96 5vz xcab 4x4 TACO TURBO BUILD

Why not get the Cx manifold? The stock is so tiny and restrictive.

 

I was going to. I thought "awesome, a bolt on solution", but I've reconsidered for a number of reasons:

1. While the CX manifold is obviously less restrictive, the most restrictive cross section of either setup is the T3 flange. I have owned cars with much smaller manifolds (in terms of volume and min x-section) that saw much higher flow, pressure and temperature conditions than this setup ever will. My Saab Viggen, a 2.3L 4 cylinder reliably (60k miles) ran 30psi boost for 360lb-ft at the wheels. That is a high boost pressure for that torque number, which is characteristic of those cars with the stock turbo. That creates some impressive heat and pressure in the exhaust manifold, but by opening up the turbine flow- swapping for a bigger wheel/housing combo, the HP/TQ goes up with less boost. The manifold was not the restriction in that situation. My goals for this project are somewhere around 280lb-ft at the wheels, but honestly, if it's limited to ~240 at the expense of reliablity/complexity I'll be perfectly happy with that. It won't take 30psi- we're talking less than 30% of that.

2. I don't want to run an external wastegate. Overkill, plus the cost, complexity, and limited fine tuning options at these low boost levels make it more trouble than benefit for me. You guys who go for more power are in a different situation with that.

3. I have resources to do the fab for these kinds of projects, and I like the flexibility that gives me.

4. I'm a little concerned about the longevity of the CX parts. If I spend $700, and it cracks and I'm constantly repairing it, I'm pissed. However if I have to touch up my welds on a bastardization like this, it's easier on my head.

5. I have reason to believe that this can approach can last a while. I know a guy who did something similar on a T100 and used it for a tow vehicle for his race car all around the US. Something like 100k miles. Granted, the T100 has a cast iron manifold, which is different, but I'd argue that the longevity might be in my favor with the steel mani.

6. Money. I'll be into this project for under $1000.

 

I would rather have a brand new manifold then the stock one that can crack under normal use. How do you know its not going to rust a hole in it soon?

 

I don't know that it wont, but the truck is rust free, including it's original exhaust system.

I know I'm taking a chance. I'll post up if there's a problem.

 

Yeah idk. I just feel like your already adding restriction to the exhaust via the turbo, and now your not helping relieve it with a better flowing manifold.

But I don't know enough to effectively speak on this matter

 

You can weld regular steel with stainless steel rods/wire... I do it all the time. Believe me, your welds *will* see holes eventually unless you over-do the crap out of them. I went through that myself with the rear mount. I'm not trying to discourage you from attempting to fab up your stock exhaust, but for $400 you can get the CX headers with no downpipe that is completely bolt on and ready to go with way more flow. Even the worst batch of CX headers aren't going to crack a mile above sea level and pushing 240-280 WHP... not even close. The torque I gained just going from NA stock exhaust to NA CX exhaust with cat and muffler (charge pipes not hooked up) made a noticeable difference.
The only way I would ever even think about justifying using the stock headers is for a well thought-out rear mount setup.

 

I hear ya, and I understand people's concerns. If it fails, I'll post pics and buy some CX headers.

 

You want an oil pan (1st gen Tacoma) with a CXRacing return bung welded in it by any chance? It takes a large return line to fit over it.

By the way, make sure you have your return line fitted before you weld the flange to align the turbo so the return line is as straight up and down as possible.

 

Thanks for the offer on the pan. I did mine already using a -12AN to 3/4NPT that I bored out on the lathe to around 17mm ID. It's not the full 19mm ID that Holset wants, but it's bigger than the -10AN line that most are running with the HX and HY turbos. The return line has a really clean straight shot into the pan- vertical for the first 14" or so, then gently curving into the -12AN fitting. I'll be sure to clock the turbo CHRA so the oil outlet sits at 6 o'clock.

What size is the oil feed fitting on the block? The one just in front of the oil filter? The internet says both 1/8" and 1/4" NPT in the various build threads I've seen. That looks like a bitch to reach...

 

In my list I have this goes into the block.
http://m.ebay.com/itm/3-8-Male-x-1-...-Hex-Bushing-Fitting-/331021153861?nav=SEARCH

Then a restrictor goes into it.
http://m.ebay.com/itm/4AN-4AN-AN4-t...-OIL-RESTRICTOR-BLUE-/171625500114?nav=SEARCH

 

The fitting to the block, located next to the oil pressure sensor is hard AF to reach. I believe its a 12mm allen wrench. I had trouble getting the allen to seat all the way and almost stripped it so make sure the allen goes in all the way (its pretty deep).

To access it better, release the tensioner on the alternator, loosen the mounting bolt, and remove the belt. Have a second pair of hands to rotate the alt up and hold it out of the way (or just pull it out). Should be easy to reach at that point.

 

Wow, I guess add 3/8" NPT to the list now too. I better pick up a few extra NPT bushings. Ace is the place...

12mm socket head on the plug pretty much rules out 1/8" and 1/4" NPT.

I'm running a -3AN line for the turbo, so no restrictor needed according to the DSM guys who use these turbos.

I was hoping there was some trick that didn't involve moving the alternator. Oh well, not the big of a deal.

User anothernord has a couple pics in the first page of his thread of the little bastard in question:

https://www.tacomaworld.com/threads/holset-vgt-5vz-fe-turbo-build.403951/

I'll route the line the same way he did.

 

^ Yes, that's the bolt I'm referring to in his build.

 

Idk if it helps, but I didn't have to touch the alternator at all, nor did I need any help for the oil feed. You also have way more room to work in than any of us tacoma guys. 3AN should be fine with no restrictor, but it all depends on the condition of the turbo and its seals. I choose to run a restrictor at the oil tap on the block to keep the pressure down within the feed line.

 

Restrictor should be at the turbo, not at the block. If its at the block, it will take a while for the oil to reach the turbo when the line drains down from sitting undriven. You can also get uneven oil feed into the turbo itself. Not recommended at tall.

 

So should you just run a 3AN with no restrictor?

 

You def need a restrictor. Too much oil and it will leak out of the turbo and it can slow the spool. Just have the restrictor as close to the turbo as possible, def not on the block. And its not a "you probably shouldn't" its a "you DEF shouldn't".

Think about it. With the engine off, the entire line drains and when you restart it, the line has to fill up again but if the oil has to go through the restrictor, it will take some time to fill up that line. If the restrictor is at the turbo, the air in the line will pass through the restrictor much faster, allowing the line to fill up much faster and allowing oil to reach the turbo quicker. The turbo needs almost constant oil feed which is why its also advised to prime your oil filter every change (if you can - can't really with the stock oil filter position).

 

Lol I don't lose any oil at all in the feed line that isn't refilled the second the starter starts to turn the belts. I tested that with the 10 foot long rear mount feed line in my old setup with no dry starts. Heck, I even had a problem with that 10 foot long oil feed line pushing oil passed the turbo seals as the engine was cranking over and the accessory power for the oil return pump was cut off for a half a second. Even if it did take more time to fill the feed line, not even the most microscopic shred of damage could occure from a cold idling turbo spinning at 600 RPMs for a half of a second (or 5 revolutions) before the oil reached it. That's ridiculous on so many levels (no offense). 3/16" (an3) is so similar in size to 1/8" that there wouldn't be hardly a difference at all in oil feed. I run an aluminum inline oil cooler, and I don't like that cooler seeing the full oil pressure for darn good reasons. I've been boosting all over 2 states for over two years with absolutely no issues at all whatsoever. Oil pressure rises with RPMs, so there is no uneven oil feed. Most (all?) oil feed flanges have a built in 1/8" or smaller restrictors already, so a 3/16" restrictor at the block to slightly lower the pressure isn't hurting anything.

 

That's not what I read. Ill try to find the build page. It was pretty insistent the restrictor was at the turbo

 

I'm sure there are hundreds if not thousands of people who would not recommend a restrictor on the block, but when you look at the physics behind it, there is nothing wrong with it. The restrictor on the block is the same diameter as a 3an feed line with no restrictor at all. I have a 1/8" restrictor at the turbo flange which is not uncommon or looked down upon. My oil also fully reaches the turbo before the truck even fires up with the cranking of the belts. There is literally no issue at all whatsoever.