beak

This is for Scions mainly, and mainly Scion tC

For the AFR:
All of the engine management systems out there can only tune the fuel curves when you floor it. But when you don't floor it, your ECU is constantly re-learning air/fuel ratios. So regardless of what changes you make on the emanage or any other piggy back system out there, the stock ECU compensates for it and changes it back to right around an air -fuel ratio of 14.7. Air fuel ratios are one of the most important tuning aspects of any engine, followed by ignition timing. Air/Fuel ratio is for every x amount of fuel, there's x amount of air. 12 parts of air, for 1 part of fuel basically

There's a fine line of tuining with air fuel ratios to get the most reliable power out of your car. Tune too rich and you foul your plugs, and loose some unnecessary power. Tune too lean and you're running too hot and risking severe damage to the motor.

When we tune for example... We like sitting around the 11.5 range, going as high as about 12.2. 12.7 is about optimal for a boosted car but for a daily driven tC with 10+ psi it may not be the best option. The 11.5 can help cope with a boost spike, or some really hot days. This will lower the chance of detonation which is usually the result from poor fuel or ignition maps.

Ignition maps adversely affect fuel. If you advance ignition timing, you effectively leaning out your fuel curve to a certain extent because the spark is starting an "x" amount of degrees sooner. Retarding the ignition timing will effectively enrichen the fuel curve because you're starting the spark sequence later.

Ok, so that means you need a new ecu?
We have our WOT tunes fully adjustable...as of this second, you need a stand-alone right now to adjust partial throttle fuel curves. There is no piggy back that allows you to tune your fuel maps unless you floor it. This is fine for lower boost, but with 10+ PSI it’s not recommended. We are in the finishing stages of the first and only application that will work on the Scion tC, both auto and manual, turbo and s/c that will allow you to change your partial throttle fuel curves and still attain your stock ECU! Please PM us with regards to this part, because I’m not turning this thread into a massive plug for us, as much as I’d like to. We will be releasing this EMS soon, both with our turbo kits, and people looking to buy it separately for themselves for their own setup.

What is a stand alone EMS (engine management system)?
A stand-alone is where you replace the ECU with a new one, and input the exact values you want, to tune every part of the car

What is a piggy-back EMS?
A piggy back keeps your stock ECU, and modifies the signals going to the ecu to allow you to adjust the tune...

What is WOT?
Wide Open Throttle

What is BAR?
BAR stands for Barometric pressure. 1 bar is equal to 14.7psi.

What is Knock?
Knock is pinging or detonation. It’s usually a result of too much compression with too high of temperatures. Common failure points are piston rings and/or head gaskets. Both cost a lot of labor to fix. Knock can be avoiding by using high-grade fuel, and tuning accordingly.


PARTS:
Turbo:
A turbo comes in all shapes and sizes. There are major differences between turbos out there. Here are some of them:
AR: The AR is what primarily determines how much lag you can expect with a turbo charger. A larger AR means a larger lag, but with more top-end power. A smaller AR gives you better spool-up but may not produce enough pwer on the top end. A larger AR is the exact opposite. The number that you need depends on your application and the turbo professionals out there know what’s best for you. (This does include myself and Paul!
Trim:
Trim is the size of the wheels on the turbo. There are two wheels. A compressor wheel (intake side), and an exhaust wheel (exhaust side).
Turbo housing:
There are so many different turbo options out there it’s hard to say which is best. There are different flange types out there as well. So when you buy a manifold with a T3 or a T25 flange for example, you need to buy turbos that are flanged the same way, so that things bolt up. Exhaust and compressor housing also affects spool and top-end power, and is very similar to the AR values. A T3/T04B is smaller than a T3/T04E. A 16G is smaller than a 20G. All have different flow characteristics and are efficient in different areas. Once again, a turbo professional can help you decide which is best for you.


Wastegate (WG):
The wastegate is what controls your boost levels that your turbo is running. There are two types of wastegates. Internal wastegates are attached to your turbo and turbo housing itself. Externals are attached to your manifold. Both types of wastegates follow the same princible. They control your boost levels by bypassing exhaust gases past the turbo. This limit’s the energy coming from your motor to a certain amount to what the turbo actually sees. Because your turbo isn’t seeing an increase in energy (exhaust gas) after a certain point, the boost stops going up and is regulated to the desired level. Internal wastegates have an internal flapper that diverts gas within the exhaust housing out to your down pipe. This is a very simple and inexpensive way to control boost. The more expensive and reliable option is an external wastegate. External wastegates take the exhaust gases from your manifold itself and dumps the excess gases outward. You have an option to dump it into the air (open dump) or run a pipe connecting the wastegate to your exhaust. Open dump is loud, not smog legal, and dirty. It does however yield a little bit more power and gives a different sound to the car. For a daily driven tC where ultimate power isn’t a concern, plumbing the wastegate back into the exhaust is still the best way to go. It’s quiet and keeps you out of trouble. Bot wastegates are fed by a vacuum source, whether it be the turbo compressor housing, or the hose that connects your intake manifold to your TB.

Blow-off valve (BOV):
Once again, two types of BOVs. Atmospheric and recirculating. Some BOV’s have the ability to be both, depending on the fitting(s) attached to them. Atmospheric BOVs are much more common. The biggest reason is because everyone loves the loud sound of the whoosh when you shift gears and try to impress people. This may be the best alternative in some applications but not all. A BOV’s purpose is to let out or divert air when boost is made then the throttle body plate closes. All that compressed air is just itching to get into your intake manifold. When the throttle plate slams the door shut, where does all that air go? It heads right back where it came; towards the turbo. You don’t want that! It causes what is called compressor surge and is very bad for your turbo. The turbo gets hotter, it wears out faster,, and it lags when you get back onto boost because now it needs to speed up again. A BOV senses the boost to vacuum transition (by being hooked up into a vacuum line) and opens up. This frees all that extra air, and basically lets it out. Atmospheric BOVs will just let it out into the air, while recirculating BOVs will divert the air back into the intake pipe. Two reasons to divert back into the intake pipe are to limit the sound output, and to allow the MAF sensor to meter the air more accurately. The MAF thinks the air made it to the motor so it tells the ECU to add more fuel. When you vent the air out, the air is “gone” and there’s too much fuel now sitting in the motor. This causes your car to run rich and under higher boost applications will accelerate wear on spark plugs, fouling them out. It also wastes gas.

MAP vs. MAF:
A MAP (manifold absolute pressure) sensor reads how much pressure is actually inside the intake manifold. It does not take into account the CFM or the air coming in, only the pressure it comes in at. Colder air is denser, so most MAP based systems use an IAT (Intake Air Temp) sensor. This helps the ECU better figure the amount of fuel needed. MAPs can use atmospheric BOVs with no side effects. MAF (Mass Air Flow) systems meter how much air is actually flowing through the intake pipe. This has been known to be more accurate way to tune, but for turbo cars it makes things more tricky. A MAF sensor actually sits in the way of the air being sucked into the motor. In higher HP cars this could actually cut back on some of the performance. On most cars out there, the difference is negligible and most companies prefer this option. It’s more accurate, and allows for better tuned OEM cars. A MAF sensor simply reads how much air flow is coming into the engine and tells the ECU how much fuel to send accordingly. Atmospheric BOVs make this system somewhat unstable, and can/will result in richer than normal conditions under the boost to vacuum transition.

Manifolds:
There are many types of manifolds out there, with different materials. I won’t get into too much detail but here’s something to work with. Materials and weld quality are what determine how reliable your turbo would be. Cast iron manifolds aren’t the prettiest but they are damn reliable. With no welds and a high heat tolerance, reliability is the last concern. They do cost a lot more to originally fabricate, because you need a mold to do it. Most shops weld log manifolds. They actually do look like a log, and are finished with a flange of your/their choice. They are simple and cost effective. Some companies weld better than others and can be more reliable. Crappy welds leads to cracking and you spending more money down the road so spend wisely now. Equal runner manifolds usually perform the best, but can be the most problematic. They cost a LOT to develop (properly at least) and need extra TLC in the welding process to make sure they hold up to expectations. The end result can be the best, but at over double the cost in most situations, is it really worth it for you?

Flywheel:
Flywheels can help and hurt you at the same time. Sure it’s more responsive, but do you road race daily? Most of you tC guys out there drive your car to and from work/school/friends in a pretty consistent basis. Flywheels have inertia. Inertia simply means that once it’s in motion, it wants to stay in motion. When it’s at rest, it wants to stay at rest. More inertia (heavier flywheels) are great in traffic. The first gear starts have more initial torque and will help get you going off the line, whether it be in traffic, at a light, or at the drag way. Once you’re in gear, you want less inertia. This is because now your engine is fighting to rev higher. The less weight it has to move, the better the acceleration, hence the quicker response. If you spend most of your time in traffic or daily driving, a stock flywheel is fine, maybe a slightly lighter one. If you road race a lot, and spend most of your time in gear and need the extra response, a lighter one is better. It’s your choice, and don’t buy one just to say you have one. You can spend 300 somewhere else that will greatly increase performance in a different way.

Clutch:
Get something that grabs and holds long-time!!! I wish it were that easy. Pedal pressure, engagement points, engagement harshness, and TQ capacity all play a major role in deciding which is the right clutch for you. We use the ACT street clutch on our Dezod tC. It holds 341WTQ and has a very smooth engagement. Pedal stiffness is increases so expect to have a stronger leg. This could lead to leg strain in traffic, but if you need the clamping force then get it. If you’re not making a lot more power than stock, the TRD clutch is a great upgrade. For most of those turbo owners out there, an ACT street clutch is one of the best options out there. The ACT race clutch is puck instead of a disc. Discs tend to be smoother on engagement but pucks have the ability to hold much more power. Do not buy a puck-based clutch unless you KNOW you’ll soon be making upwards of 400+ HP.

Intercooler (IC):
Larger the better? Wrong to a certain extent. Some intercoolers are more efficient than others, and the design plays a huge role in this. If you’re only using 8psi, you don’t need a massive 24row IC sitting on the front of your car. Yeah it looks cool, but it weighs more, and you just lost your metal bumper that’s there to save your car and life in case of a frontal accident. Core and fin, and bar and plate are two different IC designs. Bar and plate is more efficient at cooling so a smaller IC can be used without sacrificing power. The one we use keeps the OEM metal bumper and supports up to 550whp.

Pipes:
Hot Side: Pipe connecting the turbo to the intercooler.
Cold Side: Pipe connecting the intercooler to the throttle body (TB).

Fuel injectors:
Not getting into too much detail here. We know the RC injectors fit, and that 550CC injectors are more than enough to support about 400whp. Go too big and you could have an idling issue, go too small and you may not have enough fuel support for the power you’re looking to make. 550s are a great injector for 230-400whp.

Exhaust:
I want a 3”! NO my son. 3” exhausts are only beneficial at a certain point. On most cases for what most people on these boards do or have, a 2.5” exhaust is perfect. If done correctly with mandrel bends and a good muffler, a 2.5” will be the best performing exhaust for a mildly boosted tC. It keeps exhaust temps hot enough to help them scavenge, which allows for faster turbo spoolup, and more horsepower. Too big of a pipe will cool the exhaust gases down. This creates turbulence and back pressure. The result is actually a loss of power. When you make enough boost, power, and heat, then you can consider a 3”, but until then, stay smart. Save your money and go with a 2.5”. Keep in mind a 2.5” weighs less and the 2HP loss from a 3” could actually perform better because now there’s less weight to push. This will allow for better handling and braking as well. It’s a small amount but every bit helps.

TUNING:
I touched on this a little bit before. Tuning is key. It affects your performance and reliability. This part is where the magic happens so I’m going to keep this from being to generalized or specific because different systems respond differently. The first and most common thing to tune is your air to fuel ratio. This helps get the most and safest power out of your car (if done correctly). Tune too rich and you will bog, foul plugs, and lose power. Tune too lean and your car may lot last too long, as you are taking the temps up higher and risking the chance of knock/detonation. Ignition timing is the next step in tuning and can be the final bit needed to give you the extra safety you need for the longevity of the motor. Professional tuners should be doing tuning, so I’m cutting this part short. Paul and I can answer more specific questions if you must.


RELIABILITY:
Run too much boost on a daily driver and you’re engine will fail prematurely. Regardless of how perfect your tune is, higher boost always means less life in the motor. Boost is hotter, and boost makes for more pressure in your combustion chambers. If you expect to get 200k out of an aftermarket boosted car, you’re in the wrong scene. Mild boost (6psi or so) can actually last quite a long time. If you tune conservatively, adjust both WOT and partial throttle tunes, and stay on top of your oil changes, I wouldn’t be concerned with the motor at all. At slightly higher boost levels, proper tuning and maintenance is key. I’ve been driving my tC in all different temperatures for 8 months now with a turbo. The lowest boost the car has seen is 8.7psi and I’ve raced this car a lot. My motor’s running great and I know it will keep going at the rate it’s at. I change my Mobil 1 10W-30 synthetic oil every 2500-3000 miles, along with the oil filter. I’m running Denso IK22s for my spark plugs which run a little bit colder than the stock ones. Keep checking your oil levels, and don’t beat on your car unless it’s necessary. This combination can yield a long lasting, high powered Scion.

Now that you're eyes are killing you, I hoped you learned something. Boost is a fun thing to get into but you need to know what you're getting into. This is what Paul and I thrive on. If you have questions, comments, concerns, then post up. We'll take care of it.

www.dezod.com

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96 EK Hatch 343whp, and 245ft/lb torque at 11psi - Stock GSR Motor