RB25 turbine into RB20 engine
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Do you have the specs of the RB 25 turbine? I think it is made by garett. But off-hand, I'd say...more lag since it should be a little bigger, but possibly more headroom for power. Of course, you would need to match fuel delivery with the increased air flow.
hmmm...im about to purchase the RB25 turbine...anyway, what fuel pump should i use?...and how much is the cost?...
my engine is RB20 stock im thinking to bolt on the RB25 turbine...so what should i do besides the fuel pump?..
my engine is RB20 stock im thinking to bolt on the RB25 turbine...so what should i do besides the fuel pump?..
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A couple of suggestions...
a) You have to determine if there is reallly any difference between the RB20 and RB 25 turbocharger. I've never seen them, so I can't say. If we assume that the differences are linear, with regards to the engine, then the RB 25 turbo would have a potential flow rate of 25% more than your current one. This means potentially 25% more air.
b) With 25% more air, the compressor wheel would have to be larger. This means more rotational inertia...slower wind-up, resulting in increased lag. You cannot avoid this unless you are willing to invest in an anti-lag system, which will halve the lifespan of your turbo.
c) Counter-balancing the slower wind-up, is a higher volume of forced air when it does wind-up...meaning higher turbo pressure potential and 25% more O2. This has to be balanced against a comparable increase in fuel. The best way would be to change the injectors to higher capacity ones (at least 25% more) and the MAF or MAP sensor to make sure that the metering of fuel is correct. Increasing your fuel pressure by about 10% will probably get you about 10% - 20% more fuel at WOT, but slight over-fuelling at idle or lower rpm's.
d) Modifying the fuel rail is optional i.e. boring it to be slightly bigger, or changing the flow to twin entry to balance the fuel flow across all the injectors.
e) To accomodate the increased fuel flow required, you will need to upgrade your fuel pump. Using an RB 25 or 26 fuel pump is an option. Or an aftermarket one like Walbro 255l racing fuel pump. A cheaper option...though not as flash...would be to put a Bosch fuel pump (something from a >3l Merc) in-line with the stock fuel pump. This is workable, but would be a tad noisy as the pump would sit under the car.
f) To take full advantage of the increased forced air flow (i.e. increase turbo pressure), it would be wise to invest in some basic strengthening of the engine. Some things to consider...
1. Slightly thicker metal head gasket to lower the compression ratio.
2. ARP head studs
3. Slightly cooler rated spark plugs (depending on what pressure you are aiming at)
g) Finally...you will need to cool the charged air a little more. Slightly larger intercooler, or, as they use in rally...fabricate an temp or rpm controlled spray bar across the intercooler to spray water into the intercooler fins when required.
Just some things you can consider...
a) You have to determine if there is reallly any difference between the RB20 and RB 25 turbocharger. I've never seen them, so I can't say. If we assume that the differences are linear, with regards to the engine, then the RB 25 turbo would have a potential flow rate of 25% more than your current one. This means potentially 25% more air.
b) With 25% more air, the compressor wheel would have to be larger. This means more rotational inertia...slower wind-up, resulting in increased lag. You cannot avoid this unless you are willing to invest in an anti-lag system, which will halve the lifespan of your turbo.
c) Counter-balancing the slower wind-up, is a higher volume of forced air when it does wind-up...meaning higher turbo pressure potential and 25% more O2. This has to be balanced against a comparable increase in fuel. The best way would be to change the injectors to higher capacity ones (at least 25% more) and the MAF or MAP sensor to make sure that the metering of fuel is correct. Increasing your fuel pressure by about 10% will probably get you about 10% - 20% more fuel at WOT, but slight over-fuelling at idle or lower rpm's.
d) Modifying the fuel rail is optional i.e. boring it to be slightly bigger, or changing the flow to twin entry to balance the fuel flow across all the injectors.
e) To accomodate the increased fuel flow required, you will need to upgrade your fuel pump. Using an RB 25 or 26 fuel pump is an option. Or an aftermarket one like Walbro 255l racing fuel pump. A cheaper option...though not as flash...would be to put a Bosch fuel pump (something from a >3l Merc) in-line with the stock fuel pump. This is workable, but would be a tad noisy as the pump would sit under the car.
f) To take full advantage of the increased forced air flow (i.e. increase turbo pressure), it would be wise to invest in some basic strengthening of the engine. Some things to consider...
1. Slightly thicker metal head gasket to lower the compression ratio.
2. ARP head studs
3. Slightly cooler rated spark plugs (depending on what pressure you are aiming at)
g) Finally...you will need to cool the charged air a little more. Slightly larger intercooler, or, as they use in rally...fabricate an temp or rpm controlled spray bar across the intercooler to spray water into the intercooler fins when required.
Just some things you can consider...
wow!!!!!...this is a SIFU!!!...SALUTE!!
thats hell a lot of things to look into...i have to plan 1st before changing..maybe later i'll put on the RB25 turbine...at the moment, i'll get a bigger IC, a bigger air filter and a metal gasket...gotta change a few things 1st to be on the safe side...hahhahaha...i dont want to blow up my engine and it will blow up my mind...hahahahha....
can u reccomend a workshop for me to do up my car?...i heard theres a workshop nearby kepong thats good in doing the skyline engines...or maybe you yourself has a workshop?...hahahahha...
thats hell a lot of things to look into...i have to plan 1st before changing..maybe later i'll put on the RB25 turbine...at the moment, i'll get a bigger IC, a bigger air filter and a metal gasket...gotta change a few things 1st to be on the safe side...hahhahaha...i dont want to blow up my engine and it will blow up my mind...hahahahha....
can u reccomend a workshop for me to do up my car?...i heard theres a workshop nearby kepong thats good in doing the skyline engines...or maybe you yourself has a workshop?...hahahahha...
mighui...he used to be turbo king aka Road Vacuum...
ic....okok...defcon1 said:Er...excuse me...if you must use my titles, please use them in FULL...
Turbo King aka Ultimate Road Vacuum aka Da Big Sucker aka The Fat Cat...
It's quite a mouthfull...so most people just call me "Oi!!"...
"Oi!!!"
RB20det with RB25det turbine is a good setup for beginners to play wth.
There are not much Cons, you have to modify the oil and water lines that go to the turbine but that is no biggie. Any mech can do that. Make sure the turbine comes with complete with the intake flange as the RB20 one is slightly smaller and wont fit properly.
There is a few different RB25 turbines, they are all marked 45V on the housing. Same as the RB20 they are also bush type and not ball bearing but they can take slightly more beating that the stock rb20 one (Max boost 1bar but dont run at 1bar for too long...it'll eventually die). If you are going to put one in, make sure that your fuelling is sorted else you may end up detonating the engine.
Easiest and cheapest things to do are change the fuel pump to either GTR (190 ltr/hr)or Z32 (210 ltr/hr), dont bother wth a RB25det pump as it is crap and is not sufficient. Both GTR and z32 pumps are plug and play...if you can afford it then there are many other options such as Bosch 044 or Walbro. You will also need install a AFC or SAFC to control the fuelling. You should also get an Air/Fuel ratio meter so that you can measure and tune the A/F. A Wide band one is the best but they are costly, you dont have to get a wide band but just know that it wont be as accurate... tuning wise you can still do it wth reasonable results. Essentially thats it, you should be good to go.. you can always add on more things as you move on.
I tried this setup before RB20DET wth RB25DET(Stagea turbine) with R32 GTR cams and i was quite happy with the setup. There is a never ending list of things you can do to increase your RB's potential so go slowly step by step and have fun doing it. Cheers!
There are not much Cons, you have to modify the oil and water lines that go to the turbine but that is no biggie. Any mech can do that. Make sure the turbine comes with complete with the intake flange as the RB20 one is slightly smaller and wont fit properly.
There is a few different RB25 turbines, they are all marked 45V on the housing. Same as the RB20 they are also bush type and not ball bearing but they can take slightly more beating that the stock rb20 one (Max boost 1bar but dont run at 1bar for too long...it'll eventually die). If you are going to put one in, make sure that your fuelling is sorted else you may end up detonating the engine.
Easiest and cheapest things to do are change the fuel pump to either GTR (190 ltr/hr)or Z32 (210 ltr/hr), dont bother wth a RB25det pump as it is crap and is not sufficient. Both GTR and z32 pumps are plug and play...if you can afford it then there are many other options such as Bosch 044 or Walbro. You will also need install a AFC or SAFC to control the fuelling. You should also get an Air/Fuel ratio meter so that you can measure and tune the A/F. A Wide band one is the best but they are costly, you dont have to get a wide band but just know that it wont be as accurate... tuning wise you can still do it wth reasonable results. Essentially thats it, you should be good to go.. you can always add on more things as you move on.
I tried this setup before RB20DET wth RB25DET(Stagea turbine) with R32 GTR cams and i was quite happy with the setup. There is a never ending list of things you can do to increase your RB's potential so go slowly step by step and have fun doing it. Cheers!
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