device) and did the swap... I got about 32 MPG and it'd make it past 90 MPH (but start overheating at that point ) All and all a great swap, with much better drivability. It was the second SPFI swap I did... my first was to my lifted wagon which I still run... I've had some recent problems with it and water getting my coolant temp sensor... but I was managing about 25 MPG with my 29"s... Here's the both of them... Quote Link to comment Share on other sites More sharing options...
bobjr94 Posted February 22, 2008 Author Share Posted February 22, 2008 If you can keep 32mpg i would do it then. Mine ranges from about 28-34 depending on how its running today and how cold it is. I would like to have more consistency so that will be the next on my list of things to do. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted February 23, 2008 Share Posted February 23, 2008 The mileage increase is negligible at best. A properly tuned and running feedback Hitachi could turn in similar mileage numbers. Count on 1 to 2 MPG increase over properly tuned stock carbs, better driveabilty and easier maintenance. The performance is going to be largely the same without futher supporting modifications such as a larger mid-pipe and muffler, higher compression pistons, larger valves in ported heads, and a recurved cam. You'll get somewhat better throttle response and better off-the-line torque. But the top end will be virtually unchanged. Adjust your valves if you have solid lifters. Can't stress that enough to EA81 owners. GD Quote Link to comment Share on other sites More sharing options...
bobjr94 Posted February 23, 2008 Author Share Posted February 23, 2008 Thats the problem, keeping a carb tuned. I drove home in 102 degrees last summer and its been as cold as 17 this winter and carbs cant compensate for that. Some good electronic feedback carbs with coolant temp and oxygen sensor can maybe half way but not the mechanical open loop system like my brat had. When I got mine it ran like crap and sometime would almost die out. Its hard to diagnose all the mechanical valves and vacuum switches, so I took off all the feedback stuff and rejeted the carb jets a few #s smaller and its run pretty good since then. This is the first car with a carb I have had in a long time and Im not missing my fuel injection. Also a f/i swap could get rid of the mechanical advance distributor and failing vacuum advance. Quote Link to comment Share on other sites More sharing options...
kingbobdole Posted February 23, 2008 Share Posted February 23, 2008 ^^ thats one of the reasons I converted the wagon.. my carb was failing and I had no love to rebuild it. There is also another advantage if you might wheel it... No upwards fuel starvation. But in my boo, the drivability and lack of maintenance is well worth it... Ohh! and On my wagon, thanks to the lack of compression, I run a snot load of timing... really makes her move. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted February 23, 2008 Share Posted February 23, 2008 Thats the problem, keeping a carb tuned. I drove home in 102 degrees last summer and its been as cold as 17 this winter and carbs cant compensate for that. Some good electronic feedback carbs with coolant temp and oxygen sensor can maybe half way but not the mechanical open loop system like my brat had.. Depends on the carb. Hitachi feedbacks ARE closed loop systems - all of them. The non-feedbacks are simply carbs - there's no feedback loop at all - closed or otherwise. When I got mine it ran like crap and sometime would almost die out. Its hard to diagnose all the mechanical valves and vacuum switches, so I took off all the feedback stuff and rejeted the carb jets a few #s smaller and its run pretty good since then. Hhhhmmm - well I wouldn't have done it that way. At least not without some serious analysis of the function of all those items, and a wideband to tune it with. But if it works for you - great. The time investment of tuneing a carb by seat-of-the-pants is far too great for anything less than a track only car IMO. This is the first car with a carb I have had in a long time and Im not missing my fuel injection. Also a f/i swap could get rid of the mechanical advance distributor and failing vacuum advance. The vac can's can be rebuilt for about $25. There's nothing wrong with carbs. The only thing really "wrong" with them at this point is they are all old and worn out, and the rebuild parts availible are of poor quality and come in highly generic "kits" that often do more harm than good. They are also very complicated for the home mechanic to work on and they contain a lot of miniturized mechanical parts that are sometimes difficult to put back the way they came out. The SPFI is not without it's issues - for an FI system it is primitive. It has very little self-diagnostic abilities, and unless a full understanding of it's systems and theory of operation is grasped, it can be difficult to adapt. The wireing is also a pretty large project for most people. GD Quote Link to comment Share on other sites More sharing options...
XT6 Magic Posted January 23, 2009 Share Posted January 23, 2009 It's well worth doing though. My EA81 in the wagon has never run so well. GD's writeup is perfect. -Jeff Quote Link to comment Share on other sites More sharing options...
mountaingoatgruff Posted January 23, 2009 Share Posted January 23, 2009 i can't speak for my hatch in it's carb'ed days - i only had it a week before injecting it. it's carb was shot and missing parts from an earlier "rebuild." my average mileage with about 40% city & 60% highway driving and the d/r 4speed was up to 34mpg per tank (i did the math for every tank and it depended entirely on my driving style - i got as low as 22mpg once). it had plenty of pep and ran like a champ. only problem i ever had with it was with the egr solenoid. if you go injected, use newer nippon denso solenoids - the hitachi ones are poo. you can get the nd ones from newer subes. some folks remove those solenoids but i'm in cali and violating smog laws is not cool. Quote Link to comment Share on other sites More sharing options...
mellow65 Posted January 26, 2009 Share Posted January 26, 2009 GDs great write up http://home.comcast.net/~trilinear/EA81_SPFI.html Quote Link to comment Share on other sites More sharing options...
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