I bought a turbo that was said to have a .98 AR on the EXT side and it came with a spare divided 1.15 housing. By the 1.15 is that the AR or soemthing else. The !.15 divided housing is a bit larger aswell. With that do you think i should run the .98 undivided or the divided 1.15 for a weekend warrior and at times my date-moblie?

Thanks
~Luke

 

uh... it the only way we know. Which size depends on the car, port, blah blah.

 

Oh alright, i though the AR had to do with the way the blades on the wheels were set up. With the car it is a FD with street port and enough mods to support either .98 AR or 1.15 AR.

Thanks
~Luke

 

the best i know, the a/r has to do with the amount of exhaust gasses that hit the blades. Larger A/R more gas slower spool better top, smaller a/r less gas quicker spool slower top. I believe the trim has to do with the blade angle, but what do i know

Chris

 

YES, you can use either as long as there both bored for the same trim turbin (most likely the same sinse it was a "spare"). If you go with the 1.15 A/R housing it will spool the same or ever so slightly slower then the .96 IF you run a divided manifold with it. Your top end will also be superior using the 1.15 as opposed to the .96. So go with the 1.15 and its a win win situation except you must got with a fully divided manifold to take advantage of the benefits which will cost more then a undivided.

A/R is area / radius ratio of a housing..... just think of it as a water hose.... smaller A/R tighter the nozzle is squezzed or your thumb over the end, allow less water to flow but it comes out faster (quicker spool but limited flow) and larger a/r being the hose is wide open (flows well but water comes out slower.

By the way, .98 A/R is a little odd, I'm not recalling nor finding any Garratt housings in that size, sure its not a .96???

Furthermore.... turbine trim has nothing to do with A/R... turbines in the Garratt family for the T4 family are N, O, and P trims... theres also a Q trim.... Hopefully you have a P-trim... anything else wont work welll with a rotary except the Q-trim which is usually reserved for ultra high horse power application and will result in excessive lag on a street car (some people tolerate it). The P-trim wheel uses a 2.544" minor diameter and 2.922" major wheel diameters.

Hope this helps,

~Mike..............