Subaruist Posted May 1, 2014 Share Posted May 1, 2014 I am curious about three possible versions of engine for 2nd Gen EA81/82 type Subarus. I prefer the Carbureted engines with no timing belt, and will have nothing to do with any engine using a timing belt. Nope, nope, nope... I think the Carbureted engines are far more reliable and durable, especially under harsh circumstances or even neglect. There are obvious performance points with fuel injection, no doubt, but it has its own weaknesses as well. Maybe a Turbo could out race me on the street, but you can only go so fast on narrow, winding dirt roads. - where delicate air filtration would not likely breathe too easily for long. I would love to be able to put turbo onto a carbureted engine which has no timing chain - something in the shadows of my forgotten experience tell me its not just possible, but maybe even one version of stock engine of this or similar description existed. What I fantasize about is a dual carb, dual turbo engine! (if that's possible) - I would probably have to cut away most of a hood to do it right, but I would love it - is this possible? - Is it possible without having an effective degree in automotive mechanics improvisation ? Please do tell! Link to comment Share on other sites More sharing options...
GeneralDisorder Posted May 2, 2014 Share Posted May 2, 2014 Turbochargers themselves are relatively "delicate" and need proper air filtration or you will blast the aluminium compressor wheel with debris and erode it - not to mention destroy the "delicate" mechanical seals. Though I would not characterize the fuel injected air filtration systems as "delicate" - in fact they are very little different than the carbed models. Most automotive carbs run horribly off-angle and getting them to deal properly with higher-than-atmospheric pressure is challenging at best and depending on the carb model may be impossible at worst. Subaru never attempted it AFAIK. EA81T's were MPFI. Your fear of timing belts and chains is completely unfounded in the Subaru world. In 17 years of working on and driving thousands of Subaru's I have NEVER seen a timing belt break. Tensioners, idlers, and water pumps fail if not replaced every 100k or so - these can *lead* to belt skipping and/or failure. Belts never break on their own in my experience. Chains are even better and often last the lifetime of the car. Belts and chains are efficient, quiet, and VERY reliable. In fact the last time I saw a belt break was on about a '96 Camry 4 cylinder. It did no permanent damage. GD 1 Link to comment Share on other sites More sharing options...
Subaruist Posted May 2, 2014 Author Share Posted May 2, 2014 (edited) Thanks for the info - concerning timing belts, It's a preference, and also a milestone of sorts to me... On one hand, I love the simplicity of the original engine types, and if you can build a good vehicle without a timing belt, that performs admirally, then why add one? Thes older engines if nothing else prove that you don't need a timing chain/belt. Also, I have a real thing about when Subaru decided to get fancy, and went 'boxy', and they became like other normal, mundane vehicles. I don't need a timing chain, I don't want a timing chain, I don't care what they do for a vehicle, lol... On the other hand, the Brat I just got, looks like I might go "Street" with it for the most part, and for that a turbo seems a possibility, and would make it just a bit more sexy, but from what I know, and what you just confirmed for me, that would mean not being able to use it in rough, dirty long-term off-roading. Regarding this problem with Carbs and altitude. I have been more or less aware of this issue from the start, but honestly have never seen it happen in any Subaru I have owned, which was 1st and 2nd gen models. I have spent a lot of time in the mountains, usually above 4,000 feet, and often above 14,000, with California and non-california models, and it is very unlikely that every Subaru had a "High Altitude" setup, so I am very curious about this... Is it really just a minor difference in perfromance that I might not notice? I have also not noticed any problems with tilt/angle/ect with carbs. - Maybe I'm just really, really lucky??? I dunno. But I am a Carb man from now on I guess..... Might have to settle for just Dual Carbs if I ever can make that happen. Edited May 2, 2014 by Subaruist Link to comment Share on other sites More sharing options...
tweety Posted May 2, 2014 Share Posted May 2, 2014 I too share the dislike for belts and chains for what appears to be little gain and more complexity. Just my opinion. However, in terms of turbo, dual turbo and other possibles by Subaruist I'm at a loss as to why supercharging is not even thought about where a boost (sic) of power and torque is desired. I'm not suggesting I'm an expert in this modification at all but I have installed a homemade crude supercharger set up on the stock ea81 and apart from some areas of dissatisfaction (see below) the concept doesnt seem to have been explored to its full potential. Briefly- the system I used was an ancient Toyota SC12 with a side draft Dellorto carbie, custom made manifolds each side of the SC and apart from experimenting with water injection there was no other mod done. Regardless of this (at a modest 5 psi boost) I achieved 30-33% increase in torque and power respectively. see http://www.ultimatesubaru.org/forum/topic/145588-ea81-engine/ Nowadays there are superchargers that are more compact, lighter, far more efficient than ever before. For example Sprintex make twin screw superchargers for mini's and Harley's V-rod see http://www.sprintex.com.au/ My frustration with my set up came from lack of knowledge and ability to get the set up running economically. Correct jetting was found from dynoing but at some revs the jetting was woeful. Fuel injection might have been a solution. It needed professional input. At any rate we know supercharging achieves its power from idle through the rev range. I can vouch for the power increase. My trike with a VW auto and a SC Ea81 lifted the front wheel with ease. It was proof enough. Hence my question? Why isnt supercharging, set up correctly, with a modern supercharger considered in the context of bolt on power increase? 1 Link to comment Share on other sites More sharing options...
turbosubarubrat Posted May 2, 2014 Share Posted May 2, 2014 It can be done quite a few members on here have put turbos on their ea71 and ea81 motors. Get a factory dual carb intake and see what you can do with a turbo on it http://www.ultimatesubaru.org/forum/topic/131650-dual-carb-ea-81-build/?hl=%2Bea81+%2Bturbo+%2Bcarb&do=findComment&comment=1123215. The ea81t with factory mpfi have good power for a 1.8 even with the 3 speed auto behind it but it would be awesome to put a d/r 5 speed behind it. If i ever find a turbo brat or coupe im going to do it since it would be super fun to drive around and just cruse around in. 1 Link to comment Share on other sites More sharing options...
Subaruist Posted May 2, 2014 Author Share Posted May 2, 2014 Tweety, you are in inspiration! I must admit, Even though I may have done a few things most people here would not think too sane, I was just a poor and rebellious young man when I got into Subarus, and am not fully versed in all such things as Turbo, Super-chargers, blowers, etc. How would such things handle extreme long-term off-roading on dusty roads ? Link to comment Share on other sites More sharing options...
apintonut Posted May 2, 2014 Share Posted May 2, 2014 (edited) Alot of old after market turbo carb setups moved the carb before the turbo so that it drew air though the carb the air and fuel through the turbo and the into then engine Edited May 2, 2014 by apintonut 1 Link to comment Share on other sites More sharing options...
Adam N.D.J. Posted May 2, 2014 Share Posted May 2, 2014 I have seen a few setups with a side draft carb that fed either a turbo or supercharger going in to an EA81. Biggest complaint that I have heard about it is that there is always a sweet spot once you get the jetting right, but then things go wonky above and/or below said spot. I believe that is has a little bit to do with the fact that most people use a carb that is not intended for the flow characteristics of a forced air system. One problem I have personally seen is that at higher rpms the fuel bowl is being depleted faster than the fuel line can fill it up. In an injection system your injectors duty cycle changes with the amount of air going in to the engine, but also, at the same time your fuel pressure regulator is taking a signal from your intake and raising the pressure of the fuel, so you have more fuel to flow through the more open injectors. Taking this in to account I have thought up some ideas that use an external pressure regulator to try and get more pressure to the carb to account for this. Although, this is of course just one problem, and at the end of the day me and carburetors have agreed to stay away from each other. These days forced air systems are so easy to come by. I think that one of the easy set-ups that one could use for their EA81 would be of the centrifugal supercharger. This is essentially a belt driven turbo. They are compact and can put out enough boost to wake up a minimally modified EA81. Plus if you keep an eye out you can find them for pennies on the dollar. I saw a honda kit on the craigslist for 600 not too long ago. There as many different ways of getting the fuel (and spark, air, ect) in to the engine as there people to think up ways to get them in there. This board has had a lot of different ideas over the almost 2 decades it has been around. I remember the early days there were some really crazy ideas. I am not sure how far back the current iteration the of the board goes back, but I think that if you look in to the archives you can come up with some of the more off the wall stuff. Also you have me as a resource, I am always game to having my brain picked on different things, and I have been down about as many roads as one person could go (maybe even a little crazy). Just remember, no idea is too crazy, at least until the engineers tell you it might be. 1 Link to comment Share on other sites More sharing options...
apintonut Posted May 2, 2014 Share Posted May 2, 2014 Google vw or corver turbo (I've seen them on pinto and Nissans too) its called a downdraft turbo setup 1 Link to comment Share on other sites More sharing options...
tweety Posted May 2, 2014 Share Posted May 2, 2014 Yes, its been mentioned.... the easy throw on supercharger is the suck thru meaning air filter, carbie supercharger and manifold. Fuel and air mixing thru the SC isnt what it is designed for. So we are really only interested in these pages on doing it right and maybe someone will make a bolt on kit with a compact SC compressing air thru a sealed carbie into the engine. Think of how many would sell? Beats looking for dual carbies, turboes and the like. Modern SC's would likely be installed with no bonnet bulge unlike the SC12 I had that would stick up inches above it. Dusty off road conditions would be like any other assembly- good sealing with good gaskets and proper air filter. What is amusing is that the original EA81 manifold is sufficient. Internals must be good but I didnt get into things like benefits of higher compression, port polishing etc. Water injection was tried and came on at 2psi but it didnt change the poor economy I dreamed of. So in my case with an old designed lobed supercharger with fuel and air mix and no other engine changes it produced 5psi to give the extra power and torque as on the graphs. Extra boost like 8psi - you just change one of the pulleys. More than 8 psi and engine internals need strengthening. Imagine is some professional used a modern twin screw SC and adapters to suit as a kit? A few more pics. You'll notice the 'V' shaped manifold that goes between the carbie and the SC. its actually one half of a twin carb manifold from a Datsun 1600 think a lynx manifold. you can see the custom home made manifold (with blow off valve for backfires) between the SC and the stock manifold. How would such things handle extreme long-term off-roading on dusty roads ? A supercharger is just an air blower. An oldie should have few scratches on the rotating lobes. You engine is likely to fail before the SC fails especially a new SC. 1 Link to comment Share on other sites More sharing options...
jono Posted May 2, 2014 Share Posted May 2, 2014 Bit eye opening aren't they those pics !! Tony would enter his forum, ask some questions, and next minute he has found a SC12, another few days and it on and running in a few more days. If it was me, it will happen in another six years time ! Once spoke to guy running EA81 with twin carbs, twin turbos in a VW Beetle, reckoned it would do a WRX off at the lights but needed a days planning to take a corner - so it is do'able.Know no more detail than the shop that set it up, must go poke nose around one day. Gees, while I have an EA81 turbo side head off, should investigate an oil supply and return hole for a turbo fit :evil: it is just about to get twin Hitachi breathers fitted..see if a turbo exhaust fits without turbo dimple ...... 1 Link to comment Share on other sites More sharing options...
Adam N.D.J. Posted May 2, 2014 Share Posted May 2, 2014 The EA81T takes the turbo oil supply from the pump, and then the return goes in to a pipe plug in the right head. On a regular EA81 it would not be that hard to run the supply line from one of the ports on the pump to where ever you have your turbo mounted. The return line is the only thing you would really have to figure out. If you run it in the regular location (for a Subaru) then all you have to do is drill a hole in the back of the right head and press in a brass pipe boss. I actually did this on my EA81T when I could not find a new right head, and used a left head instead, as long as you drill the hole low and get in to the pushrod area then you are set. The oil will drain back in to the pan via the pushrod path. Just some quick meandering thoughts on my way to work. Link to comment Share on other sites More sharing options...
Subaruist Posted May 2, 2014 Author Share Posted May 2, 2014 I have seen a few setups with a side draft carb that fed either a turbo or supercharger going in to an EA81. Biggest complaint that I have heard about it is that there is always a sweet spot once you get the jetting right, but then things go wonky above and/or below said spot. I believe that is has a little bit to do with the fact that most people use a carb that is not intended for the flow characteristics of a forced air system. One problem I have personally seen is that at higher rpms the fuel bowl is being depleted faster than the fuel line can fill it up. In an injection system your injectors duty cycle changes with the amount of air going in to the engine, but also, at the same time your fuel pressure regulator is taking a signal from your intake and raising the pressure of the fuel, so you have more fuel to flow through the more open injectors. Taking this in to account I have thought up some ideas that use an external pressure regulator to try and get more pressure to the carb to account for this. Although, this is of course just one problem, and at the end of the day me and carburetors have agreed to stay away from each other. These days forced air systems are so easy to come by. I think that one of the easy set-ups that one could use for their EA81 would be of the centrifugal supercharger. This is essentially a belt driven turbo. They are compact and can put out enough boost to wake up a minimally modified EA81. Plus if you keep an eye out you can find them for pennies on the dollar. I saw a honda kit on the craigslist for 600 not too long ago. There as many different ways of getting the fuel (and spark, air, ect) in to the engine as there people to think up ways to get them in there. This board has had a lot of different ideas over the almost 2 decades it has been around. I remember the early days there were some really crazy ideas. I am not sure how far back the current iteration the of the board goes back, but I think that if you look in to the archives you can come up with some of the more off the wall stuff. Also you have me as a resource, I am always game to having my brain picked on different things, and I have been down about as many roads as one person could go (maybe even a little crazy). Just remember, no idea is too crazy, at least until the engineers tell you it might be. Thank you for another wealth of info, Adam. I especially like "at the end of the day me and carburetors have agreed to stay away from each other." - About the statement "no idea is too crazy, at least until the engineers tell you it might be" - I am acustomed to the form of thought along the lines of "Screw the engineers" and "if all else fails, read the instructions!" - Mostly because they all seem to be written by the same chinese guy who has no understanding of english, lol... Link to comment Share on other sites More sharing options...
Subaruist Posted May 2, 2014 Author Share Posted May 2, 2014 Tweety, very good info there, and obviously a good job of mechanickery, but I have to say, that lop-sided beast is too damn big, lol.... - Forget a hood scoop, I'd have to just take the whole hood off and maybe put a little trim around the hole - if there was any room left, lol... Link to comment Share on other sites More sharing options...
Subaruist Posted May 2, 2014 Author Share Posted May 2, 2014 The EA81T takes the turbo oil supply from the pump, and then the return goes in to a pipe plug in the right head. On a regular EA81 it would not be that hard to run the supply line from one of the ports on the pump to where ever you have your turbo mounted. The return line is the only thing you would really have to figure out. If you run it in the regular location (for a Subaru) then all you have to do is drill a hole in the back of the right head and press in a brass pipe boss. I actually did this on my EA81T when I could not find a new right head, and used a left head instead, as long as you drill the hole low and get in to the pushrod area then you are set. The oil will drain back in to the pan via the pushrod path. Just some quick meandering thoughts on my way to work. This is what I love! Don't have a right head, use a left head instead - I love that its possible, I love these machines... Link to comment Share on other sites More sharing options...
Subaruist Posted May 2, 2014 Author Share Posted May 2, 2014 Ok, I am admittedly fairly ignorant about this subject, but can understand most of what you guys are saying, and given the factors of relative complexity, expense, work, resulting size, resulting boost in performance, etc. I wonder how much effect just a big scoop funneling air into the carb might have - Don't know if it would do much, but it would probably look real cool if done right? Link to comment Share on other sites More sharing options...
Subaruist Posted May 2, 2014 Author Share Posted May 2, 2014 Bit eye opening aren't they those pics !! Tony would enter his forum, ask some questions, and next minute he has found a SC12, another few days and it on and running in a few more days. If it was me, it will happen in another six years time ! Once spoke to guy running EA81 with twin carbs, twin turbos in a VW Beetle, reckoned it would do a WRX off at the lights but needed a days planning to take a corner - so it is do'able.Know no more detail than the shop that set it up, must go poke nose around one day. Gees, while I have an EA81 turbo side head off, should investigate an oil supply and return hole for a turbo fit :evil: it is just about to get twin Hitachi breathers fitted..see if a turbo exhaust fits without turbo dimple ...... You said "Once spoke to guy running EA81 with twin carbs, twin turbos in a VW Beetle, reckoned it would do a WRX off at the lights but needed a days planning to take a corner" - I don't get it, what would you have to do in the middle of a turn, aside from the usual changing gears, etc??? Link to comment Share on other sites More sharing options...
cubastreet Posted May 2, 2014 Share Posted May 2, 2014 Beetles were never known for their cornering ability with the stock engines (~40HP).... Link to comment Share on other sites More sharing options...
Subaruist Posted May 2, 2014 Author Share Posted May 2, 2014 Beetles were never known for their cornering ability with the stock engines (~40HP).... Ok... I'm thinking that I'm still not getting this.... I would guess that you are just saying that a particular model had cornering issues, - right? Otherwise I simply do not see how any kind of turbo or other engine gadget would have any effect on cornering whatsoever... I mean, going too fast to take the corner? That would be a lead-foot problem. Gear shifting, definitely, but surely this has nothing to do with turbo, super-chargers, etc, right? Link to comment Share on other sites More sharing options...
tweety Posted May 2, 2014 Share Posted May 2, 2014 That big lump of a supercharger is heavy, ancient (1989) and huge. Most modern superchargers are about the size of half a shoe box or smaller. And you can mount it where ever you like. You could mount it at the rear of the engine off an extension shaft from the front. Or mount it to take the place of AC compressor. Mounting of a modern supercharger is the easy bit- being so small. Getting the manifolds air tight and carbie jetting is the challenge. My posts are more to highlight to Subaru owners wanting to soop up their engines that there is an alternative to turboes that often have lag and need exhaust connection. Along with SC's having instant power down low. And to put it out there to some innovative engineer that a bolt on powerplant for a EA81/82 could be made with a compact SC. There are thousands of EA owners that would consider buying a kit to increase output by 30% with say 1-2 days installation time. Even the light aircraft industry. Link to comment Share on other sites More sharing options...
Subaruist Posted May 3, 2014 Author Share Posted May 3, 2014 All good points, but I still don't see the thing about turbos and cornering, unless I guessed right in my last post on this...... Link to comment Share on other sites More sharing options...
tweety Posted May 3, 2014 Share Posted May 3, 2014 Porsche is the only manufacturer IMO that got the handling right for a rear engined car. Even then the early 911's could be a death trap if you backed off half way through a corner instead of pedal to the metal. The car would head off in a direction you didnt expect it to go. Porsche owners knew this thankfully. VW beetles were designed to take corners at a ridiculously low speed. Remember they were designed in the 1930's with an engine that couldnt pull the skin off a custard tart. So modify an engine with or without turbo'es and leaving the suspension stock is asking for trouble. It's because every corner would require a throttle input not exceeding the cars ability to take the corner without risk. Not easily done. What about extra straight line speed and an animal appears? Extra good handling is a must. And thats not mentioning if a turbo cuts in half way around a corner. This is all I can think of to answer your query Subaruist. Link to comment Share on other sites More sharing options...
Subaruist Posted May 3, 2014 Author Share Posted May 3, 2014 Porsche is the only manufacturer IMO that got the handling right for a rear engined car. Even then the early 911's could be a death trap if you backed off half way through a corner instead of pedal to the metal. The car would head off in a direction you didnt expect it to go. Porsche owners knew this thankfully. VW beetles were designed to take corners at a ridiculously low speed. Remember they were designed in the 1930's with an engine that couldnt pull the skin off a custard tart. So modify an engine with or without turbo'es and leaving the suspension stock is asking for trouble. It's because every corner would require a throttle input not exceeding the cars ability to take the corner without risk. Not easily done. What about extra straight line speed and an animal appears? Extra good handling is a must. And thats not mentioning if a turbo cuts in half way around a corner. This is all I can think of to answer your query Subaruist. Another wealth of good info, and yes, you did answer my question with "And thats not mentioning if a turbo cuts in half way around a corner." Now it makes sense to me! Thank you. You have indeed sold me on alternatives to turbo! 1 Link to comment Share on other sites More sharing options...
jono Posted May 4, 2014 Share Posted May 4, 2014 You said "Once spoke to guy running EA81 with twin carbs, twin turbos in a VW Beetle, reckoned it would do a WRX off at the lights but needed a days planning to take a corner" - I don't get it, what would you have to do in the middle of a turn, aside from the usual changing gears, etc??? :D would happen before the turn as it took some planning on how to take a corner, as it did not handle at all well at the sort of speed it was being propelled at Link to comment Share on other sites More sharing options...
jono Posted May 4, 2014 Share Posted May 4, 2014 (edited) Porsche is the only manufacturer IMO that got the handling right for a rear engined car. Even then the early 911's could be a death trap if you backed off half way through a corner instead of pedal to the metal. The car would head off in a direction you didnt expect it to go. Porsche owners knew this thankfully. I heard this one day at a shopping centre, looked around corner to see a 911 convertible whose driver los tit in a left hand turn, collected a keep left sign and its half cubic metre of concrete anchor, accompanying them on their career into and over a square concrete gutter. Median strip gravel swept everywhere as a result, bent axle and whopping great ding in rear guard and his pride - exposed while he waited an hour for a tow truck! Edited May 4, 2014 by jono 1 Link to comment Share on other sites More sharing options...
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