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Discussion Starter · #1 ·
Ok, so bear with a turbo noob for a bit here. I'm looking into a new turbo(s) for my truck, but don't know a lot about sizing and all that goes into a turbo. I have read a little about the 4094vvt's, and like the idea of keeping the fast spool time and the turbo brake of the vvt, but would it be better in the long run to get twins IF I am going to spend the money and time to change them out?
What are some pro' & cons to either set up? Can I do vvt twins? I have efi from rob, so tuning shouldn't be a problem, and my goal is 5-600hp at the wheels.
Thanks!
 

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where you located in AZ?

At 5-600 rwhp you will be pushing your luck on a stock bottom end LBZ.

4094's are great turbos, but I just don't see the point of having one for the $$ spent. IMHO I would go fixed vane S366. I had one on my LBZ and it spooled faster than stock with way lower EGT's. Granted I lost the turbo brake, but drive pressure on a fixed turbo will be a lot lower.



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5-6 pushing bottem end??? i thought it was more around 6-7??
 

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I'd go with twins over a 4094 personally. As stated you'll be limited with a stock bottom end, but twins will be great with good tuning on a stock engine.

Nobody knows when you'll pistons will break. Lots of people say 550-650, but some people get lucky like Rob. I think he had 683 with HUNDREDS of passes on his if not THOUSANDS of passes. In addition to that he towed Max'd Out everywhere with that truck.
 

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What about twining a 4094 don't mean to jack your thread
 

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Build your tranny first.... without that you are pissing in the wind.

Then if you want my opinion.... get an S475 over stock, 40 over injectors, and have Rob hook you up with new tuning. Myself and many others run/have ran that setup with ZERO problems on an LBZ for 2+ years. And I run a daily driver tune that has been dyno tested to run about 600HP+. No one can tell you exactly when your truck will break. It could break being stock, it could break with a 4094, it could break with twins, or it could never break.. who knows. But I can say that I've seen more guys buy a 4094 and then ditch it months later for something else than anything.
 

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you can make over 500hp on a stock turbo... with a 4094 its not crazy to think you could hit 600. But like they said, you should built your trans first or you will certainly fuck things up. I would like twins with mild tuning some day, but its all preference. you can get "stock feeling" spool up with twins.
 

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Discussion Starter · #10 ·
where you located in AZ?

At 5-600 rwhp you will be pushing your luck on a stock bottom end LBZ.

4094's are great turbos, but I just don't see the point of having one for the $$ spent. IMHO I would go fixed vane S366. I had one on my LBZ and it spooled faster than stock with way lower EGT's. Granted I lost the turbo brake, but drive pressure on a fixed turbo will be a lot lower.
I'm up in Chino Valley, although I'm in Prescott most of the time, that's where my route is.

I'd like to build the trans, but not sure how far into it I'll need to go, maybe TC, clutches, and Trans-go?
And if I'd put a S475 (I think that's what # nouse used) over stock, does that mean I'd keep the turbo brake?
The truck never goes the track, I don't tow as much as I used to when I was drywalling, and my wife drives it more than I get to, so this is more for fun and fuel economy:rolleyes: than anything else, plus I plan on keeping the truck for a long time, and want to build it so that it lasts a long time, too.

And what is drive pressure, exactly? I've seen trucks in diesel power with a boost and drive pressure gauge, and I know they are different things, but that's about it. Turbos seem a little like voodoo, they spin, and make people happy, but that's all I know :cookoo[1]:
 

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Drive pressure is the "boost" on the exhaust side coming from the heads to the turbine of the turbo. It's the "drive" if you will for the charger. On max offort stock turbo trucks, Ive seen north of 70psi drive pressure to 35-40psi of boost. That is severely pushing the stock turbo past it's efficiency range.


As far as power levels go on stock engines, the general rule of thumb Is keep it under 550 for Lb7 and 650 for LBZ/LMM, but plenty of trucks have blown up under that "magic number" Good tuning helps a lot, but so does the day it was built..



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5-6 pushing bottem end??? i thought it was more around 6-7??
Every LBZ/LMM is different, sadly. Crack with stock turbos with a tow tune, or live to see 50k miles of 700rwhp running 11.60's with dual pumps and injectors then throw a rod out of the block when idling...


What it all boils down to is how far you feel comfortable pushing your luck. Sometimes it works, sometimes it doesn't..



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when pushing the limits of the motor all you can do is prepare for the worst but hope for the best.


i like my 4094 billet, but if i had to do it all over i'd like to go with twins for the fact that you still have stock spool up, turbo break, and the hp they make seems to be safer for a stock motor. meaning dp and egts are lower.
 

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Discussion Starter · #14 ·
Can you use the 4094 as a low pressure turbo? Or do you have to use a larger fixed vane as the LP charger?
 

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where you located in AZ?

At 5-600 rwhp you will be pushing your luck on a stock bottom end LBZ.

4094's are great turbos, but I just don't see the point of having one for the $$ spent. IMHO I would go fixed vane S366. I had one on my LBZ and it spooled faster than stock with way lower EGT's. Granted I lost the turbo brake, but drive pressure on a fixed turbo will be a lot lower.
If i kept a vvt it would have been a danville performance turbo or twins
Pistons like to crack around 550hp on an lbz.
It all depends like Brian said below, My truck is coming up on 60k on a tune over 500rwhp, and 20+k of that is over 600rwhp. I drive under 1800rpm usually though so that probably has a big factor in it..
I'd go with twins over a 4094 personally. As stated you'll be limited with a stock bottom end, but twins will be great with good tuning on a stock engine.

Nobody knows when you'll pistons will break. Lots of people say 550-650, but some people get lucky like Rob. I think he had 683 with HUNDREDS of passes on his if not THOUSANDS of passes. In addition to that he towed Max'd Out everywhere with that truck.
X2 on the twins. I regret not doing that in the first place. I believe it is how you treat the engine and luck! You aren't gonna be making 600hp at 20% throttle and less!
Every LBZ/LMM is different, sadly. Crack with stock turbos with a tow tune, or live to see 50k miles of 700rwhp running 11.60's with dual pumps and injectors then throw a rod out of the block when idling...


What it all boils down to is how far you feel comfortable pushing your luck. Sometimes it works, sometimes it doesn't..
My luck has been pretty good so far, though on stock sticks still:thumb
If you drive like a jackass expect it to die at 600hp or less. If you only occasionally let loose, you may see more power for more time, then again, you may not..

If i had the will to start over, i would do an s475/stock setup or a garrett fixed vane turbo.
 

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Can you use the 4094 as a low pressure turbo? Or do you have to use a larger fixed vane as the LP charger?
you cant use a 4094 with a stock turbo if that is what you are asking. the turbo you would use is much cheaper than a 4094 and flows almost double anyways:thumb
 
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