putting rb25 turbo on rb20

[drift007]

hey just wondering if theres anything tricky about swapping the stock rb20 turbo for an rb25 turbo? is it just a unbolt the rb20 then bolt on the rb25 type of job? and are there any benefits in doing it?

cheers

[CEF11E]

you will get 15-20 rwkw difference with no tuning and you can up the boost to 16-17 psi without riskung ceramic in the cat. This combo with a good tune will get you 200rwkw. its a great upgrade.

[R32Big_boy]

I am in the middle of doing this right now. Today my friend managed to get the turbo off, and on. HOWEVER, the bend that bolts onto the compressor housing is different. I didnt get it when i bought the turbo which means finding one from the wrecker. But other than that its been a piece of pi55!

[Roy]

  CEF11E said:

you will get 15-20 rwkw difference with no tuning and you can up the boost to 16-17 psi without riskung ceramic in the cat. This combo with a good tune will get you 200rwkw.  its a great upgrade.

Will be interesting to see if it really makes 200rwkws. Thats pretty good power

[cameron]

  CEF11E said:

you will get 15-20 rwkw difference with no tuning

Yes

  CEF11E said:

and you can up the boost to 16-17 psi without riskung ceramic in the cat.

No, :uhh:

The stock RB25 turbo wont handel much over 14psi for long periods of time. Before you put the exhaust wheel into the cat. If that doesnt happen the turbo will over spin and you will lose power.

Best safe efficency for a RB25 stock turbo would be around 10 - 12psi

Other than that.

Its fairly simple job, Just have to re-seal gasekts - If their still good other wise if their broken get new ones. Dont loose the copper washers for your water lines - you need 2 washers on each line.

Jun

[Cillham]

what do i believe 16-17 or 10-12 because ive heard both figures from many people

[R32Big_boy]

10-12, the exhaust wheels are still ceramic, and still bonded to the compressor wheel. This means too much boost=a lot of heat=bond breaking down and sending the exhaust wheel out the back end of your exhaust!

[R32Big_boy]

Oh and does anyone else have the markings they can tell me on their turbo's? are they 45 V 4 just so i'm sure, coz i have to find the bend that comes off the compressor outlet from a wreckers and dont want to get something thats different. Help would be great thanks guys.

[Jolinator]

i was under the impression on an rb20 you could get away with running a little more boost due to the fact the turbo doesnt have to work as hard, filling only a 2ltr engine, and that you could run around 15psi kinda thing no problems ?

[CEF11E]

The ceramic delaminates due to the velocity at the point it meets the metal shaft.

example

the turbine produces 14psi at 100,000 rpm on the rb25, (lets call this point of stress)

then we devide 2500 by 5 20 get 2000 so we also devide 100,000 (shaft speed) by 5 fo get 80,000. So the shaft spins 20% slower to produce the same PSI.

So if you increase the shaft speed to 100,000 on the rb20 you will be spinning it at the same speed as the rb25 but producing around 15-17 PSI

See

These figures are used as an example and do not reflect the actual speeds of the shaft.

As the turbo has a larger compressor, It will produce more volume of air through the valves for a given PSI rating. (more airflow) at a lower temp because it is using less effort to generate the same volume.

In my experience you almost will not notice the difference in spool up time. plus the rb20 turbo drops off at around 6000rpm but the rb25 turb pulls hard all the way to redline!

:rave:

[CEF11E]

  Roy said:

Will be interesting to see if it really makes 200rwkws. Thats pretty good power

i will be getting it dyno'd over the next week roy so i will post resaults with graph as soon as its done

[Ronin]

I've had an rb25 turbo on my r32 for a fair while now. I run it at 14psi with no probs. makes 180-190rwkw depending on the day.

As sombody mentioned earlier the only differance when putting it on is that bendy pipe that bolts onto the compressor won't fit the new turbo. I had to cut and shut with another peice from an earlier series rb20 to make it fit.

You will notice the power delivery is alot different to the stock turbo aswell, a little laggier but much more pull up top. Really goes well once its wound up. :whip:

[joh21m]

how much do rb25 turbos go for? decent ones that is...

[predator]

$300 - $600..

i bought one for $320.. another for $500.. both are in excellent condition.

[sweetr33]

mine says V2 on the from cover i think and its a series 1 r33. V4 is a better one apparently.

[joh21m]

can u just swap the turbo over, or do u gotta have bigger injectors, fuel pump etc...

[sweetr33]

straight turbo swap, depending on the boost u run, i would recommend a fuel pump anyway, saves hassles. Walboro intank pumps are my choice for mild setups anyway, fitted one to a mates cefiro with rb25det in it. Had to chop the wires and use connectors but that was not big deal

[hako]

i just completed this swap last weekend, using a r34 gt-t turbo (nylon impeller, same as r33 s2 i think)

it came with the compressor outlet elbow so it was no biggy

findings are more power on less boost (2-3psi less) altho it is slightly laggier then i imagined, however this could be a tuning issue

top end is much better tho

[R31 POWER]

hako what banjos and oil/water lines did you use?

[USRB25S13]

What kinda boost would be safe on a Acura GSR motor. It's a 1.8L 4 cly that revs to 8,000 RPM's. 10:1 compression ratio. I would think 10-12 PSI should be safe.