turbo question

[turbo4g63]

a friend of mine has a turbo that he purchased a while back but never installed.

it is a garret turbo, the exhaust side is enormous, i read the a/r was 1.10 on the exhaust side, and .60 on the compressor side, why is the exhaust side so massive. who would use this, and lastly if anyone is interested, he wants to sell it

[Driven]

Larger hot sides are usually used on larger displacement engines. That being said though, 1.10 doesn't tell us anything. You need to know the frame size for comparison. A T3 .83 could be smaller than a T4 .60. A/R is a ratio of area over radius... so the number itself doesn't tell you anything.

Figure out what brand turbo it is and get the model number off of it. There is probably a plate on the CHRA or the compressor backing plate with the part number. Then you can determine what the turbo really is.

BTW, I ran a 1.05 A/R T4 hot side on my DSM last year.

[Action Park]

93
A large hot side in comparison to the cold side is usually found on diesel trucks. Also, single turbo rotary engines usually run big turbines even though I think the mismatch is still too great(by the time a 1.1 ar hotside is needed, you're making more than a standard t4 comp wheel will support). Open exhaust will allow a larger turbine. Nitrous obviously will too in a race only application. People often think that turbo selection is only to be determined by engine size, ve, and revs, but there are other factors at play. The turbo on my car would be a horrible choice for, say, a Honda. In your friend's case, I'd say look for someone with a diesel truck to sell it to.
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