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Discussion Starter #1
I did a lot of lurking in these threads and gained a lot of knowledge from old posts. I wanted to give back. I plan on maxing out the stock engine. The consensus is 12 psi is about the max it will handle. I wanted to start by making adequate fuel available. I bought a used mapecu3 from the for sale secton here on customtacos. Tred talked me into using an additional four injector rail instead of 500cc injectors in the stock rail. I'm really glad I went the additional injector route as it was easy to tune and whenever it wasn't in boost it started and ran like stock! Here are some photos of my 2003 Dodge Neon returnless fuel rail and "grey injectors" each 200cc I added to my lower intake manifold.

2002 Tacoma 3rz Additional Injectors (6).jpg

2002 Tacoma 3rz Additional Injectors (9).jpg

2002 Tacoma 3rz Additional Injectors (10).jpg
 

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Discussion Starter #2
The factory fuel filter is a pita to get to and I had to put in a tee after it to supply fuel to my additional fuel rail. I put on a new fuel filter and changed the location to one more accessible..right up top. I ordered a banjo bolt (summit racing ATM-2277) it's an auto-meter part number 2277 Fitting, Adapter, 1/8 in. NPT Female, 12mm x 1.5 Male. That allowed me to not cut the original hoses. It made the installation really easy.
 

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Discussion Starter #3
I wanted to make loads of midrange power and lots up top if I wanted to wind up the engine. I found a great deal on a used Treadstone log style exhaust manifold in the for sale section on customtacos. I bought it and started turbo shopping. I didn't really want an external wastegate because they add complication to an already complicated system. After reading rave reviews about Holset he351cw turbos with their quick spool up and great flow I started shopping for one. I got one off ebay that needed rebuilt. I rebuilt it and it will probably outlast the truck now since it lives such an easy life compared to what it had to do on the cummins diesel. The dsm and Honda guys love these turbos and I see why now. They are huge but spool very fast without costing much. Both turbine and compressor housings are 360 degree clockable too making them easy to fit. I had a leftover wastegate actuator from my 1g dsm I modified to fit the Holset. The actuator spring would do 10psi on my dsm but does 8 psi on the Holset without a boost controller. As you can see it fits tight but fits very well! I was concerned it was too big before I put it in. I later hammered out the sheet metal inner fender a little so it didn't touch the compressor housing when the engine rocked toward the passenger side under power.
 

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Discussion Starter #4
I wanted it nice and quiet so I retained the stock exhaust system for now. I made a downpipe that transistioned from the 3.75" outlet of the he351cw down step by step to the 2.5" inlet of the stock cat. I only had orange ceramic paint so that's what it got. I eliminated the front cat and added a bung for my wideband o2 sensor in addition to the stock afr sensor.
 

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Discussion Starter #5
I wasn't intercooled for two months until I did lots of intercooler shopping to find something that would fit easily.
 

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Discussion Starter #6
In the previous post you can see I had the maf sensor right next to the turbo. That didn't work well. The turbo made the air turbulant and drivability was bad. Also, I was sucking in hot air. I reinstalled the stock airbox and put the maf back in the stock location so I could draw in cold air from inside the fender. Intake air temps were much lower after doing this. This photo shows how I made the connection between the stock airbox and turbo. I used a flexible intake tube kit from Advance Auto Parts. It leaked a bit so I wrapped it in Gorilla Tape to make it air tight. It worked great but I knew I needed to make the maf blow through eventually. The maf was reading air temps close to ambient according to my bluetooth ELM327 and scangauge andriod app. I knew I had to get the temps the ecu was seeing closer to what was actually going into the engine. The maf isn't in it's stock location in the photo because I took this photo after I moved it to the blow through location.
 

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Discussion Starter #7
The intecooler installed easily. If I had gone any larger I would have had to cut things. It fit with no cutting other than the two holes I sawzalled on each side of the radiator. It's a 28" x 7" x 2.5" Bar and Plate intercooler with 2.5" inlet and outlet. I bought it from ebay in a kit with pipes clamps and couplers for cheap ($150 shipped). I only used a few of the pipes:
One 90 Degree 2.5"
One 45 Degree 2.5"
One 180 Degree 2.5"
Spectre 9405 3" Maf Mount Tube Kit (I use the largest plastic insert)
Three 90 degree 2.5" silicone couplers
Two 2.5" to 2.75" transition coupler (one on throttle body, one on turbo outlet)
One 45 degree 2.5" to 3" coupler for Spectre Maf Tube
One 2.5" to 3" coupler for Spectre Maf Tube
 

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Discussion Starter #8
My truck came with steel wheels I never liked. I picked up these stock aluminum wheels with Goodyear Wrangler Authority 265/75r16 tires already mounted off craigslist. I didn't really want bigger tires but it looks so much better now. As an added benefit my speedometer finally reads correctly. It was reading about two mph slower than I was going with the stock tires. It's dead on now according to GPS. That's a Lund tri-fold tonneau cover on the bed. This tonneau is a really nice design. Tri-fold is definately the way to go.
 

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Discussion Starter #9
I hooked up a fuel pressure gauge and sure enough my fuel pressure was dropping at rpms higher than 3500. I added a Vortech T-Rex fuel pump I had leftover from a previous (supercharged Mustang) project. It flows [email protected] according to their website. I have it activated by a Hobbs Switch set at 1 psi. Fuel pressure doesn't drop anymore.
 

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Discussion Starter #10
I was worried I might be getting things too hot on the exhaust side so I installed an EGT probe today. I put it in the wastegate blockoff before the turbo. I went for a drive pushing it pretty hard and EGT's never get over 1550*F so I'm safe from melting anything. The ebay meter I bought logs the max temp reached which is nice so I don't have to watch it while driving.
 

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Discussion Starter #11
I got a request for some photos of the intercooler tubes going through the holes I cut out. The driver's side has lots of room for the pipe. The tightest area is on the passenger side inside the engine bay. There is an A/C line that comes in right above where you want the intercooler tube to make a sharp bend upward. I had to run the tube in a couple more inches before making the 90 degree bend straight up. It lightly touches the rubber part of the A/C line. This is all 2-1/2" tubing.
 

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Discussion Starter #12
This morning I preped to delete the catalytic converter. I cut the wire going to my check engine light. I hate check engine lights and we don't have emission testing here in Cincinnati. I have a URD extension harness between my Mapecu3 and the stock ecu so I didn't have to cut the wire in the stock wiring harness in case I ever want to take it back to stock. I also unplugged the rear oxygen sensor. The next step is to replace everything between the downpipe and muffler with a straight pipe. The pipe just to the rear of the cat is tiny. It looks like 2" diameter and must be a major bottleneck to all this boost I'm pumping into the engine.
 

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Discussion Starter #13
I learned a few things about the rear oxygen sensor when I unplugged it and tried to drive. It doesn't like that. My long term fuel trims went to +36 at every rpm. The truck was running 10:1 air/fuel ratio. Major problem! You cannot even drive the truck if you unplug the rear sensor. I would have fouled the spark plugs within a few miles. I put the rear o2 sensor back in but with a twist. I have heard from many sources that if you add a two spark plug defoulers to the rear o2 sensor when you remove the cat you won't get a check engine light. So instead of putting the sensor back into the pipe like stock I moved it out of the exhaust stream so it only sensed a smaller percentage of oxygen like it would if it was behind a cat. I welded a npt pipe fitting onto the exhaust and you can see what I did from there. I drilled a 3/16 hole inside the welded fitting in the actual exhaust pipe. I think I may have drilled too small of a hole in the pipe because when driving 10 miles I got a P1036 code on my android scangauge app. This means flow over the sensor is too low. I reset it and will drive some more. If it comes back I'll drill the hole in the pipe out to 1/4". As for now the truck runs FANTASTIC!! I'm using the mapecu3's electronic boost controller to control a MAC valve to give me more boost. I'm making 11 psi of boost right now and it is a lot of power! I'm still using the stock head gasket and the stock clutch is holding even with 4wd launches on dry pavement. Removing the cat opened up a lot more flow! As you can see in the photo the stock pipe directly after the cat is 2". The rest of the entire exhaust is 2-1/4" so why the hell is this pipe 2"? My original downpipe was crap. It went from 3-1/2" to 2-1/2" too quickly. I think this caused flow velocity problems. My new downpipe in the photo is a 3-1/2" elbow to a 3" pipe. I use two 45 degree elbows both in 3'. Then I go to 2-1/2" pipe. The 2-1/2" pipe fits perfectly over my muffler's inlet. The muffler's is 2-1/4" id inlet and the 2-1/2" od pipes id are both 2-3/8"! It sounds like stock. I don't hear anything when the truck is running, I mean nothing, it is extremely quiet just like stock.
 

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Discussion Starter #14
I did lots of research about rear o2 sensors this weekend. URD makes a fantastic product for people like me who want to eliminate the cat and not throw a cel code. It comes at a price currently of $108. I don't need it that bad. I found many posts of people who have removed their cats using anti-foulers to move their rear sensors out of the exhaust stream. The result is the rear sensor doesn't get as much oxygen running past it and therefore it doesn't realize there is no cat in the pipe. Anti-foulers are $5 but the rear sensors on tacomas have a two bolt flange instead of the world standard 18mmx1.25 bung. So I had to get creative. I welded a 1/2" npt pipe fitting onto my exhaust and used two RockAuto.com Polution Control Industries part# 811 flanges to make it work. It's not pretty but it works. I did bore out the id of he pipe with a hand drill to 1/2". The last 1/2" of oxygen sensor is wider at the base complicating everything. There may be a better way to do this but I used what I had and it works. I'll update if the 3/16" hole I drilled in the pipe keeps throwing a P1036 code (low flow over rear o2 sensor). If it does I'll drill it out to 1/4" and see if that keeps the code away.
 

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Discussion Starter #15
My scangauge android app shows the voltage coming out of the rear oxygen sensor. With the 3/16" hole it would show only small amounts of voltage very rarely. I drilled out the pipe inside the bung to 1/4" still got p0136 code and still showed voltage rarely, drilled o 5/16" still got code, drilled to 7/16" still got the code. At 7/16" it shows voltage a lot more often. The only time it isn't showing voltage is cruising on the highway and wide open throttle. The next step is to move the sensor closer to the exhaust stream. The sensor should be putting out voltage that oscillates up and down during part throttle and have a steady reading at WOT. It should be slightly leaner readings than if it was directly in the exhaust stream with no cat since I am trying to fool it into thinking the cat is still there.
 

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Discussion Starter #16
I put the rear o2 sensor back to stock. It throws a P0420 code as it should because it's getting too much exhaust now without the cat. What I didn't realize is the ecu would stop trimming fuel! It leaves the fuel trims at zero. This gives me the option to build a fuel table and trim the fuel manually. It may take some time to get all the values correct but it may work well to do it this way. I'll try it and if this doesn't work well I may be back to buying the urd rear o2 simulator. Once I trim the fuel manually I may get the simulator anyway so the ecu can fine tune my manual trimming.
 

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Discussion Starter #17
It runs so much better now that the ecu isn't trimming fuel. I spent a lot of time yesterday and today tweaking my fuel table and aux injector table to get the open loop fueling just right. It is MUCH easier to do this if the ecu isn't constantly changing fuel trims. I got it dialed in really nice now. I'll post some logs soon. I attached all my Mapecu3 tables.

On a side note I don't think I would've been able to tune the open loop without the additional injectors. I first tried to add fuel in boost at 1500-2500 rpm before the AFR sensor kicked it into closed loop by using the fuel table. To my surprise it didn't matter what numbers I put in the fuel table it would go lean 17:1 or worse under boost 1500-2500 rpm. I gave up, reset the fuel table values back close to zero and did all the open loop tuning with the additional injectors. It works great this way. For some reason the ecu seems to have a limit to the amount of fuel it will put out 1500-2500 rpm no matter what the MAF is telling it to do. The only way I could see around it was to add fuel with the additional injectors.
 

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Discussion Starter #18
I noticed I was still down on power even though I got the air/fuel ratio dialed in. I started looking at timing. The timing is great at high vacuum and cruising. At cruising speeds it is 31-35 degrees. But if you put the throttle on the floor and have zero vacuum or go into boost the p0420 code pulls 8-10 degrees of timing and is down on power as a result. So I added 8-10 degrees of timing to my entire timing map from zero vacuum to 15psi. Wow that woke it up! It runs 18 degrees total timing at 10psi and 14 degrees total timing at 12psi now. I'm going to tweak it some more but this seems to work well.
 

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Discussion Starter #19
I spent some time yesterday and today building a timing map while the truck is showing a p0420 emissions code. I put it in the attached spreadsheet. Timing is pulled a lot from where it runs without the p0420. I made this table by looking at my boost and rpm then looking at my android scangauge app that tells what timing the ecu is running.
 

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Discussion Starter #20
These are the timing values I entered into my mapecu3 on top of the timing values the ecu is outputting due to the p0420 code.
 

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