Hennytime

iTrader: (33)

let me just say im pretty ignorant to lsx boosted setups as ive just read about them. i always wondered why some people chose smaller turbos like 80mm when you already spent the money to get a built to the teeth fuel system, motor, trans, ect ect that can handle more power than the turbo. why did you stop at what you did and why not go the the absolute largest thing you can stuff in your bay. I myself plan on a turbo in the next year or at the latest two years and am hoping for a st80, but wonder if i will regret not going larger (same idea like when you got your first stall converter) look forward to your opinions

GrandmasterCow

iTrader: (5)

probably due to turbo lag as a smaller turbo will spool quicker on the street if its a DD or mostly street driven.

MY99TAWS6

iTrader: (3)

As you go bigger you will get more lag. You can do a few things that help like downshift your manual if you are in a higher gear but going up thru the gears the car can be a bit doggy or a lot doggy.You can use a two step in an manual to also help build boost off the line and autos build decent amounts of boost with a stall.But it all comes down to how you want your power. If its a drag car then huge turbos make sense. And remember massive power means massive traction problems so better tub and cage and the whole nine yards if you to put 1000 plus hp thru the chassis.You will need some huge tires under there.
Also do you want a powerband that goes from say 5000 to 7000 or do you want one that goes from say 3000 to 7000 with boost maybe even starting in at 2000 and hitting full by 3000 with the smaller turbos. And yes you will give up some maximum hp and top end power but hey how often do you go over 200mph anyway?And the smaller turbos have gone 10s in the 1/4 without much difficulty.

The factory usually purposedly undersizes turbos in its cars. Gives like was said,quicker spool up and better wider street power band.Race cars kind of suck for daily driving.

ninetres

iTrader: (35)

80mm turbos can make 1000 wheel, and the large frame T6 turbos are tougher to stuff under an F-body hood. Also, MOST set-ups are not using 6 bolt heads so a BIG turbo will push water on any decent amount of boost. And the lag issue like mentioned already.

Hennytime

iTrader: (33)

so for you its more of a reliability/maintainability issue? I was under the impression that stalled auto's eliminate much of the lag for larger turbos.

Websy21

iTrader: (34)

ST80 should be plenty enough up to around 370ci, even with a 408 I am sure it would still do fine as a T6 and large downpipe as long as you didn't want the max out of the combo. I'll be running a 80gts on my 370, I didn't want to mod my kit but if it could be easily done I would have upgraded to either a pte88 or ST80. Either of those should be a great match for 346-383 for the street/strip.

Websy21

iTrader: (34)

You do not want a large t/c for a boosted car, it will flash too high. 3000-3400 seems to be the norm. The more hp the higher it stalls right, most FI cars are running allot of power and this would leave you with a very short powerband. Not too mention most likely leaving out your peak.

MIGHTYMOUSE

iTrader: (59)

a t76 has enough juice to lift the heads off a stock shortblock, thats why.

I agree that others enjoy good street manners, especially those with manual trans.

I also find that most 'built' engines, fuel systems etc.. are still only good to power levels still attainable by a t-4 flanged turbo and on top of that the car will have to undergo a signifcant 'knife' to go t-6

in short

t-76 can blow up a stock engine
large t-4 like 76/80/88 can hang with a big engine and fuel system
giant t-6 takes heavy mods (race car-type mods) along with a giant engine build and fuel system (1500+ hp range)

Pro Stock John

iTrader: (34)

Well the turbos can get pretty big, here is my GT47-88. It's reportedly capable of 1400 hp.

Hennytime

iTrader: (33)

well the lines im thinking along are the dual walbros, 60 or 70lb injectors, built 4l60-which ill have in a few months and when it goes 4l80 or if its a conversion yet a 6l80/90 and a 370 from tsp wit hall the bells and whistles like arp bolts and afr heads ect ect. again i know its bunches of money and time, but its just like any other addiction. i just see the ofi kit and the ky turbo kit being able to fit a s91 in there and some times wonder why not since its only a few more hundred dollars on the cost of the headunit alone. again the fastest car ive riden in was a twin turbo ford gt and that got me hooked...and pretty much made my little 450rw car boring