6 cylinder jap engine: RB26 or 2JZ for my CAPRI?

boXXer

boXXer

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6 cylinder jap engine: RB26 or 2JZ for my CAPRI? Edit: BMW M50 turbo?

Hi guys. So i currently have a CAPRI powered by a cosworth YB engine that shat itself a month and I'm not keen on rebuilding it as they aren't the most reliable of things. I don't really Know much about 6 cylinder jap engines, but I've Been looking at either the RB26 or 2JZ Engines as a alternative. So my questions are as follows:

1. Which is more reliable? (If at all)
2. Parts availability?
3. Tuning potential? I'm looking for 450hp single turbo
4. Gearbox options. Not too fussed about running standard boxes and would rather use a conversion that uses a BMW diesel gearbox or similar.
5. Ecu tuning? Aftermarket or factory

Anything else I need to know? bearing in mind my YB is gunna cost me approx 5k to rebuild properly.

Thanks in advance.
 
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RB isn't worth mentioning when the 2JZ is involved.

BMW diesel boxes are good and cope well but can be very short ratio (final drive dependant)
 
As above, if its an RB or a 1/2JZ, JZ every time. Strong and an ox.

Ive had lots of JZs over the years and never had a problem, recently bought an R32 GTR which is stock and that let got on just over 70k miles.
 
I haven't got much knowledge of those engines but I'd say 1/2jz purely for the sound :) that's what I plan for my capri at somepoint :)
 
There is so much evidence plastered around the net to show the 2jz is the better tuning engine especially where reliability is concerned, and a lot of people around the net too who have tuned both rb26 and 2jz will also say the same, ive even seen people admitting it on the skyline forums. However both are amazing and if your lucky enough to have either then that is awesome. Try this for a read: http://dustrunnersauto.com/rb26-vs-2jz/ and http://www.gtr.co.uk/forum/127087-rb26dett-v-2jzgte-skyline-v-supra-engine-whats-big-difference.html I have heard alot of people running BMW boxes also not really looked into it much though. :thumbs:
 
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1jz would be great option for you ideal if you only want 450bhp, very strong engine and capable of 550 on standard internals no problem. Best part of it is a 1j is less cost and if ever you did blow the bottom end a 1.5jz 2jz bottom end can be mated keeping your head and manifolds and turbo reducing costs.
 
Thanks everyone. So good info there. Over the last few days I've also been looking at turboing the BMW M50. Seems they will do 450 on a stock bottom end with a decomp headgasket and ARP bolts. Anyone shed any light on this?
 
I thought RB26 was more tailored towards higher revving than the 2JZ?

2JZ is unbelievable in terms of reliability though. Correct me if I'm wrong but the 2JZ block is cast iron and virtually unbreakable unless you seriously screw some stuff up...!
 
EddFD3S said:
I thought RB26 was more tailored towards higher revving than the 2JZ?

2JZ is unbelievable in terms of reliability though. Correct me if I'm wrong but the 2JZ block is cast iron and virtually unbreakable unless you seriously screw some stuff up...!
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RB26 blocks are cast iron too. Most alloy block motors will support a decent amount of power before they need sleeving though.

Both 26 and JZ have their strengths and weaknesses - the oil pump drive in RB's is a well documented weak point - most engine failures are down to this. It's not expensive to sort if you have the engine apart anyway.
If using an aftermarket ecu without air flow metres the itb setup makes tuning somewhat more complicated (in short, you don't get a clean pressure signal to the MAP sensor, using an alpha-n overlay table is one way tuners get around this).

The cambelt tensioner bracket is probably the JZ's biggest weakness, billet brackets are available from the states though.
The stock twin turbo setup is pretty limited by it's design, so any upgrade beyond US spec turbo's requires ditching the lot and is very costly.

A lot of half truths and outright bullshit gets stated whenever this discussion comes up. The biggest advantage a 2JZ has is it's extra capacity. (Though a 26 head on an rb30 block negates that).


If it's going into a nissan, the ease with which an rb of any sort bolts in/and suitable gearbox bolts on make it the way to go.

In anything else, if you are fabricating mounts, adapting a box, etc anyway, then 2JZ is the way to go.

Probably.
 
H05TYL said:
RB26 blocks are cast iron too. Most alloy block motors will support a decent amount of power before they need sleeving though.

Both 26 and JZ have their strengths and weaknesses - the oil pump drive in RB's is a well documented weak point - most engine failures are down to this. It's not expensive to sort if you have the engine apart anyway.
If using an aftermarket ecu without air flow metres the itb setup makes tuning somewhat more complicated (in short, you don't get a clean pressure signal to the MAP sensor, using an alpha-n overlay table is one way tuners get around this).

The cambelt tensioner bracket is probably the JZ's biggest weakness, billet brackets are available from the states though.
The stock twin turbo setup is pretty limited by it's design, so any upgrade beyond US spec turbo's requires ditching the lot and is very costly.

A lot of half truths and outright bullshit gets stated whenever this discussion comes up. The biggest advantage a 2JZ has is it's extra capacity. (Though a 26 head on an rb30 block negates that).


If it's going into a nissan, the ease with which an rb of any sort bolts in/and suitable gearbox bolts on make it the way to go.

In anything else, if you are fabricating mounts, adapting a box, etc anyway, then 2JZ is the way to go.

Probably.
Click to expand...

This, no 15yr old boosted engine is "unbreakable". Its that myth which fuels some of the awful quality of engine builds that you see so often. Considering the price difference and the sort of power you want, your best bet would be a 1JZ and a BMW box. You'll need a rear sump from a Soarer to get it in a Capri. Ford rear end ratios tend to be quite low (3.09 on the 2.8 axle, no idea if it'd take 450bhp tho) so suit the short geared BMW boxes nicely.
 
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