Sizing a turbo for my LX450
 

Hey guys i am looking into boosting my lx450 (basically a 80 series landcruiser). i have a few question regarding sizing a turbo for my rig. i have gotten a few numbers from dusties thread on here in which he did the same thing. he came up with a mass flow for our engine (1 fzfe) of 25 lbs/min @ 4k rpm and 15 lbs/min @ 2500 rpm also he is apparently using a Garrett T04e 46trim with a compressor a/r of .70 and a turbine a/r of .84. I am looking for a T4 turbo, since that is the only flange they offer for the turbo manifolds available for my truck, and would like to use a Holset. I have done a few calculation from Graham Bells book to get engine air flow rate:

CFM= (Capacity x RPM x VE x Pr)/5660

Pr: 1.64-1.82 which correlates to 6-8psi @5800' elevation (Denver)
VE: 85%

RPM, CFM, lbs/min
1500, 162.2, 12.3
2500, 270.3, 20.5
3500, 378.4, 28.7
4500, 486.5, 36.9
5500*, 594.7, 45.0

*Redline

these number are much different then the ones dusty used so i wanted to see which ones you guys think are correct to use on a compressor map.

i am looking to be building boost around 2K and have 6-8 psi max for now. im trying to bring it up to roughly ~300hp, it has 212 currently.

with a 300hp target i should only need about 28-32 lb/min or 368-421 CFM correct?

i am new to the hole turbo thing so any insight would be welcome!

im running a t04e 60-1 p trim turbo with a .91 a/r housing on a 4.6 liter v8, almost the same as yours but yours has heads set to make more midrange torque.

I have 2 psi at 3200, 4 psi at 3800 and 6 psi at 4000rpm where my wastage opens up.

If you got the same turbo as me and used a slightly smaller (.7-.8 a/r) housing, you would have spool where you want it and it wouldn't drop off. this turbo flows a lot you will be happy.

let me know if you have questions.