I don't know if you guys have seen this site, but I checked it out today and its pretty infomative in terms of estimating how much HP you can get by changing certain aspects of your engine. Turbo Calculators

That being said, on the Turbo Power Calculator there are some values that I'm not sure about, such as the Volumetric Efficiency of B-Series engines as well as the compressor efficiency of the turbochargers shipped with the DRAG/MAXREV/GREDDY kits. Do any of you physics gurus have any information on how to approximately determine these values? By changing the VE 10% you can drastically increase the power output of the turbocharger.

They also have a calculator that will take your displacement, Max RPM and planned amout of boost and it will give you a recommendation of which compressor trim and turbine a/r to get, with the approximate HP you will make.

Let me know what you guys think. They have alot of other good stuff at that site too.


[Modified by Project_Integra, 4:59 PM 1/29/2002]

 

It would be a great site if you could read the numbers. They are all chopped up

 

To be able to read all that stuff you have to have an understanding of how to read compressor maps. Its not that hard you just have to know what the symbology is and what the numbers you input mean.

Project Integra
about the VE I'm just guessing but the only way you can change the VE % is to get different Turbo cams or a more efficient head design.

I made an EXCEL spreadsheet similar to the turbo calculator program and the only thing that I'm having trouble nailing down is:

1) the conversion factor for air, to change it from "CFM" to"LB/MIN" I only have the conversion factor for 1 air temp, 112* degrees.

2)for the "VE" I just use some reasoning. for a VTEC engine at redline I use 95%, and for VTEC X-over I use 80-85%. for NON-VTEC engines I use 85-90% depending on RPM and redline. The only people that can probably answer this question are the Honda engineers.

To be able to use that online calculators you need to know your own BORE and STROKE, all my EXCEL program needs is the engine size in Liters. In the end my EXCEL is very close to the numbers on the TurboCalc.

EDIT: as for compressor efficiency, most kit makers like DRAG, FMAX, REV-Hard will give you a compressor/turbine that you specify If you waant to chose your own. Or you can leave the decision making to the Kit maker themselves. I think that the compressor maps for Mitsubishi are a company secret, cause I have been unable to find any maps for the Mits series turbo's.


[Modified by BlueShadow, 2:37 PM 1/30/2002]


[Modified by BlueShadow, 2:38 PM 1/30/2002]

 

When I get to my office I'll post my little excel sheet that I use to size compressors at work. It calculates lbm/min mass flow rate into an RPM/psi grid and corrects for the changing density and temperature under boost. On mine you just enter the engine displacement in cubic inches and the max compressor efficiency. I like having the mass flow rate handy when I'm staring at a compressor map.