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Madd Tyte JDM yo ®
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7,014 Posts
Discussion Starter #1
i was considering future possibilities for my 89.5 supra. at this point, i dont want to blow my wad on a JZ swap. im just wanting to build a 7M to put it back on the road and save for a full swap later on.

i was thinking i could do another 1j swap since itd be cake the 2nd time around. but of course, 1JZ parts are less common and usually more expensive than 2JZ parts. the things i was primarily concerned about was valve train components, induction and turbo system stuffs. i like the 7500rpm rev limit and OBD1 ecu. everyone always wants to do the 1.5J swap and get the 3.0 bottom end. i figured, what if i keep the 1j bottom end for the short stroke and then just put a 2J head on t. ill be able to use 2JZ cams and such, 2JZ manifolds and turbo kits, fuel rails, and all sorts of neat items. i wont need custom machine work or wait for shipping or anything like that.

i still consider an OBDII 2JZ aristo swap, since i can get a NEW toyota engine harness for ~$900, and my friend owe's me his stock ECU for essentally rewirng his entire engine wiring, piggy backs, nitrous and everything that makes the car go.

its kind of up in the air... i mean, the labor required for the swap is virtually the same, i can spend a the same and do a full 2JZ swap.

i dont know, what do you guys thing? reverse 1.5J or full Aristo 2JZ?
 

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GT40 1.5JZ
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1,210 Posts
Why not just put the 2JZ cams into your 1JZ head. Another thing, can you run the 1JZ harness on the 2JZ head? If you can, then what's the real difference between the two heads?

I say just go for the 2JZ all together. I'd rather have a 1.5JZ simply because of wiring issues. You've got the MAP sensored harness with the 3.0 liter block. Sounds good to me, what about you?

-joseph
 

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280 Posts
Doesnt the entire valvetrain interchange between the 1j and 2j? Aside from the cams that need a little work, but they still fit.
 

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Trev
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1,512 Posts
Personally, I think it is a great idea! You do get the whole 2j head (how much less does that flow than the 1jz anyways?) But that will allow you SO MANY more options later! Initially, you get the 2jz twins, but you will be able to use any 2j single kit later. Cams are present....I just can't think of anything wrong with the idea.

Trev
 

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Republican
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8,421 Posts
Thier is a reason people don't do this. I know some company tried it on thier race cars and they said the response was horrible. it was disscused awile ago... thats all i can remember...
 

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Madd Tyte JDM yo ®
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7,014 Posts
Discussion Starter #9
well, i like the revviness of the 1JZ. i know the consensus is that the 1jz head flows BETTER than the 2JZ head... but is better necessarily MORE???

cuz in the DSM world, the 4G63 head from the 2G's flows "Better" than the 1G head because its a smaller port design and the intake velocity is greater and builds more power everywhere under the curve. but the 1G head from the 4G63 flows "MORE" than the 2G heads due to larger intake ports. so they have greater volume of flow rather than improved velocity.

im starting to think that the 1JZ head may flow better due to smaller ports and improved intake velocity which yeilds greater cylinder filling it the midrange with great response for under the curve power development.

however, if i was able to get a 1JZ short block and a 2JZ head, i could have endless possibilities for aftermarket upgrades for cheaper prices. the aftermarket support for USDM/stateside 2JZ/mkiv upgrade components is far greater than that of the 1JZ. thats my main angle, not necessarily that i intend on making MORE power than a straight 1.5J conversion.

if i do a reverse 1.5J and use the 1JZ harness and ecu, id be slightly limited. granted, it IS map based, but there are limitations to the stock ecu, especally for upgrade ecu's. for the 2JZ, i can get a G-Force ecu, but for the same money, i could run an AEM EMS which COMES plug-n-play with base maps loaded... PLUS, matt scranton lived 45 minutes from me and can help me tune it.

but, then again, there is always the thought in the back of my head; if im going to go thru the whole hassle of a swap... why not opt for the extra cubes anyways? MKIV's and 2JZ's are more plentiful down here than many other parts of the country. one of the guy's at a local speed shop, XAT racing, is able to import Aristo motorsets for dirt cheap, like $1200. add a $900 harness, the 2JZ ecu i should have by now, $150 flywheel and $300 bellhousing, ive got almost everything i need. so many choices.
 

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Your Neighborhood Pikey
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3,341 Posts
If you had a 2JZGTE with a single, you COULD run it on a 1JZ harness. I say single since the 1JZ harness doesnt have the VSV connections for the turbos, but outside of that, it will run a 2JZGTE motor. Also, CKAnderson was correct. Apex-i experiemented with putting a 2JZ head on a 1JZ bottom end for their racing program. It was scrapped because the motor's response was deemed to be very poor. I cannot say anything more on that because the article i read was very brief on the matter and that's about all they said.

If you're looking for a cheap option, you could get a 2JZGE motor and run it on 7M electronics, and put a nice single on it. The 7M electronics will run a GE motor. That would be fairly cheap I would think.

I think the biggest expense in the 1JZ is the swap itself. I've found that nothing outside the swap is expensive. You must be a little more resourceful in finding parts, but I've found that maintenance parts are no more expensive than a 2JZ equipped car.

Turbo kits? I have a Boost Logic 67 kit for my car that cost me $3400 total for everything. This is a 700rwhp kit. You can source a new turbo kit for less if you wanted to.

The stuff is out there. Don't be afraid, you have the skills necessary bud, just look at the great bonuses of your 1JZ and dont look back.

- Hams.
 

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GT40 1.5JZ
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1,210 Posts
If all you're looking for is the rev-ability of the 1JZ block, just get a 2JZ with a rev limiter cut. AFAIK, the 2JZ block can rev to 7k easily, STOCK everything. It's a perferct square engine, but it can still rev. I think that it'll out-weigh the rev-ability of the 1JZ anyday. It has .5 liter more displacment and can still rev just about as high.

If you want to rev your engine any higher, get a honda. :bigthumb: Or a 600cc super sport bike (My 49-state R6 redlines and 15,500 stock)

-joseph
 

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Madd Tyte JDM yo ®
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Discussion Starter #12
yo chris, yea i know what you are saying. i guess if the motor is going to be doggy w/ the 2j head, i dont want to waste money and time tryng to find out for myself that it sucks...

i figure ill just do the 2J swap and opt for the extra cubes. BPU'ish would satisfy me for quite a while, especially if i convert to parallel twins.

$3400 is a shit load of money for me to spend on just a turbo kit. i refuse to buy pre-assembled kits when i know damn well that i can build my own manifolds, downpipes and everything else.. or peice together a setup slowly. i would if i had a nice job and was banking like crazy. however, im an average joe with a champagne taste on a beer budget. this is where my fabrication skills come in handy ;)

i know the maintenance items are no problem. thats not what i was worried about. i was just referring to upgrade items like manifolds and such. i want to try to run obdII 2JZ because of the improved timing maps and such. they can make much better power under the curve than the OBD1 MKIV's... and thats what im after; a nice all-around street car w/ good power from 2000-7000.
 

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Hate to bring this topic up again but did anyone actually do this swap yet? I have a 1J sitting in the shop that I am thjinking of doing this swap with. I am just going to take all everything from the head gasket up and put it on the 1J.
 

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anorexicpoodle said:
Big ports, small engine. Its not a good combination.

what about a 1g 6 bolt 4g63 dohc? It has huge ports...

As for 1jz parts hard to find? Crower gp for your valvetrain needs. I beileve there is a guy on this board making a killer 1jz single manifold. Intake manifolds are the only thing really lacking. What else is there? everything else is basically 2jz bolt on parts.
 

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airbats801 said:
what about a 1g 6 bolt 4g63 dohc? It has huge ports...

As for 1jz parts hard to find? Crower gp for your valvetrain needs. I beileve there is a guy on this board making a killer 1jz single manifold. Intake manifolds are the only thing really lacking. What else is there? everything else is basically 2jz bolt on parts.

Everything is relative to the displacement. The 1G 4G63 head was designed for a 2.0 motor. The 2JZ head is designed to fill 3 litres. Having only 2.5 litres (and signifigantly shorter stroke) drawing in the intake charge through MUCH larger ports (lower velocity) will result in less then ideal results.

And an interesting tidbit, yamaha designed the 1JZ head (as we all know) but the 2JZ head is a toyota design, take that for what its worth, not that one is better, but it could explain some of the fundamental differences.
 

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I dont know, they went to a smaller port head on the 420a, but I believe the 1g head is superior. I bet if you went with some 6 inch tapered runners on a 2jz head on a 1jz you would see some gains. The stock intake has a lot to do with velocity, and I bet the stock setup isnt that great. They usually arent.

And since we are using forced induction, I dont think the draw really matters? This is just what im trying to get, I dont know a whole lot, but this makes sense. The pressure is already in the manifold, so its coming through the runner and filling the void as the valve opens, so if you design your intake for velocity, the the larger ports should be benefitial?
 

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airbats801 said:
I dont know, they went to a smaller port head on the 420a, but I believe the 1g head is superior. I bet if you went with some 6 inch tapered runners on a 2jz head on a 1jz you would see some gains. The stock intake has a lot to do with velocity, and I bet the stock setup isnt that great. They usually arent.

And since we are using forced induction, I dont think the draw really matters? This is just what im trying to get, I dont know a whole lot, but this makes sense. The pressure is already in the manifold, so its coming through the runner and filling the void as the valve opens, so if you design your intake for velocity, the the larger ports should be benefitial?
velocity wont matter as much once under boost, but it means everything to building boost. so if you just want peak power, then why bother messing around with a 2.5 block anyway, and if you want response, youre barking up the wrong tree.
 

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I guess some people want to be different. Smiley has a regular 1j engine with no headwork and from what I hear is damn-near untouchable. I heard he raced a twin turbo Lengenfelter Corvette (don't know if I spelled that right), and didn't put car lengths on him but BUS LENGTHS!!!!!!!! :bigthumb: I think it all has to do with the setup. But let there be no doubt... the 1j CAN HOLD ITS OWN!
 

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fbody to supra to fbody
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jblaze said:
I guess some people want to be different. Smiley has a regular 1j engine with no headwork and from what I hear is damn-near untouchable. I heard he raced a twin turbo Lengenfelter Corvette (don't know if I spelled that right), and didn't put car lengths on him but BUS LENGTHS!!!!!!!! :bigthumb: I think it all has to do with the setup. But let there be no doubt... the 1j CAN HOLD ITS OWN!
Alright now that I would love to see. 427 twin turbo is no slouch by any stretch of the imagination.

-J
 
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