I could be getting a 1994 Tercel with a 1995 5EFE engine. I want to turbo charge the engine. I like tinkering with stuff, and I don't have any extra money, that is why I love driving Tercels. I am trying to think of a better way to lower the compression the 5EFE so I can run high boost. I don't want to buy pistons, and I don't think that's necessary. If the engine gets damaged, I can easily source parts every few weeks at my local wrecking yard. I would rather try to make the stock parts work, and if it fails once, then I can try getting the parts and starting over. I don't want to fail, but it would still be cheaper than $450 forged pistons.
What are the thoughts and opinions on the following?
To lower compression, I could use stock pistons and rods. I could have the big ends resized, which could shorten the con rod. I should be able to shorten the rod by quite a bit this way. If I shorten the rod .078" I would take the 9.4 compression down to 8.0:1. I have never had a rod resized, so I don't know what the limits are, but I know they do this type of stuff all the time to increase compression, stroke, etc!
If i took the rods down in length by .050" I would have 8.5:1 compression.
I know that lower compression isn't absolutely necessary, but I think it would be good to have a safety margin to prevent blown head gaskets. I built my own mega squirt from scratch (soldered the entire board myself) and I am going to tune everything myself. I've never done it before so I NEED some safety margin!
Anyway I remember reading an article about a ford 2.3L engine that has a piston top to block deck clearance of .125" and it only had 7 or 7.5:1 compression, and the engine could run HUGE boost, and had something like 400 or 500hp out of an old Ford 2.3L engine (this was in the 80's). I also remember reading an article that said, the squish clearance (the piston to cylinder head quench area) isn't that important on a turbo engine since the incoming air velocity is so high, that the fuel mixture tends to burn good and so detonation isn't a major problem. I know that if you open up a cylinder head on a naturally aspirated engine you can actually cause MORE pinging (detonation) if you don't have the right squish area. The squish area is one of the most important factors in determining detonation for a given compression ratio. Better designed heads can run higher CR without pinging. But apparently on a turbo engine, the head design and the squish area is not terribly important due to the high air velocity.
I think lowering the pistons down in the bores would be a cheap way to lower compression, what do you think??
Another question. The 5EFE rods. Why are they so weak? I read that turbo connecting rods are almost never a weak link unless you are using nitrous. Nitrous hits the piston and rods with a peak cylinder spike, wheras the peak force on a con rod is not much with a turbo motor, at least not compared to doubling the RPMS or using nitrous (See Maximum Boost by Corky Bell). IN the book it says con rods are not an issue. I don't get it? Compression doesn't seem to ruin con rods like high RPM does right? Could someone cite a specific example of someone (name a name) of a person who had a 5EFE rod fail because of normal turbo boost. I am talking below 20 PSI. I wonder if this is just a myth that has been blown out of proportion? I am sure you can destroy a rod in any engine with terrible tuning and abuse!
Ok... any other ideas examples and suggestions would be great. Anything that might help me turbocharge the 5EFE in a way that is very cheap, but still safe and reliable.
A thick medal head gasket will solve your compression and head gasket blowing problem . also you can use it over and over again . So don't use one of your milled heads or blocks . maybe you also can grind some medal off the head pocket for more cc volume in the head.
get oversized main bearings and regrind the crank to the middle of the crank like a reversed stroke job . since you are going to use megasquirt then you can add a few more injectors that squirt water/alcohol into the engine as a detonation fighter ( or If your really cheap use a windshild washer water sprayer hahahaha ) I dont know If that one works . I read that in a book once. thats all I can think of at this time other than use a few blowoff valves to ensure that your boost dosnt get over 5-9 psi with the stock config .
I never thought about regrinding the crank mains. I know that you cannot regrind the crank rod journals since it will shorten the stroke and decrease the engine displacement! But if you regrind the mains you would have the same stroke, but you'd be sitting the pistons farther down in the bores, so you'd drop compression quite a bit! I wonder what is cheaper, offset grinding the connecting rods themselves, or grinding the mains on the crank? I will make some calls today.
With the water injection, it is very simple.... I have invented a new water injection system, it is probably already patented, but I have never seen one anywhere. It uses no pump. You simply inject water into the throttle (directly in front of the butterfly valve on the turbo side). The water container is pressurized and 100% sealed. The vent for the water container must go to the end cap on the intercooler, or to a large slow moving air stream, so there is no vacuum. The high air speed in the throttle body will always have LESS air pressure (not more air pressure) than the rest of the turbo piping. That means the throttle body can always still be used to SUCK in water, even on a boosted engine. Why use pumps and motors and electronics, when you can simply mimic a damn carburetor. Why has nobody thought of this!!!!! Read about "Bernoulli's priniciple!!!!!!" my gosh... I am so mad that this hasn't been done...
Anyway I was thinking more like 15 PSI of boost..... With a slug motor, why not? I'll make sure it has almost NO compression that way it won't ever blow up, and since the 5EFE is designed for torque, it isn't going to lose a lot if you lower the compression slightly, it has a long stroke, and a small bore, so it should be responsive at lower revs no matter what!
When I'm done I'll call my car the SLUG!!! I can see it already! I am soo excited! ha ha!
I never thought about regrinding the crank mains. I know that you cannot regrind the crank rod journals since it will shorten the stroke and decrease the engine displacement! But if you regrind the mains you would have the same stroke, but you'd be sitting the pistons farther down in the bores.
cool brain storming ....oh about that crank rod journals decreasing the displacement .I dont think It would make so much of a difference that the turbo couldn't overcome any loss in displacement .and as a rule a shorter stroke can rev a bit higher due to the smaller circumference of the rotating mass of rod swing . not a bad side affect if you ask me .
You are right, short stroke motors are more durable, as many engines (have to be) de-stroked to be used for racing and they seem to work very well! Like the Chevy 302 engine that was put in the Chevy Z28 Camaro, that is just one example!
I could shorten the stroke, let me do the math and I'll see what it comes out to.......
OK If I took away .040" stroke (1 mm), that would only decrease the engine from 1496 to 1478cc. That isn't enough to affect anything, at least not with boost. I will call and see if this practical or not. I know some engine shops may not be familiar with what I'm trying to do, and they might even get irritated by my request. When I was building my 3E-E, they told me to throw it away... But I've been driving it for 5 years and I love it. So I'm glad I didn't listen, lol!
I really think the 5EFE would make a better fuel economy engine and daily driver with the longer rods, longer stroke, and smaller bore, it is a perfect turbo engine for a daily driver, as opposed to the 4AGE which doesn't seem practical for stop light to stop light driving with a turbocharger. I think the lag would be more noticeable and the fuel economy would suffer because of the lack of low end response. I am really trying to make a powerful daily driver that never feels like a peaky race car. I want something with a fairly linear power curve.
Hey man, good advice... 3E-E's are really a dime a dozen around here. And they are easy to wheel out of the junkyard in a wheel barrow... If I ruin one, its fine, unlike a stupid 4AGE 20 valve that cost 1 billion dollars if you destroy a cylinder... lol... 3E-E's are $100 for a full long block engine with mint pistons and a good bore... !!!
Anyway I know 3E-E's are strong, I've tried to destroy mine. I bounce it off the rev limiter everyday (every single day) for 40,000 miles, and the pistons have 140,000 miles on them, I never bought new pistons when I rebuilt the engine 40K ago.
Perhaps I am half asleep, but what you mean "rock it hard as fu@$?"
Can you really use 2 head gaskets stacked on top of eachother??? You haven't blown them yet with 12 PSI???
What turbo are you using, what fuel system, etc???
hey is megasquirt as easy as some make it sound ? I have actually read most of the mega manual but havent got my feet wet yet ,but I do understand most of what I read . fear of the unknown is what worries me. I have plans to use megasquirt on my ae86 sr5 as my first squirt project and am even thinking of msquirting my 73 yamaha dohc 500 cc street bike. the bike has been in storage for 20 years and only has 7000 miles on it. so the drivetrain would make a great home grown chopper.
Are you asking if building a megasquirt is hard, or if tuning it is hard? I think tuning the megasquirt is harder than building it. I built mine in 6 days with no electronics experience. I've been soldering for 10 years, but I've never soldered any fine electronics. If you want to do it, it is very easy, but you need a new soldering gun, don't even think about trying to solder the board with your old burnt wood burning iron!
Buy a new 15 watt fine (3 prong/grounded cord) electronics soldering gun at Radio Shack, it is really cheap, and buy 3 new tips for $2.99 each. Buy some very thin (.030) rosin core solder, and you are all ready to go!
I built the Version 3.0 PCB (Board) with the old Megasquirt and Spark software. I went with slightly older firmware, instead of megasquirt version II firmware, because the Squrt n Spark software/firmware has a million features! You can turn on solenoids at certain RPM's for nitrous or water injection, or a boost controller, etc. You can literally run accessories and set what RPM or boost they kick on at, and you have traction control, etc.
If you aren't good at soldering, don't build a megasquirt, you can get one made from diyautotune. If anyone needs help, I have a very good understanding of megasquirt since I had to research it so much to build it. I designed my meqasquirt to work with ANY toyota ignition system! You just use the COIL - negative wire and run it into my megasquirt, and then you run the megasquirt output wire to the negative post on the coil, the megasquirt doesn't replace the ignition system, it just sits in between the coil and the toyota ignitor box, and it controls the timing via your own custom settings. But it is easy since if something goes bad, you can just disconnect the megasquirt and you will have a fully stock ignition system.
If anyone needs more info let me know.
HERE are pictures of my megasquirt building Along the way you test every single circuit, about 12 or so total, and make sure that each solder joint is good, and that everything works!
I have one of those cold heat soldering irons that they sell at those as seen on tv stores . have yet to fire it up. I don't know if it will be adequate .
I would not use anything but a tiny grounded electronics soldering iron. You solder each connection for about 1 second, and each joint has to be exactly the same as the last. The timing and heat control with the cold soldering iron cannot be easy to manipulate. If they have a very tiny tip that is very sharp to a point, it might work.
Why bother with the CR at all? Plenty of cars run high compression and turbos. Honestly, 9.6CR isn't all that bad. I'd say run what you brung and make sure your tuning is good.
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