420a turbo build / What do I need? -- WRITTEN BY PWEE05
Please see post from “red97gst” A/F Ratios, Boost Pressure, Combustion

I want to start by saying building an engine is almost like ordering a hamburger. Everyone likes something different and your build should reflect that. If you do decide to build you have complete freedom to build EXACTLY what YOU want.
(excluding California R.I.P.)

The 420a (A588) engine is a Chrysler made engine. Good news: Chrysler has been turbo charging cars for over 20 years. Unbelievably started from the K-car platform, don’t laugh, http://www.allpar.com/eek/k/k.html and there is a video floating around of a Dodge Caravan AWD destroying a Camaro SS at the track running a 12.96! Definitely one of the funniest, and most shocking things I’ve ever seen (Soccer Mom meets V8 racer AND WINS!!!). So don’t worry we can make your 420 scream. Bad news: besides oil leaks, you have to spend some money.

The eclipse 420a is very similar and is in some dodge models of the same years with only slight differences. The head is reversed (compared to neons), but building internally will be the same and you can even search for neon, avenger, or sebring parts if you can’t find any for an n/t eclipse. Never hurts to cheat, but make sure they are correct before purchasing.

There is a long list of what you will need for more power but don’t fear, you can turbo a stock 420 car, do so cautiously (I will get into that later). If you look at the below pictures you can clearly see a difference between the connecting rods. The picture to the left is a piston and rod assembly for a stock 420 engine. The other is an aftermarket Eagle made rod which can support over 300hp. The stock rods, obviously, can not take much of a beating and must be replaced if you want higher hp numbers.


If you take a look at the first piston picture you can see that it has a “dish” in it. This is to reduce compression. The second is a high compression piston for a different engine that is only here to give a comparison. The stock 420 engine has a compression ratio of 9.6:1. A stock turbo car will be somewhere around 8.3/8.5:1 compression. Under boost periods the compression ratio will increase because you are forcing air and fuel into the cylinder, thus the need for pistons providing a lower beginning compression ratio. Stronger metal composition doesn’t hurt either.

With turbo applications you do not necessarily need an intercooler if you are scrounging for money. HOWEVER, without an intercooler you MUST keep the mixture rich to keep from predetonation. THIS WILL DESTROY YOUR ENGINE!!!!!! Also, run 92 octane or higher (pump gas) to prevent predetonation.

Another thing that some shops do with turbo builds is allow a little bit more space between the piston and the cylinder wall than is normal. This will let the piston safely expand under boost periods, caused by increased heat. I am mentioning this because sometimes you can hear the piston “slap” against the cylinder walls and it may be interpreted as something else.

On to a list of things you should do to build your 420 for pressure. This does not include machining of the block/head and/or labor:
Stronger piston rods------------------------------Air fuel controller (AFC)
Stronger pistons and rings-----------------------Larger fuel injectors
Metal head gasket---------------------------------Larger fuel pump
ARP head studs can’t hurt------------------------High flow exhaust
- (for a lower hp build you can use bolts)-------Fuel management unit (FMU)
Turbo charger--------------------------------------Turbo manifold to fit your turbo
Oil lines---------------------------------------------Coolant lines depending on your turbo
Down pipe or O2 housing-------------------------Waste gate if not internal
Blow off valve (BOV)------------------------------Boost gauge
Boost controller------------------------------------MAP sensor check valve (missing link)
new head bolts/studs------------------------------new rod and main bearings
Suggestions
Upgraded ignition system-------------------------Vacuum line
Light weight crank pulley-------------------------Copper 110 exhaust gaskets
new oil pump--------------------------------------new O2 sensors
turbo timer ----------------------------------------new water pump
timing belt, pulleys, tensioner--------------------new seals
Intercooler-----------------------------------------Charge pipes


If you want to build for MORE POWER (350whp+) you should include:
All of the above-------------------------------Adjustable cam gears
More aggressive camshaft-------------------Titanium valve spring retainers
Stainless or titanium valve springs----------Port and polish of the head
Larger throttle body---------------------------Larger intake manifold
Larger exhaust--------------------------------Heavier clutch pressure plate/flex plate
Stronger drive-shafts--------------------------Front Mount Intercooler
Charge piping---------------------------------Stand-alone engine management system

To give a comparison this is what I have in my engine.
I enjoy road course racing, not ¼ mile:
JE 8.6:1 pistons and rings-------------------Eagle Rods
Clevitte main and rod bearings-------------ARP main studs
ARP head bolts-------------------------------Felpro head gasket and seals
Melling oil pump------------------------------Stage V port and polish
crane stainless valve springs----------------Crane titanium retainers
Accel 30lb/hour fuel injectors----------------Prothane engine and trans mount bushings
Walbro fuel pump-----------------------------FMU
Apexi AFCII-----------------------------------Screaming deamin coil pack
Crane firewire spark plug wires------------Ac delco double platinum spark plugs
ported stock intake manifold------------------------Treadstone cast turbo manifold
Knock off BOV----------------------------------XO2 22x12x3 bar and plate intercooler
Missing link MAP-----------------------------AEM UEGO wideband
Crane camshafts - Intake Duration 250@006 Lift .374 inch, Exhaust Duration 250@006 Lift .374 inch
Removed air conditioning & power steering (by choice, not necessary)
Garrett t3 super 60 (35lb/min) turbo (fast spooler for pulling out of turns)
My own welded and fabbed (exhaust pipe,,cheating again) charge pipes
And of course I replaced all of the preventive things I mentioned earlier.

I built this way because I like a very rough, loping idle and using the very efficient eclipse suspension for tearing up turns. I wanted a turbo that would spool quickly out of turns and power to fly away down straight aways. I will, for now, not be going over 250whp.

Now, I promised you I would get into turbo charging a stock 420. This is treading thin ice but you can do it. Low pressures and low volume turbos are key. You still need to upgrade your fuel and exhaust system:
Fuel pump-----------------------------Injectors
AFC------------------------------------FMU
Missing link----------------------------High flow exhaust
BOV------------------------------------Wastegate if not internal
Manifold--------------------------------Turbo
O2 housing and/or downpipe---------Boost controller
Charge pipe----------------------------Oil and possibly coolant lines

The turbo can be 14b, t25, SMALL 16g, gt 28 will work fine but please keep the boost under 8psi. You can’t get over 225whp (guesstimate) for very long on a stock engine without a big BOOM. This gets back to the weak rods and compression set up for an engine supposed to only see natural aspiration.

Always watch your exhaust gas temps (EGT’s) and if you have the luxury of a 4-lead O2 sensor keep an eye on that too. If it reads below .92 volts you are getting too lean. A dyno and an AEM UEGO Wideband O2 is the best way to tune, but you can do it with a long stretch of highway, a heavy foot and voltmeter. WATCH FOR COPS!!!

If you are wondering about costs, this could take all day because of the variety of places offering parts and services. Let’s just say that the total amount I have in the engine and turbo set up I could buy a small island. (around $5k but you can get away with around $2500.00 if you stay stock) If you ask me, “was worth it?” I would tell you definitely.

To touch briefly on bolt-ons, if you buy out the entire stock of all bolt-ons available for this engine you will only increase to “a noticeable difference.” It is a good place to start learning though.

The sky is the limit but make sure you know what you are doing, and if you don’t just ask for help like I did. Slowboy racing put my bottom end together, ported and polished my head and has taught me so much, but I still don’t know everything. Everyone has to start somewhere and if I missed something please don’t hesitate to correct.

--The above article was written by pwee05


*****THE FOLLOWING QUOTES WERE PULLED FROM THE ORIGINAL TOPIC "420a Turbo Build"*****

4g64 Going Turbo/Need Some Help -- WRITTEN BY X_DEFIANCE

Ok So ive been told by a number of people NOT to turbo my 4g64 because
of the compression ratio [10:1], so im wondering what i can do to "safely"
turbo it and get some good raw mitsu power out of it. So far this is what
i have [not on the car except for the MSD].
(IMG:http://i12.ebayimg.com/03/i/08/10/88/91_1.JPG)
1g GSX DOHC head

(IMG:http://i12.ebayimg.com/06/i/08/25/0e/5f_1.JPG)
1g throttle body

(IMG:http://i8.photobucket.com/albums/a39/tavo_80816/1gintakemanifold_1.jpg)
1g Intake manifold

(IMG:http://i2.ebayimg.com/04/i/08/34/19/89_1.JPG)
450cc blue injectors
stock cams & gears

(IMG:http://i4.ebayimg.com/06/i/07/f4/c0/9c_1.JPG)
[I have a pair of Evo 8 cams and gears as well i figured it'd be a decent upgrade] :banana:

(IMG:http://i3.photobucket.com/albums/y85/x_defiance/Photo222.jpg)
MSD2 DIS ignition

I know the ECU will have to be upgraded, and i will probably need low compression pistons, also the obvious stuff [headder, exhaust etc]. Now what i'd like to know is what kind of Turbo should i use, and what other upgrades will i need. IM not looking to put down more than 250 whp for the time being :beer:

*****THE FOLLOWING QUOTES HAVE BEEN PULLED FROM THE ORIGINAL TOPIC "4g64 Going Turbo"*****

The 420A, assuming it is strong and healthy with strong compression on all cylinders will safely handle 275 hp. hahnracecraft.com. hahn racecraft makes stage 1-5 turbo kits for the non turbo 95-99 eclipses. Stage 2 is the highest you can go without internal mods. But the stage 2 was nice when i had it. I left it in the dust with a stage 4 now at 17psi and 325 hp 20G turbo, and 315 ft. lbs of torque. Great turbosystems

you have to upgrade internals before making more power or you will damage/blow your motor

heres a write up for a 420a build.its from another mitsu forum. by slow420a



First off let me state that this is only a list of recommended upgrades. This is not law. Many things can be done in different orders, I do not know everything so if I do happen to leave something out or something is out of place please give me the heads up so I can make changes. Second the 420a was not meant to be a “go fast” motor, but it can be. Everyone who drives a 4g63, us 420a guys get the point, we should all sell our cars and buy GST’s and GSX’s because we are wasting money.

*Stages with the star should be completely finished because some parts need supporting mod’s.

[Anything] boxed off is optional, but recommended

+ are notes

(Reason for or describing product)



Stage one
-Cat back exhaust (Something 2.5 or bigger to increase air flow.)

-Plug wires(Improves spark, most old motors need plug wires replaced anyway.)

-Ignition coil (This stage is inexpensive and it’s something you will need in the long run.)

-Plugs (Bkr7e-11 gaped out to 20-35, DO NOT install yet, it’s a cold plug and will make your car run crappy when n/a)+ Believe it or not the plugs are made for an Audi.

-Straight pipe [optional] (The stock cat can be gutted to get the same effect but either straight pipe or gutted stocker you will not pass inspection.)



Stage two
-Turbo kit

+ This is actually tricky. Thanks to Chris (gsgoingfast) and his “how to build a turbo kit for under 1g” lots of people are making their own kits. Also Conceptillusions released their kits this year, and Hahn sells their manifold, turbo, oil line kits, ect. Separate now. As of today your options for a turbo kit follows,
Stage one kits- Conceptillusions 1400, Hahn 2g, Star 2g, Chris style 1g, or a Hahn custom kit 1200-2g.

Stage 2 kits- Conceptillusions 2200, Hahn 3400, Star 2900, Chris style 1g, or Hahn custom 1200-3g.



Stage 3
*… the expensive stage!

-Built Head (New valves, seals, springs, retainers, rockers, [*cams, adj. cam gears, ignition retard, starter amp.].)

-Head port (Conceptillusions offers 3 types of port jobs. 1 being mild and requires little supporting mod’s. 3 being an extreme port and requiring a bigger throttle body, intake manifold either after market or ported, and a ported exhaust manifold.)+while it’s their get them to check the head for heat warp.

-[60mm TB, ported intake manifold or a obx/venom] (Only necessary if you go with a stage 3 port job, but useful non the less if you do get them with a 1 or 2 port job.)

-Built bottom end (8:6:1 forged compression pistons, forged rods, mopar bearings, milling oil pump.)+ Make sure to get block honed by a machine shop, [Blue printing the block is usually cheap and cost effective, total seal piston rings go for 120 bucks but not necessary]

-Replace all studs head, intake/exhaust manifold with APR studs. Replace all gaskets with mls gaskets. +Never reuse gaskets, why go this far and cheap out on a 15$ gasket.

-[Crank scraper and baffles/trap doors.] (The 420a oil pan can cause the lower bearing under cyl. 1 to spin when making hard right turns, 200 bucks for nearly nothing seems like a lot but it’s a cheap insurance for the expensive motor you just put in your car.)

+Please let someone who is a trained professional assemble the motor. Improper instillation of the cyl. head can cause it to warp, and improper timing adj. can push a valve into the shiny new pistons you paid so much for, and also ruin the 400 port job.

Now that the motor is built you can turn up the boost, but you have to watch your fuel. Everything listed so far is good for 10psi. I assume if your still reading you want to go past 10psi. Stage four is for the person who wants to go above 10 but wants to stay under 15psi. Stage 5 will list some things that are in stage 4 because some people what to go higher and instead of confusing everyone I will just list it 2 times.



Stage 4
+ This step helps the tuning process for the do it you self person that wants to stay above 10psi but under 15psi. If you are a sick and twisted individual, and want more boost than 15psi skip stage four and go directly to stage 5.

-Gauges (wideband kit, oil pressure, pyrometer, fuel pressure)

-Safc (**** has an excellent write up on install and tuning your car with this unit, great reading!!)

-Vortech sfmu (Replaces the cartech or obx one that comes with sooo many turbo kits, reason for switching, rock solid fuel pressure under WOT and you can use it to adjust the static fuel pressure.)

-Injectors (For sizes refer to Corbins site, again only if you wish to stay under 15psi.)+Safc is needed to control bigger injectors, many kits like Hahn and Star come with injectors big enough to run this stage.

-MBC or electronic boost controller. (Self explanatory)



Stage 5
– In this stage, like stage 2, things are not so cut and dry and there are a lot of routs to take to achieve high hp.

Bigger turbo (This is all up to personal preference. At this point a Super20G for the Hahn manifold would probably be the best way to go. Another possibility would be getting an evoIII16g w/an external waste gate setup on the Star manifold. There are about a million different combos the best thing to do is read about what other people have and what they like about it. Rule of thumb bigger the turbo, more lag, more hp, external waste gate needed).

Now for the fuel

255lph fuel pump (The pump that comes with most turbo kits max out at this stage.)

-Setup one- SAFC, Crane ignition system (By far cheapest way to go but the SAFC is limited, and you need to get someone who knows their crap to tune it. Its deff. not the safest way to go.)

-Setup two- Hahn Portfuler, Crane ignition system (This is probably the best way to go. After 15psi all you need is a dyno tune to work out the trimming.)

-Setup three- Custom 8inject setup, Crane ignition system (This is a knock off of the Hahn system but is a lot cheaper if you make it your self.)

-Setup four- AEM Standalone plug and play (Expensive route, deff. need a pro to tune it, or you need to know your crap, but can be the very best.)

-Setup five- Accel DFI 3BAR (Same thing as the AEM just a different company, very good.)

-Setup six- Megasquirt (Very cheap, this is the ultimate do it your self unit. Started off as type of a piggy back but can be used as a standalone with a few mods. If you want to save money and have brains to work this thing it’s the only way to go.)

-Stiff Suspension(Wheels like to hop especially on fwd cars, a stiff suspension will keep you wheels on the ground, again something that’s up to personal preference. I recommend Tokico Premium HP)



Stage 6
+This is not a stage but merely a list of things that will break and need to be replaced, but these can be done at any time during the time line.
-Clutch (Spec stage 4 or 5, depending on you torque numbers. [Billet pressure plate and an Aluminum Flywheel].)

-The 98 neon r/t tranny (Strongest transmission availed for the 420a. While you’re in there get a phantom LSD put in. Helps the traction problem) +The gear ratios are different for the r/t tranny, but the final drive is the same. What’s this mean? Faster tranny, no change in spedo readout!!

-Solid motor mounts (HP is lost when the motor rocks back and forth while shifting)

- Axles (Replace them when they break, Conceptillusions and exileracing both sell Fidanza Axles, and your tranny will explode before these snap.)

There’s A lot more that can be done to the car to make it perform better like tires, nitrous, oil cooler, radiator, egr block kit, water sprayer, methanol sprayer, weight reduction, brake kits, ect.

wow i can still remember a few months ago looking on this forum wanting to have the same mods...now i have more..lol

Anyone one have a guide like this for the 4G63 ...(It is not that I can't put a turbo on correctly my self me and a friend put one on a 95 neon that was already beating v6s and stuff stock). Its just every car that someone is going to turbo needs the same type of upgrades to the engine. Just wondering if there is a guide

Ok well, need a little help if possible. I'm buying my buddies 96 RS, its got the Apexi N1 exhaust, 97 front bumer, an after market cold air intake and a short sifter, not much else to it. The other day i was at a shop a few towns over and discovered a 1st gen gs-t. lets say i bought both cars. the Rs for 2500 and the gst for 1500. thats 4000 there. I want to swap the 420a in the rs for the gst's. is it possible, and are all the correct parts needed there? i just need some feed back before i go out and buy both cars and find out that i cant do the swap. any help would be appreciated. Thanks!

Just buy the GST and be done with it

that was a thought, but i dont like the body style of the 1st gen and this one is pretty beat up inside and out , but the motor runs great

you do not have to change pistons you can do a little work on you head and install cam to lower the comp. you can probably bring it down to 9:1 -9:2 the only way you wanna change your pistions if your going for mad boost

hi i have a 93 eagle talon dl. i was wondering if you guys would have any sugestions on what i would all need to do to get it to run with a turbo either runing on stock internals or doing a little internals up grades ?

what all do i need and what do i need to do to turbo my non turbo 4g63????

Hey man i just got a 98 Eclipse that I'm slowly trying to get together, its really not what i'm use to. i had a 77 nova super charged and every thing. but the question i had is what would you suggest be my first step to modifing my new tuner.....all i've done is throw a ram air on it, a muffler, and some led underneth for some ground effects. but nothing really to boost the horse power. The eclipse has a 2.0 DOHC non turbo. so what do you think should be my frist step? :beer: :57: bro

yo i have installed a 94 4g63 non turbo engine in my hyundai elantra, i did this without research, all i knew is it was the same motor just a bigger bore, 1.8 to 2.0
BUT i desperately want boost, can i turbo it? all i see is turbo upgrades. what do i need to do? email me PLEASE!! decensy@hotmail.com