Very nice write up iTune. I understand it clearly now, thanks alot...

 

Well volume has a decent amount to do with is as well as temp. A 16g flows somewhere in the neighborhood of 575 CFM at barometric pressure or 14.7 PSI. whereas a t-3 GT-35R flows generally around 820 CFM at 14.7 PSI. Same pressure Way more volume.

 

That has absolutely nothing to do with it. This is one of the biggest misconceptions and misunderstandings about bigger turbos.

It doesn't matter if the turbo can flow 100000 CFM at 15 psi....your 2.0L engine can't. You have to understand that this isn't just a turbo by itself. A turbo's compressor map is used to match it to an engine size, VE, and RPM that will be used. But, it's flow at a certain psi is simply a rating of what the turbo is capable of, but that is not what your engine is capable of.


Eric

 

Unless he wrote the following, and he might have, he should have listed the source of the original article:

http://www.turbonation.com/turbo.htm

Nice article BTW.

 

i actually was in a huge hurry when i wrote that post... i meant to add the link to the top half. sorry about that...... i didn't proof read it either.....lol

i actually found that article because i didn't have time to sum it all up myself....i thought it was accurate and would be a good read for the thread starter.

Everything else is me.


CJ

 

I do realize that, But lower intake tempuratures and a slightly better VE under load isnt going to account for all of that extra air. Lets face it your not going to be adding that much more fuel if your not adding more air. I do realize that there is other factors involved in a larger turbo making a better performing vehicle. Such as the stock turbo just running out of steam <cfm> in the upper rpm band, so a larger higher flowing turbocharger continues to provide more flow higher in the RPM band. If tempurature had everything to do with it, Boosting a naturally aspirated vehicle, would hinder performance. Your saying that in this scenario a stock turbod vehicle provides every last bit of air that engine is able to injest. And that is simply untrue.

 

I won't even waste my time to write a story to you.

I would suggest you read up a bit, study compressor maps and how to read them, apply them to an engine (not open space), and then post again.


Eric

 

Im sorry, But I just cant see 70whp be only attributed to a denser charge, So if I drive my s2000 or my evo in the mid winter I will see 70whp? Both of the compressors on each of my vehicles are capable of flowing enough air. I'm here to learn as well, and I'm not arguing with you just for the sake of arguing. If your right, Then great but a little more proof would be nice. Proove your point please.

 

Denser air is all of it.

The two turbos are not the same:

1. The compressors do not have the same efficiency at the same boost level
2. The hot sides are not the same size. A bigger hotside, usually on the bigger turbo, will increase Volumetric Efficiency.

Voluemtric airflow (CFM) through an engine is dictated by:

1. RPM
2. Displacement
3. VE
4. Pressure ratio

Mass airflow includes the above and temperature.

Temperature comes about because of the compressor's efficiency, IC efficiency, intake temps, and anything else that can raise/lower the temps. So, in the case of the bigger turbo making more horsepower at the same psi, it is all because of compressor efficiency and VE. That's it.

There is a lot of good reading on this if you want to learn.


Eric

 

Thanks for clearing that up a little bit, I did realize that more dense air contains more actual air per psi. But I always thought that the efficiency axis on a compressor map was only measured through a constant speed and the working line was a better interpretation of how a compressor is going to act under load, And a larger turbocharger is going to have a much smaller effective efficiency zone, because of the increased lag inherent with larger units, and when the throttle is opened the compressor moves very quickly to the surge line, and then slowly back into its sweet spot. making it slightly less efficient turbo.

 

There is no efficieny axis. A compressor map has efficiency islands, where the percent efficiency is given for the axes of pressure ratio and airflow. You use the map to plot the airflow of your engine to see where it will land at different boost levels.

Eric

 

Efficiency axis
A sub-plot shows the variation of isentropic (i.e. adiabatic) efficiency with flow, at constant speed. Some maps use polytropic efficiency. Alternatively, for illustrative purposes, efficiency contours are sometimes cross-plotted onto the main map.

 

Your IQ dropped because you realized you didn't know the answer either, and YOU own an Evo. You never came back because you don't know crap. What a tool.

Self OWNAGE FTW!

 

Do you have anything better to do than to copy and paste from answers.com Here is the link, just so everyone sees: http://www.answers.com/topic/compressor-map

Gas turbines and their maps may be a little different than turbos on your car. Show me a compressor map for a turbo that we use that has an efficiency axis.

Why don't you read what you actually pasted....SUB-PLOT. The compressor maps that we use don't have sub plots for an efficiency axis.

Please don't try to go to the internet and copy and paste stuff because I didn't want to write a story to educate you about turbos. This is the ECUFlash forums. You can ask your turbo questions in another.


Eric

 

Actually it was dictionary.com