- Thread starter
- #51
Allen2g
Proven Member
- 91
- 3
- Jan 9, 2019
-
Winnipeg,
MB_Canada
Aha no big deal, im taking the build slowly. Gna run stock boost till i get a pump and raise it to around 15On a stock fuel system that's running well you can get away with 15psi safely. Just watch your AFRs in upper band when the flow demand is higher. A rewire could assist you depending on age of pump.
Looking at airflow ratings and depending on 16G (S/B/3), the 16G flows generally around 450ish CFM at 15psi, the 14B 405cfm, and the T25 even less than that.
The 16G moves more air mass than a T25 at any pressure due to the larger and more efficient compressor wheel. Due to the larger wheel, it's also able to provide this air mass at a lower temperature but, honestly, we're not talking 10C differences so we'll ignore temperature as we aren't overdriving either compressor.
In the end, more air mass translates to more HP but under your peak torque point we are arguing very small peanuts and not much different than a 14B. Butt dyno won't tell the difference and once you're in the upper half, though, the T25 being ~14psi stock will begin to fall off whereas the 14B or 16G will continue to cram air and still be underutilized.
My largest concern with a swap like this is by running a 16G the heavier rotating assembly will introduce more lag and worsen transient response from a T25. The 14B is a bit laggier than the T25, and the 16G is an itty bit moreso than the 14B.
So what that translates to is a potentially noticeable lul in your powerband when you start building positive pressure in your intake, especially at low rpm. I found the even heavier wheel on the B16G will start to really take off after the 5psi mark though, so a small should be a bit better than that.
Moreover, to run a 14B or 16G you'll have to swap to a DSM-flanged manifold and regardless of 2G, Evo3, FP, et al, this adds more lag due to decreased exhaust gas velocity vs. volume. Noticeable? Perhaps. You may have to watch boost creep as previously mentioned in the upper RPMs. I've never had a problem keeping any pressure on a 7cm^2, except battling falloff at a steady EBC duty cycle.
You'll see a change in the upper RPMs but when just tooling around town, I'd wager you'll be slower. However, it's not for too long, right? So go nuts. In the end, yes, you can do it. For your purposes, no, it won't really be an upgrade... yet. =D