RB20DET or RB25DET Conversion Worth it?

[dougybe]

For non track purposes is a conversion worth the time/money/effort? For a 240/260z of course..

 

Just thought I would throw it out there for comment.

 

I'm a new guy by the way, in Brisbane.

 

Doug

[C.A.R.]

Welcome Doug.

You've really asked a too broad a question...

What sort of road driving are you intending to do? Commuting? Spirited road driving?

[RB30X]

And how much can you do yourself?

 

I'm lookin at doing an rb30/26 conversion but apart from custom engine/gearbox mounts, I hope to do most of it myself.

[sexual_sushi]

Hi Doug, welcome.

 

If you can do 95% of the work yourself I say go for it. If not you can have just as much fun with the L series and obviously won't have any hassles with engineering/roadworthy. It would probably also mean the car is off the road for less time and some "less dedicated" people doing the conversion get overwhelmed and give up half way through.

 

As Steve will probably mention, if you are doing it for fuel economy purposes the initial cost of the conversion outweighs any fuel savings in the future.

 

I would say research how to get the most out of your L series... electric dizzy, round top su carbs or fuel injection and head work etc and stick with that but that is just my opinion.

 

And finally check out what some of us Brisbane guys are up to (running Z not required)

http://www.viczcar.com/forum/index.php/topic,4266.0.html

http://www.viczcar.com/forum/index.php/topic,4205.0.html

[dougybe]

Thanks guys. I was not looking at doing the work myself, but considering purchasing a 240z with the conversion in place and running.  At the moment I have the option of getting a standard 240z with good body and L28 engine and no work required or a 240z with RB20DET, but with body work and interior work required...

 

Think I'll have to weigh up the pros and cons of each.

 

Thanks again.

[C.A.R.]

I'd be looking at the 240 with the L28.

Just my 2c...

[RB30X]

Excuse my dumbness as I am new too.

 

This L28 you rave about, this is the 2.8L injected (non-turbo?) engine found in the 280Z's is it, or is there a carbied version as well.

 

Is it worth spending any time and effort on the 2.4L or 2.6L engines??

[C.A.R.]

Rb30x, that is correct.

As they say there is no substitute for Cubic Inches. So the larger L28 is the one to use.

Unless your running to class rules or you want to keep the car original, that would be the main reasons for sticking with the L24/L26

[RBZ 260]

hmm ill bet my rb20det will give run for the cubic inches money of the L series. sure does to the mighty 6L HSV 

 

and than still return a respectable fuel economy if daily car.

 

though for originality i guess the L series will be better option. but im just not a big fan of carbies and non twin cam cross flow heads

my 1c worth.

 

 

[RB30X]

or is there a carbied version as well.

[zzzzed]

yep

[Mr240z]

rb30x.....L28 with triple 45dcoe weber's....Nice.

 

I run a L24 with triple 45's and love it...Building a strong L28 atm.

 

Got to love the sound of weber's in the morning....

 

                                        Pauly

[zedevan]

for the price of the conversion you could probably buy the car the engine was orginally from

 

:-\ but the zed is cooler

[dougybe]

With out a doubt buying a R32 or R33 would be cheaper than 240z conversion, but where is the fun in that. I love my Datsuns too much to sell out for a 90's Nissan. Would prefer the 90's tech in 70's style... Plus I've driven/am driving modern cars and they become so same same. Want character.

[Toecutter]

Just getting back to your question mate. Most people with 240's and 260's that run L28's simply pull out the injected L28 from a 280zx and run the early 240 SU carbs that have no emmissions gear on them. It's a common, reliable and cheap conversion for teh ealier cars, typically done with no fuss re enginnering certs etc. Just plonk it in and advise Vic roads fo the new engine number. You pick up a running L28 from $100 to $400 for an oldy. Of coarse you can also bolt on tipple carbs, run the old EFI, multiple throttle bodies with an aftermarket comp. Alot of options just depends on $ and what your expextations re as far as power goes!?

 

Sulio

[stevo_gj]

For non track purposes is a conversion worth the time/money/effort? For a 240/260z of course..

 

I would suggest for starters reading these threads:

 

Descriptions of the different traits of engines in Z cars:

http://www.viczcar.com/forum/index.php/topic,2557.0.html

 

Recently another new member asked about engine conversions and there's some helpful info in here:

http://www.viczcar.com/forum/index.php/topic,4202.0.html

 

Here is where I discuss the relative costs of conversion vs fuel efficiency when talking to another new member about possible conversions:

http://www.viczcar.com/forum/index.php/topic,3995.0.html

 

It's funny reading my posts from 9 months ago when I was new here 

 

I intend to convert my 75 260z to run an RB25DET in the next few years - after I've traveled a bit. You sound like you have the same thoughts as I do with regards to a modern powerplant combined with old school styles.

 

There are two ways of looking at it: If you restore an early Z and put an RB engine in, it will NEVER be worth as much as a car in the same condition with an L series engine. I guess you can't beat originality for most buyers. A good RB25Z can go for between 12-25K but an 'original' spec Z in the same conidition can go for a good several thousand dollars more.

 

You can also look at it like this:

 

How much is a modern sports car of the same cool factor as Zs? Put a new engine in a Z for around 10-12K (i'm doing very little of the work on my conversion) and you'll end up with it being a decent competitor speed wise, and one of the best looks wise.

 

Anyway, that's just how I look at it. Do some research and make up your own mind 

[(Locky)]

i would never put a rb20 in anything, even a silvia where its pretty much a drop in wire up conversion

 

stuff spending 6+g on putting one in

 

if your going to go the RB route, spend the lil extra and go the 25 much better engine

 

i myself, sticking to the L28 for now, but i would love to see put a SR in one 

thinking a NA+T so you have the higher compression so it comes on boost near instantly, plus it will be a lil cheaper. not going to get huge numbers, but 180rwkw with near instant boost in a 70's car is pleanty 

[sco_aus]

Ok, first things first. Look for one with an RB25DET, coilovers, Simmons, better brakes, 250rwkw, CV conversion, 2 way diff, great suspension setup, fresh respray and more, with just a few small things to finish it off.  Then get yourself $25k and give me a call. 

[jasonb]

hey mate hows it going, im currently doing an rb25det conversion, can be found in memebers project forum, awesome setup but if you wanna do it properly its definately gonna start adding up... i have spent about 28k so far on parts alone, without suspension, diff, rims n tyres, oh plus interior(seats, gauges ect) haha oh plus paint. yes its definately not cheap but with that i will have a pretty solid car! will end up around i spose the 40k mark... dam im stupid to spend that at 18 on an apprentice wage but hey live and learn

definately go rb25, dont even consider 20, waste of time imo... for the extra 1000 or so when you look at it 39000 or 40000... 1000 isnt that big of a deal and you will be thankful you have an extra half a litre

 

anyways im prob just goin on by now so all i say is best of luck hope you have a car your happy with which ever way you go

 

Jason

[gav240z]

It all depends on budget. RB20 is a cheap engine and if you do 90% of the work yourself and want to set a strict budget it might be worth doing.

 

Check out our featured car RBZ 260 built

http://www.viczcar.com/Featured-Rides/Johnny-Kostic-s-Datsun-260z-2+2.html

 

If I was building a 260z 2+2 on a budget and wanted a cheap power upgrade for low cost I'd consider a RB20.

[RBZ 260]

rb25det are bit like toyota engines slack! though with few changes they can be pretty damn good.

 

i chose the RB20 path first i got a realy good deal on it. second im using the car as daily so fuel economy comes into an account.

 

also aftermarket goodies can be added on to produce close to 230kw at the wheels

 

230 at the wheels in a Z is quite a handfull.

 

i got the streched heavier version and still it will clean up cars that have 4wd of the line and still have enough top end to compete against the big V8.

 

and still return around 10-11l per 100km.  i like to see that happen in a RB30 or even RB25. Sure u have more tourque to fry the tires but what the point.

[Scando]

I reckon the RB20's are a great engine.  There's a guy that won the class I race in three years in a row with a R32 with a second hand engine he bought for $400 with some bolt on goodies and good fuel to get around 230-240rwkw.  Other guys in the class are pushing close to 300rwkw out of them with more developed bottom ends and good fuel.  If anything goes wrong with them it's also very cheap to get replacement parts.  However an L28 is even cheaper again and is a very simple design so there are less things to go wrong.  This is well worth considering because mechanical repairs will also be part of your running costs.

 

For your application if you do go for an RB keep it as standard as possible.  It'll still have plenty of power in a Z and be more economical and reliable.

[24OZ]

the RB30 gets my vote for bang for buck

cheap to buy(even the whole VL/R31 for a more complete conversion)

plentiful....especially NA

plenty of torque

respond very well to a turbo kit, NA-T ,if you keep the boost sensible with very little lag

put a twin cam head on later if you want more power

lots of cheap secondhand performance gear and knowledge available on Calaisturbo forum