ea82 turbo power; is it possible???

[Tycho]

The reason no one has flow numbers to show what a poor design the EA82 head is, is that just by looking at the short turn radius on the intake and exhaust, anyone with a flow bench would just have a little chuckle and set the heads aside, rather than waste their time.

 

Look at how the seats are cut too. You already have this super tight short turn that is impossible to radius adequately (on both int and exh!), and to make things worse the seats stick all the way down into the throat, turning what would be a terrible short turn into a sharp 90 degree (especially on the exhaust side, you can often feel the bottom inside edge of the seat on the short turn).

 

Then you look at the bowls which are all wrong on both sides, and the one intake port on each head (MPFI) which has the weird casting lump in it to clear various valve gear (which creates a flow separated cavity and associated choke and wet out) and the "S" turn exhaust port on the other side ... and the siamesed exit which is massively oversized where the cylinders dump into a common volume (massive velocity drop and associated reflected pressure wave here).

 

Then you look at another engine that came out in 1985. Let's take the Toyota 4AGE for example. Some other members here have MR2s, I have one too. The 4AGE made 115 HP from 1.6L NA. The EA82T made 111 from 1.8L @ 7 PSI in 1985, later 115. 134 in Europe?

 

But who cares about those numbers anyway. Factory numbers are just a reflection of the horsepower-hour duty life goals of the manufacturer. Far more important would be to look at the air path in and through the engine as well as the intended operating range (this is where you find "what is possible" rather than simply "what is").

 

So the 4AGE is 81x77 bore/stroke, winds out to 7000+ RPM, and makes power "up top". I'd call this a short stroke high RPM engine that needs ports capable of high velocity but not massive volume. Toyota actually shrunk the intake ports on the 4AGE in the late 80s and picked up power in doing so ... they raised the ports a hair to yield a better intake short turn at the same time.

 

The EA82 is 92x67 bore/stroke (with an awesome 1.75 L/R rod ratio which is why the cylinders never wear out), is self governed in NA form basically (power drops off so quickly at high RPM that you don't really have to watch out for redline), but with a crazy short stroke. It's so massively oversquare it's not even funny. This makes it terrible as a torque motor as big bores love to knock/detonate (which is a supersonic propagation of the flame front ... the can of marbles sound is a bunch of little sonic pops hitting the physical bounds of the chamber as unhomoginized pockets of gas explode instead of burn) ... not to be confused with preignition (which is a hot spot in the chamber starting ignition before the spark) at low RPM. This is part of the reason for all the broken ring lands on EA82Ts.

 

Where do massively oversquare engines like to make power? Up top. Way up top. Check out the geometry of sport bikes, Formula 1 cars, etc. Big bore means lots of room for valves and lots of room for quench area which nips detonation in the bud in high CR engines. Short stroke means super low piston acceleration which helps rods live and also leads to lower peak flow velocities for a given volume ingested (which is awesome from an efficiency standpoint). What is required for a high RPM screamer? Super steep super high velocity ports. What does the EA82 have? Super shallow (hence the sharp short turn) super low velocity ports (and comically terrible manifolding to go with that). High RPM engines SCREAM for massive intake plenum volume. Liters and liters of it. The Spider manifold is a huge improvement over the original MPFI, but still needs maybe 3x the plenum volume to feed an engine that would spin as fast as the bottom end would like. But that's not a problem because the heads are such a massive joke that the engine will never make power at those RPMs anyway.

 

The EA82(T) has the geometry of a F1 engine with the heads and manifolding of a tractor. The performance suffers as a result (and ends up much closer to the tractor at the end of the day).

 

Then you have the cracking problem. I myself think that's almost entirely a function of a log manifold that concentrates heat on the 1/3 head, along with turbo coolant and oil dumping into the same head, plus the favored flow of cold water out of the radiator is in the 2/4 head. I bet if the water pump was on the other side of the block the coolant issue would be greatly reduced. I also bet that the 1/3 injector issue is related to the heat issue in that head.

 

Baring actually moving the coolant pump or reverse-flowing the engine with an electric pump, I'd bet that a proper header (like the TWE I've seen some pictures of ... but maybe with a biscuit welded into the flange to keep the siamesed ports separated a few inches into the primaries), re-routing of the oil return direct into the pan, and a radiator that's sized to keep temperatures near that of the T-Stat (the radiator is supposed to be able to reject MORE than the max thermal load of the engine, thus keeping engine temps within a few degrees of the T-Stat itself), you'd never see a cracked head. That's even without an intercooler and oil cooler (which should have been included as OE).

 

Has anyone run a poll on which head cracks most of the time? I'd wager that it is extremely biased to the 1/3 head.

 

Anyway, it's such a massive turd that it's a bit fun to hack on tho. I have a freshly built shortblock that was decked to give about 8.0:1 SCR coupled to some heads I ported along with a ported log manifold, ported/gutted downpipe (and no other exhaust), and a soon to be installed spider manifold (which will probably include a SDS EM4-F standalone install as, like the other poster, I've had a bunch of sensor failures ... tho they are just about all fixed now!). Right now, on the stock ECU and manifolding with the aforementioned "un-corking", it's a fun rig! If it holds together long enough, I intend to see what can be had with 7 PSI. A very chilly 7 PSI with much less restriction on the exhaust side ... i.e. TD04L or HL perhaps (after all, FI engines make power not only relative to boost itself, but also relative to the intake/exhaust pressure ratio). Besides lower intake charge temps, I think the increased exhaust flow of a TD04L is a major contributing factor in some of the positive results members have had with those swaps, even at stock boost levels.

[Nug]

Intelligent input!

[naru]

+1, Great answer!

[NorthWet]

Interesting post, but 3 observations:

 

1) It probably belongs in a different thread, as this seems OT from what the OP wishes and is mostly a response to a casual comment about the head not flowing well. (Might have been better in something on its own, or like the thread that I started about the EA82, its problems, and possible inexpensive fixes.)

 

2) None of the porting issues are truly fixable. They aren't even really improvable without a flowbench and a pile of heads to screw up. Theory is fine, but engine builders have learned over the decades that things aren't always what they seem.

 

3) All of this still plays into the opinions by GD and others that things can be improved only if you have a wheelbarrow full of money to throw at a 25+ year old design that was not meant to be a high performance engine.

 

Reread what the OP wants, especially after he has been flamed a little and discouraged by our "learned" responses... and try to listen.

[subaruwolf]

 

and

i have about 160hp i was NOT giving it full throttle, nor shifting hard

Edited December 30, 2010 by subaruwolf

[Myxalplyx]

im going to get a water/air intercooler for my 1988 Subaru GL-10 turbo wagon, and completely gut the exhaust system of the cats to help it flow better, and try a cold air intake with one of those cone air filters. but, what else can i do to make this engine a little bit better?

 

Upgrade your fuel injectors and tune your exhaust gas temperature to be as 'cool' or cooler than stock. Tune your air/fule ratio to be 11.0:1 during heavy load and wide open throttle. That's it! Please let us know how all this goes.

[beataru]

 

and

i have about 160hp i was NOT giving it full throttle, nor shifting hard

 

I wish my GL-10 ran as smooth as yours

 

In other news...

 

The TWE header does make a difference in spoolup, however... it also sandwiches against my power steering.. which is NOT GOOD.

[Myxalplyx]

I wish my GL-10 ran as smooth as yours

 

In other news...

 

The TWE header does make a difference in spoolup, however... it also sandwiches against my power steering.. which is NOT GOOD.

 

Yeah, I actually had to put some type of heat wrap in there so my power steering line would not heat up as much. Had to bend the PS line a bit too. A pain!! But man.....that header/uppipe and downpipe rawks.

[Tycho]

2) None of the porting issues are truly fixable. They aren't even really improvable without a flowbench and a pile of heads to screw up. Theory is fine, but engine builders have learned over the decades that things aren't always what they seem.

 

3) All of this still plays into the opinions by GD and others that things can be improved only if you have a wheelbarrow full of money to throw at a 25+ year old design that was not meant to be a high performance engine.

 

Reread what the OP wants, especially after he has been flamed a little and discouraged by our "learned" responses... and try to listen.

 

2. Exactly (there is really no way to improve things). The RX rally car notes from Subaru show where they ported. They basically just worked on improving the short turn radius, but even if you blend it as best as possible, you're going to get massive flow separation right where the throat meets the seat. A wet flow bench with some UV dye in there would be good for a few laughs. You'd see fuel wetting out in a massive way and huge cavitation on the short turn side of the valve.

 

The main area where things aren't what they seem (where flow is concerned) is in cross section vs flow rate. Bigger is not always better. As far as shapes go, regardless of cross section, for non-turbulent flow (intake side), straight is best and equal length (port roof to port floor) is best (straight is equal length of course ... but you can also get equal length by turning a "C" into an "S" ... impossible on a flat engine tho). Any and all deviations from this require additional flow energy (i.e. a reduction in volumetric efficiency) due to shear. You don't need a flow bench for that part of things. You can actually just section a mold of the port to create a cross section profile then "back out" the velocity numbers from that. It won't tell you everything tho.

 

You DO need a bench on the exhaust tho, as I'd bet one would find massive gains there by building up the port divider all the way to the flange, reducing overall cross section, and turning the siamese into two much smaller ports. It'd be very difficult to know without numbers tho.

 

3. I don't think you need as much money to make "big" power (in EA82T terms) as has been claimed. If you took care of the heat issue FIRST, head gaskets, head studs, forged pistons, etc simply become redundant. Take care of the heat issue and you won't have the expansion/annealing problems that contribute to gasket failure (walking heads) and head bolt thread pullout (weakened aluminum). Knock will also be greatly reduced thus eliminating ring land failure. Suddenly you don't need studs, MLS gaskets, or forged pistons. Head cracks won't be a problem either, especially if you dump the log manifold and go to a TD04L or larger (HL perhaps) exhaust housing on the turbo (with a nice downpipe and exhaust system). Later spool is good for decreasing knock ... and making power up top means lower peak torque which rods and cranks tend to like. Slightly less torque at higher RPM can really reduce peak loading on the internals. Opening the exhaust yields more power at the same given cylinder pressure (easier on head gaskets and head bolts) as you get a better scavenge effect (higher VE, less combustion endgasses left in the chamber) and thus a better burn with less fuel and less boost which results in less knock too. More complete burn from not having to run pig rich all the time increases mileage and decreases EGT as you turn more potential energy into pressure and less into heat.

 

Oh, one other neat trick for solving the head gasket and knock problems. You can mill a "ring" in the deck in the aluminum around the bores. I haven't looked to see how thick the closed deck webbing on the EA82 is (should fish out my spare block and take a peek), but if you could put a 3 mm ring all the way around the cylinder, this would massively reduce peak temperatures in the top of the cylinder and probably lead to near infinite head gasket life. Lots of sleeved and/or deckplated builds that were originally open deck incorporate this trick to retain the advantage of that design with the added stability provided by a closed deck. This would be like $50 bucks of machine work on the block. Not expensive. One can also do some radiusing on the oil and water pump and block passages to improve coolant and oil flow substantially. I did this on my current EA82T. Took an hour or two of my time (so basically free).

 

Here's how ERL does it:

http://www.erlperformance.com/honda-k20-erl-superdeck-i-sleeved

 

To what the O.P. wants:

1. Get a hugely "oversized" radiator

2. Uncork the exhaust and get rid of the log manifold (your heads will thank you)

3. Don't rely on the knock sensor to pull timing. It can only react. Set your ignition so you don't get knock (pistons will last forever). Use good gas.

3. Intercool and oil cool (less knock, more timing).

4. Do it all on a freshly built longblock where you've had the heads and deck surfaced (fresh surfaces combined with proper cooling ... the head gaskets will not give you a problem)

 

Then if you want more power without upping the boost, there's a lot to be found by spending a few minutes on a few specific areas of the cylinder heads. They'll still be junk, but much improved junk. Also, spyder manifold swap will yield horsepower at higher RPMs if you have done the heads (if you haven't, the heads will likely choke flow before the OE intake manifold).

 

The head gasket problem is a symptom.

Cracked ring lands are a symptom.

Cracked heads are a symptom.

 

Solving the underlying problem is not that expensive. Get exhaust heat out quickly. Get coolant heat out to maintain T-stat temperatures under load. Get oil heat out for the moving parts benefit.

 

To make more power, don't start with boost and timing. Those two come last. You add boost to a healthy engine with overhead ... rather than trying to make a modified engine healthy.

Edited January 4, 2011 by Tycho

[soobie_newbie67]

hey, i dont remember if it was this thread or a different one, but some one was mentioning the TD04L turbo to put in my Subaru, but they mentioned ring land problems if you over boost. on stock pistons, where is that "overboost" area at? how much over 7 psi can you go before having problems?

[NorthWet]

No set place, partially because (IMHO) there is no definitive cause(s). There has been anecdotal reports of broken ring lands, but little investigation has been posted.

 

I have not hunted down all of the anecdotes, and IIRC nobody really supplied much info on my "EA82" thread, so it is unclear to me whether this was just with stock turbo pistons (not to mention if with one or both castings of turbo pistons) or if the NA pistons in high-compression builds also died this way. No mention was made (that I noticed) as to whether the piston rings were also broken or if any were stuck in their grooves.

 

My guess is that the primary cause is prolonged detonation, and this could happen at stock boost if other factors conspire to allow it.

[WoodsWagon]

Don't know if it's been mentioned yet, but I'm a big believer in water/meth injection.

 

I have a toyota tacoma with the 3.4l v6 that I put a trd roots style supercharger on. It's a 9.6:1 compression ratio engine, and I'm running an undersized pully on the supercharger so it's putting 8.5psi into the engine. That's a really hot 8.5psi from the supercharger going into a high compression engine, with no tuning, no injectors, no pump, nothing.

 

I got an extra windshield washer resevoir from a T100 in the junkyard and mounted that up on the fender. I rewired and plumbed that resevoir to work with the wiper switch, and the stock down-in-the-quarter panel resevoir is now grounded by an adjustable pressure switch. I put a spray nozzle from an 06 Civic (which is a mist rather than a jet) in the intake tube before the throttle body.

 

When the pressure in the manifold goes over the threshold set on the pressure switch, the pump kicks on and starts spraying in intake. That mist gets drawn through and mixed by the supercharger rotors, and is likely vaporized before it gets to the combustion chamber by the heat in the air from the supercharger. The latent heat of evaporation of the water cools the intake charge and the methanol adds to the fuel.

 

I use plain blue winter washer fluid, which is 30% meth 70% water.

 

2 years of abusive driving, towing trailers, roasting multiple sets of tires off the back and the motor is sitll holiding up fine.

 

There are limitations to my setup, when driving I have to use less than half throttle, or go all the way to WOT. Around 3/4 throttle there's an area that will have enough boost to detonate, but not enough to kick the pump on. If I adjust the pump to come on sooner, it will spray below half throttle and choke the engine. So I just adjust my driving habits to fit it. There are much better meth injection systems out there, and homebuilt versions for around $300. Mine cost me $45, and I'm willing to put up with it.

 

You may see great results from using a high pressure system in the charge pipe after the turbo. Using a low pressure system like mine before the turbo will likely lead to water droplet damage to the turbo impeller blades. Look into a homebuilt system using a pesticide sprayer pump and nozzles. It may be the key to keeping these POS motors together.

[beataru]

Windshield Washer Fluid FTW. Ive debated about doing this on my car... but with my driving habbits, I would need to have a 55gallon drum in the back of the car.

[NorthWet]

... It may be the key to keeping these POS motors together.

If you truly think that they are POS, perhaps you should avoid them...

 

As far as controlling the coolant injection, possible using a boost-pressure bleed to the tank might work better than a straight on/off pump. Other possibilities include either a PWM or PCM controller for the washer pump. Or perhaps replacing the regular TB with an SPFI TB and driving its injector.

[beataru]

Or a funnel into the intake and a passenger with washer fluid :-p

[WoodsWagon]

If you truly think that they are POS, perhaps you should avoid them...

 

As far as controlling the coolant injection, possible using a boost-pressure bleed to the tank might work better than a straight on/off pump. Other possibilities include either a PWM or PCM controller for the washer pump. Or perhaps replacing the regular TB with an SPFI TB and driving its injector.

 

My personal experience with the 82t has been less than favorable. I've got an 86, and the computer will work for the first couple times you start the car, then glitch into a default mode while running so it holds the injectors on at about a 50% duty cycle. That dumped enough fuel in to fuel wash the cylinders, and the varnish from the massive coat of fuel and the thinned oil caused the lifters to collapse and the valve to hang open so a bunch of rockers fell out. I put them back in with a prybar and sufficiant swearing.

 

If you wait a month with the battery dissconnected, the computer will "heal" and it will start and run again. I checked all the capacitors in the ECU figuring one was shorting and then the insulation was healing when it was discharged, but all seemed ok. So the next logical source of an intermittant but repeatable failure would be the flash rom. They can get unstable over time.

 

I will stay away from them, the EJ's I've swapped into my other cars are a lot more fun. However, don't discount my water/meth injection advise just because I don't like the engine.

 

You cant use injectors because the water/meth mix will corrode the pintle and coil. So no PWM using a spfi throttle body. You don't want to use a boost pressurized tank because there isn't enough pressure for atomization and you will be spraying water droplets into turbine impellers moving at near-sonic speeds, which will erode the impeller.

 

You can use PWM to control a high-pressure pesticide sprayer pump, going through a proper jet on the charge pipe leading to the throttle body, or port jets in the manifold runners. This is how the real kits like Snow performance and Devil's Own do it.

 

With real nozzles in a high pressure system you need to have good filtration to keep them from clogging. You need check valves to keep the lines full and the jets from dribbling. You need failsafes to let you know when the resevoir is low, the pump isn't working, ect. All I have is the stock low washer fluid light on the dash, and that lets me know I have one WOT run to 100 left in the tank.

 

Water/meth injection is easily doable on an affordable budget. Do some research on how to home-build a high pressure system, hit up Grangers for a pump and jets and get testing. It's suprising the difference it can make, and it's way better than cooling the combustion by overfueling and running rich ratios or retarding the timing to avoid detonation.

 

When I'm beating the snot out of my truck, or towing, I use about 1.5 gallons of washer fluid to a 16 gallon tankful. If I'm driving nice, .5 gallons a tankful. At $2 a gallon for washer fluid, it adds $0.15 a gallon average to my price of fuel. We got raped at the pump for that much more just in the last week.