Skyline Rb25 Efficiency

[tridentt150v]

I just read the tutorial on selecting a turbo. You have to know your vehicles efficiency. How do you calculate this???

[R31Nismoid]

What tutorial?

[Rolls]

Its in the DIY section, I think they provide some rough estimates in that guide. Try googling.

[Abo Bob]

And Sydneykid says:

My rule of thumb for volumetric efficiency on a DOHC 4 valve engine is 90 to 95% depending on what's done. A fresh engine with cams and porting etc is closer to 95%, compared to an old engine with stan'd cams and cast ports that would be closer to 90%. Simple

[tridentt150v]

Thanks, I thought that, but its nice to get confirmation. I sent 'nuffin wurks' a PM on it but recieved no reply, so asked here.

[tridentt150v]

What tutorial?

Here:

http://www.skylinesaustralia.com/forums/in...showtopic=59279

[BAMR33]

Why not just see what other people have been successful with and use that as a guide. There are that many different factors effecting the effeciency and output of a turbo it would be very hard for anyone without a good knowlege to calculate this.

[tridentt150v]

The trouble is there are just way too many ways to skin this cat!!!

Between intake, compressor, turbine, exhaust, cams etc etc you really have to figure some things out for your particular set up.

Granted though, you look at what other people are using and this gives you something to go on.

[Abo Bob]

There's nothing wrong with understanding why rather than just picking something that empirically appears to work.