This java program allows you to enter your engine parameters and desired boost level, etc, and then plots the points on various compressor maps for you, in case you don't want to do all the calculations yourself. You can overlay different maps to find out what turbo and trim best fits your needs, or whether your current turbo is operating out of its efficiency range. It's pretty awesome.

http://www.turbofast.com.au/turbomap.html

I also know of another one that you have to pay for from www.turbocalculator.com that I plan on trying out soon to see how they compare.

 

ive got www.turbocalculator.com this if you want it. its 11.3mb we could proboly use aim to transfer it

pm me

 

Neal, after messing around with the java calculator, i was wondering what you use as far as volumetric efficiency (VE) for the different rpm points. I'm sort of at a loss for guestimating what the values would be. I figure they will drop from a maximum at the peak of the torque curve, but i'm not sure how much or at what rate. Would that be a correct assumption. To me it would seem as though the VE would be at a peak when the torque is the greatest, because at that point it is creating the most power with the amount of air "ingested" into the system. i don't think it would be based on hp, as it is a function of the amount of torque produced at a given rpm (everyone knows the formula i hope ). I suppose you could derive the VE from the slope of the torque with respect to the rpm... but that's alot of math

I know things like cams and intake manifold design (VIM's speciffically) increase the volumetric efficiency (VE), but how much more so than the stock design? Based on their baseline VE%'s, our motors should have a VE of about 85-95%. Going off torque curves i've seen, those with a VIM lose far less torque in the upper rpms after the peak. Average loss is about 50lb/ft after 5k for USIM and an average of about 25lb/ft for the MEVI/'00VIM. I would think that would be one of the prime reasons the boosted guys with VIM's gain so much more power. But what kind of efficiency do you think our cars produce? I bet there's a formula out there for determining volumetric efficiency based on airflow and torque (again HP is a function of torque).

I could be totally off base here, but it seems to make sense if you look at it...the question now becomes how to determine the VE...

what do you guys think our efficiency is?

 

Subs - thanks for your help last night

Anyone have any ideas about the above?

 

Mad-Max.. your correct.... VE plays into it.

CFM is what I was using, and that is not as hard as VE. I had no "hard" data.. I just talked to pepole and came up with a "informed" guess.

A 100% guess would be 90% @ peak TQ 60% @ redline with USIM and like 80% @4000 rpm

 

so since the VIM's loses approximatly one half of the power at the redline from peak torque, it's efficiency should be close to 75% [(90-60/2)=15]...

I know this is all theorectical bs, but i'm really trying to plan my course of attack now so i know what i need to buy, and get the right stuff the first time around.

Anymore info you guys would care to enlighten us newbs with would be great

 

i punched in the stock info in desktop dyno 2000 for the VE engine with roughly the HP/TQ i mad on the dyno and it gives you the vol eff % every 500rpms

http://www.cardomain.com/memberpage/423954/6

 

awesome...the VE has very similar characteristics of a VQ with a VIM right?

Ona side note, i picked up a couple books from my school library today, got alot of reading ahead of me:
-Maximum Boost by Corky Bell - couldn't believe they had it...
-Seventh International Conference on Turbochargers and Turbocharging
-Advanced engine Design and Performance 2001 by the Global Powertrain Congress