CorvetteTrader

I have a vortech set up with andy's brackets, but not andy's kit. (long story, I bought it used and never will I do that again.) The head unit is a v2 t trim. I just got my motor back monday (ls6, 386, forged and stroked, 60# injectors, walbro intank pump, and msd boost a pump) and I'm trying to figure out the smallest pulley that I can run on this set up. I have a 3.0 and a 3.6 but I am unsure which to run or if I have to buy another one. Also I live in Colorado at 5000ft.

Thanks for everyone’s help in advance. I am still a newbie and this forum has helped me learn more than I could have ever imagined.

Shane

user_name

Vortech has a calculator on their site. Check it out.

DeltaT

How big is your carnk pulley and is going to a larger crank pulley an option for you? On my t-trim I have good results with a 2.95" pulley but had slippage with a 2.85". A bigger crank pulley gets to be a better option around there.

How fast do you plan to spin your motor, and what the CR?

Jim

CorvetteTrader

6600rpms max and the crank pulley is stock...

DeltaT

And stock is how big? You need to know that for the calc.

Jim

CorvetteTrader

7.5 inches, thanks

c5mtl

im planning the exact same setup...forged 383 with a t trim...i have a 8 inch inovator crank pulley and plan to run a 3.15 blower pulley....but i have the 8 rib set up....i think at 6500 rpm im at 59000 impeler rpm's....the max impleler speed for the T trim is 55000 but plenty of guys overspin them by a least 5000rpm....im guessing it cant hurt unless i was going to sustain thoses rpm's like roadracing but i dont plan to....i think your going to need some more fuel at thoses boost levels

DeltaT

My 50# injectors on my 383/T-trim were maxed out by ~6000rpm. I had to go to 72# ones to have the headroom to spin to 7000 occasionally and still keep my AFR ~11.8 and a sane duty cycle. She put down 632rwhp at 11.7# and then I changed my air intake to 4" large radius bends and got it up into the 12.87# range @ 6400 which comes out to a blower speed of 54,823. Above that point I couldn't squeeze out any more boost. 7" crank pulley, 2.95" blower.

Jim

c5mtl

a buddy on mine picked up 1.5 to 2 psi on a s trim by spraying meth before the blower...i have a small nozzle (m3)in in the dongle...i 'm hopping that will give me the extra psi ...if my coolant temp dont stay in check im going to get myself one of the dewitts shorter rads and then run 4 inch pipe and a huge filter

madmatt9471

I'd go with the 3" and do a SD tune due to the altitude you are at! Try that for starters and possibly go smaller later or an Over Drive Crank Pulley

Thanks,Matt

CorvetteTrader

alright, new to this... sd tune? Please educate me

SiL3NtXWS6

sd = speed density, no MAF

robert miller

But make sure you find a very good tuner for this. Like a shop from the forum. You will not believe the guys out here will tell you, yes I can do that..

CorvetteTrader

Learned that leason already.... that's how I ended up with a forged motor. So what are the benefits of doing a SD tune and why? I'm here to learn

Shane

c5mtl

in a setup like ours...after about 5000 rpm the maf cant read the airflow so most tuners kind of put in an best guess on airflow and fueling....with sd tune you replace your map sensor with a map that can read you acutal boost levels and fuels according for that boost level....i'm sure its much more detailed than that but thats my limited understanding of it....after about 550rwhp sd is the way to go....BUT many guys have had great result keeping the maf till way higher that 550...even some guys at 800...

dsmlights

well you could get a bigger Maf if you wanted to stay with Maf tune..

c5mtl

its not the size of the maf...its the maf the air gets read.....i think its safe to say the maf was never designed to read the air flow a supercharger can produce...

CorvetteTrader

Alright, so are you going to pick up more overall hp with an SD tune or is it going to be a better torque curve? Also, are there any good tuners that can do an SD from here in the Northern Colorado/ Denver area?
Thanks for all of the help so far,
Shane

2004SpiralGrey

But aren't u supposed to no spray meth before the MAF?

c5mtl

he is on a sd tune so he has no maf....and i think i doent really matter anyways...even with a maf by the time it gets to maf its gone all mixed into the airflow or evaporated