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1G Installing a turbo 4g63 into an nt 4g63

Posted by mavisky, Feb 18, 2003

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  1. mavisky

    mavisky DSM Wiseman

    Joined Sep 13, 2002
    Atlanta, Georgia
    This Tech Article was originally written by Mavisky in February 2003. It is and has been a great tech article and has helped many DSMers including myself. I, 9!'clipseDOHC, am expanding it now only to help further the DSM community. This is a very common topic and I hope that this tech article will be a one stop information source and will continue to guide others attempting to swap there non-turbo 1g's into the turbocharged monsters they should have always been.

    Mavisky's Intro: Over the past two years i've been converting my car from a september 91 build date 4g63 nt over to a gst. As you've most likely seen user xhypno has a fairly well put together setup for sticking a set of turbo only parts onto your nt and creating a 7psi or so car. Now this is a good deal for most people since they aren't looking for the kind of time or money it takes to do a full conversion like i did to my car, also it eliviates some of the troubles high hp dsm's have.

    On the other hand though it limits you severely in the type of power you can make. The piston ring lands on the nt pistons (now we're mainly talking the nt 4g63 here) are in a terrible position. While more than sufficient in strength for a nt motor only pushing out 135hp out of its 2 liters, once boost is added problems suddenly arise. The ring lands are so high up on the piston skirts that a shockwave from pre-ignition (knock) can easily crack the land causing the ring to separate, lose compression, and god forbid internal engine damage. The obvious cure to this is to simply replace the pistons, but we're going to go a little farther than that, although we will spend some time on that as well.

    9!'clipseDOHC's Intro: I bought my 1g N/T DSM in January 2003. A 1991 Eclipse GS. I rebuilt it and learned a lot about the 4G63. I read this article and many other threads and decided To try the swap. I had a very low budget and my car was my DD at the time. Yet the opportunity presented itself and I jumped on the it. I was working at a junkyard when a 1991 Plymouth Laser RS Turbo FWD arrived at the yard. I pulled the engine, transmission, ECU, and wire harness out of the car. I had the engine rebuilt to factory standards and attempted a swap back in 2005. However I ran into problems with the engine, with money, and with it being my daily driver and ended up pulling it out and putting my GS engine back in. That motor sat on a stand in my parents garage for 5 years until I redid the swap in 2010. I learned from my mistakes and this time I had much larger budget, I wasn't dependent on my DSM as a DD, and I had spent a lot more time researching. This time the swap worked perfectly. You can see my entire build in my blog here: DSM Forums - 1g Non-turbo -> Turbo swap.

    This swap is very doable by most people with basic mechanical knowledge and the willingness to put the time into researching and formulating a plan, and the money into acquiring parts and doing it right the first time.


    This Tech Article will attempt to cover transforming any 1g (1990-1994) non-turbo (N/T) DSM (Eclipse, Talon, or Laser) into a 2.0L 4G63 Turbo FWD DSM.

    Planning a preparation are critical to the success of your project. Research and formulate a plan first, before you spend any money or pull any parts. Sourcing out the engine and other parts needed for the swap is the most challenging part of the whole procedure. The actual mechanics of it are fairly simple and straight forward. Once you have a plan, start searching. Get the big stuff first and work your way down. Junkyards, classifieds, and ebay are your friend for this.

    Choosing the engine:
    Getting ahold of the engine and its accessories is the most important part to not spending all year trying to pull this off. I believe that there are only a few really good methods in going about this.

    One: Find someone with a wrecked awd or fwd turbo. I personally picked up my engine for $1200 with my choice of whatever accessories i wanted.​

    Two: Search the junkyards for a complete car with engine and all accessories still attached to it. Most could probably be had for nearly the same price as buying one off of an individual.​

    Three: Build or buy a jdm engine and then find either a local parts car or one in a scrapyard to get ahold of the accessories you either won't recieve, or in the case of the jdm, may be damaged.

    Four: Since the pistons are the main difference, and the weak link, between the 4G63 N/T and T, You can just swap out the pistons and then source all of the bolt on parts listed below. The N/T block does not have oil squirters but that is not generally an issue), the crankshaft and rods are identical, most N/T block are already tapped for the knock sensor, and the heads are the same with the exception of the intake cam. If you take this route it can end up being just as expensive (pistons, machine shop, etc.) as buying a used engine, but at least you know that everything is new and in working order. That may or may not be the case with a junkyard engine.​

    A little bit about oil squirters.
    2.4 L 4G64's and NT 4G63's did not come with the piston oil squirters in the main oil gallery. The cast bosses are still there and can be drilled and tapped if you want to add squirters. However many people believe that they are not necessary. Drag racing and street driven motors in particular can do without them because the runs are short and the pistons crowns aren't subjected to constant high temperatures like a road race or rally racing motor. In endurance type engines oil squirters can improve the reliability.


    Let's talk about pistons for a minute.
    The weakest point in any piston is the top ring land. The thin ring of piston material is fragile because its not supported, and detonation can cause it to crack and break off. The N/T ring lands are much weaker then their turbo counterparts and, as you can see in the picture below, are located closer to the combustion chamber, making them even more susceptible to knock. Simply put, N/T pistons can not handle the high cylinder pressures that turbo engines see.

    Here is a comparison between 1g Turbo pistons (left) and 1g N/T pistons (right with the rings).

    Pistons to consider in your turbo swap are aftermarket forged (generally 8.3:1-9.0:1), EVO 8 or 9 (~8.5:1 cast), 2g turbo (8.5:1 cast), or 1g turbo (7.8:1 cast). The compression ratio (CR) of 4G63 pistons is determined by the piston dome. The domes are flatter and less dished in the higher compression 2g and EVO pistons. Choose your CR based on the use of your engine, amount of boost, type of fuel, and tuning method. Higher compression isn't always better.

    Lower CRs are easier to tune and more forgiving, allowing you to run more boost and timing without worrying so much about knock and EGT. Higher compression pistons can make more power with less boost and timing but your tuning has to be very precise and is less forgiving of mistakes.

    If 91 octane is the highest fuel you can get, consider a lower CR. If you are going to be running E85, then you can look at a higher compression piston. Also your turbo has to be taken into consideration, a turbo that like high boost should be parred with lower CR pistons.

    What about cast and forged? Stock DSM turbo pistons are cast which allows them to be run with a very tight bore, this makes them ideal for daily driven factory vehicles. However the problem with cast pistons is that that are not as strong or ductile (the don't bend, they brake) as forged pistons. This makes them less able to resisted the effects of detonation (knock) and can cause them to crack and break. The downsides of forged pistons are that they need more pistons to wall clearance (which can cause piston slap, an annoying noise, especially on cold starts).

    Another important aspect to consider in pistons is the weight. The lighter the pistons the less force acts on it and the higher the rev limit that can be safely used. A lighter piston of the same strength as another will last longer. Plus less rotating mass frees up more power.

    Here is a quick video comparing 1g, 2g, and EVO pistons.
    YouTube - Graveyard Motorsports DSM and EVO Piston Compairison

    What about the Cylinder Heads?
    The turbo and N/T 4G63 cylinder heads are identical with the exception of the intake camshaft which has a 252 duration while the turbo has a 257. Both exhaust cams have 244 duration. The N/T intake cam also has 5* more overlap. Here is an in-depth explanation of 1g 4G63 camshafts:

    Also the 4G63 turbo is oil fed from the passenger side of the head. On the non-turbo this has a bolt blocking it off. You will need to get a 10 mm x 1.25 banjo bolt and a feed line. The Mitsubishi part numbers are:
    MR239830 = 1G Oil Supply Line
    MF650102 = 10mm Banjo Bolt For Head​

    Engine Accessories:
    First we'll assume that you were lucky enough to find a complete longblock 6 bolt through either a fellow dsmer, performance shop, or scrapyard. Now the list of things you will want to get ahold of that pertain to the engine.

    1. Complete turbo long block (block and head including internals and bolted attachments such as oil pump and such).​


    2. MAS Sensor - The turbo mass air sensor has a 7th wire coming out of it as opposed to the N/T's 6 wires.​


    3. Solenoid Pack (Fuel Pressure and Purge Control Solenoids) -​


    is the wiring connector which plugs into the engine wiring harness
    Yellow is the purge control solenoid valve. It is part of the EGR system, if you have eliminated your EGR, you can eliminate this solenoid as well.
    Green is the fuel pressure solenoid. This allows the ECU to temporarily raise the fuel pressure for hot starting purposes. If you have an aftermarket fuel pump, you can eliminate this solenoid.​

    4. Turbo Intake Manifold and Throttle Body - The turbo intake manifold is already tapped with the vacuum line nipple for the BOV, also it has the correct studs in it to use the turbo throttle body and elbow.​


    5. Turbo Exhaust Manifold - pretty self explanatory hopefully, although make sure its at least for a 14b and not the automatic's 13g with the smaller opening. A 2g manifold is recommended here as is is less prone to cracking and can be better ported.

    6. Turbo and related cooling and oil lines - now here is one that's an option. you can either go with a trusty 14b for awhile and stock lines or step up to the plate with a combination of any turbo/ oil feed line.​


    7. Intercooler (Stock side mount or aftermarket front mount) - you will need!​

    Stock 1g SMIC


    Aftermarket FMIC.

    8. Intercooler piping- I recommend starting with a sidemount and stock piping for most people to keep the initial cost down.

    9. Turbo Fuel Pump - This is an absolute must have, the N/T fuel pump has no business handling ANY boost. The turbo fuel pump can be used if you are planning on running no more then factory boost (12-14 psi). If you are planning on running more then that, go with a Walbro 190 or a Walbro 255 and an Adjustable Fuel Pressure Regulator (AFPR). Here is a comparison done my RRE on fuel pump flow rates: RRE Instructions
    Here is a post to help you decide which pump you will need based on the size injectors and air flow of your turbo: http://www.dsmtuners.com/forums/newbie-forum/393264-x-hp-fuel-injectors.html#post152473744

    10. BOV - Stick with the stock 1g bypass valve for now, its a great design and its cheap and adaptable.

    11. Turbo Fuel Injectors - get the 450cc's from a 5 speed. 1g automatics came with 390cc injectors paired with a 13g turbo. Mitsubishi fuel injectors are color coded (see chart below). 450's have blue tops and 390's have brown. Compare those to the stock N/T pink 240cc injectors.​


    12. Injector Resistor Pack - little silver case on the firewall with 5 wires coming out of it. There are two basic types of injectors. Low impedance injectors with a resistance of around 2.5-3 ohms, and high impedance injectors of around 12 ohms. Turbo DSM's use low impedance injectors with a resister pack. This is because low impedance injectors have a faster opening response times and generate less heat when operated at higher flow duty cycles. The stock N/T fuel injectors are high impedance 240cc injectors.​


    13. 1g FWD downpipe - You will have to ditch the stock pre-cat setup. If you are planning on making more power then the factory 195hp then forget about the stock 1g turbo downpipe and go with a 2.5" or 3" downpipe.

    14. Wastegate Solenoid or MBC - You will want the stock solenoid unless you are planning on using a manual boost controller (MBC).​

    Hallman ES MBC

    Stock Boost Control Solenoid (BCS) or Wastegate Solenoid

    15. Knock Sensor - check the condition of the old one you got, if all the goo is running out of it, expect high counts of knock and prepare yourself to replace it. As mentioned above, most non-turbo block will already be drilled and tapped to accept the knock sensor.​

    Here is the knock sensor hole on my N/T 4G63 block.

    16. Oxygen Sensor - The wiring for the o2 sensor is longer in order to reach across the manifold and down to the o2 housing.

    17. Thermostat housing (upper and lower) - the thermostat housing has the extra lines built into it for the cooling of the turbo and oil filter.

    18. Water pipe - this also has a coolant line for the turbo built into it.

    19. Oil filter Cooler - now this is going to be a needed item although make sure and match it up to numbers 17 & 18 so that they're all the same year. 1990 turbo DSM's came with an air cooled oil cooler and a different oil filter housing. 1991-1994 DSM's came with a water cooled oil cooler (see picture of cooling unit below).​


    20. Oil Pan - The turbo oil pan has a built in post for the turbo oil drain.​

    Well now that we have your engine hopefully all accounted for and in order we need to move on to putting that power to the ground. There are a few different methods here and you are free to choose whichever you like.

    First, here are the 1G DSM transmission code numbers:
    1G 1.8 and 2.0 non-turbo manual transmission = F5M22
    1G 1.8 and 2.0 non-turbo automatic transmission = F4A22
    1G 2.0 turbo FWD manual transmission = F5M33
    1G 2.0 turbo FWD automatic transmission = F4A33
    1G 2.0 turbo AWD manual transmission = W5M33
    1G 2.0 turbo AWD automatic transmission = W4A33
    Also for reference:
    And for U.S. manual AWD transmissions:

    As you can see the non-turbo and turbo transmissions are different. However the N/T transmission WILL bolt on to the turbo 4G63 (assuming you use the corresponding clutch and flywheel) but how long it will last is another question entirely. If you chose to retain the N/T transmission, be prepared for it to break. Pictures of N/T Tranny After Some Real Boost (20psi on EVO3 16G)

    1. Retaining the 1g N/T transmission (F5M22 or F4A22) - The 1g N/T transmission can be retained in this fiasco in its exact form. you simply need to also utilize the 1g N/T clutch and flywheel. Assuming your flywheels match up, prepare to do some grinding. The turbo crankshaft has a locating pin on the end of it for the turbo flywheel. The N/T flywheel does not have the alignment hole for this.

    It's not a big deal, simply grind the pin smooth (make sure it is completely smooth since its the flywheel's mating surface to the crank and you wouldn't want a wobble there). I personally started by using a hard cutting disk on my dremel and then using a grinding stone to finish the job off.

    You will want to upgrade the stock N/T clutch as it is totally uncapable of withstanding anywhere near 200hp. Mine lasted a month of careful driving I believe. As far as N/T clutches go, the choices are out there, but I personally don't have alot of experience with most of them (and am shopping for a replacement of the current one i have). Most upgraded clutches should be able to contain the power available from a 14b but above that is uncharted territory.

    2. Using a turbo FWD transmission (F5M33 or F4A33) - The GST transmission is a pretty simple install. In addition to the transmission itself, you'll need to make sure you have the flywheel, clutch, and rear aluminum cover from all the same year.

    3. Using an AWD transmission (W5M33 or W4A33) - If you are only able to find an AWD transmission it can be used but you will have to do some modifications to it first. You can eliminate the viscous coupler and weld the center differential OR eliminate the viscous coupler and a spool to the center differential. Check out these thread for more info:​

    The best thing about using the turbo transmission is that it has been proven to work at high power levels. Another perk is that a lot of performance transmission companies like TRE, Jacks, Dogbox, and ShepTrans will work in this transmission as opposed to the N/T.

    ECU and Wiring Harness:
    Here is the 1g turbo ECU Color Coded Pinouts, this is invaluable when working with the engine wiring harness: http://www.dsmtalk.com/gallery/data/500/Drawing2_Model_1_.jpg

    You will need the turbo ECU. Simple as that. You can either obtain a stock 1g turbo engine wiring harness or modify your factory Non/Turbo harness by adding the following wires:

    7th wire from MAS - the 7th wire from the MAS needs to be run back to ECU pin #6 for the '91+ vehicles (ECU pin #14 for the '90 model). This wire is for the stock boost gauge (which is worthless anyways) so you can skip this step and use the stock N/T MAS, especially if you are keeping the N/T gauge cluster (as it doesn't even have the boost gauge. Either way, make sure you buy a real boost gauge.

    NOTE: The italicized portion above is incorrect. Pin 1 is the extra wire found on the turbo MAF. It is for the MAF reset which...

    Knock Sensor - One wire can be grounded to the engine bay somehow, the other white wire needs to be run back to ECU pin #9.

    Wastegate Solenoid - One wire here will be grounded, the other returns to the ECU pin #105. Or you can switch to a Manual Boost controller (MBC), in which case this solenoid will be unnecessary.

    Injector Resistor Pack - Here is a tech article written by TimG on how to wire the Fuel Injector Resistor Pack into a non-turbo harness: Injector Resistor Pack Wiring (1G N/T -> Turbo Conversion)

    Here are the factory ECU prints. The highlighted ones need added, and the model is in the upper corner so you don't get confused.

    1g nt maf wiring.jpg
    nt injector wiring.jpg
    maf wiring.jpg
    resistor pack and knock sensor wiring.jpg

    Vacuum Diagrams
    The turbo engines have a LOT more vacuum lines than the non-turbo engines. Questions which are often asked involve how to route all these extra hoses. Here is the factory routing:

    If you chose to remove your EGR system you can remove almost all of your vacuum lines. If you descide to remove this system, you can run your remaining vacuum lines as shown here: Taboo speed shop vacuum diagram and removal for 1g and 2g.

    (with the exception of the MBC, it should be hooked up this way).

    Oil and Coolant routes
    There are also a lot more Coolant and oil lines on the turbo engines. It is designed this way to lubricate the turbo and keep the oil cool since the turbo produces so much heat.

    Here is a page from the Factory Service Manual (FSM) showing the coolant routes from the thermostat housing, water pipe, and oil cooler ring.


    #35 connects from the thermostat housing to the FIAV and #36 connects from the water pipe to the FIAV. #40 connects from the oil cooler ring to the water pipe and #'s 41, 43, and 39 connect from the oil cooler ring to the thermostat housing.

    These two diagrams show how to route the hoses for the turbo's coolant and oil.

    20101231230855-jpg.jpg 20101231230952-jpg.jpg

    The coolant line on the back of the turbo connects to the nipple on the front center of the thermostat housing (the nipple above the 2 coolant temp sensors, beside the a/c thermoswitch).

    The coolant line on the front of the turbo loops under the turbo and connects to the water pipe almost directly behind the turbo (slightly to the passenger side).

    **A note on doing this swap on a 1.8L 4G37**
    I have never personally done the 1.8L 4G37 to Turbo 4G63 but skatershawn has and here is what he has to say about it:

    So 1.8L owners don't fret, all you need in addition to the above parts is the 2.0L driver's side engine mount, cross member, and axles.
    EDIT: The cross member is only needed if you plan to use a automatic, turbo transmission. The 1G FWD turbo cross members from vehicles with a manual transmission are the same part number as that for the 1.8L, regardless of transmission type. The 1G FWD turbo with an automatic transmission has a different part number for the cross member than the manual transmission version.

    Required tools
    • A service manual: Factory Service Manual, Haynes, or Chilton's.
    • Cherry picker/Engine hoist
    • Jack and 2 stands
    • A selection of 8mm, 10mm, 12mm, 14mm, 17mm, and 19mm sockets (deep and standard) and wrenches.
    • Flat and philips screwdrivers
    • Pry bar, breaker bar, and cheater bar.
    • 32mm or 1 1/4" socket for the front axle nuts.
    • Torque wrench for putting everything together
    • A chain wrench to hold the crank shaft while removing and installing the flywheel and clutch
    Last edited by a moderator: Sep 8, 2016
    19Eclipse90 and o0GuitarKid0o like this.
  2. mavisky

    mavisky DSM Wiseman

    Joined Sep 13, 2002
    Atlanta, Georgia
    an idea just popped into my head. some of you guys might possibly be running around with automatic transmissions. well unfortunately i've never owned one (and don't intend to) and so therefore i have absolutely no knowledge of the dsm automatic for the 2.0 nt or any other for that matter.

    if you have any questions regarding it i'd try and take it up with someone in the transmission forum. if you do get an answer let me know and i'll post it over here :thumb:

    so far this is the only thread i've found:

    Will n/a auto tranny hold up with turbo mod?

    although i'll keep looking myself.
    1993eclipseGS likes this.
  3. mavisky

    mavisky DSM Wiseman

    Joined Sep 13, 2002
    Atlanta, Georgia
    here's some pics i took recently while i was putting my new tranny in.

    here's a pic of the nt throttle body and intake.
  4. mavisky

    mavisky DSM Wiseman

    Joined Sep 13, 2002
    Atlanta, Georgia
    the resistor pack mounting.
  5. mavisky

    mavisky DSM Wiseman

    Joined Sep 13, 2002
    Atlanta, Georgia
    here's where i passed the wires through for converting my nt harness to a turbo harness.
  6. mavisky

    mavisky DSM Wiseman

    Joined Sep 13, 2002
    Atlanta, Georgia
    this engine has been in my car for a year now and i have had no engine related troubles. i've had some trouble with the transmission, but those were my fault and not due to any overpowering of the transmission i've experienced.
  7. Ludachris

    Ludachris Founder & Zookeeper

    Joined Nov 12, 2001
    Roseville, California

    Street Build 8K  0

    1997 Eagle Talon TSi AWD (sold)
    manual · 2G DSM

    Road Race Build 6K  23

    1991 Mitsubishi Eclipse GSX
    435.0 whp · 399.2 lb/ft · 1G DSM

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