OK, then what is a 13BT lb/min rate??

On the first sticky of this forum I read JEFFSHOOTS formula for calculating CFM. Then after checking out the link that JZ 97 SS 1500 posted i got a totally different figure:

Jeffshoots formula I calculated equals about 578.79 CFM or 40.50lb/min @7000 rpm.
The site by JZ 97 SS 1500 says that the max lb/min rate of a 13B is 20lb/min @7000rpm

I am trying to figure out which trim to use in conjunction with my TO4B.

H-trim is at 72% effeciency with 40.50 lb/min @ 2.0PR BUT with the 20lb/min it is at surge limit.

S-trim is below 50% effeciency with 40.50lb/min @ 2.0PR OR 72% effeciency with 20lb/min

V-trim is @ surge limit with 40.50 lb/min @ 2.0PR OR 72% effeciency with 20lb/min

I got all these figures off of the comp maps at Turbonetics site w/ their TO4B.

 

the 2 rotor 13 series motor requires approx 1.92 CFM to make one rwhp.

if, for example, you want to make 400 rwhp you need:

400 X 1.92= 768 cfm or 768/14.29= 54 lbs/minute.

there are alot of other considerations w regard to sizing turbos.... what are your specific objectives?

howard coleman

 

Well, I am looking for about 360 to 370 to the wheels. My motor is street ported as well. I think I am gonna need something bigger then a TO4B, maybe a 60-1 Garrett GT series.

 

Yeah, I would like to find out this information too.

I assume that porting plays a roll in this, but im running 9.4:1 compression too and am not sure about that.

Aiming for 300-350rwhp depending on boost (pump gas at all times), but would like to keep a 3" hiflo cat.

This is going to be w/ a hybrid. I have a h-trim compressor only right now and was thinking of doing a full t04b compressor housing and whatnot. But I might need a tad bit bigger for my goals w/ a cat.

Interesting to see all of the t04b maps
-Ben Martin

 

Oh, and could you post the links to those threads you are referring to
Thanks,
Ben Martin

 

The link is in the first official sticky in this "single turbo" forum. Both are actually.

 

What manifold pressure are you using to calculate these mass flow rates? If I had to guess it looks like one of them is using atmospheric pressure, and one is using 1 bar.

 

I designed a calulator based on only:

1) AFR
2) Fuel flow

PM me with your email if you are interested. Here is some info:

https://www.rx7club.com/showthread.p...low+calculator

Justin