I have searched and I cant find what that is. My turbo is a borg warner 57 trim .55AR. What is that?
what exactly is AR?
- Thread starter mtoxracerfss
- Start date
It's a ratio measurement to express the Nozzle to Wheel relationship.
Bigger the AR the Bigger the Hole in the Nozzle.
Bigger the AR the Bigger the Hole in the Nozzle.
Read this:
http://www.supracentral.com/print.php?content.57
A = Area of exhaust inlet
R = Distance from the center of the turbine to the center of the exhaust inlet
A divided by R give you the A/R Ratio.
http://www.supracentral.com/print.php?content.57
A = Area of exhaust inlet
R = Distance from the center of the turbine to the center of the exhaust inlet
A divided by R give you the A/R Ratio.
Thanks that helped a lot guys! So basically bigger = more HP but more lag as well?
Also my turbo is .55 as i said, 57 trim, and the guy said it can support 550hp in my car. True? If so is it going to be laggy? Installing it on friday-saturday.
Also my turbo is .55 as i said, 57 trim, and the guy said it can support 550hp in my car. True? If so is it going to be laggy? Installing it on friday-saturday.
chosing the a/r ratio of a turbo is one of the most dificult choices when buying a turbo. bigger generally means more flow. so more topend and yes more laggy. that said, .55 sounds alittle on the smaller side for 500hp no?
If it's a .55 on a HUGE Wheel it isn't it's all relative and without knowing some of the dimensions you can't really say one way or another...... 
IJ's correct. I have seen a/r's of 1.00 and spool quite quickly because the wheel was a larger wheel.
I have also seen a .67 a/r take a supra in the 600 range.
Last, the exhaust housing a/r is more dependant on how much volume the turbo must accomodate. For example, if you have a very large diesel engine with large amounts of exhaust volume, you want a large housing. The exhaust housing controlls most of your spool time & lag.
The compressor housing is again, dependant on the engine its going on and the compressor wheel its mated with. Too large of a wheel in too small of housing will produce surge. Too small of a housing on too large of an engine will starve the engine of air.
I have also seen a .67 a/r take a supra in the 600 range.
Last, the exhaust housing a/r is more dependant on how much volume the turbo must accomodate. For example, if you have a very large diesel engine with large amounts of exhaust volume, you want a large housing. The exhaust housing controlls most of your spool time & lag.
The compressor housing is again, dependant on the engine its going on and the compressor wheel its mated with. Too large of a wheel in too small of housing will produce surge. Too small of a housing on too large of an engine will starve the engine of air.