4.8 Turbo Sizing

[Mr.Cornelius]

Ok...I'm ready......

I have been rolling it around in my head for a few wekks now and have kinda thought of a STS Type of system that I would like to build myself...I would like to mount a turbo about 1-1.5 feet after the "Y-Pipe". I have a consederable amount of experience in fabrication and welding and belive that this wouldn't be that big of a deal. I would like to have some input on this and would like to know about the size of turbo I would need for this...for about 8-10lbs of boost. Also I have no other engine modifications or ECM Mods. I know that I will at least need a reflash and bigger injectors. I have searched what seems to be all of the web and have come up with nothing but a bunch of forums on ricers... and dead ends I need some help...

[ff_jeff]

I think a 68 on the turbo should be ok.
As for tuning. Check out Nelson Performance - Performance without Sacrificing Drivability you'll get great power and drive-ability results. Make sure you figure out the oil system.

[Justin_Inc]

**** the remote mount turbo! If your going to fab it just fab up a Front mount! A MP T70 turbo .68 A/R would fit that 4.8L perfect and make some pretty serious power with piss all for lag.

[r.barn]

Low mount turbos are nothing but trouble.
Put that sumbitch in the engine bay where it belongs.

I went with the turbo size that Trick Performance uses on their
base kits. A Turbonetics 62-1 with .81 a/r. It is maxed out at about
12psi but should be just right for you like it was for me.

I've got a front mount 4.8 build about to wrap up here right after
Christmas

[George C]

70 or 76 mm would suit well

[ducky]

rear mounts arent THAT bad.... lol

[r.barn]

rear mounts arent THAT bad.... lol

yes they are. really is the WORST place to put a turbo.

turbos like to be hot.
the exhaust gasses going thru the turbo like to be hot.

The closer the turbo is to the engine, the warmer the gasses going into are
and the warmer the turbo the better.

Hot gasses have faster velocity are expanded more and thus spool the
turbo much better.

Only way I would do low mount turbos on our truck is 2 small twins
hanging off each manifold down by the bellhousing.

Remote mounting a low turbo should be a plan of last resort if it
just will not fit up in the engine bay.

[ducky]

yes they are. really is the WORST place to put a turbo.

lol whys that? have you run one?

[r.barn]

lol whys that? have you run one?

I edit my post with all the reasons.

Been around lots of turbo installs.
Very familiar with turbo design dynamics.
Not my first trip down the turbo road.

My last "homemade" project

[bangbangskeetskeet]

yes they are. really is the WORST place to put a turbo.

turbos like to be hot.
the exhaust gasses going thru the turbo like to be hot.

The closer the turbo is to the engine, the warmer the gasses going into are
and the warmer the turbo the better.

Hot gasses have faster velocity are expanded more and thus spool the
turbo much better.

Only way I would do low mount turbos on our truck is 2 small twins
hanging off each manifold down by the bellhousing.

Remote mounting a low turbo should be a plan of last resort if it
just will not fit up in the engine bay.

Ok now why is it that THE FASTEST GTO in the country...which runs mid to low 10's...is on a REAR MOUNT???? Can you answer that? I mean I didnt know that 10's was slow?? What do you run?