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420A How to build a 420a stage 2 turbo kit for under $1000

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Well, I have been getting a lot of e-mails and PM's asking me for this so here it is.

Basically, I've been dying to turbo my car since the day i got it. But I've always been way to poor to afford a $3000 stage 2 turbo kit. I also realized that the price you pay for the kit is a lot more then what the actual parts are worth. You are actually paying almost double the part value for the convinience of having the kit put together for you. I didnt want to pay twice as much for the same parts, so i decided to undertake this project. There are two basic reason's to make your own turbo kit. One reason would be because you are poor and cannot afford a real one, or the other is because you want a kit with the best of the best parts. And if you were to buy a Star or Hahn kit you would just end up replacing most of the parts anyway.

This article will be in many sections, so if it appears incomplete its because i havent finished it yet. This will show you how I built and installed an intercooled turbo kit for under $1000, but I cant promise the same for you. It all depends on the parts you use and the skills you have.

First things first, what you will need to do the job. you need a basic set of metric sockets and wrenches, adjustable wrenches, pliars, vice grip, Mig welder, welding skill, screw drivers, just the basic tools. Jack stands are pretty much necessary and a creeper is reall nice too.

Now the parts list. these are all the parts i used, and there cost without shipping, and where i got them. links will be posted if i bought them from online stores.

Garrett T3 turbo: $100 - Ebay
2g smic: free(i got it from my friends bro)
Exhaust Manifold-
Two 1.5" diameter steel Weld el 90* elbows and two 1.5" diameter steel Weld el tee's-McMaster-Carr
420a header flange and T3 flange-
Total Cost: $90
Crushed 1st Gen BOV: $40 - Ebay
Down pipe: 2.5" mandrel U-bend: $15 -
T3 wastegate flange: $15 - Ebay
2.5" generic 2 bolt exhaust flange: $6 -
Total cost: $36
6' of 2" intercooler piping: $24 - Napa
4 couplers: $15 - Home Depot plumbing section
1 rubber elbow: $6 - Home Depot plumbing section
Walbro 255 lph HP fuel pump: $106 -
Vortech 12:1 FMU: $90 - Ebay
Fuel hose/ Vaccume hose: $30 - autozone/carquest
Hose clamps of multiple sizes... many many hose clamps: $20
Autometer boost gauge: $50 -
Autometer Gauge pod: $30
FCD: $20 - member
Nuts, Bolts, and Washers: About $10 - Home depot, Ace, any hardware store
Oil Line kit: $70 - Ebay(you could do it for much cheaper, ill explain later)
Parts to modify wastegate: $6 - Home depot

And the grand total is: $723!

now all that of course is without shipping and that a big thing that will differ from person to person. on things i didnt know the exact price of, i estimated a little to the high side. with shipping for everything included, i probably paid somewhere around $900. still not bad for a stage 2 kit.

Now that we have all the parts, its install time!
The basic parts(Weld Els and flanges) are show in the picture above. this is basically a hit or miss, guess and check type thing. first thing i did was cut the Tee's and lined them up on the flange. then i did the same for the elbows. I welded the tee's and elbows together first, then welded the whole piece to the header flange. below are a pic of the Weld els and header flange, along with the manifold when I finished. i sprayed it with Copper Spray-a-Gasket, and it produces the gun metal shown(you can see on the header flange that some of that copper hasnt burned off yet). After the main section is done, i threw the manifold onto the car, and lined up where i wanted the collector(which i got here which you can also get the other manifold supplies) to go. then i cut the hole out with a whizzer wheel, and welded the collector onto the manifold(had previously welded the collector and t3 flange together). All of this welding was done with a Mig welder(and they are some of the ugliest welds ever but they get the job done). you can also drill and tap the EGT probe in the #4 cylinder now if you have an EGT gauge.


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There are many parts that can be installed before you actually go turbo. The Fuel system is one main thing. I installed the Fuel pump and FMU weeks before i saw any boost and everything ran perfectly fine. I also installed my gauges before too(call me a ricer if you must, but i had a boost gauge before boost :p)

The fuel pump is pretty strait forward install. first thing you need to do is remove the back seat. On the passanger side, there will be a little cover being held on by 4 screws. remove these screws and pull the cover off and push it to the side. you can try to unhook the wiring harness and remove the cover completely but i couldnt get it off. next remove the fuel lines attached to the pump cover. Have some towels incase you get some excess fuel spilling out. The hard line is not braized as some have said(atleast the fuel pump side isnt) and i just popped it loose with a wrench. remove the hard line and return line. there are 6 bolts that are 5/16(not metric for some reason) that hold the pump cover on. remove these, and the pump should pull right out. now, on the pump there is a screw on the brass bracket, remove this, and unplug the harness and unhook the hose(you will probably have to trim this hose shorter), and the pump should pull right out. put the new pump in, with the new filter, and look at the bracket. you will see that the new pump is longer and the bracket needs to be modified. just drill a new hole a little above the old one on the bracket and it should fit now. now do the reverse of taking it out and it should all go back into place fine, but dont reconnect the return line. we still have to install the FMU. i might have forgotten something small but its been a little while since i did it. i followed the vfaq for the GS-T and it was pretty close to ours. here are the pics of the fuel pump being taken out and apart


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Heres some pics of the pump after modification to the bracket. Notice the screw hole is moved up


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The FMU is very easy to install. Mine wasnt labled with "In" or "out" so i had to search to find out. use some fuel injector hose and connect the stock fpr return line to the side nipple of the fmu. then connect some fuel line from the bottom nipple to the fuel pump's return line. then tap a vacuum hose to a vac source from the manifold. i used the brake booster line to feed my FMU and my boost gauge. heres some pics of where mine is at. if you are confused about where its mounted, the las pic shows where the screws come through... a little present for my back seat passangers haha


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I spent $70 on an oil line kit. i got it and some of the pieces werent right, and all of the pieces were at home depot for a lot less. so here is what you will need.

1: oil sensor socket
1: 3/8 NPT hex nipple
1: 3/8 NPT female tee
1: 3/8 NPT to 1/8 NPT reducer
1: 1/8 NPT to 1/4 Flare
about 6 feet of 4-an SS line

I got an autometer oil pressure gauge too, so I had to also get:

1: 1/8 NPT hex nipple
1: 1/8 NPT tee

on the driver side of the back of the block there is a bright grean plug. you must first slide the red lock to open, then pull the plug off. use the socket to remove the stock oil pressure sending unit. i didnt have any oil come out but it wouldnt hurt to have some towels handy just incase. the 3/8 nipple screws into the block. next put the 3/8 tee on that. on the back of the tee you can reinstall the stock sending unit. on the opening left in the tee, put the 1/8 reducer in. then the 1/8 to 1/4 flare fitting. the SS 4 -an line attaches to the flare fitting. now on my turbo i threaded the oil feed hole for 1/8 NPT threading. i then got a 1/8 NPT elbow, and connected another 1/8 to 1/4 flare there to feed the turbo. Make sure you use teflon paste on all of these connections.


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The oil return is the biggest pain yet pretty simple. the hard part is you have to take off your oil pan and drill a hole and weld it. First thing first, make sure you drain the oil before removing the pan. To take your oil pan off, first you have to remove the center beam. remove the bolt for the motor mount, and then remove the 2 front bolts on the bottom, the 1 bolt on the bottom in the middle, and 1 more on the rear end of the beam. should come off then. there is also some tranny dust protector that must be removed. now just remove all the bolts around the oil pan and it should pull off. Now you must drill a hole in the oil pan, and i bought a 1/2 to 3/8 bushing, and welded it into the pan. i drilled where the HRC instructions say to drill. ( 1-5.htm ). then i got a 3/8 NPT male to barb fitting and screwed it in there. Now the oil return on the turbo is the one piece that cannot b bought at home depot. it needs a flange and gasket and bolts. this is one thing the oil kit did deliver on. but otherwise, the inside of the flange has a 1/2 NPT male to Barb fitting. I used some thick heater hose from carquest and clamped it onto the 2 barbs. be careful welding the bushing tho, mine still leaks. now for re-installing, some people replace the oil pan gasket, but its expensive, and designed to be re-used so i just re-used mine. put a little rtv by the oil pump when you re-install the pan... yes i know thats an ugly weld, but i was trying to fix the leak LOL.

All of step 4 can be done and was done weeks before the turbo went in. as you can see in the second pic, there is a plug in the bushing. i also just put a cap on the end of the SS feed line.


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This is probably the vaguest of topics to cover. you have many different choices. there are electronic FCD's and there are mechanical like the Missing link. i originally went with the missing link, which installed easily. but there was a problem with mine, and my car kept loosing vac to the MAP sensor and would die. so i wentwith an electronic FCD from a member for less then half the price and it works great. basically just tap the 3 MAP wires and use a volt meter to adjust the voltage with the adjustment screw. i used my S-afc II as a voltmeter to watch the MAP sensor voltage. so this part is basically up to what you have.

here are some pics of my FCD wires tapped, the Brake booster tee, and the vac lines for the BOV and other stuff

you can also tap all your vac lines now. i tee'd off the big brake booster line on the back of the IC manifold. i tapped my boost gauge and FMU from this line. i tee'd the BOV off of the PCV valve. heres some pics of the vac lines


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This step is also quite vague. you have many choices when it comes to this. you could go FMIC, SMIC, 1g SMIC or 2g SMIC or no intercooler at all. since i have a 2g SMIC ill show you how i mounted mine. mine is actually only being held on by one bolt with a lot of washers LOL. first i had to remove the fuse box's bolts and move it around so you can remove the black plastic piece right under it. this is where the inlet is. then i had to butcher up some of the splash gauge to fit the IC outlet. Then you have ot figure out where you want to route your IC pipes, and make the pipes. heres some pics of the pipe when i painted them and my IC mounted.


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This is where the dive is made. go to home depot and find a bolt/nut compbo that will fit to hold the turbo and manifold flange together. i could only fit 3 of the 4 bolts in the holes, but it seems to be working just fine. bolt the turbo to the manifold and bolt the manifold to the head. Now, get your exhaust flanges and U-Bend and fab up a DP. this is basically a hit or miss also. i took the o2 bung off my stock cat back and welded it on my downpipe. I re-used all the gaskets from my header i had. After you have the DP welded up, you need to make some IC pipes. Now connect your Oil lines, and your are ready to rumble.

If you are using a turbo with an internal wastegate that is factory set at a higher boost level then what you want, look at the next step.

alright, here is the finished project, finally! you can see my home made MBC in the pictures. the thing is touchy but works great. used the writeup on this site. anyways, i cranked the boost up to 8 psi, Holy shit huge difference, its so much faster now.


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I wanted to run fairly low boost and i had no idea what the stock wastegate was set at so i did this mod. i figured it would be much better to have the wastegate open too early then too late, because an MBC can fix it opening too early, but is useless to making it open ealier. What you need to do is go to Home depot's spring section and buy a fairly long, fairly stiff spring. also buy a nut and a couple of washers(if your actuator rod already has threading on it then use that threading). the first thing you need to do is to cut the wastegate actuator arm. mine already had threading on it so i was lucky. if it didnt have threading you would have to use a die and make it. place a washer on the rod, then the spring, then another washer, and then the bolt. now weld the actuator arm back together. the spring should put pressure on the arm, counteracting some of the pressure needed to open the Wastegate, which means the wastegate opens sooner. here are some pics of it. the mod worked perfectly, Im only boosting 4psi right now. as soon as i get the IC piping made i will crank up that boost.


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Well thats it. I hope this helped you out, and i warn you that you are doing everything at your own risk and i am not responisble for anything that happens. work in a safe enviroment and dont do anything stupid. Good luck, and PM me anything i forgot or any questions you have that i could have put in but forgot to.

Ive been getting asked for pics of my downpipe, so i took some tonight when i took it off to be painted. i found a nice suprise at autozone today. instead of the high temp 1200 degree paint they normally have, they had "Flame Proof" paint, good for 1300-2000 degrees! it says it is a ceramic coating and i got the alluminum color and it actually looks like a ceramic coating LOL. anyway, heres some pics. its so short because i bolted it to the tsudo flex pipe i got with my header. you will see what im talking about in one of the pics.


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Here's 3 reasons why the home depot rubber couplers wont work... well i had a few straight ones in use for a little while and all of them stayed in tact. but the elbows, these are only 3 of them. i think i went through 6 total. definitely get real silicone couplers.


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