Turbo compressor map calculator against engine flow.

Draco · Post by **Draco** » Mon Apr 11, 2011 1:14 pm

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

I am not getting mine right....hope it helps someone...or someone can show me what I am doing wrong...

300sx · Post by **300sx** » Tue Apr 12, 2011 4:34 pm

ok.. i will try to explain acording to MY understanding , since you asked so nice on the phone

there are two ways of doing this.. either you trust the recommendations of others on this forum that has done it before or has a bit of turbo experience , (this is NOT meant sarcastic, i mean to prove a point)

or you do the maths for yourself..

So ok then, the maths are not easy (at least not for me, i hate maths)
go here, read it through a few times, its about as dumbed down as the maths can get, but it helps to choose a compressor, which is what you want..

http://www.turbobygarrett.com/turbobyga ... ch103.html

ok, so now a few of the guys in the know have sugested the Garrett GT3071R, but now you want to know why.. if you have gone through the calculations in the link above,(the example is for a 2litre) , you will know that to reach your stated goal of 400hp at the flywheel, your engine will need to flow about 44lb/min , at a pressure ratio of around 3.3.. which will be roughly 2.3 bar boost on your gauge.

this pic is close enough for comparison, which shows why this compressor will be a good choice FOR YOUR STATED POWER!

http://www.turbobygarrett.com/turbobyga ... larged.gif

obviously there is a reason why nissan never equiped the ca18det with this compressor stock, you will not have much usable boost under 4000-4500rpm, thus drivability will suffer.

can your 1.8l even spool this turbo? if you look at the spec of this turbo and the turbine options on garrett's website, you will notice a very dumbed down turbine flow map at the right.. it allows you to make a rough guess at where a given turbine housing will start spooling..

for a simplyfied explaination on how to read these, go here..

http://www.dieseltruckresource.com/dev/ ... l?t=168543

allowing us to make a rough guess that the a/r .63 housing option should start making boost at about 4000rpm on your ca18det..

lastly, this is a much better calc than the ray hall one, if you use it right.

http://www.squirrelpf.com/turbocalc/index.php

hope this helps?

Daniel · Post by **Daniel** » Tue Apr 12, 2011 4:37 pm

Some nice info here, Thanks

Draco · Post by **Draco** » Wed Apr 13, 2011 7:53 am

Thanks Nico, I must say most of that is jibberish, I am stupid like that

I do undertsand how to read compressor maps better though, I found squirrel yesterday and the output data and what I see on the compressor map does not make sense, on the output data they are mentioning over 40 psi of boost, is that meant to tell me that with that turbo I need to boost over 40psi to get 400hp...the same with a T61, differance is on a T61 40 psi is to much boost to handel, but the T2860R-1 handels 40 psi???

I guess I am doing something wrong....great tool but if you a fool...like me...I am still lost on the best turbo to get and what makes it worse is it has to be a T3 exhaust housing because the mani is a T3 or T4 flange, so checking T28 compressor maps is not helpfull in the end.

I have found another calculater that also looks ok, maybe you can tell me what you think.

http://www.not2fast.com/turbo/glossary/turbo_calc.shtml

300sx · Post by **300sx** » Wed Apr 13, 2011 11:11 am

they are mentioning over 40 psi of boost, is that meant to tell me that with that turbo I need to boost over 40psi to get 400hp.

yes, that is correct. i mean, did you really think you were going to get 300kw out of a 1.8l without boosting the balls off it?
so in simplest terms, if you read the garrett primer again, for ANY engine to make 400HP, it needs to flow roughly 45lb/min air.
so to get that out of a 3l engine is easier, it will flow about that at say 1.2 bar boost.
to get your 1.8l to flow that much you need say 2.5 bar boost.. and of course a commpressor that can do that, and of course an engine that can handle that much boost.

it does not really help you switch from calculator to calculator, if you dont understand the what and why..

Draco · Post by **Draco** » Wed Apr 13, 2011 11:16 am

300sx wrote:
they are mentioning over 40 psi of boost, is that meant to tell me that with that turbo I need to boost over 40psi to get 400hp.
yes, that is correct. i mean, did you really think you were going to get 300kw out of a 1.8l without boosting the balls off it?
so in simplest terms, if you read the garrett primer again, for ANY engine to make 400HP, it needs to flow roughly 45lb/min air.
so to get that out of a 3l engine is easier, it will flow about that at say 1.2 bar boost.
to get your 1.8l to flow that much you need say 2.5 bar boost.. and of course a commpressor that can do that, and of course an engine that can handle that much boost.

it does not really help you switch from calculator to calculator, if you dont understand the what and why..

So of dit nou reen of nie reen nie...ek is nogsteeds in my moer in...

Dankie Nico!!