small engine turbo build
Turbo Mini Forums

hi all hope you can help/advice me i'm on the learning curve and unsure if i'm reading the turbo compressor maps correctly.

*conversions taken from s4wiki* (rounded to 2 decimals)

to start i roughly worked out i wanted around 115bhp @ fly (100whp)
To convert horsepower to m3/sec, divide by 1620
therfore 115bhp/1620=.071m3/sec 11.5lb/ft

then as i have a target goal of running @1 bar (14.7psi) i worked out my pressure ratio as follows
(required boost + 14.7)/14.7=PR
therfore (14.7 +14.7)/14.7 =2:1 @ 1 bar makes sense :)

so i'm looking at .071m3/sec and a pressure ratio of 2:1 (i also have faith the head will flow around 180cfm (.085m3/sec or 14lb/ft) at around 6800 so i roughly worked that out to see if when at top revs where i'd be with relation to the turbos efficency)

k03

so the k03 would not stay in its efficiency being slower spool up at lower rpm (reduced exhaust gas velocity) but coming into peak efficiency as rpm rises?

K14

k14 similar only slightly better for higher boost levels and a slightly more efficient turbo?

ct12b (think this is slightly bigger than ct9)

seems as though this turbo would run within its upper efficiency for a longer rev range compared to the kkk's if im going about this correctly

below is a link to the compressor maps and many more including pressure maps for eatons and plenty of mitsibushi and garret turbos, the turbo's i chose above are chosen simply as they're in my garage:) again any help much appreciated.


http://www.not2fast.com/turbo/maps/all.html#kkk

Edited by B4G on 14th Jul, 2014.

You either pick a horsepower target and work out the boost required or work out the horsepower from a given boost. You have assumed both

There is a guide on the Garrett website.

Or use my guide:
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=213848

The thing that most people miss is checking the turbine performance will meet your expectations and not choke the engine.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

ok thanks for the link, yeah i thought you took both for the x and y and went directly up from your flow rate until you reached the desired pressure ratio, the point of intersection is then within the turbo efficiency ranges or not?
i will have a read

Edited by B4G on 14th Jul, 2014.