Building a Homemade turbo Kit

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One of the questions that seems to come up quite often on this site is about what is needed if you decide to piece together your own turbo kit.
This is easy to do in your own garage if you have a means to cut pipie and a welder.
If you have the technical know-how to put a flywheel into your car you can put together a turbo kit using resources on the internet.
Most people start by searching eBay and find a kit similar to this
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these usually run for between $700 and $3000 dollars depending on the company you order from and the quality of the parts but price of a kit does not always ensure quality parts.
A good option is to assemble parts individually and put the kit together yourself.
This can save you thousands of dollars and depending on your ability to haggle you could get a good working kit for only a few hundred.

The parts needed for a turbo kit are as follows;
Turbo
oil/coolant lines
charge piping
intercooler (If you choose)
Blow off valve
Exhaust manifold
wastegate
down pipe
engine management (last but more important than the turbo)


First off lets talk about turbo options
Since we are going bare minimum the best choice for a turbo is a used turbo off a car that came turboed from the factory.
common choices are
Mitsubishi turbos (DSM Trader hosted by DSMsource.com - Main Index) this includes DSMs which offer a turbo well suited to a 1.5 or 1.6 liter engine capable of making plenty of pull
here is a 14b turbo off a first generation manual DSM
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notice that it has an internal wastegate
Ford SVO turbos were 60 trim t3 with .63 a/r on the exhaust
Nissan Turbos offered a large variety including many different t3s
here is a nissan turbo from a 1985 nissan 300zx
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notice that this does not have a wastegate with it, originally the car had an internal wastegate yet the housing was removed in order to allow for the use of an external wastegate.
it is easy to find a used turbo, eBay and forums like this one frequently have turbos up for sale.

Oil/coolant lines
Turbos need oil to lubricate and maintain the amount of working that one of these little units put out. A majority of kit on the internet that you order require that you install a 'T' fitting where your oil pressure sending unit is and run a line from that to your turbo and then a drain turbo goes for the turbo to the oil pan, Ideal is a steel an line which i have since upgraded from after using a plastic line that leaked like crazy that you can see in some of the pictures.
Many factory car turbos are watercooled in order to prolong longevity. if your turbo has the option to watercool it i would recommend doing so as it will prevent coking (hardening of hot oil from a too rapid cool down) and it will keep the turbo alive longer. You can run water lines from one of the loops near the throttle body.


Intercooler
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this is option but so many people use them because of how helpful they are.
as you compress air it heats up not to mention heat that is conducted into the piping from being right next to a hot engine.
Many cars came with intercoolers that came with turbos these will work the most ideal spot for the most common type of intercooler (air to air) would be an area with high air flow to allow for convection to do it's work. This is why most people choose to place their intercooler behind the front bumper cover. This will require modification as far as adding mounts and making room since honda didn't intend for anything to go there.

Charge Piping
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this is the part where you get to be creative when putting together a kit as far as size of the piping I recommend measuring the outlet of your turbo's compressor and either side of the intercooler as well as your throttle body. It is best to have similar sized charge piping to allow for smooth airflow. Bigger is not always better as too large could create excess lag, too small mind cause air to back up keeping the compressor from working an optimal efficiency.

options are;
order mandrel bends from JC Whitney Auto Parts & Auto Accessories - Car, Truck, Jeep, Motorcycle, VW, RV & ATV - Aftermarket Parts & Accessories or many other sites
order a kit
go to an exhaust shop and have them fabricate charge piping since it is similar to how an exhaust snakes it's way back from the engine.
with a pipe cutter and a welder it is easy to do this yourself, get creative and connect the turbo compressor to the intercooler and the intercooler to your throttle body.

Blow Off Valve
Required on any turbo system in order to protect the throttle plate or compressor from being damaged from excess pressure. These can be commonly had from DSMs and shouldn’t cost more than $75 for a used one. Once obtained a flange is welded on the charge piping between the intercooler and the turbo.

Exhaust Manifold
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There are so many different types of exhaust manifold out there. The cheapest option is to make your own, many companies offer kits to make a simple 'log' style manifold. In my experience I usually buy a second hand exhaust manifold and modify it to fit my car, this required me to machine flanges which wasn’t hard since I had access to an entire machine shop, not something many people do.

Wastegate
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There are two types of Wastegate, internal and external. Depending on your turbo will decide which one you need and which exhaust manifold you will need to get also. An internal wastegate is mounted as part of the turbo as a whole unit. An external wastegate is mounted on the exhaust manifold, and therefore must require a flange be welded to it.
Most factory turbo cars have turbos with internal wastegates/
Here is a list of cars and there wastegate pressure setting:

Garrett T3 42/48 - 8psi

Most all chrysler 2.2l turbos w/ the goofy t3 - 5.5psi-6.5

.60/.63 Tbird/meurker/svo - 10psi

RHB5 from the Subaru and Probe - 8psi

84-88 nissan 300z t3 .60ar/.63ex. - 5psi

87-88 rx7 twin scroll turbo - 6.2psi

Mitsu TD04L(WRX) - 7 psi

t25/14b (Mitsu Eclipse) - 8psi

starion 14g Before 1987 - 7psi

starion 1987+ - 11 psi

garret t28 stage 1 - 8.5 psi

garret t28 stage 2 - 10.5psi

garret t28 stage 3 - 15 psi

K26 external - 14psi

Garrett T3 42/48 - 8psi

GReddy 15g (mitsu td04h-15g) - 5.5psi

CT26 (MK3 Supra) - 5psi

TB25 (Garrett, 89 Pontiac Sunbird GT) - 7 psi

IHI VJ20 (JDM Mazda 1.8 GTX) - 8.8 psi

K03 - 4 psi

Down Pipe
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The end of the line of turbo parts this is simply where gases from the exhaust housing of the turbo escape into the exhaust system. This is hot rapidly expanding air and since you already have a turbo in the exhaust system to create back-pressure for your high rpm, small displacement engine it is a good idea to set up a downpipe that allows for the air to escape and clear it’s way for more air to come as soon as possible. Most applications use at least a 3 inch down pipe it is debatable as to what size exhaust is ideal and it mostly comes down to the application.
I like to use large downpipe and then as clear an exhaust after that point for the above mentioned facts.

Engine Management
The most important part of any turbo system this is what keeps engines alive for thousands of miles more even after running over 100000 miles.
I never mind putting a couple hundred aside for this since it is saving me the trouble of getting a new engine after blowing mine up.
The new movement in tuning is grass roots tuning, there are programs available that allow anyone to tune there car with the use of a home pc and a knowledge of programming.
Since much of this is above my head I leave it to the people who know what they are doing and look up someone locally to program it for me, they are never that far away or you can order a program burned onto a chip that is roughly built for your setup.
Sites I recommend looking at are:
Welcome to PGMFI
Crome, TurboEdit, Uberdata --- DIY Honda ECU tuning and chipping resources, products write-ups and links. Widebands, Fuel Pumps, Intercoolers, ECU Chipping, Wideband Tuning & more
When using grassroots tuning as described at pgmfi.org it is recommend that you use larger injectors you can buy after market or use DSM injectors by following the instructions on Homemadeturbo.com in the tech section.
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depending on the time, money, part and thought you put into your project you can have a 13 second car for less money than most people buy greddy turbo kits.
 

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i was wondering how you only get 160 whp out of a turbo ls.. not a bad write up although i do have one question. where is that dumptube going now kinda looks like it would go into the manifold or something..
 
i was wondering how you only get 160 whp out of a turbo ls.. not a bad write up although i do have one question. where is that dumptube going now kinda looks like it would go into the manifold or something..
low boost only 2-3 psi is all i could obtain, i think because i relocated the wastegate mounting bracket slightly. factoring drivetrain loss of 20% thats about 60hp over stock.
i was going to have it loop around or flip the wastegate upside down and just dump it straight to the ground.
 
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