With such a large variation in reported dyno results I didn't think it would be possible to draw any firm conclusions (such as an equation) about how much power can be had with the FDs twin turbos. Nevertheless, I gave it a shot and collected posted dyno results from the forum. Suprisingly, the results are rather consistent as can be seen in the attached graph. The model could be made better by considering what mods are being used. Since most of the data points follow the model quite well, it could be concluded that most people upgrade their cars in a similar manner. Anybody care to validate the model by running their twins at 20psi

Given this data, power can be approximated as:
PeakPower = 114.7 + 15.7 x Boost(PSI) Horsepower

For this data set:
average error = 7.7%
standard deviation = 42 hp

Outliers:
- GoodFellaFD3S consistently makes more power than average for a given boost level. Good tuning!
- 10psi had a lot of variation. Some of the samples here were using stock or very rich tuning.

 

Not just good tuning. The BNR Stage 3s are a full 20% bigger than stock on both compressor and turbine side. Interesting stuff to see, thanks for doing the leg work .

 

There is a reason for taking Math 100 in college! Suddenly I don't feel like I wasted my time so much.

 

while this formula seems to give reasonable results the trouble is that about 1/3 is fixed as a constant, whereas each of our cars have variables here .. a key 2nd parameter to include in the equation is fuel rate or (injector size x duty cycle). One standard deviation of 42 Hp is very very large. basicly saying i have 320 Hp plus or minus 84 Hp (2 deviations)

 

why would you say plus or minus 2 SD?

 

The standard deviation as I have presented it doesn't lessen the value of the model. It only says that the modeled power is widely distributed. This is not surprising since the data has a large range of boost pressures. Since power is apparently linearly related to boost, the power neccesarily has a large deviation. The large standard deviation indicates that you shouldn't try to use an average value to represent this data set. For the model, it is more important to look at the error. BTW, a perfect model would have had a standard deviation of 52hp.

 

Many many factors affect horsepower on a dyno. Your graph means nothing to include GoodFellas if you are only talking about factory twins. It does show that the BNR's are doing what they are supposed on the comparison. You need to take into account that the stock twins run-nonsequential make a bit more than a sequential car at identical set-ups. Running 20 psi will make around 400 as seen before. They wont take very many pulls at that level.

 

man goodfella i envy u, i wish i could get thos BNR TWINS.. because im never going singel

 

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You could just use absolute manifold pressure.

If you aren't separating upgraded compressor & turbine sets it's a bit meaningless, as the full fat compressor/turbine upgrades have significantly more flow.