Building RB20 into RB2.2

[R32 GT]

Hi guys, after getting my RB20 up to around the 350hp mark with relativley simple mods, it looks like it has cracked a ringland and is loosing compression on clylinder #1, and getting some major blow buy.. After only 116k! Needlees to say im a bit pissed off, but i put it down to major miss treatmeant before i brought it.

Anyway i managed to souce a mint RB20DET replacement for $300 that i will swap over with the current set up on the weekend.

Now i intend to rebuild the other motor into a 2.2, and want to know if anyone else here has undertaken this?

Basically over a year or so ill be slowly doing bits at a time. I have been looking into the use of toyota 4AGZE pistons(prepped) (taking bore out to around 82mm) and modifying head to suit. They are similar length to the RB20 ones.

I will be using a TO4 with t3 exhaust wheel, off a RB25 making around 500-500hp, externally gated. Obviuosly the head will be port/ polished and cammd..

Im aiming for around 280-300 rwkw (NZ dyno)

Any input would be great (esp on the use of GZE pistons) and anything else that will be required ie sump baffling and oil system etc..

Cheers

32GT

[Roy]

I think you will find that the 4AGZE pistons are 81mm, so wont quite get you to 2.2L. Perhaps ring around and see how much you can source some 82.5/83mm pistons for.

There are a few threads floating around on this.

[Minorci]

If price is no object, Tomei have a piston kit for an rb22 and rb24, although the rb24 requires you to use an rb26 crankshaft.

[rsx84]

HPI has just started an artical on building an rb24, that may be a help??

[Cubes]

I wouldn't bother with the RB20..

Grab your self a R32 RB25DE and bolt it in.

[Ahh32]

4AGZE pistons are 80.5mm (forged ones) $ same as RB20 ones

With the RB25 crank and rods and these pistons, will make a 2.2.

Only prob. Is with this setup the pistons will sit approx 1mm lower (from top of block) than the standard setup.

[G0DF4Th3R]

what mods for 350

hahah

[jnr32r]

other thing is sourcing 6 4AGZE pistons if you wanna go second hand, youll need 2 motors. If you gonna buy new, might aswell go for new 80.5 bore. So not much saving there.

[riceline]

if you need a RB25DE botom end or RB25DET botom end message me have one of each im wanting to sell

[R32 GT]

Thanks for the replys, i have a RB25 crank but i might look at getting custom forged pistons to suit and do it that way, i have seen that tomei kit but as always money is an object in the long run...

Joel, as you know from SDU i aint interested in a RB25, each to there own. Plus a 2.2 is somthing different.

[Cubes]

Yer I don't know from SDU as I havn't been there for quite some time.

Really it is pretty pointless doing up a RB20 when you can have no legal isses etc with the RB25. 2.2litres is going to be bugger all and at the end of the day if you are looking at making some serious power (over 250rwkw) then the RB20 is going ot be as laggy as hell. Not good for the street.

[R32 GT]

 

Yer I don't know from SDU as I havn't been there for quite some time.

 

Really it is pretty pointless doing up a RB20 when you can have no legal isses etc with the RB25. 2.2litres is going to be bugger all and at the end of the day if you are looking at making some serious power (over 250rwkw) then the RB20 is going ot be as laggy as hell. Not good for the street.

True i havent seen you on SDU for a while But then again after looking around here it makes SDU look pretty inferior as majority of these users are ex SDU lol

But anyway, i have reasearched the 2.2, and looked at the results they are getting in japan. and the 2.2 and 2.4 for the build cost is blowing everything else away. They turbo i have is designed for a 2litre and by 3900rpm will have some serious pull. I like how the RB20 goes and have found it cheap to get good power out of, have not met many other RB25 powerd vehicles that can beat it.. So ill stick with my RB20 Block and have a play. There is a guy here with a 300rwkw RB20DET on standard internals running low 11's with alot of traction issues, so they are definately able to do it - keep in mind this is not a daily driver.

[Sydneykid]

Hi R32 GT, RB26 standard crank and rods are the go, used with 82 mm pistons they give 2,335 cc's. :aroused:

The reason why you are beating many RB25's, is not that they are RB25's. It is because they are usually in R33 GTST's that weigh a lot more than a R32 GTST. Given equal car weight, a 300 rwkw RB25 will be faster than a 300 rwkw RB20 because the RB25 will have higher average power. Try a 300 rwkw RB31DET and you will get smashed. Max power is only one measure, and it is far from the "best" measure at that.

I have all the bits necessary to make an RB24DET, and I might get around to it one day. But the reason I haven't to date, is because it was cheaper and easier to get 300+ rwkw out of an RB31DET. And it has a shoot load higher average power than I could ever get out of an RB24DET.

But don't let anyone talk you out of it, if you really want to do it. You just need to be aware of the choices.

[Cubes]

Yer I'm ex-SDU.. I joined many years ago now.

But yer if its not a daily driver have a play the rev's will be nice to play with down at the track.

After seeing a RB20 head next to the RB25 head the valves on the rb20 look like little toy valves.

Convert the head to solids and get the thing reving.

[Roy]

No one loves the RB20 My brothers Bertram needs a new anchor, apparently thats all my Rb20 is good for

Joel, i agree with what you are sauyign to a certain extent, but have you been in an RB20 with 250-300rwkws... i dont think they are as laggy as you think... try 1.2bar by 4,800rpm which by GTR talk is when the average 2530 setup come on full boost....i cant argue about the characteristics of the power delivery though

RB20s rock !!!! Go the 82mm bore, run 8.8-9.0:1 compression and blow all those RB25 away

[Cubes]

I havn't been in a RB20 with 250-300rwkw.

I'm basing my experience on the how mine was when I slapped a larger turbo on it for a little while and found it to be slower where I need it to be quicker. It made 1bar around 4100rpm which unless I really reved the thing constantly it wouldn't go anywhere. Almost a little embarrasing as ppls would look over with that boy racer look at you.

I know of one bloke who made nearly 250rwkw on a RB20. That was on full boost (17-18psi I think it was) by around 5000rpm. I remember him telling me it was too laggy and generally had the on off feel which = lack of traction.

[Roy]

But wasnt your larger turbo a VG30? Im happy with how my car drives and performs, im wasting money on my current setup just so i KNOW what a well setup RB20 with 420hp turbo drives like.

Im also spending the money so i can sell the turbo complete with ECU, injectors, AFM, cooler, manifold/wastegate. Unfortunately you cant just throw a big turbo on the std manifold and make big power, but if you pay a bit off attention to all the bolt ons they go really well with more off boost power/performance...which is a good thing as you do have to wait that little bit longer for boost to chase the horizon!

Just trying to balance the books a little...not start an argument

[Cubes]

hehe yer it was a crappy vg30.

I've also since had a rb25 turbo on it which made it a little more laggy.

Really i don't like it any more laggy than it is with the rb20 stocker on it.

If I was aiming for around 400hp I would have stuck with the rb20 no doubt.

But always a but I got greedy and wanted more.

My other half is starting to harrase me how much I'm spending. lol..

Just had the car resprayed so that cost another few thousand dollars.

Then it will get defected and not allowed back on the road lol..

[meggala]

yes roy you have a good point if you use quality stuff you will get the results too many peopel put price first and suffer witha compromise I didnt this time and have no regrets plus as you say you have a nice package to sell when you off load the car.

go the 2.2 id sit down and think about it the tomei piston kit isnt that dear as they have spent the time developing the whole pakage. they have the compression right etc the guy I knew with one pull the motor down 2 years later and got great money for the pistons casue they were still in great nick. he was running an rx6 turbo the car was making 600 hp or so.

meggala

[Lithium]

I like how the RB20 goes and have found it cheap to get good power out of, have not met many other RB25 powerd vehicles that can beat it.. So ill stick with my RB20 Block and have a play. There is a guy here with a 300rwkw RB20DET on standard internals running low 11's with alot of traction issues, so they are definately able to do it - keep in mind this is not a daily driver.

I hear some whale defending necessary!

You have hardly any other RWD skylines around which can keep up with yours, and from memory the ones that have at all are 33s or 34s (ie, RB25 powered). From memory the only R33 you have raced at the drags beat you - and all the other 33s around here are virtually stock (at the moment), and all this is with the RB25 in the heavier body. Also, dyno figures wise - the R33s on average are way higher powered at CF than the R32s, yours with bigger turbo, S-AFC etc was in the middle of the cat-back exhaust and pod filter R33 brigade - so the RB25s are actually making more power too. An R33 with a road tuned S-AFC and bigger turbo would be in a whole different power/performance class.

The GTSt you mention was doing low 12s on slicks, and needed NOS because with the RB20 was unable to spool the turbo well enough for a decent launch - and has a built RB25 now.