Same Boost, Different Turbo, More Power?

[WrenchesInTheGears]

sorry if this is abit of a noob questioni guys

ive been reading up abit on power modifications, bolt on mods mainly not keen on cracking open the engine. ( r32 gtst rb20)

just wondering, everyone is saying get a different turbo, i think mine has a vg30, but alot of people are saying get a hks 2530, and all different things.

there is this but im just wondering.

what is the difference between running a rb20 stock turbo, a vg30 turbo or a hks 2530 turbo all running the same boost pressure, 12psi for example. apart from the obvious spool time

will the hks produce more power/torque with the same boost? if yes why?

also if you had a grand to spend on an rb20 to make a fair bit more power without running too much boost and keeping standard engine managment what mods would you do? it already has a front mount, pod, free flowing exhuast, bosch fuel pump.

cheers

Alex,

[NYTSKY]

Searched?

http://www.skylinesaustralia.com/forums/RB...ipe-t54854.html

http://www.skylinesaustralia.com/forums/Rb...su-t115398.html

http://www.skylinesaustralia.com/forums/GT...Que-t34332.html

A grand wont get you much. If you bolt on another turbo you will need a tune. So there is an ECU to consider.

[WrenchesInTheGears]

none of those threads really explain what makes a better turbo make more power with the same boost?

[R31Nismoid]

Airflow - simple as that.

A turbo just flows air. Bigger turbo's, flow more air. More air = more power.

So thats the basic part.

However there is a consideration and that is the efficiency of the turbo. Larger turbos generally require you to run more pressure to get into the efficient area of the turbo so that you see the benefit of using them.

EG a HKS2530 you wouldn't put on and run 12psi. It'll probably make 170rwkw. They shine closer to 16-20psi and will make around 230rwkw.

So running the same boost one turbo from another, sometimes, won't give you much power if at all. You need to run the turbo where it is efficient to make the most of it.

VG30 turbo's seem to not be useful past about 16psi, and RB20 turbos about 10-14psi.

www.hotstuffworks.com or use google. Plenty of websites around that will go into much further details.

[WrenchesInTheGears]

cheers, makes sense i guess.

i was thinking of upping boost to 14psi, atm it runs about 10-11 according to the cheap boost guage.

if i did this would it be safe, or should i up fuel pressure aswell?

[R31Nismoid]

No point running anything other than a factory turbo without a Tune/ECU.

[WrenchesInTheGears]

fair enough, so no gains can be had from under the bonnet tuneing, eg boost, fuel pressure, ignition timeing?

would a power fc be a worthy investment? how easy are these to play around with for a DIYer

[paulr33]

pressure does not equal volume

thats why one turbo makes more power

think of a car tyre at 40psi

then think of a bike tyre at 40psi

then think of a truck tyre at 40psi

now its obvious to us that the truck tyre has more air volume inside it, ie more air, but the same pressure

so its possible for a compressor wheel whilst it has the same pressure in the pipe work / engine, that it flows more air

the more air the engine has, the more power it makes

[paulr33]

read the PFC FAQ in my signature for info the on the PFC and how to use it

the PFC is amazing to tune on any car, even a stock mild GTST , the results are amazing once fully tuned

my car still has basic mods intercooler, exhaust, clutch, tyres, fuel pump, boost controll and aggressive PFC tune, it drives amazingly