4.8 Turbo Sizing

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12-21-2008, 01:57 AM
Mr.Cornelius

4.8 Turbo Sizing

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... :argg: and dead ends I need some help...:doofus:
12-21-2008, 02:09 AM
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.
12-21-2008, 02:17 AM
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.
12-21-2008, 03:03 AM
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
12-21-2008, 04:01 AM
George C

70 or 76 mm would suit well
12-21-2008, 03:29 PM
ducky

rear mounts arent THAT bad.... lol
12-21-2008, 03:48 PM
casey23

Quote:

Originally Posted by 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... :argg: and dead ends I need some help...:doofus:

62-1 is a great start.. even a MP70 with a .68 hotsite would work Great.. I have a Big turbo out back and dont think i will ever put it back under the hood... I had a 70mm .96 under the hood and it was Ok....... With my new combo i was not happy with the mounting of the turbo Anyplace under the Hood So in a last ditch idea i put it under the truck just behind the passanger.. Nothing is Cheap about FI... bottom dollar 2500+ if you dont skip steps and I would also make sure you leave a little in budget for Guages... Boost and Wideband if nothing else.... Injectors and possibly fuel pump will also need upgrades........ everyone has Flocked to Front mounts but I have chose to be different and look at all options before you start spending....
12-21-2008, 04:04 PM
r.barn

Quote:

Originally Posted by duckysbht

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.
12-21-2008, 04:07 PM
ducky

Quote:

Originally Posted by r.barn

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

lol whys that? have you run one?
12-21-2008, 04:11 PM
r.barn

Quote:

Originally Posted by duckysbht

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
http://i74.photobucket.com/albums/i2.../install46.jpg
12-21-2008, 04:15 PM
ducky

Oh ok thanks r.barn
12-21-2008, 04:24 PM
r.barn

Quote:

Originally Posted by duckysbht

Oh ok thanks r.barn

If your really interested in learning whats going on in a turbo
system I highly recommend the following book.

Amazon.com: Maximum Boost: Designing, Testing, and Installing Turbocharger Systems (Engineering and Performance): Corky Bell: Books
12-21-2008, 05:14 PM
George C

rearmounts do work but i wouldnt do one for a true daily driver. the location of air filter is horrible, one thing i like is stealthy
12-21-2008, 09:24 PM
Mr.Cornelius

Ok as for the oiling system I was thinking of a system where NONE of the engine oil runs throught the turbo...but on its own oiling system with an electric pump and cooler....

may I ask why rear mount turbos are so bad??? I though alot of you ran them. Its not that I'm trying to be cheap, but I would like to spend a lil here a lil there untill it is done....than install the system on my truck.
I know rear mount turbos cant be THAT bad or STS would have been outa buisness along time ago. I know theres a lot of pros and cons to BOTH systems

thanks for the sizes this will kinda give me an idea on how to do this...

Thanks for the head up on that book...I'll have to order it after christmas...

BTW I'm not trying to open a can-o-worms...I'm just trying build my first turbo system and maybe learn a little bit in the process. I kinda need a lil guidance...lol
12-21-2008, 10:18 PM
Sleaper

It's more just personal preference. Rear mounts work fine and are still capable of making a lot of power. The main argument will be lag and efficiency between front mount and rear. Front mount, as r.barn said, will get the hotter gas since it's close to the engine and therefore SHOULD reduce lag. Plus, rear mounts have the air filter under the truck instead of in the engine bay. Having a turbo in the engine bay also generates a lot of heat under the hood which can be fixed with a turbo blanket.

In rear mount applications, you can help keep exhaust hot by wrapping the pipes all the way back to the turbo and put a turbo blanket on.

Like you said, there are a million reasons to go with one over the other and ultimately it comes down to which one you want. :twocents:
12-21-2008, 11:08 PM
casey23

This a Pic contest??????

HEY R.BARN........... Alot of us have Cool pics of things we have built in the past ... I am a Die Hard Supercharger Guy myself... And allways made fun of Guys who try and run with us with turbos !!! I have a few Garage shots myself... and My complete motors Dont fit on Girly Engine stands.....http://i171.photobucket.com/albums/u..._photos/yo.jpg
12-21-2008, 11:16 PM
casey23

Quote:

Originally Posted by Mr.Cornelius

Ok as for the oiling system I was thinking of a system where NONE of the engine oil runs throught the turbo...but on its own oiling system with an electric pump and cooler....

may I ask why rear mount turbos are so bad??? I though alot of you ran them. Its not that I'm trying to be cheap, but I would like to spend a lil here a lil there untill it is done....than install the system on my truck.
I know rear mount turbos cant be THAT bad or STS would have been outa buisness along time ago. I know theres a lot of pros and cons to BOTH systems

thanks for the sizes this will kinda give me an idea on how to do this...

Thanks for the head up on that book...I'll have to order it after christmas...

BTW I'm not trying to open a can-o-worms...I'm just trying build my first turbo system and maybe learn a little bit in the process. I kinda need a lil guidance...lol

Dont let R.BARN change your mind on anything...... Use the engine oil for the turbo... Rear mounts do have alot of parts.... My own truck has 16 Clamps that are 2-3 different sizes... about 8-10 couplings... You can nickle a dime a kit together in a few weeks for a good price under 2000.00 bucks.. the part that will hurt you will be the Tune ( 400-500) and Injectors 250-350.00 the turbo parts depending on how exotic you get with turbo,wastegate and BOV 600-1200.00?? if you get in any trouble feel free to contact me for a little tech support or links on getting good prices for the best parts........
12-21-2008, 11:25 PM
r.barn

Quote:

Originally Posted by Mr.Cornelius

I know rear mount turbos cant be THAT bad or STS would have been outa buisness along time ago.

STS should be out of business for all the crap I've seen about their kits.
My tuner was a dealer for them, and after almost getting sued the 2nd time,
dropped the line and designed their own kit.
Every time I've seen one being installed I was thoroughly unimpressed with
materials used, routing and design. ..... just say'n

If the truck guys are having good luck with em, then I'm knock'n on wood for you.

Anyway, back to topic. A 60-70 mm turbo is good size for a 5.0L motor.

and right back at you Casey :)

http://www.bowzerbird.com/flash/flas...tions/poop.jpg
12-21-2008, 11:29 PM
ff_jeff

I think if STS were that bad, This would not have been the first time I would have heard about it. They also cater to everyone. Seriously, if you have an exhaust, They can make a kit for you. :nutz:
12-21-2008, 11:37 PM
casey23

Quote:

Originally Posted by r.barn

STS should be out of business for all the crap I've seen about their kits.
My tuner was a dealer for them, and after almost getting sued the 2nd time,
dropped the line and designed their own kit.
Every time I've seen one being installed I was thoroughly unimpressed with
materials used, routing and design. ..... just say'n

If the truck guys are having good luck with em, then I'm knock'n on wood for you.

Anyway, back to topic. A 60-70 mm turbo is good size for a 5.0L motor.

and right back at you Casey :)

http://www.bowzerbird.com/flash/flas...tions/poop.jpg

I Know your possibly the Smartest guy on here man........ But did you see or even read the part where he said he wanted to BUILD HIS OWN !!! Your the one smashing Rear mounts yada yada... After a better look at your pics if i didnt know better that motor on the stand has a Blow Threw Carb... :rolleyes: Speaking of a ****ED UP design....... I want to see the part in that book that talks about what a POS a Blown threw twin turbo setup is in a street car...
12-21-2008, 11:51 PM
ducky

Every kit has its own flaws. I honestly have yet to hear about flaws with STS other then the oil pump that comes with the kit. Thats always easy to upgrade though
12-21-2008, 11:58 PM
Justin_Inc

While I agree, a rear mount system is good, and will work, and usually work well, they are not for an all out drag application and if you run it in any sort of bad weather, i really wouldn't recommend a rear mount. just like anything else they have they're place. STS is a good company that produces good kits, however with everything you'll always have issues somewhere on the line, no one has 100% success with 0 failures. The more complicated you make something, the more room for errors there are.

You'll get differing opinions from just about anyone you ask really, chose what you think will be best for you and your application.
12-22-2008, 01:02 AM
ff_jeff

Quote:

Originally Posted by Justin_Inc

...no one has 100% success with 0 failures...

Chuck Norris does.
12-22-2008, 09:03 AM
Mr.Cornelius

Quote:

Originally Posted by casey23

Dont let R.BARN change your mind on anything...... Use the engine oil for the turbo... Rear mounts do have alot of parts.... My own truck has 16 Clamps that are 2-3 different sizes... about 8-10 couplings... You can nickle a dime a kit together in a few weeks for a good price under 2000.00 bucks.. the part that will hurt you will be the Tune ( 400-500) and Injectors 250-350.00 the turbo parts depending on how exotic you get with turbo,wastegate and BOV 600-1200.00?? if you get in any trouble feel free to contact me for a little tech support or links on getting good prices for the best parts........

I don't plan on going too exotic, I just want a good match and a good lasting product for my application... I am allowing myself untill June to get this done. This should give me the propper amount of time an money
12-22-2008, 09:29 AM
GasGuzzler

Quote:

Originally Posted by ff_jeff

Chuck Norris does.

:spit::tvhaha:
12-22-2008, 03:14 PM
bangbangskeetskeet

Quote:

Originally Posted by r.barn

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?