Toyspeed.org.nz Message Board

by **BL8KK9T** » Tue Oct 25, 2005 8:33 pm

am new to the whole JZ engine businesss,,,,,

so am just woundering what are the advantages of having a 2jz block with 1jz head?

by **Adamal** » Tue Oct 25, 2005 8:52 pm

I have been told that the 1J head flows better than the 2J head.

by **wde_bdy** » Tue Oct 25, 2005 8:54 pm

Its not all its cracked up to be. Became popular in Japan as a brand new 2JZ shortblock was cheaper than rebuilding a 1JZ. Now its a "JDM" mod so its cool, if you want a 2JZ just get one rather than mixing and matching.

Callum

Toyspeed Profile - MrOizo · by **MrOizo** » Tue Oct 25, 2005 9:34 pm

i have heard that the 1JZ hgead flows better but there is no data to support this ... oh wells...

by **Silent Knight** » Tue Oct 25, 2005 9:47 pm

MrOizo wrote:i have heard that the 1JZ hgead flows better but there is no data to support this ... oh wells...

There is bound to be some data somewhere...

I mean why would people bother doing a 1.5JZ if there is no actual gain. If you look what a stock 1JZ and 2JZ does in comparison to a stock 1.5JZ you will definately see a difference.

I don't have any data on me at the moment that will support this but the guys in America will definately have somewhere if you look on the Supra Forums and I think Lextreme also has some info on it...

by **99gtt** » Tue Oct 25, 2005 10:30 pm

The reason people do a 1jz head is because a 2jz is exspensive ,not because it flows more . Contact Full throttle nz he has done extensive flow bench work on both and found the 2jz better. Nyle buckleys reason for the 1jz head ( price)It is hard to come by the 2Jz head ,dont believe me ,then try and find a 2jz head to prove me wrong.

by **edwagon** » Tue Oct 25, 2005 10:36 pm

It is my understanding that it is mainly a cost thing, apparantly the 1jz head flows slightly better than the 2jz head when they're both ported to hell because of a water jacket or something in the way on the 2jz.
As a standard item tho I don't think theres much difference.

Website · by Si » Tue Oct 25, 2005 10:59 pm

there are alot of myths.

some say 1jz flows better. some say 2jzgte flows better than the 1j but not as good as the 2jzge.
some say the 1j is a better head to port&polish.

look at my situation, i have a 170,000km old 1j. solution to freshen it is to by a 2j na block and use that.

however a 2jz with 1jz head and stock single turbs, mashes the firewall on a jza70. so you need to go single turbo anyway, so theres no point in going straight to a 1.5jz as a "first" mod

by **the fallen303** » Wed Oct 26, 2005 10:07 am

will let you know in a month or so when my 1.5 replaces the 1jz in the car atm. only thing we will be changing at that time, so will be able to get dyno results of differences. will also be doing this with a 2jz-gte in the next year or two into my fathers new project mk4 race car, so see differences there as well. rumors from japan say a gain of about 100hp, and a friend that has done this engine saw an increase of 400nm. this is over the 1jz. not sure about differences between doing it to a 1jz or a 2jz. be interesting to see starting with the 2jz and putting on the 1j head.

by **Mr Revhead** » Wed Oct 26, 2005 6:27 pm

i know there is a HUGE gain to be had in the 2jz with some porting.

by **Gadget** » Wed Oct 26, 2005 6:46 pm

the fallen303 wrote:will let you know in a month or so when my 1.5 replaces the 1jz in the car atm.

Well crikey, you'll notice a huuuuge difference. Seeing as though a 1.5JZ is basically a 2J bottom end, you'll have all that wonderful torque of a 2J

Oizo's std 1J made 165rwkw, and my stock 2J made 214rwkw... 50rwkw should make for a decent kick in the pants in anyones language... As for the 1.5J comparet to the 2J... I too have heard that the 1J head is meant to flow better, but it's not a mod you seem to see done to JZA80's, so I wonder how much truth there is there.... maybe it's just 'the thing' to do to your *A70...

by **Silent Knight** » Wed Oct 26, 2005 6:48 pm

Didn't your Supra have a Mines ECU and zorst etc done to it though?

by **Gadget** » Wed Oct 26, 2005 6:59 pm

Silent Knight wrote:Didn't your Supra have a Mines ECU and zorst etc done to it though?

Nah, that 214rwkw was stock, I've done the ECU and 'zaust since...

by **99gtt** » Wed Oct 26, 2005 10:05 pm

This trend started by people using the NA block ,doing a turbo conversion and finding the price of a 2jz turbo head was not worth the money when you could buy the 1j for alot less and spend the saved money on porting and polishing etc. Instead of changing the vvti head on a NA 2j why not use it ,exspecially if you are spending money on doing head work anyway.

by **the fallen303** » Thu Oct 27, 2005 10:45 am

we've seen 240rwkw from the 1jz so far, still stock fuel, turbo's, ecu. just exhaust work and filters, still stock front mount for now.

as far as i know, the 1.5 is similar in theory to the likes of putting a 245 head from a hemi onto a 265 (from what my mates told me).

by **CozmoNz** » Thu Oct 27, 2005 11:17 am

the fallen303 wrote:rumors from japan say a gain of about 100hp, and a friend that has done this engine saw an increase of 400nm.

Duhhh.... before or after the gear ratios

by **Gadget** » Thu Oct 27, 2005 11:24 am

the fallen303 wrote:we've seen 240rwkw from the 1jz so far

That must be a significant boost increase!

by **the fallen303** » Thu Oct 27, 2005 5:09 pm

1.1 bar

by **strx7** » Fri Oct 28, 2005 10:32 pm

anyone know why there is the port shape difference between the 2JZGTE and the 2JZGE heads?

I'm just interested to know. I have a rebuilt 2JZGE in a LN130, goes very well as one would expect, 3 inch exhuast, haltech E6X, K & N etc. Once its run in I'll think about turbo'ing it.

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