Leggyobw97 Posted March 9, 2019 Share Posted March 9, 2019 The OE cast iron pully is certainly *much* cheaper to make than the billet aluminum fully machined after market pully. Although retail for aftermarket parts is typically a fraction the cost of a stealership part. That is the reason I put a light weight pully on when my OE got damaged. $100 vs. $170, at least at that time. That was almost 15 years and about 150,000 miles ago. And I drive it kinda like a racecar. Lots of harsh rpm sweeps and full throttle. So I'm very sure that the perfectly balanced in first and second order vibrational moments H4 will not blow up if you use a light weight pully. There are some stronger third order vibrations created by the right, right, left, left firing order, but that bears on the engine mounts and main bearings rather than the crank. Also, the H4 has significantly less torsional vibration than a V since the firings are evenly spaced in time rather than having a stutter when the engine crosses from one bank to the other. The only difficulty I've heard of with reducing rotational mass with the H4 is if you are going to use a significantly less advanced/optimized engine management system such as Megasquirt with the 6 tooth crank position sensor. If you have a light weight pully *and* a very lightened flywheel you can allow enough variation in rotational speed between the very few sensor teeth to confuse the less advanced computer. That can be fixed by using a more modern crank timing sprocket with 36-2-2-2 teeth. Does that crank timing sprocket match right up to the EJ25D? My engine was replaced by a shop 5 years ago and they put a newer one in... the only difference I've noticed is that I think this one has a smaller intake manifold. The ignition coil for my VIN was too large for the new manifold. Everything else has matched up. And if it does, do you have a part number for it? In the event I do decide to go down that road with lightened flywheel and crank pulley. Link to comment Share on other sites More sharing options...
doublechaz Posted March 9, 2019 Share Posted March 9, 2019 I'm not (yet) an engine swap guy. So I know some stuff about it, but I don't know which parts cross or their numbers. But you can't switch tooth counts without switching computers to match, and then a metric crap-ton of other wiring things don't match up. Most people swap the computer and wiring harness when they swap mismatched engines. If you are dropping the OE computer and going to Megasquirt or some other aftermarket programmable computer, and never going back to OE, then you can swap the tooth count because you can just tell the megasquirt about the tooth count change. Link to comment Share on other sites More sharing options...
Leggyobw97 Posted March 9, 2019 Share Posted March 9, 2019 I'm totally lost on that ECU stuff. I was looking at some piggyback modules, but its all foreign to me. Can you give me some links to check out? I feel like if I type "megasquirt" into google I'm gonna get some uh, profane material. I'm eventually going to want a tunable ECU, once I go down the road of modifying my air intake/exhaust, and I'm never selling this car, so I'm not worried about making major changes like a totally new ECU, IF it means added performance without sacrificing the ability to daily the car. I should start a new thread, because I have a lot of questions about ECU tuning, with regard to deleting EGR, under what circumstances you'd use a JDM ECU, how to get rid of the fuel cut at 113 mph, and the stuff I already mentioned. Link to comment Share on other sites More sharing options...
choover1101 Posted March 9, 2019 Share Posted March 9, 2019 Not saying this is the best route, not saying its a bad route either, but since you asked... https://r.tapatalk.com/shareLink?url=https%3A%2F%2Fwww%2Ers25%2Ecom%2Fforums%2Fshowthread%2Ephp%3Ft%3D230918&share_tid=230918&share_fid=8898&share_type=t Sent from my SAMSUNG-SM-N910A using Tapatalk Link to comment Share on other sites More sharing options...
doublechaz Posted March 9, 2019 Share Posted March 9, 2019 You can start with Megasquirt here: https://www.diyautotune.com/ Yes, I expect googleing that could be risky. They have options to buy one ready to use out of the box through to you solder the whole thing together before you ever start on the car. I'm not sure it's the best way to start out. You would certainly learn a lot with them. I think Haltech is a more finished and polished way to go, but then it costs a lot more. https://www.haltech.com/ I'm sure there are a number of others that would beat these guys in various ways. Note: I haven't used any of these yet so I don't know what pitfalls there may be. YMMV. Link to comment Share on other sites More sharing options...
Leggyobw97 Posted March 10, 2019 Share Posted March 10, 2019 It looks like the Megasquirt relies on an external MAP sensor, but our engines use MAF. It also looks like you'd need a special type of ignition coil. The Haltech website only listed products for the WRX, not the Legacy. Didn't they use MAP? So it's not just the ECU, you'd need to figure out how to convert the EJ25D to MAP and wire up an external-spark ignition, or something like that? Link to comment Share on other sites More sharing options...
doublechaz Posted March 10, 2019 Share Posted March 10, 2019 The Megasquirt has a MAP sensor in the ECU itself, you have to run a vacuum line from the intake to the ECU. I think it can drive our coil directly, but you might have to have an option in the ECU. It's an ECU that you build yourself, so options are possible. The Haltech is capable of pretty much anything, but you may have to change some things and you'll do a lot of wiring. As far as I've seen all the ECU options involve serious mods, redesigns, mega wiring, etc. I don't believe anyone makes a dropin ECU solution for our cars. I also haven't seen a currently produced piggyback system for our cars, just things that were made many years ago. If you spot a current piggyback system, I'd appreciate a link to it as I've exceeded the capabilities of the OE ECU with the few mods I've done. Link to comment Share on other sites More sharing options...
Leggyobw97 Posted March 10, 2019 Share Posted March 10, 2019 I was checking out some of the stuff here: https://www.nengun.com/subaru/legacy-touring-wagon-bg5/electronics#m:90;c:334;u:1;g:2 Namely the HKS Speed Limit Defencer, because with a stock engine, my biggest problem is not being allowed to go over 113 mph. Eventually I may want to do some of the mods I mentioned, and that's when I would need a re-programmable ECU. It looks like a lot of those products in that link are for the EJ20 though, not sure if they're compatible with USDM EJ25. Link to comment Share on other sites More sharing options...
doublechaz Posted March 10, 2019 Share Posted March 10, 2019 What year did the 113 limit come in? I've had my 1995 5MT up to 125. Does your speedo work normally after installing that thing? Without changes to the code in the ECU the only way I can see to bypass a speed limiter is for that thing to lie to the ECU about what the speed sensor is reading. That would be fine on a track where track gear will give you your speed, but for something like driving on the Autobahn you wouldn't know your true speed. Link to comment Share on other sites More sharing options...
JaxSubie Posted March 10, 2019 Author Share Posted March 10, 2019 Ordering a few suggestions you guys have given this week so that I can stock some parts up and jump in for a build in a weekend. UNFORTUNATELY my breaks are sticking and I have to order calipers and rotors all the way around before I can play with my motor any. I want to upgrade the system so I'm going with braided stainless steel lines. Any leads on some affordable companies for calipers and rotors? Some of the research I've done is pointing to a pretty expensive job to upgrade all four tires. Sent from my Pixel 2 XL using Tapatalk Link to comment Share on other sites More sharing options...
doublechaz Posted March 10, 2019 Share Posted March 10, 2019 Feels like tires have gone up over recent years more than other stuff. Maybe it's just that we don't buy them as often. But the four tires do cost. I like the idea of the stainless brake lines. I got a small improvement in pedal feel with the master cylinder brace, but that is probably a more expensive way to go for the amount of change. It's time for me to do my front brakes as well. A little binding going on and uneven direction on stopping. I guess it has been 50k. Link to comment Share on other sites More sharing options...
Leggyobw97 Posted March 10, 2019 Share Posted March 10, 2019 What year did the 113 limit come in? I've had my 1995 5MT up to 125. Does your speedo work normally after installing that thing? Without changes to the code in the ECU the only way I can see to bypass a speed limiter is for that thing to lie to the ECU about what the speed sensor is reading. That would be fine on a track where track gear will give you your speed, but for something like driving on the Autobahn you wouldn't know your true speed. I'm not sure which models/years did and didn't get it the speed limiter, but I do know the GTs typically don't have one. Maybe I could swap in an ECU from one of those? You might be right about the HKS module, it says it's designed for use on the track. Did you see the Greddy EMS on that page? Would be nice if we could use something like that. They sell the wiring link for the EJ20, maybe it matches up to the EJ25? The ad says to check the mfg website for other vehicle wiring links, but I got a 404 error when I tried to check. Link to comment Share on other sites More sharing options...
doublechaz Posted March 11, 2019 Share Posted March 11, 2019 The place to start for ECU swapping is to look at the factory wiring diagrams for the car in question and the donor ECU car. If every single pin matches, and you check part cross for each sensor for each car then you may be able to swap pretty easy. If All the sensors match up but they are on different pins at the ECU there is a way to take the wires out of the connector one at a time and move them so things match up. If Greddy makes an adapter harness that matches your car exactly then that would be an easy swap to the ECU they say it is for. That is the kind of thing you need to put an aftermarket ECU in easily. Or you can make that adapter harness yourself from the factory manuals mentioned above. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.