lt4 fd

Hey guys I was wondering if 2 grand national turbos are about the right size for a 5.7 or 6.3 liter motor taken to 5500-6000rpm, I dont know what size they are and I have no idea where to find compressor maps for them. The 3.8 it was in tops out at like 4400 stock so 2 in a motor less than twice the size out to be about right for that size motor and those rpms, correct? BTW its not for an F-body. They were suggested on the turbo mustangs forum in a sticky on the junkyard part of the forum just so you know.

texlurch

They would work fine on a 350 or a 383, would be slightly rpm limited on a 383.
Other options are T3's off the Thunderbirds or Saab, and some Chrysler products, or GM 6.5 diesel turbos like I have. You can often find some good deals on Ebay also.

You can also look at the same cars for small intercoolers, or a single large one off the turbo diesel trucks.

lt4 fd

Yeah the list on turbomustangs.com did not say which ones would be good or atleast I dont understand what TDo3E and all that **** means and saw something I recognized which was the grand national. Got any specs I could possibly relate to or somewhere I can find out what T3 means and what sizes the ones you listed are or even maybe a compressor efficiency map?

lt4 fd

along with the above how much power or cfm (whatever its rated at) will a cummins or powerstroke or the like intercooler support and what are thier dimensions.... like if its too large can it be cut to size or is that a bad idea. Also what about using more than one intercooler?

texlurch

The T3 is the basic frame size of the turbo, and then you have different ratings on the air and turbine sides. For the turbine you need around a .60, and at least a .48 or larger on the air side. The numbers will be stamped or cast into the housing. The TD03 is smaller, and probably too small for a V8.

The Powerstroke intercooler flows plenty, but it is pretty big. You can definately use two small ones, and then y it back together at the inlet. That is how mine is setup.

Here are some good sites, cut and paste...

http://www.stealth316.com/2-turboguide.htm

http://www.grapeaperacing.com/GrapeA...maro/index.cfm

http://www.toohighpsi.com/

http://www.dune-buggy.com/turbo/turbo.htm

http://www.relentlessracing.com/new_diy_turbo_page.html

http://www.homemadeturbo.com/forum/index.php#1

lt4 fd

Thank you very much!

CamaroUK

Would a T04E turbo from a 6.6 diesel truck be big enough to use on an LT1 as a single turbo setup?

lt4 fd

TEXLURCH- Hey Ive read maximum boost by corky bell and learned a lot but dont remember coming across what you were talking about with the ".60 on the turbine side and .48 on the compressor"... trying to figure out what that means.

texlurch

Those are a/r or trim numbers, basically a ratio between the impellar and the housing. Smaller numbers will spool quicker, but not move as much air, and become restrictive at the higher rpms.

About halfway down this page it explains it well:

http://www.dune-buggy.com/turbo/turbo.htm

lt4 fd

OH right lol I know what that is.

lt4 fd

One thing that somewhat confuses me is say you have a .90 turbine a/r and a .40 compressor a/r, that would mean it would spool slower but the small a/r on the compressor side would help make up for it by building booost faster or does the small a/r on the compressor side just mean it flows less air at a certain boost or what? Also how do you find a good combination just test and see? Also a turbo that can flow more air at a certain boost whats that mean? I guess if the small turbo will make 15 psi at a certain rpm and has the same effeciency as a larger turbo that can flow more air at the same rpm at 15 psi whats the difference, its still 15 psi right?

texlurch

My understanding is (and I am far from an expert), you want to size the turbine size to handle the flow from the engine (twins on a V8 you have to figure for 1/2 the displacement), and spool at the rpm you want. You also don't want it to small because that will limit your rpm and power abilities. On the air side, you want to size it to match your intake capabilities, and HP goal. There is a formula to calculate how many CFM you need at a given rpm for a given HP.
Pressure and volume are too different things; a bigger compressor that will flow the same PSI will be more efficient, and should also lower your IAC temps. The more you compress air, the hotter it gets.
If you can find a compressor map for your turbo, you can see where it runs out of efficiency, and decide if you need more or less.
That is the trick, deciding how much power you want, and where in the rpm band. With a higher stall and an auto, you can crutch it around a bit.

A lot of the mustang guys run T3/T4 hybrids, to get enough air in and out. But for a 350 and higher rpms, you need more than the T3 for twins (at least in my opinion).

But junkyard shopping you have to look at what is out there, and make a educated guess on what will work for your application. I lucked out and got a pair that seem to do the job for me (at least so far).

lt4 fd

Thanks for the info, Im gonna try to find the compressor map for the gn turbo, do you have the one for yours?

texlurch

Nope, sorry. I have searched all over but haven't found one.