Quote:
Originally Posted by inopsey
a turbo can only flow so much air (compressor limited power number, ie 60 lbs/min) and max power (as limited by fuel), is limited by knock (and max timing) which is usually fuel dependent. therefore max power (torque) is determined by knock, and E85 allows for more timing (and therefore torque) than pump. a gt2871 is very close to making max power (power limited by max timing advance) on pump fuel.
i agree E85 will allow for more timing to be added (producing more power) than pump in most situations, but the increase with a gt2871 when using E85 compared to pump fuel is small compared to a bigger turbo, which will see a much larger increase in max timing advance (torque) when comparing pump and E85 fuels. this concept is know as minimum base timing (MBT) for best torque and is how you tune. this is also why if you tune using a proper dyno it doseent matter what gear you tune in, its a matter of hitting the right cells on the map and tuning those cells for MBT.
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Uh, the gains will be the same percentage as any other turbo. You don't need a big turbo to take advantage of E85's high octane and high latent heat of evaporation. Ever seen a T25 on E85? It'll make 250whp, which is up at least 30whp from pump gas. That is a significant amount, and it will be more on a 2871r. You can probably make 450+whp on a well done setup, and it won't need the laggy .83 housing to do it.