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The Hyperbolic ER27 Twin Turbo Build


Gravityman
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Hey Subaru Freak!

 

Well Here it is the beginning of an extreamly overkilled/extravagant (HYPERBOLIC, if you will) build up of my ER27 to become the first ever documented twin turbocharged ER27 or ER27TT. I am sure that I will receive a ton of criticism on this thread a well as a lot of :banana::clap::headbang::Flame::burnout: :cool: :drunk::brow: and probably but hopfully none of these :confused: :-\ :dead::mad::( ! I am letting you know now that I will be jumping around a little in this thread, there is SO MUCH to cover and SO MUCH going on with this project that it will be hard to just stay on one subject at a time. Feel free to jump around also, I am sure there will be many question.

 

Here is the foundation as to where I am now. I did not just start working on this project yesterday. I have been researching, reading, experimenting and testing for about 3+ years now. I do not claim to know everything about building an engine let alone a twin turbo. I feel that the only thing that makes you an expert is by many years of experiance and trial and error. My experiance started about 5 years ago, whatever that makes me, I don't know, a novice/ journeyman?

 

I bought my 1984 EA81 Subaru Brat in mid 2003. My original plans were to do a simple EA82 engine swap. I figuared that if I was going to do a swap I might as well just get an EA82T for that extra bit of power. As I worked toward finding parts for the EA82T in the junkyard I found myself staring down the front of an ER27 and was completly mesmerized. This was the first of many signs of things to come. From that point on I knew that it was destiny. I pulled the engine out with one of my buddies over the weekend, It cost me $100. After that everything just started to fall into my lap. Next I scored 2 turbos of which map to my engine perfectly and I was actually payed $200 to buy them. I found the perfect intercoolers that fit in the front of my grill clip with very little modification. The exducer on the compressor of the turbos were the exact size of the intercoolers and the new throttle bodies. I could go on forever.. I should just write a book. Many things between then and now have brought me up to this point.

 

I guess It is only fair to show you the engine that has been going through this cinderella story. It is not pretty but it will show you what any engine is capable of no matter how ugly it is. All you need is a little TLC, a lot of imagination and a huge wad of cash, OOH and an EXTREAMLY UNDERSTANDING WIFE!!! This is what I started with.

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Currently my engine is at the machine shop having some machining done to it. I just had the cylinder heads decked and the valve seats ground to receive new valves. I am getting ready to port and polish the head then cryotreat and ceramic coat the valves, combustion chamber and exhaust port. The block will be getting honed and decked with O-rings cut and installed around each cylinder bore. The O-rings coupled with the copper head gasket should seal the combustion chamber perfectly. Holes are going to be drilled into the crank journels to act as piston oil jets. I just bought brand new EA82 turbo pistons that have been ceramic coated on the crowns and moly coating on the skirts which will also receive cryotreatment.

 

Cylinder heads back from the machine shop, decked and valves ground. Ready for the Port and Polish.

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I am sure that many of you have seen this before. I had these rubber coated copper head gaskets custom made for the ER27TT.

7299Copy_of_Copper_Head_Gaskets0001.jpg

 

Here is a pic of the new pistons, pins and clips before I got them ceramic coated. I will post the ceramic coated pics once I get one. These are freakin' sweet!!!

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Here are the turbos that will be mating to the ER27. I am in the process of polishing the compressor housings. Later I will be having the turbine housings sent off to be ceramic coated. These are identical TA0301 Garrett turbos.

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Here are the Saab 900 intercoolers. I went with these not only because many other people on the board have in the past but they are symmetrical to each other. It will allow me to plumb up from the turbo to the intercooler with ease. I also have an EXTREAMLY TOP SECERET DESIGN in store for them!

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I am scrapping the stock intake manifold and plan on building my own either out of carbonfiber/basalt and high temperature epoxy resin or at last resort aluminum. The throttle body will be converted of throttle bodies. I picked up a throttle body setup from a twin intake nissan 300zx turbo. Notice how perfectly they line up with the saab 900 intercoolers. This is just a taste of how the setup will look in its most fundimental form. Seperatly the throttle bodies are smaller then the stock throttle body but combined the are much larger.

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For my Fuel management I am running MegaSquirt II V3 along with Edis for my ignition. I personally built the MSII but have yet to hook it up to my XT6 for testing.

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I found out some unfortunate news about the block today. The bore on one of the halfs had a LOT of pitting caused by water sitting in the bore. I know that no one makes aftermarket sleeves that drop into the cylinders but it looks like he will be boring out the entire sleeve insert and installing another one. He assured me that there should be no problem with this repair minus the extra cost, SUCK!!!

 

This will obviously be a long on going thread. Feel free to ask any questions, add advice or criticism. I originally wanted to try to keep this all on the downlow but I felt that it wouldnt be fair to everyone that helped me get to this point.

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1) I think someone did a twin ER27 before, but I might be wrong (I know single has been done several times). In any case, I think you're right about the documented part.

 

2) How do you plan on doing the exhaust, as far as heads to turbos? This is one that I've thought about alot - ballancing the output of the turbos might be tricky if done wrong. Same goes for turbo to intake. Basically, I don't think you can effectively run the two banks completely separate.

 

3) Congrats on implementing o-rings!

 

4) Looking forward to more of this buildup!!

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1) I have only seen proof of a supercharged ER27 (pictures only). I have also seen a few pictures of turbocharged ER27s but with limited pictures of the buildup. I have never seen anything that had to do with twin turbos. There is another guy on XT6.net that is working on a turbo ER27.

 

2) The exhaust from the cylinder head to turbo, turbo plumbing to intercooler and intercooler to intake manifold will be completly equal throughout. I am plumbing everything to be completely symmetrical. I guess it will be like two 3 cylinder engines combined to make a 6 cylinder.

 

This is a very rough sketch of how I want to plumb the turbo. Side view.

ENGINE_SETUP4_SIDE.jpg

 

Front view

ENGINE_SETUP5.jpg

 

Hope that helps make sence. Now all you have to do is put all the pieces together.

 

3) I am totally stoked about the O-rings also!

 

4) Thanks! I appriciate it!

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i really like the idea of a CF intake mani, you could get it exactly the shape you want for best flow and it would save quite a bit of weight too. and how trick would that look!! however you probably wouldnt want to be building something pressurized out of fiber stuff if you dont know exactly what youre doing and have the ability to vacuum form it to get all the air bubbles out. also getting flanges to work might be a little tricky unless that stuff bonds to aluminum really well.

 

I like the drawing, is there room for the piping to go over the radiator like that in the really low hood of the xt6? sorry i havent seen under the hood of one in quite a while and am having a hard time visuallizing where the rad is. nice short plumbing like that tho.

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Correctamundo, MAP is the way to go. I originally planed to run 2 MAF sensors, in fact I have 3 of them but once I found that I can run MAP with MS2 I scrapped the MAF idea. Its not as exact and it would have had to been ghetto rigged!

 

The piping into the turbos will be (if I can remember correctly) 2.25in diam 2-1 ceramic coated and glass wrapped stainless steel.

 

DAYUM:headbang: :headbang: :headbang:

What is DAYUM?

 

I have the capability of vacuum bagging the carbon fiber. I am going to be building all my pipes from the turbo to the heads out of basalt and carbonfiber with a high temp epoxy resin. The reason I am using basalt is it is capable of handling very high temps, this coupled with the strength and stiffness of CF should prove to be a great combination. I am still working out the kinks with how I plan to mesh the CF to the throttle and fuel bosses. I think I will epoxy the CF to the aluminum and then sandwich it between another piece of aluminum, Dont quite know yet.

 

The radiator will be mounted in the bed of the brat along with the fuel cell and battery, Somewhat like what you see on baja racers.

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There was (not sure if it's still out there) a TT kit for the Impreza a few years back. They kept on delaying it because they were having trouble getting the two banks to run acceptably in a completely separate setup. If I remember right, the fix was a ballance tube between the two exhaust banks.

Or, I could be on glue :clap:

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I am planning on making a balancing tube between the 2 intake ports to keep the boost pressure equal. I gave it little thought about putting a balancer pipe between the 2 exhaust pipes. I think the main reason that they would really need it is due to only having 2 pistons on one side. I would imagine it would be difficult to keep the pressure maximized in the exhaust pipe with only one cylinder every rotation of the crankshaft. If I am correct in my thinking I should be getting 1.5 times the exhaust output then a 4 cylinder thus increasing the back pressure. Also, by keeping the length of the pipes as short as I plan I should have no problem spooling the turbo. HOPEFULLY!!! I guess it is all theoretical. Correct me if I am wrong.

 

I will assure you if it doesnt work with seperate exhaust pipe then I will add a balancer. Thanks!

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There was (not sure if it's still out there) a TT kit for the Impreza a few years back. They kept on delaying it because they were having trouble getting the two banks to run acceptably in a completely separate setup. If I remember right, the fix was a ballance tube between the two exhaust banks.

Or, I could be on glue :clap:

or could it have been because twin turbos on a 4 banger is not even a remotely good idea? believe me I have a ej20h setup in my possession, and convoluted would be a reasonable description. personally I don't think TT's have a place until there's at least 6 cyl's and space or cost is an issue. there are several "single" turbos out there that a 2.7L 6 cyl would work awesome with and are available dirt cheap.
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The 2.2tt was a sequential setup where this will be a parallel setup. The sequential setup requires all the exhaust pipes feeding to the turbos one after another. 2 turbos, one small one large in a row. After one turbo gives out the next one takes over. If that makes any sense.

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I first wanted to lift it because it thought I would have to when I originally planed to mount the radiator on top of the engine. When I went to mounting it in the back I figured I didnt need to lift it. Because I am turbocharging it I couldnt see any benifits to running a lift; balance, center of gravity wouldnt be my friend with alot of power.

 

I plan to run it between stock height and lower. I would love to rallyX it but without a sponser it would be way to expensive to maintain, but that doesnt mean that I probably wont every once in a while. My main plans are to autoX. I will be running KYB AGX with adjustable coilovers so ride height wont be a problem. As far as the drag strip, I plan on destorying plenty of american "muscle"!

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This is half the reason I am just starting this thread. I started the project about 3 years ago and this is how far I am. Also, money has been playing a big roll in the build. If I happened across about 3K I could be done by the end of the month but since that is no where in sight probably at least a year. I will be deploying again soon so there will be a lot of down time. I do plan on finishing the engine before I leave though. Hope this helps!:-\

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This is half the reason I am just starting this thread. I started the project about 3 years ago and this is how far I am. Also, money has been playing a big roll in the build. If I happened across about 3K I could be done by the end of the month but since that is no where in sight probably at least a year. I will be deploying again soon so there will be a lot of down time. I do plan on finishing the engine before I leave though. Hope this helps!:-\

 

I was asking because I would make a trip to see my brother, and maybe get lost near goldsburg along the way to check this out in person :headbang:

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That would be cool!!! The truth is I have so much crap and so many project going on at one time my garage looks like a toronado hit it. I am guessing that sometime around June next year after I get back from my deployment I should have enough money saved up to be able to modify the Brat frame, install the engine, plumb the turbos and intercoolers, build the intake manifold, tune the megasquirt to the engine and hopefully dyno tune the engine. I also have to convert the Brats underside into the XT6's suspension parts. I have a long way to go from here but If I get enough money from this deployment I can successfully build and tune fast enough to get it running very quickly. :headbang:

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Update on the build. I just got back from the machine shop with some pictures. First of is a pic of cylinder 4, before I bought the engine it appearantly had water sitting in the cylinder. The water caused massive corrosion and pitting on the interior wall. My machinist will be completly boring out the fixed iron insert and will be manufacturing a new sleeve to put in its place.

 

Here is a pic of the damage.

100_6027.JPG

 

Next something that I suspect no one on this or any forum has seen... The ER27 Twin Turbo ceramic coated and moly coated pistons. These are actually brand new EA82 turbo pistons, if you didnt know that already. I think they are a thing of beauty!!!

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I am currently having the cylinder heads flow tested and then I will start porting the heads. Once I finish porting the heads they will be flow checked again. Once I figure out the newly ported flow numbers I will send off for my camshaft to get reground and have the max valve lift set to where the highest flow rate was recorded.

 

Hope this makes sense, I have been up for about 26 hours now, about to go to sleep.

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