I have searched a little and noticed that a million people are trying to figure out the same thing I am, "WHAT TURBO SHOULD I GET?" I know it involves many different factors but is there a way to calculate and compare the different turbos with what cfm they will put out at certain psi and how fast they will reach a certain psi with certain engine specifications? I am assuming that spool time is going to be a bit of an estimate but generally there has got to be a way of getting a number...all I know is that this forum could really benefit from a sticky about this subject.

 

well seeing how this forum goes it depends what week it is for what turbo bandwagon the people are on. I think this week is an even week so I would say the SC61.

Next week it maybe a toss up between the gt35 or the FR t3/67 trim

 

thats kinda funny but not real helpful
maybe a how-to on reading compressor maps(i think thats what they are called) would be nice?

 

i just found http://www.turbocalculator.com

anyone have the software

also found this site a little over my head right now till i get a chance to read up on it.
http://not2fast.wryday.com/tur...shtml

 

I think there are too many ways to calculate which turbo is "right" for your application...

I've used the turbo calculator software one time and it said that the right turbo for my car is a T25! (I have a 60 trim T3 .48/.60)...

There are too many factors to consider, mainly, what are your goals? Is it a daily driver? Built or stock? Horsepower goals? etc etc...

I think this is why there is no single answer to which turbo is the best for each application. You will also get differing opinions from everyone as to which is the right turbo for any given application.

The best way is to research, learn how to read compressor maps (there are many write ups already in existence, including a very detailed one in Maximum Boost)...and then pick which one will meet your needs...

Sorry, it's not an easy answer, but I don't think it should be...

 

I found it best to just talk to the experts directly instead of asking everyone on a forum. Art, Jeff Evans, and even Rod Short at Precision are great people to talk to about turbo sizing.

 

I would agree with Muckman, ask.

 

aight thanks fellaz i knew it wasnt an easy answer nor an exact answer but u are prolly right just go to the professionals.

 

Well im not sure if this is the type of info people are looking for or you are. But ill have a shot at it....

GSR...stock B18C1.
Precision sc34
Running 0.5 bar spring (7.25psi)
Reaches full boost around 4600-4800 rpms
Pulls all the way to 8k
Gets me around 250whp and really no turbo lag at all. Basically a street turbo setup for no lag and still plenty of power. I've got the basic setup of Inline Pro Mani, Tial 38mm Wastegate, Revhard piping, Revhard 2.5" downpipe, 2.5" straight pipe, 2.67" kakimoto exhaust, Greddy Type R BOV, Skunk2 IM, Spearco FMIC, Dual Centerforce clutch, 7.5lb Fidanza flywheel, RC 550cc Injectors, Walbro 255 fuel pump and I believe thats about it. Car pulls pretty damn hard (weighs 2,440lbs).

I talked with Arturbo about my setup and my goals for my car. This is the turbo he suggested. . I have not one complaint.

 

whats ur 1/4th?
this may be a decent way to go about it...have ppl list the setup,spool time as well as hp numbers...so post away guys try to keep the chatter to a minimum though, compliment setups through pm

things to list:

CAR
COMPLETE SETUP(please list EVERYTHING)
SPOOL TIME(at 'x' psi)
HP
1/4th or 1/8th times (if you got em')
feel free to include dyno graphs and such

 

Dang your picky.

 

I will post some formula's later.

 

sounds fun haha but that should be good stuff

 

Assume:
Boost: 20psi
Pressure drop IC: 1.5

Absolue Pressure or PCO:
Boost+Atmospheric Press+IC drop
20+14.7+1.5

Pressure Ratio or PR:
PCO/Atmo Press
36.2/14.7=2.463

Desity air post Compress and IC(R=53.3 ideal gas law):
Di= Boost PRess+ Atmo Press/ Rx12(460+post ic Temp)
= 20+14.7/53.3x12x(460+130)
= 9.19x10 to the -5th power(lbs/cubic inch)
Dohc VE = 90%
Eninge Displacement 1.8 GSR = 110
MF= (Di+ Eninge Displacement in cubic inches x RPM)/(2x VE)
= (9.19 x 10 -5thPower x 110 x 8500rpm)/(2 x 0.90)
= 47.7 lbs/min

CMf= Mf x the sqaure root of the sum of (actual Compres Inlet Temp in degrees Rankin/ 545)/(Athmo Press/Corrected Compres Inlet Pres)
CMf= (47.7 x the square root of 545/545)/(14.7/13.95)
=45.3 lb/min

now the book uses 35.9 lbs/min i don't know why???/
Use PR and Air flow in the compressor map. Make sure i don't come close to the surge line (left of the compressor map)

Calculate HP: Airflow(CFM) x 60/(A/F ratio) x BSFC
: 45.3*60/12*0.50
:453 BHP

Some links :
http://www.turbofast.com.au/TFmatch.html
http://not2fast.wryday.com/tur...shtml


Calvin

 

good stuff it will take me all week to figure out all that haha