Twin Turbo guys please help

[hd2500]

Im looking for a little help with which turbo to get to compound my lb7. I know little about turbos and thought this would be the place to ask! I am just looking for turbo info and not a kit to buy because i will be building a kit myself. I have stock internals, so i would imagine a larger turbo would make my internals last a little longer because of the turbo lag so torque in the lower rpm range would be a little lower. Is this correct? What A/R ratio should i be looking for? turbine and compressor wheel mm? My goals are for around 550hp and to make the internals last as long as they can at this hp level. thank you for any input, and I will keep searching the forums for knowledge

 

[SSchmi5519]

I would do a s475.
1.32AR T6 96mm turbine wheel. Add a race cover if you can afford the extra $.


Sent from my iPhone.

 

[$chultz38]

472 96 1.10 is also a good turbo for your needs

 

[TLyons90]

X2 on a s475 and a lot of people also go big or go home and put an s480 but smarter to go the 475 route...

 

[Chevy1925]

X2 on a s475 and a lot of people also go big or go home and put an s480 but smarter to go the 475 route...

if i was to do it over again, i would have went with the 480...

 

[countrycorey]

What does the 475 with the race cover get you over the standard 475?

 

[ikeG]

Race covers are bigger in volume and may have better inlet designs. In theory they would spool slower...

 

[MAXX IT OUT]

I would go with the S480, the only difference is the compressor wheel. I would get a standard cover if your wanting to do it on a budget. You can get the S480 for a bit more then the S475.

 

[MAXX IT OUT]

The S475 is $650 and the S480 is $900.

 

[Dirtymaxx03]

Adding a turbo is going to greatly increase low rpm power (torque). So it will have a negative affect, if any (self control), on your bottom end.

 

[hd2500]

Thanks guys I really appreciate it. With my current mods, and adding a s475 to her with new tunes to accommodate, what go do you think I will be at? I don't want to be too high, but I could always just have it tuned down a little. Thanks again

 

[hd2500]

Also, is a turbo something I should worry about buying used, say from a forum or ebay, is is this something everyone buys new and not something to leave to chance?

 

[moparkxracer]

my personal opinion is if you don't plan on building the engine don't go bigger then a S475, I would get a new one they are cheep if you get a used one you'll have a 50/50 chance it will need to be rebuilt costing the same or more as what you would have spend to get it new to begin with.

 

[SickLL7Crenshaw]

My buddy has a customer that has a kit for sale. 4202 Garrett over stocker. Lb7 kit. PM if your interested and I'll let him know.

 

[SSchmi5519]

The idea behind the race cover is that it is a more free flowing cover, and respectively relieves the IHI from having to suck air through a restrictive compressor cover.

As far as spool time/making the engine live etc: proper de-torqueing the tune calibration that is in the truck is more beneficial than turbo lag.

 

[plowboy_lbz]

If your only looking for 550hp why not go with a modified stocker? It would be cheaper than a twin kit, but twins are nice. Most people go with the box stock s475 96mm 1.32 a/r because they are cheap and actually work very well. You can spend some more money and upgrade to a 1.10 a/r. This is becoming an ever more popular topic. Many people seem to think the 1.10 a/r will deliver better spool up and greater drivability. I have no complaints about my s475 1.32 a/r

My buddy has a customer that has a kit for sale. 4202 Garrett over stocker. Lb7 kit. PM if your interested and I'll let him know.

Whats the specs on the Garrett?

 

[MAXX IT OUT]

There is a GT 4202 for sale on here cheap, but it needs a new compressor wheel.
http://www.duramaxdiesels.com/forum/showthread.php?p=783303

 

[Chevy1925]

Thanks guys I really appreciate it. With my current mods, and adding a s475 to her with new tunes to accommodate, what go do you think I will be at? I don't want to be too high, but I could always just have it tuned down a little. Thanks again

on a max effort tune with rail that will hold with stock injectors. id say around 600hp

Also, is a turbo something I should worry about buying used, say from a forum or ebay, is is this something everyone buys new and not something to leave to chance?

unless you dont mind the chance of possibly rebuilding it, i would buy new unless its from a well known user here.

my personal opinion is if you don't plan on building the engine don't go bigger then a S475, I would get a new one they are cheep if you get a used one you'll have a 50/50 chance it will need to be rebuilt costing the same or more as what you would have spend to get it new to begin with.

475 or 480 are already beyond the limits of a motor so dont use that as a "safe zone".


Also the power difference and spool up time between them are hardly any different. A well fine tuned wastegate on the stock charger or vanes makes all the difference in the world.

 

[mackthehack]

I have the exact turbo you need for this setup, a box Borg Warner 475/96/1.32ar. If you're interested in it pm me.