Turbo conversion chart?

[J.R. Adkins]

OK you turbo guru's! I need to find a chart that will convert turbo housings from CM sq. to AR ratios. What is the AR ratios for lets say for instance the hx 35/18cm sq and the hx 40/18 cm sq? Is there a website that has this? Thanks!





J. R.

 

[Alan Reagan]

I don't know what an AR ratio is, but here's a sight that can provide some calculations for you:



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



What is the AR ratio?

 

[HVAC]

A/R = Turbine Area

I have always struggled with comparing Holset housings with Garrett for instance. Like when comparing a Ford turbo to one of our Holsets on a Cummins engine.



Where our housings are measured and rated in terms of the cross section area, the A/R is a ratio which is dependant upon another dimension.



It was oh so simple while we were sticking to using Holsets. As time progresses and Switzer turbos for example are becoming more popular, we will need to get more familiar with A/R.

 

[Chipstien]

I wish I knew what the approximate cm of Pier's Hybrid.

 

[Alan Reagan]

Thanks, HVAC. I've been doing a lot of calculations on turbo efficiency, air movement, heat, etc but haven't run across that one.



The area of the turbine housing exit point defines the A of the term A/R ratio. The R is defined by the arc between the centreline radius of the housing and the turbine shaft (or centre of the exducer bore). The A/R ratio is one determinant of turbo lag.



Does that help?



Area of the circle is 2 X Pi X R or Pi X D isn't it?



Go to this website to see a visual of where to take the measurements. You'll have to scroll down till you see a picture of the turbo with the A and R labeled.



http://wwwrsphysse.anu.edu.au/~amh110/turbo_page.htm



Merry Christmas.

 

[formula]

The circumference of a circle is:

2 x pi x r OR pi x D (D=2r)



The area of a circle is: pi x r^2



And just for kicks, the volume of a sphere is:

4/3 x pi x r^3



r = radius

D = diameter

pi ~= 3. 1415926535897932384626433832795



Cheers,

Sean

 

[Diesel Freak]

Originally posted by formula



pi ~= 3. 1415926535897932384626433832795



Cheers,

Sean

hehe and I thought I was a Geek!



jk

 

[formula]

There's more where this came from

This value of pi should definitely improve your measurements of A/R's... just make sure you have a super accurate caliper



3. 1415926535897932384626433832795028841971693993751058209749445923078164062862

089986280348253421170679821480865132823066470938446095505822317253594081284811

174502841027019385211055596446229489549303819644288109756659334461284756482337

867831652712019091456485669234603486104543266482133936072602491412737245870066

063155881748815209209628292540917153643678925903600113305305488204665213841469

519415116094330572703657595919530921861173819326117931051185480744623799627495

673518857527248912279381830119491298336733624406566430860213949463952247371907

021798609437027705392171762931767523846748184676694051320005681271452635608277

857713427577896091736371787214684409012249534301465495853710507922796892589235

420199561121290219608640344181598136297747713099605187072113499999983729780499

510597317328160963185950244594553469083026425223082533446850352619311881710100

031378387528865875332083814206171776691473035982534904287554687311595628638823

537875937519577818577805321712268066130019278766111959092164201989380952572010

654858632788659361533818279682303019520353018529689957736225994138912497217752

834791315155748572424541506959508295331168617278558890750983817546374649393192

550604009277016711390098488240128583616035637076601047101819429555961989467678

374494482553797747268471040475346462080466842590694912933136770289891521047521

620569660240580381501935112533824300355876402474964732639141992726042699227967

823547816360093417216412199245863150302861829745557067498385054945885869269956

909272107975093029553211653449872027559602364806654991198818347977535663698074

265425278625518184175746728909777727938000816470600161452491921732172147723501

414419735685481613611573525521334757418494684385233239073941433345477624168625

189835694855620992192221842725502542568876717904946016534668049886272327917860

 

[BushWakr - RIP]

It's ok guys, he's just escaped from the evaluation ward over in 1st Gen Forum... ..... I'll take him back and he won't be any more trouble... ... ..... heeerrre formula, come on boy... ... .

there ya go,,, here's your porkchop, good boy...



Bob.

 

[Diesel Freak]

LMAO!

 

[formula]

Originally posted by BushWakr

It's ok guys, he's just escaped from the evaluation ward over in 1st Gen Forum... ..... I'll take him back and he won't be any more trouble... ... ..... heeerrre formula, come on boy... ... .

there ya go,,, here's your porkchop, good boy...



Bob.

Them Canadian porkchops are addicting Better watch yer fingers Bob



Sean