ToddAuto

I need some advice on building an engine for my truck. I just purchased and installed a T3/T4 Tein turbo kit for my tuck. After 3 days I now have a turned bearing. I am purchasing another engine this week to build so I can just swap engines when I'm ready. What is going to be the best way to build the engine to handle this twin turbo setup. I want a great Street/strip truck and daily driver.

xRec

Sounds like you should start with a tune. Which engine did you purchase?
you should go with a 4l80e trans with a rebuild to handle the twins properly

ToddAuto

I had one of the the local guys to put a base tune on it when I put the turbos on. And I have not yet purchased the engine, I am looking around right now to see what's going to be best.

JoeNova

Did you have any engine work done at all when you put the twins on?

ToddAuto

I did not have any work done to the engine, the truck was all stock. the engine has 140k on it and I was only running 6psi of actual engine boost. I figured the 6psi would not cause any issues. guess I thought wrong. so now I am going to purchase and engine and build it. I am thinking just going all forged rotating assembly. if im building an engine I want to do it right so that I can raise the boost to about 12psi, and run a water meth injection. the trans is also coming out to be built. this is my first forced induction build so im kinda learning as I go

JoeNova

Do you have a wideband? What were the AFRs in boost? How is the oil return lines plumbed back to the engine?

You spinning a bearing likely has nothing to do with the power increase. If you replace the engine without knowing why it happened, it will likely happen again.

ToddAuto

I have a wideband but it is not hooked up yet. the oil return lines are 5/8 hose run straight down from the manifolds into both sides of the oil pan on the top side. the oil psi has not dropped below 30psi at idle and is around 55psi at 3/4 throttle. I should not have drove the truck hard until the wideband was hooked up and the fine tune was installed. everything will be done 100% right on the next engine, but if im building an engine I want some advice on what crank, bearings, rods, heads, cam, intake, I should run. want to build a great engine with plenty power but keep $$$$ in a decent range.

JoeNova

Best bang for the buck? A stock engine. Even at 12 PSI, you likely aren't anywhere near what a stock engine can hold.

It sounds like your spun bearing was from negligence.

ToddAuto

That's what i am thinking now. what would a stock engine with upgraded bearings hold? at 12psi with twin turbos and small cam what is the projected rwhp range?

JoeNova

That's not nearly enough info to give you even a ballpark number.

ToddAuto

sorry for the dumb questions. this is all kinda new to me

JoeNova

You just haven't provided any real info.
You say you want projected rwhp with a stock engine, 12 PSI, twins, and a small cam.

If that's a stock 4.8 with a stock cam, twin ebay 52mm turbos at 12 PSI with an auto like a TH400, it might be no more than 350-400rwhp.

If its a 6.2 L92 with a small custom turbo cam, twin 66mm or 72mm turbos at 12 PSI through a 6-speed or locked auto, it could be 700+rwhp.

ToddAuto

The engine that i have now is a LM7 5.3L, the heads on it are the cathedral Port 61cc aluminum heads, its in a 2004 GMC Sierra 4X4 with factory 3.73s, it has the factory 4L60 trans,(will be built when i build motor), i am running twin T3/T4 Hybrid Turbos. The question i have is what cam and heads should i add to the setup and should i go with an all forged rotating assembly or just upgrade factory bearings?

JoeNova

T3/T4 hybrids still gives absolutely no indication of size.

Rotating assembly depends on power goals. The older pressed pin rods and pistons are good to a little over 700 hp at the crank. Any higher and it will take some effort to make them reliable.

In your situation, I would start off with stock heads and cam.

ToddAuto

Ok specification on the turbos are AR 63 turbine and AR 50 compressor. i wasn't sure until i just looked. and i think i have come to a conclusion to just purchase an all forged rotating assembly to upgrade into the new engine, keep the stock 61cc aluminum heads and put a mild cam in it. and i don't know where you got your HP numbers from but this truck comes with 290rwhp factory, at just 8 psi of boost im pretty sure im over the 400hp mark now as is.

JoeNova

A/R doesn't ive any indication of turbo size either. You need inducer/exducer wheel measurements.

These trucks don't make 290rwhp from the factory. They make roughly 290 at the crank from the factory. Once you put them on the dyno and measure drivetrain loss, they usually put down less than 250 HP to the wheels. At 8 PSI on an efficient setup, you might be at 400 at the wheels. But since you're running a basic tune with no wideband with a pair of tiny ebay turbos, its probably far from efficient, and a bad tune probably has something to do with your spun bearing. Btw, you also said 6 PSI before, which I'm sure probably put you around 350 to the wheels.

A forged rotating assembly is going to be a complete waste of money for what you're doing. You spun a bearing, you didn't break a rod.