2j twins on the 1j

[zSP3CTERz]

I did a search here and on SF and can not find any good information. So if anybody got a link post up please.

(1)anyway i was wondering what would it take to get the the 2j twins on the 1j
(please be specific). i have heard of people doing it before.

(2) Also what kind of performance gains would you get out of it.

Thanks in advance

 

[Jostar]

NOt worth doing it my friend, Save for a small single & you good.. It requires fabrication...
& it's a pita to be removing twins.....

 

[zSP3CTERz]

Yea just wondering...how hard it was

 

[Bigzavs]

Fastlane88 did them, so you could send him a PM about it

easier to do a single, but def sleeper status with 2J twins on a 1J

 

[87M-GTE]

Well, i know for sure the 2jz and 1jz manifold to head foot prints are different, not sure about manifold to turbo though.

 

[86_sports_1jz]

i would just go single turbo, less of a headache trying to fab up manifolds that will fit the 2jz twins and 1jz head. plus i think the gains are better in the long run

 

[pbasil1]

I would think the gains would be poor for all the time, money, and work involved. Slap a gt30 on the 1j and it will be just as responsive, and make as much power.

 

[pnutcar]

This has been covered lots already. My buddy Ryan has em on his car. Search SUPRARACER01 on here, SF, and youtube- he's got a writeup.

They're quick for the lil money he has in it.

 

[SupraRacer]

wow all the hate from a nuch of people who really have no idea what they are talking about...sorry for any hurt egos out there, but unless you have:

A) done this and seen the results

or

B) ridden in one of possibly three cars out there you have zero room to speak.

Stock 1j twins have been proven time and tiem again to support over 400whp, hell i did 395whp on the stock injectors FMIC and piping, untuned. The JDM 2j CT20's are MUCH larger turbos and can popout close to a 100whp more without breathing hard. 14lbs ont eh CT20's couldnt rival my Ct12a's on 18lbs, not to mention that the power doesnt fall off after 7200 like it did with the stock twins, they still come on under 3K rpm and even with cams power doesnt fall off at 8500rpm.. Thats over 5500rpm of powerband, what most people dont seem to realize is, its not the power you make, but the power under the curve, meaning its not what you peak out at, its how long you make a sustained amount of power, trust me 400whp from 4000-8500 will beat out a big singled car with 100whp more...ask me how i know

http://www.supraforums.com/forum/showthread.php?t=489665&highlight=ct20

there is the writeup, pics and testimonials. You can find the twins for $200shipped, and the modification to the exhaust housings was $280 custom Dp is ~$100. And for a setup that will do ~475-480whp with a usable powerband, explain how you can do a reliable single and make the same power for the same price....

 

[enjoi.this]

Thats over 5500rpm of powerband

If thats fact +1 on twins, very streetable and reliable.

 

[soapra]

I have done the 1jz twin to 2jz twins and it's not that easy. Oil feed lines dont fit. I had the spacer flange made along with the downpipe flange. The power is there, and it's a good bang for the buck upgrade.

 

[SupraRacer]

Oil lines bolted right up for me? And i just had a 3/8" spacer made to spread the twins apart some, used 2j oil feed gaskets(same as the ct26 btw) and although i had to bend the rear turbos drain toward the firewall a bit they dropped right in for me.. used the stock 1j lines. Cars been running again for about three weeks now.

 

[FIL]

I have put a set of Japanese (I think) 2JZ twins onto a 1JZ-GTE in a JZA70....

I'm currently in the process of converting it to a single, I swore while I was fitting up the 2JZ turbos that when I next removed the turbos, I would go single, it was that much of a pain...

The turbos I used were, I think, from an Aristo, they had been modified a little by Ray Hall from http://www.turbofast.com.au - last time I checked there were still photos of the turbos and details of the mods he'd done to them on his site under the history of his Lexus project.

Asides from the work Ray had done before I got the turbos, I had to make a spacer to go between one of the turbos exhaust housings and the Y pipe, and I had to port the 3 holes in the 1JZ half manifolds, as you cannot use the 2JZ half manifolds on the 1JZ head.

Oil feeds and returns are ok, I didn't have any major issues with that, I did have to re-route one of the heater lines as it foulled on the rear inlet housing... And your turbo outlet to intercooler plumbing will need to be re-done, you can force the stock 1JZ pipe on, but it'll get hard and brittle and roughly once a year... I ended up replacing it with an oversized 90 degree silicone bend, and using a couple of those T-bolt clamps to really tighten it down hard, it held up with over 1.5 bar of boost running through it...

Speaking of boost, don't expect the wastegates to be able to flow more than enough to keep max boost down to less than 17 psi, this setup was a heap of fun to drive, good response and plenty of boost on tap, but it just wasn't practical to work on the turbo side of the motor...

Perhaps your deal will be a little different though, as you won't have a brake booster and clutch master thrown in there to deal with as well... Not sure how cluttered that side of the bay is in a LHD A70...
My suggestion:

Before you decide to do this, remove the 1JZ stock turbos, with the engine in the engine bay. Then consider that what you are putting back in is going to be slightly longer and wider, and whether you really want that pain.

Removing the turbos this time, was even trickier than installing them, there's just no room to move...

 

[SupraRacer]

There is plenty of room to work on them even with the ABS there. I was even able to remove the rear turbo from the exhaust housing in about 20mins, by simply jacking the back of the transmission up until it hit the tunnel, gives you nearly and inch more room to work with it, You can get to most of the lower bolts with a 6" 1/2" extension and a swivel attachment, there are only 3 that you have to use a wrench, and figure about 10-15mins on each nut with the wrench. You basically did exactly what i did, i had a 3/8" spacer made to move the rear turbo back to line up with the rear manifold, i only had to modify one hole on each manifold by having a bolt thread welded and retapped about half a hole over. Other than that it bolted right in, you use the 2j coolant lines, and hardpipes, and the 1j oil return lines. I removed the sequential exhaust flapper and jsut mounted the o2 housing without it. Now i just need a custom downpipe made(im using a 7m dp and modifying it to fit) and i need hardpipes badly, car wont boost over 15psi, when i try to turn the boost up, it goes down...

So you say you ran 1.5bar through the aristo Ct20's? How long did they last? I have a set of blown 2j twins, and an extra aristo Ct20 ehxaust housings and y-pipe, i highly doubt it will fit, but im going to attempt to see if the ct12b's would bolt up the ct20 exhaust housings. There is a rumor that the wheels are the same size just the shafts are differant sizes. Only a few ways to test this out.