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What RB for my Z


Guest Anonymous

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Guest Anonymous

Hey guys

 

have been thinking about a Rb swap for my 240 Z but am still unsure of which Rb to go for.

 

I live in Australia so RB's are relatively cheap. I need to rebuild my original motor and gearbox anyway so a minimum Rb20 swap will still be quite economical. My question is what is the difference in performance between the 3 Rb options (driveability wise). Have been quoted the following prioces.

 

Rb20det approx 160kw $2,400 Au for front cut

Rb25det approx 190 kw $4,500 Au for front cut

Rb26dett approx 220kw $7,500 Au for motor & rb25 Box

 

Have been told that the easiest fit is the rb25. Is this true

 

Can you use the standard engine managment for the rb20 or 25 or do you have to go after market.

 

Anyway can someone give me some good reasons for why you would put an rb25 in instead of a rb 20 and why you should then put a rb26 in instaed of the rb25. I'm not interested in having a "rocket" just a good streetable drive that has plenty of go when required.

 

Whould be happy to just spend a few grand fore a rb20 but would be more than happy to spend more if the other rb motors are worth it.

 

Thanks for your advise.

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if you have the money rb26 is the way to go. the 2.0 and 2.5 can be made powerful but are not as reliable as the 2.6. If you want a peppy ride the 2.0 is good. but the sr20 is a lot lighter and about the same power. the 2.5 is also good and can make some serios power with bolt ons. ultimatley its up to ... all the motors need some fabrications to fit but are well worth the effort.

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Guest zline

I agree with stony, I can tell you a place to get you extremly cheap front cuts, but you must have a registered importer to accept the import for you -- i mean super super cheap.

 

 

btw, if you want to buy a GT-R or front cut send me a PM and i can get you a great deal on it...

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He is in aussie zline and talking in aussie $. Datto, Figure out how much power you want and work backwards. Dont forget the rb30 turbo that came in the c/dores. There are guys getting big power out off them and they are probably cheaper than any of the other options. I wouldnt bother with the rb20. If i was going to do a 2lt I would use a four as well. Probably a fj20. Cheep and mighty tunable.

 

Douglas

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Guest Zpeed

Hey

 

I've got some good experiance with relation to Rb20 and Rb25 engines in Z cars and also in there original skyline cars etc

 

In the Z the Rb20det is great when in boost, but when not in boost its basically sucks, the engine isn't that fantastic, the head cannot flow for good amounts, but is a cheap and good engine, If you plain on getting this engine, i would strongly recomend putting in a 3.9 or higher ratio diff, as then you'll have alot better boost control, but basically with the Rb20det if you want power you really have to downshift to get it so the turbo spools nice and good. but make sure you get the front cut off a R32 with a Rb20det and not a R31, as the R31 is not that great... smaller turbo and intake etc..

 

the Rb25det, is what id say is the best for the buck, what you've been qouted $4500, is way over priced, search around a bit more and try to get at least a front cut for $4000, this engine off boost is great, has good power off boost, but when boost hits its alot better than a rb20det, its got more power, and has a much better flowing head, and intake manifolds. again a higher ratio diff would be better, but not extremely needed, a 3.7 lsd would be fine for the application... also the R33 gearbox is alot stronger. with a bit of boost and custom cooler, and exhaust etc, on a stock computer you can get a good 210rwkw, and that in a 240z/260z is just fantastic..

 

and yes you can still use the original computer, i know a guy in NSW that is running a Rb25det with original computer in his 240z, and has been running the stock engine as he doesn't want to break anything, but he says its smooth and much better than his original L24 with carbies.. but to get the best power, make sure you get a full 3inch exhaust, a nice sized intercooler, and a CAI,

 

its up to you, id recomend a Rb25det, Rb26dett's are fantastic engines, if you don't mind spending the extra cash id go for a Rb26dett as i believe they are overpriced compared to a toyota equivalant,

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Guest Anonymous

Thanks for the advise Zpeed.

 

Family Friend (long lost uncle's mate) owns a jap car and parts import business in NSW so will be trying to get a good deal on either the rb25 or 26.

 

Looks like the 25 will be the way to go (unless I get a great deal) as I don't want anything too serious and it looks like it would be the easier (much cheaper) motor to drop in.

 

Thanks again

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Guest zline
or custom mounts that set the motor really low. then your oil pan is really exposed under the car

 

so go custom on that too !! =P

 

oh and stony i'll have a price for ya soon bro, its just my supplier is lagging

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Guest Anonymous

Zpeed, asked my bud who will do my staino 3" exhaust and intercooler but he did not know what a CAI was.

 

Please enlighten me.

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Guest 81na ZX
or custom mounts that set the motor really low. then your oil pan is really exposed under the car

 

so go custom on that too !! =P

 

DRY SUMP! :D aussie/kiwi skyliners advocate dry sumps for and big drag RBs ;)

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Guest sooley

Im selling an RB25DET bottom end if you want it to start the conversion. Its fine. Ive got the head off it and it seems in excellent condition. Ran fine when it was going. I only needed the head so you can have it for $700 if you want it.

 

Sooley :D

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