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NA-T Bible

NA-T Bible

Ankit Sharma |

Providing in-depth information on what is involved with turbo converting an NA 2JZGE motor to GE+T, sourcing a GTE motor has never been an easy task, so the easier it is to understand this process the better it will be in the long run

This article has been pulled from Supraforums.com & my.is, just in-case they go under again, we don't want to risk losing such an important resource!


Feel free to sticky this so others can add, this needs to be the start of a "Come to Jesus" talk with NA owners so they know how to turbocharge the mighty 2jz-ge. To any moderator: feel free to edit my post and make it more concise and/or readable.

Hopefully, by being on this website, you understand the basics of the 2jz series of engines. In the United States, Toyota released "technically" 2 versions of the 2jz motor, the GTE and the GE.... both come standard with DOHC, 24valves, EFI, etc... what else can you expect from Toyota?

Differences between the GE and GTE (not comparing either VVTI editions):
-Most obvious difference to anyone familiar with engines is the TURBOS. The GE has none, thats what the 'T' in GTE means.

-Another is the style of intake manifold, the GE has a manifold developed for more torque development in the lower-part of the rpm band vs the GTE's short runner type. The GE doesnt have more torque; its just that it develops more than it would if it had a GTE-style intake manifold. Hope you knew that.

-Compression, the GE runs a 10:1 compression ratio and the GTE runs a 8.5:1 compression ratio. The differences are obtained through a thicker headgasket (.2mm for GE vs 1.6mm for GTE) and lower compression pistons on the GTE. The higher compression allows the GE motor to make the most of its power since it lacks turbos to begin with.

-Injectors and Airflow sensors, the GE runs 330cc top-feed high impedance Denso-style injectors and uses a Karman Vortex air-metering sensor to read how much air volume is being injested. The GTE runs 540cc side-feed low impedance injectors (though uses a resistor pak to raise the impedance for the ECU's sake)... measured through a hotwire MAF sensor. The GE's airflow restriction is around 450hp from the stock AFM and the GTE is around 650-700hp depending on several factors.

-The heads are slightly different. Some say the GE flows better than the GTE, though no concrete numbers have come from a flowbench to prove it. The GTE motor has larger intake ports on the head whereas the GE has larger exhaust ports on the head. You make your own decisions.

-The exhaust manifold and intake manifolds port spacing and studs are completely different and will not work with one another unless some machining is involved with the manifolds themselves. There are people who have successfully grafted the upper part of the GTE intake manifold onto the lower part of the GE manifold.

-The GE motor runs a distributor-based ignition system with spark plug wires and a single coil. The GTE runs coil-on-plug ignition with individual coils for every plug. The distributor gets in the way somestimes of the turbo intake pipe (HINT HINT, you can run the GTE or IS300 coils and delete the distributor leaving room for moooarrr turbo!!! See Post #4 for ALI Sc300's Awesome ECU mod which allows you to run the GTE ECU on your GE along with the Gte coil-on-plug)

These are just motor differences, there are many little others such as oil squirters, oil feed/return lines, transmissions, etc.

Now onto Similarities:
Both the GE and GTE bottom ends are VERY strong. The only difference being the pistons themselves. Thats right, the rods and crankshaft are the SAME parts!!! The 2jz motor itself was DESIGNED to be turbocharged from the beginning and is built VERY strongly from the factory. No one yet knows the limits of a GE setup, though there are several 1000whp setups on the GTE with the stock bottom-end. Dave H uses a GE motor and ran a 9sec 1/4 mile time with the stock GE block ( a spare 220k mile motor to be specific!)
All in all, it is very doubtful that you will need to build your motor when designing a NA-T setup unless you're gunning for ridiculous amounts of power. The stock cams are roughly the SAME.
There are a few things to keep in mind when deciding what you want to do. The biggest decision RIGHT NOW is whether you want to build a DIY kit or order a pre-built one from a reputable shop.

Going the DIY
is very rewarding and you will learn more about your engine than you thought possible. I personally went this route TWICE on my first two setups on my SC300. But I had the typical problems.
-The Price is a good bit cheaper. Face it, you can source your own parts off ebay, used items off of SupraForums and Clublexus classifieds, etc and probably build a kit for much cheaper IF you get everything. This isnt always the case
-The installation is a bit more difficult since you're putting together parts that werent necessarily designed for one another and may require some fabrication
-Used parts dont last as long and a lot of times they just arent as good of a quality as new stuff is (new stuff is ALWAYS coming out for the GE car nowadays).

Buying a Kit
is much simpler and easier to follow. You will still learn a lot about your motor if you install your kit yourself and still have the oppurtunity to purchase some used parts if you can find good deals, etc. Buying a kit you KNOW that it will work correctly if its a reputable shop such as BoostLogic, Sound Performance, PHR, Dave H, etc. People have already done them, posted their results and their problems so you can be ready for it when its your turn. You can purchase a turbo kit, fuel kit, aem kit, and be done with it and have a monster on your hands. They literally come with everything you need... being from the other side, I can tell you that this is an immense PLUS. It doesnt quite sound like it... but having done it twice, this is the way I will do it a 3rd time.

Parts in a Typical Basic NA-T kit (note this is not everything you need)
Turbo manifold (there are log and header types, headers flow for more power, but spool slower)
Blow off valve (It helps to relieve charge piping pressure reducing turbo surge expanding the life of your turbo, Get one.... )
Wastegate (bigger you go, the more control you have and less chances for spikes and creep)
Downpipe (connects to your exhaust)
Intake pipe (connects from your turbo inlet to your filter or AFM)
Oil feed and drain lines (feed and drain oil to/from the turbo)
Turbocharger (large varieties of these, this is what makes boost!)

In the basic kit you usually run directly off the wastegate spring. Most kits keep you running on the stock compression levels (10:1 remember?) in the first "stage" or two, until you get serious about power anyways. This results in quicker spoolup and better off-boost response but you cannot run as much boost without risking serious damage to your motor.

-10:1 compression limits you to around 7-8psi without fiddling with your ignition timing (stock timing has a big "spike" of advance around 4000-4500rpms that will cause detonation if running more than 8-9psi and the base timing is not retarded 3-4 degrees)
-stock injectors will also limit you powerwise. I've seen several setups make OVER 400whp on the stock fuel setup (upgraded fuel pump) but its still best to upgrade them (and with a way to control them too -- SAFC, emanage, MAP ECU, AEM standalone, etc)... generally I wouldnt go over 350whp with the stock 330s.
-intercooler options, some kits come with some dont, most of the lower-priced ones dont and you are left to fend for yourself in the intercooler arena... you NEED one to run more than 5 or 6psi reliably

What you REALLY need for a well balanced kit
-strong turbo manifold, either a strong cast unit or a strong (IE 321 Stainless Steel) tubular header manifold... Dave H's manifold runs via Weld Els and it is VERY strong and beefy. His manifold is more of a hybrid, not really a log and not really a header. ALSO the Xs power manifolds seem to work good for the price, but it is a more cheaply made manifold.

-turbocharger to suit your powerband preferences (a later discussion perhaps?). Most people go with a T04E or PTE style turbo that makes around 400whp at 10psi of boost. Used or new holset turbos are a fairly good cost effective option as well.

EDIT: Thanks for suprapunk pointing out something: If you are building your own kit: Ensure that your exhaust turbine lines up with your manifold Like make sure its a T4 hotside and a T4 flange on the manifold, and make sure you have the correct hotside outlet as well to mate to your downpipe (v-band, on-center, etc)

-35mm wastegate, Tial or HKS brands are good stuff. Many kits are running 38 and 40mm gates, which is fine, they cost more. Depending on how much power you'll be making with your turbo, you need to decide what to run unless a kit-maker already picks one.

-fuel and a method of controlling that fuel to supply enough for your power needs. On more basic setups I recommend the Emanage blue. Affordable and can tune your car very nicely. Most basic kits can make good power with MKIII Supra Turbo injectors. They are also top feed (but low impedance, need resistor box or inline resistors) and denso style but flow 440cc instead of 330. The Lexus V8 AFM modification is affordable and can make the 440s easily tunable with a simple fuel controller. Anther rout (very cost effective) is to run the GTE ecu which can get you to around 400-500hp depending on which Gte ecu model you choose

-a FRONT MOUNT INTERCOOLER. Do it once, do it right. The sidemount jobs cannot compare with the Front mounts other than being harder to see. You can pick up good quality units off ebay for under $300 these days.

-A 3 inch downpipe and 3" exhaust system! At least 3 inches all the way back if you can. Turbos need FLOW, give them a bigger exhaust and they will spool faster and give you MORE POWER.

-GOOD spark plugs and good conditioned ignition system (get a new rotor and cap for your distributor pronto!). NGK 3330s and NGK 6097s are both great plugs, they are pregapped at .031 which is perfect for turbo applications under 19-20psi of boost

-Oil feed/drain lines properly sized. Typical setup is -3 or -4 AN feed with a -10 (no smaller) drain line. Garret turbos require much less oil than most people think; and dumping high pressure (60psi+) oil into it and then having a small return line blows the oil seals on the turbo very quickly. You want NO flow resistance on the return line. You can do this by having a BIG return line like a -10 or use a oil-line restrictor (can pick them up at atpturbo.com). IF you buy a premade kit that comes with a oil-line kit then don't fret, its already been tested and setup with the turbo you'll be running from the kit.

Keep in MIND!!! That all of this is how to get power reliably out of the MOTOR. The transmission and the rear end are completely different subjects. Your stock clutch WILL NOT withstand more than 300whp and last for very long. Your stock transmission WILL NOT WITHSTAND more than 400-450whp for very long and driven hard (your mileage may vary).
Autos are very different from the stock 5-speeds. Do your research on driveline modifications!
Keep in MIND!!! That all of this is how to get power reliably out of the MOTOR. The transmission and the rear end are completely different subjects. Your stock clutch WILL NOT withstand more than 300whp and last for very long. Your stock transmission WILL NOT WITHSTAND more than 400-450whp for very long and driven hard (your mileage may vary).
Autos are very different from the stock 5-speeds. Do your research on driveline modifications!

In the bigger power arena, you need to bypass several obstacles. One most notably being the stock ECU with regards to fuel metering. There are only so many bandaids you can run before you run out of airflow (even with the V8 AFM). This means by going to speed density!

Speed density is a completely different way of measuring the air intake in the engine vs the mass-air system used in the stock GE.

The stock GE system uses Karman Vortex as its way of measuring air. If you've ever taken apart your intake and see the sensor itself, you'll see a waffle-style (or honeycomb) front on it. What this does it cause small vortexes to form after the air enters the system. The more air that enters, the more vortexes (and the larger they get). The quantity and amplitude of these vortexes is measured by a small speaker inside the housing. You can see it if you look carefully. Do not damage the honeycomb up front, you will cause the sensor to read bad.

Speed density uses two seperate sensors to measure how much air has entered the system.
-The first sensor is a pressure sensor that senses how much pressure or vacuum is in the intake system. This is called the "MAP sensor" MAP is short for "manifold absolute pressure". By absolute, this means TOTAL pressure including atmospheric pressure (which is 1 BAR at sea level) by the way. If someone has a 3 bar map sensor, it means it can read 29.4psi of pressure ABOVE atmospheric (14.7psi = 1 BAR). Obviously, this is a little sensor, and causes no intake restrictions of ANY sort.
-The second sensor is an air temperature sensor. When air cools, it becomes more dense, with more oxygen molecules. This sensor allows the ECU to compensate with more fuel to keep a safe mixture when the temperature rises or drops. It is called an IAT sensor - or "intake air temperature" sensor. This sensor also causes no restriction.

Almost all aftermarket ECU solutions are Speed Density (also called MAP-based) and this includes the AEM ECU. It can run via AFM, but its a waste not to utilize the extra flow and control with MAP. The "MAP ECU" is a piggyback solution for the stock ECU. Like the older VPC, it translates a MAP-based signal into an AFM signal that the ECU can use (and isnt any the wiser). Both the MAP ECU and AEM allow you to run MUCH larger injectors.

Ok I'm running a speed density system, I am cool!
Not so fast! You need BIG fuel injectors for that too. Luckily, the stock fuel rail is a top-feed unit, has an FPR plug on it that is right around 1/4" NPT in size, and has a good enough internal diameter to flow enough fuel for over 700whp. Boost Logic, SP, Titan, etc now offer NA-T fuel systems that either use the stock rail or replace the whole thing completely. These systems are generally customizable to the size injectors you want and most use TWIN Walbro Fuel pumps. Nice eh?

After that, you will already need to be running a GOOD turbo header... the cast jobs work well in the low-power arena, but with the big boys its all about FLOW.... and cast units DONT On the header setups, you will already be using a larger wastegate (40mm+) and at least a 3" downpipe. A lot of companies will have a 4" downpipe and midpipe combo to upgrade to if you're going to be making big power (dont really need that unless you're hitting over 700-750hp).

A FRONT MOUNT INTERCOOLER!!! I'd laugh if someone tried this with a stock sidemount

A turbo that can flow the amount of air you want. Do some research, because there is a HUGE turbo selection out there and new ones are coming out all the time that offer better and faster spool, more flow and power, and more extras ( like jet sounds from the ported shroud housings hehehe )

At this point you MUST be running a thicker headgasket. Why? Because you cannot make over 400-450whp reliably with the stock 10:1 compression. Stock SupraTTs come with 8.5:1 compression and can run lots of boost from the factory. YOU can get to this point by running a thicker headgasket. Your stock gasket is very thin... like .2mm vs the GTE gasket which is 1.6. Do not worry about squish-volume problems too much, since the primary source of compression drop on the 2jz-gte is achieved by running a much thicker headgasket. 2.5mm will get you to 8.5:1 compression.

The only problem left is ignition, which can be solved by running lower gap on your plugs and an HKS DLI. It boosts the ignition signal and will allow you to still make spark at higher boost when it would normally be "blown out" from the excessive pressure.

After this point, you can start tuning, running racegas and making BIG power. The stock GE intake manifold (EGR delete please!) can flow over 800-850hp and there's no point in upgrading to a high-flow unit (such as the DaveH unit) until you eclipse this point.

There are lots of little things this guide didnt have for big power, which is detailed tuning instructions (get it tuned by a professional if you dont know what you're doing!), and small tidbits you should already know. (ie Beaded intercooler pipes, new gaskets for all hardware, etc)

Please understand that this is just a basic blow by blow of how to obtain power from this motor. If you can understand this so far, then congradulations, you can probably handle the whole deal just fine.
Remember that you can always just purchase a kit from a reputable manufacturer and it will come with everything you need.

Give one of the good shops a call and tell them exactly what kind of power you want with what kind of powerband (nothing too unrealistic here k?) and they will give you an invoice or statement telling you exactly what you need. They've answered these questions many times."

 "A lot of the info came from post at ClubNa-t.com which has been shut down also making all the info on the site unattainable but luckily I saved the NA-t bible. The rest has came from general memory personal experience or other members.

ALSO if you have any valuable/ missing info to add to this just let me know and ill add it in :)

A big thanks to Ali_sc3 & Superstock"

Original Link: https://www.supraforums.com/threads/na-t-bible-things-you-need-to-know-for-your-na-t-conversion.682898/ & https://www.my.is/threads/the-na-t-encyclopedia.591569/