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caant deside what motor. rb25det or 1jz/2jz


sexy sam

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im a lexus guy i have a widebody sc400 and i have always liked the 1jz and 2jz. im getting an 87 300zx shell from a friend he had an rb20det in it so my first idea was to get an rb25det for it to make things a little easy. but now im really thinking about a turbo 1jz. can some one please tell me anything about a 1jz swap.

mods needed?

how easy is the 1jz swap?

any size problems?

any problems with cooling or inter cooler?

 

thanks

sam

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im a lexus guy i have a widebody sc400 and i have always liked the 1jz and 2jz. im getting an 87 300zx shell from a friend he had an rb20det in it so my first idea was to get an rb25det for it to make things a little easy. but now im really thinking about a turbo 1jz. can some one please tell me anything about a 1jz swap.

mods needed?

how easy is the 1jz swap?

any size problems?

any problems with cooling or inter cooler?

 

thanks

sam

I've always thought the 1JZ was a dumb idea for people in the US when the 2JZ is far more readily available, including parts for it.

 

I only know of one 2JZ in a Z31 that's been completed and that's streetfighter. He's on HybridZ but doesn't spend a lot of time here. PM him. I was with him in the early stages of swapping the VG30 out in favor of the 2JZ. The engine fits great but he made a removable radiator support to make install/uninstall of the engine/tranny easier. He started out with a SC300 auto tranny and has since moved to the R154. The engine is a stock SC300 engine with an intake manifold he built; I don't know if a stock over-the-valve-cover intake manifold would fit. He had a single T-67 in it for awhile, but he's got the Boost Logic compound twin turbo setup now. It is retarded.

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I've always thought the 1JZ was a dumb idea for people in the US when the 2JZ is far more readily available, including parts for it.

 

I only know of one 2JZ in a Z31 that's been completed and that's streetfighter. He's on HybridZ but doesn't spend a lot of time here. PM him. I was with him in the early stages of swapping the VG30 out in favor of the 2JZ. The engine fits great but he made a removable radiator support to make install/uninstall of the engine/tranny easier. He started out with a SC300 auto tranny and has since moved to the R154. The engine is a stock SC300 engine with an intake manifold he built; I don't know if a stock over-the-valve-cover intake manifold would fit. He had a single T-67 in it for awhile, but he's got the Boost Logic compound twin turbo setup now. It is retarded.

 

Alot of 1jz parts interchange with 2jz...any of the parts that don't interchange are the parts you prolly won't need...unless you are doing a full rebuild, then it doesn't matter if you have to wait a week to get parts...

 

Also, everyone i know with a 2jz, gets there parts online anyway cause it's cheaper....The 1jz is also cheaper than the rb25 and 2jz and can make 300whp with basic mods, stock turbos..

 

Of course I'm bias...:)

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im always on the lexus forums but i never pay any mind to the 1jz and 2jz stuff because i have a 1uz but i alway thought the 1jz was a non turbo 2jz with a little larger displacement. all the us sc300 have 1jz. the only reason i would get the 1jz is the price. there around 1100 when the 2jz is 4000+.

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im always on the lexus forums but i never pay any mind to the 1jz and 2jz stuff because i have a 1uz but i alway thought the 1jz was a non turbo 2jz with a little larger displacement. all the us sc300 have 1jz. the only reason i would get the 1jz is the price. there around 1100 when the 2jz is 4000+.
I apologize for being short, but you have a lot of bad information.

 

Okay, I'll write a bit more. 1JZ is a 2.5 liter and comes in turbo and non-turbo variants. 2JZ is the newer, bigger (3.0L) version of the 1JZ and also comes in non-turbo and turbo applications. I bought my 2JZGTE for $1500 shipped without the auto tranny I wouldn't be using anyway.

 

EDIT: Also, the 1JZ was never in the US market. You don't just have bad information, you have everything backwards.

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RB is much easier to install, sort of............:-)

 

You still have to purchase mounts and either run a skinny RB20 gearbox or start hacking up the transmission tunnel to fit the RB25 5spd!

 

Also, they only come in front sumps, which is a bit tedious but you can do things like keep all your stock gauges!

 

RB's aren't the easiest engines to keep cool either - I had a b$stard of a time keeping my RB30ET cool in traffic!

 

1JZGTE non-vti and N/A 2JZ's are cheap as and with JohnC's 2nd crossmember (Betamotorsport) the installation is fairly staightforward, or if you are handy with a welder you could fabricate your own mounts similar to Russjz-Zed,

 

You can get 1jz/2jz's in rear sump configurations and as far as I have heard they don't have cooling issues like you get with RB's!

 

Also, fuel and exhaust is on the opposite side on the 1jz/2jz than it is with the L-Series and RB Engines, which puts one more tick in the RB column!

 

But, for me there is enough pro's and con's to make the differences between these engines negliable - so in my mind I would go for best bang for buck option, and if you are just looking at these two engines you just can't beat the 2JZGTE for value!

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thanks alot this is really helping me. i didn't know i would have to hack the trans tunnel to fit the 25 trans. and thank you very much for clearing up my confusion about the 1jz

 

Sorry, that is really a half truth!

 

If you have a 240z you should be able to avoid hacking up the transmission tunnel, I think, if you have a 260z or 280z and place the engine sufficently far forward, once again you should be able to avoid hacking up the reinforcement within the transmission tunnel!

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I fit my 1jz into the Z with out trans tunnel mod and its right up against the firewall, 80% of the engine is behind the struts, I hear this is good for weight distribution. 1 or 2jz are nice it seems, cheaper. Im almost considering a 2jz-ge instead of my 1jz-gte for the sake of simplification and a bit of money in my pocket

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mounting the 1jz in my car was the easy part. All of the other little things that go along with it make it a complicated swap and very expensive if you do it the right way. No point in driving a car with a fast motor that can't handle the power. Thats why you need to address the brakes, chassis, suspension, ect.....

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I fit my 1jz into the Z with out trans tunnel mod and its right up against the firewall, 80% of the engine is behind the struts

 

Do you have a 240z?

 

I fitted a 2JZ N/A with W58 gearbox and from memory (was a few years ago now) I didn't have to hack into the transmission tunnel reinforcement, but I have to remove the mounting ears for the original gearbox crossmember, I mounted the engine about 10mm of the firewall, which I wish I hadn't done in retrospect - as I removed the original bonnet latch from the firewall and the shifter was really far back!

 

mounting the 1jz in my car was the easy part. All of the other little things that go along with it make it a complicated swap and very expensive if you do it the right way. No point in driving a car with a fast motor that can't handle the power. Thats why you need to address the brakes, chassis, suspension, ect.....

 

Yeah but your probably going to want to do that with either the RB or JZ engine!

 

i have a 87 300zx or a z31

 

Go the VG30DETT then :-)!

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  • 2 weeks later...

I am running a bone stock 2JZGTE+R154 in my 84 Z31. It is not as straightforward as you think but it has been done before. My engine was from a JZS147 Aristo, mated with JZA70 manual tranny, running auto wiring loom.

 

As far as I can remember, these are the issues that you need to consider before deciding on 2JZ. FYI, I have also run RB25 (in stock form and slightly modified condition running 50trim T3/T04E with stock unopened longblock)

 

1. As mentioned by tonycharger72, exhaust route is not the same as RB engines. Mine crosses from right to left right under the gearbox.

2. You need to get Supra oil sump. Aristo sumps don't work. Clears crossmember nicely.

3. Clutch master cylinder. If you still run twin turbo setup, you need to change to a slightly smaller clutch master cylinder. Same goes for the brake booster. (this applies to Right Hand Drive Vehicles. You lucky people!)

4. Tubings for hydraulic fan setup.

5. The digital tach and speedo won't work.

 

Other than that, it's normal engine transplant process of mating donor engine wiring loom to existing loom, mounting fabrication for engine and tranny crossmembers, mating gearbox's shaft to prop shaft, etc etc etc

 

Plus points:

1. R154 clears trans tunnel (barely though)

2. The torque of 2jz even in stock form, makes the transplant worth it. Far more superior compared to Rb25!

3. It fits!

4. Absolutely no temp problems, and i'm living in a country where its 95 degrees 24/7, all year round!

5. Did I mention the difference in torque?

 

If there are any questions, I will try my best to answer them. But I do apologise in advance for not being able to answer technical/detailed questions as I am not the one who did the engine transplant process. In my country, it is cheaper to pay the mechanic to install the engine instead of DIY.

 

Answering the original question, 2jz transplant is more tedious but its worth it!

 

Here's some pics to share

1. Right after completion of engine transplant, sent car for intercooler pipes and exhaust pipe works

d8f.jpg

3af.jpg

after all works done

216.jpg

 

p/s 2jz+R154 works best with 4.1 final drive ratio. Tried 4.3 but it's too "explosive" and the powerband ends too soon, while 3.6 makes the wait for 2nd turbo to spool up a bit too long but extremely effective for highway runs!

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  • 2 weeks later...

This something might make you go one route over the other simply because someone already made the complete retard's guide to dropping in a 1jz/2jz.

 

http://forums.hybridz.org/showthread.php?t=127163

 

Just thought that you might want to know what to do before you pick an engine....

 

and I would go with the 2JZ. just because I have seen those engine crank out anywhere from 500-800hp, but more important than that, they are usually able to maintain good torque ratings. 700+ horses are great, but if that same engine has only 550+ ft/lbs torque, it will be a high-strung, stressed, temperamental engine.

 

horsepower= work done over time

torque= ability to rotate an object (wheels, in this case)

just my 2 cents. :D

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