420a turbo build / What do I need?
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 (250whp+) 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 studs-------------------------------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------------------------Forced Air Inc turbo manifold
Greddy BOV----------------------------------XO2 22x12x3 bar and plate intercooler
Missing link MAP-----------------------------ARP exhaust studs
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. If/when my clutch goes then I will search for a larger turbo (probably big 16g MHI), put in a stronger clutch and shafts and go from there.

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.

:beer: thank you thank you

not a problem at all, anything I can do to help :beer:

wow so detailed. that is soooo much help. i bought a eclipse gs about a year back and at the time i didn't know(don't know much about imports my 2 cousins got me hooked) or care that it was a n/t car, i just thought "wow this is a nice lookin car" even tho it is, my cousin has a awd eagle talon thats turbo(he took out stock turbo and put in a 16g), and after the sweet sound of the blow off value and the g's pushin u into the seat I WAS HOOKED!anyways i have been dyin to find out a decent low cost way to make my car faster. i would love to put in a turbo, but even i know that that is a lot. and i thought about an engine swap witha 4g63, but again thats a lot. so could you help me out, and give me some advice. it would be a lot of help. :liebe011:

-97ggGS


.....i was also wonderin is there a chip i can get to give me alil more hp

no

aight tx eclipsed4utoo....

hey you obviously know a lot about improving horse power

can you send me anythin you know about performance chips and where i can get them

thank you

Please read Post #5.

it is alot, but worth it. Dont Swap. just follow the parts and tips in the post and you will be fine. it helps if you can do most or all of the work yourself. a machine shop will have to help a little though.

please DO NOT INSTALL "SPEED," "PERFORMANCE," OR ANY OTHER KIND OF "CHIP" INTO YOR VEHICLE. It will only cause probs and/or damage. even if they do help it is only 1-2hp and hardly not worth the troubles. our vehicles aren't like those big diesel trucks that can put in a cheap power commander or something like that and get another 60hp and monster ft lbs of torque.

Does anyone know anywhere in the chesapeake-virginia beach-norfolk area that i could take my car to and possibly turbo it at a decent price...im about to go into college and dont have that much money. Thanks for all the help in your post man. :thumbsup:

no problem, that's what we are here for.

if you play your cards right though, your first student loan refund check just may be enough to pay for your turbo build.

ok almighty god of 420a knowledge and wisdom... here i am worshiping your altar and paying homage wondering a few things of my own. SO i got this stock 420a with some megan headers and no name CAI and some iridium plugs. Other than that, WAAAAAAAAY to slow for a guy like me. I want to turbo the life out of it. However i was reading stuff on here and found out i can get 200hp from n/a? such as the tune of a stroker and piston heads? I wondering, seeing as the throttle respnse for n/a is much better, how much power COULD i squeeze out n/a? I know all about bigger TBs and Intake mani's but i really am curious how much i could get. cause im looking for like 350 hopefuly even 400 broad chested stallions out of this thing. my backup plan is to hand it to my shop and say have fun, this plan includes a turbo and lots of financing. SO to the point, i wanna know if its possible to pull 300 or so horses out of n/a and if i could do 400 with a big **** turbo and say less than ten g's or there-abouts. I do know that i would have to do pistons head cams crank clutches axles and the like, but i think if you could help by giving some insight, it would settle much easier in my tummy. gracias amigo.

definately funny :clap:

I'm sure there are people out there that have more knowledge than I do but I'll take the worship :laughing:

anyway, to your question. 200bhp is probably the limit when staying N/A. unless you can figure out a way to get the compression above 12.5 : 1 inject with methanol and make that **** squeal. It is possible with a 2.4L to get above 200bhp n/a but there just isnt't enough displacement in a little 2.0L to do it. even after bore and stroke. I could be wrong though. I just haven't heard of anyone putting enough money into an n/a car to get the horse power that high.

turbo, on the other hand, is a much easier way to increase compression by ramming air and fuel down the cylinders throat. you could have a nasty turbo car for $10k. if you can do some of the work yourself you can get the cost under that because labor is expensive. I have about 8k in mine but did all the work except putting the bottom end in the block and machining. The only problem I have now is worrying about when I will have to pick up my trans with a bucket piece by piece.

Scroll the whole way down to the bottom. There is a dyno slip to prove that the 96 eagle talon shown with the 420a engine makes 460whp on c14 and 340whp on 93 pump gas. so it can be done, it's just a matter of how crazy are you willing to go. :thumbsup:

BRAVO!! ...go on take the money and run... I mean the worship. Thanks a ton for the info. I was really just curious. I had totalled up a ROUGH estimate of all that I wanted and guestimated install costs based on the inverse ratio of work to guy by dividing the recpirical of the attendants height by the approximate weight of the turbo and multiplying the difference by the sum of four circles ...and previous work ive had done by this place. and it came out to around 8700 bucks. this excludes ANY work other than making this thing a flowing field of green for the which the stallions to graze upon. so as long as im near the mark i guess the apple is pretty much split, and there is a gash in littel tommys head on which the apple sat. But a couple staples and some super glue, he'll be fine they assured me. Again thank you for your help, im now about to call an artist i know to begin drwaings cause im not that good and because this place is showing an interest in sponsoring me. so i could get labor for free! thanks again pwee. ill look forward to showing off pictures of my steroidal stallion in the future! until next time....

"..rule number 1 no excuses play like a champion!.." -Vince Vaughn (Jeremy Ryan; wedding crashers)

wow is that a jumbled mess of metaphors and extra words. you could have said the same thing in 2 sentences but definately an enjoyable read. :clap:

i'l look forward to a dyno slip :thumbsup:

i am very new to this whole scene, im comin out of the american carb scene, lol, i have the 2.4L in my GS, and i'd like a few suggestions for what i should do to it on a low budget, and what does N/A mean?

http://4g64.150m.com/performance.html

I have a question...if I don't wanna build a Turbo engine...if I'm just gonna buy a turbo engine and put it in my car (that's not a turbo) what all would I need? I know I would need the engine and a transmission and a new exaust and a boost gauge...but that's all I know...could you help me? thanks.

please search around this forum. it has tons of general car knowledge and knowledge for the "tuner scene".

N/A = naturally aspired.

that means that you engine does not have any type of forced induction(turbo, supercharger, nitrous).

you would need a turbo car that has a blown engine. then you could replace the turbo engine with a fresh one and drive the original turbo car. many have tried to put a turbo engine in a non turbo car and many have huge paper weights sitting in their driveways.

if you have $20k or more to spend then go for it. or you could put $20k on a really bad **** car that is fast to begin with.