JZA70 Supra 1JZ VVTi vs non-VVTi - Swap

[mikeBrotherd]

Looking at swapping my gen2 1jz non-vvt for the latest gen3 1jz vvt. I like the idea of having more torque down lower in the rpm range to help move the heavy body and at the same time being 10% more fuel efficient. The price of these motors is also coming down so it would make sense to make the swap....rite?

My question is, would this mechanically be an easy swap into my jza70 using bits from the current motor?

My concern is, i haven't found many of these motors making much more then 300hp with reasonable mods, 3"exhaust, intake, front mount intercooler. I did notice that they did make a considerable amount more torque though.

Would like some answers and opinions on this idea...

[mikeBrotherd]

appearance wise they are a much nicer looking unit for me

[sergei]

Mechanically it should not be too difficult (I am not sure if you will have to get different sump for that).
Electrically there will be a lot of mucking around. Looms are very different and there will be a lot of plug swapping.

[mikeBrotherd]

not too worried about the electrical side as im an auto sparky. Its the mechanical i want to get rite, im hoping to use the sump from my 1j in my car at the moment.

[FLAWLES]

motors will swap over with zero issues as the are technicaly the same block

keeping in mind they are different in the elec side of things vvti = afm and the ct15b is rather weak and hates anything over 1bar and teh oem bov hates boost

just swap sumps over and enjoy teh vvti

and trust me mike you will enjoy the vvti 1jz

[FLAWLES]

edit

you may want to flick doctrd a pm as if i remember correctly he put a vvti 1jz in a x90 and ran into some issues of some sort, think it may have been elec related, cant fully remember as it was last yr sometime

i do have pin outs and what not on the vvti 1jzgte if needed

[mikeBrotherd]

Mint, thanks for that. Don't you have a vvti 1j in your Chaser? What are your impressions of the vvti 1j if you do?

Thanks, wiring diagrams will become my new bible when it comes to that stage, also at which point ill come knocking on your door for that offer.

I had another look at modified vvti's and it appears that they make more torque rather then power when you boost em up. For my A70 that wouldn't be such a bad thing. And the factory turbo was clearly built for response when you see the little gain from raising boost to about the 18psi mark.

[FLAWLES]

copy that i do indeed vvti 1jzgte

cant really comment on whats better or whats not as i havnt owned a 1st gen 1jzgte and the only one i have been for a ride in was johnos jza70

but if i where to comment i would say its a fast improvemnt over the old ones

torque is deffently good, ( it scared the fallen when he drove it last ) low down, vvti helps alot in that respect

have to remember in nz there is sweet fuuuu all aftermarket items for these vvti engines, a few are making manifolds and dump pipes but thats about it, everything else is ex jay pan, still tho great engine

[the fallen303]

yeah that was fun, have to swap ya one day jarred, supra for chaser, and see how we do

as for the engine. the delivery was definitely different to mine, not more power, just lower down, and smoother. wether it's worth the swap, i'm on the fence. if was putting later engine into a shell, or something else, then sure, but i don't know if there is enough of a step up from the nonvvti to the vvti engine.

probably just spend the money from the conversion on single/ecu/fuel, and would end up with similar low end torque you were after, with not more up top *shrugs*

just my 2c

[FLAWLES]

Have to agree really with johno

its alot of money to though at it......did i meantion that the elec are very very tempermental with the trc/abs/vvti

cause if i didnt.............they are

but go with what you think is spot on and let me know if you need those pin outs as i will have to dig them out

[sponsormycrown]

mechanically it would be a piece of piss although the dump pipe will be different obviously as the vvti is single turbo. but yea shouldnt be too much of a mission if youre an auto sparky electrically.

[mikeBrotherd]

probably just spend the money from the conversion on single/ecu/fuel, and would end up with similar low end torque you were after, with not more up top *shrugs*

Thats the thing, if i can sell my low kms 1jz for lets say 1k, you can pick up the vvti 1jz for 2k or there abouts, so its really only costing me 1k (My time not accounted for obviously, but hey its a hobby).

In saying that, looking on TM, i have found 2jz's for as little as 2.5k and the produce some nice low down torque too....who wants to be the black sheep anyway

[Py7h0n]

Don't waste your time with VVTI - Not worth the pain.

Swapping for a 2JZ bottom end would make a world of difference though!

[mikeBrotherd]

Im kinda leaning that way now, tried to find good responsive turbos for the 1jz and its a delicate mix of lag and upper rev limit power.

2jz's can command the bigger turbo's and will have the bottom end torque that im after.

[Rookie]

All JZ's have shit flowing heads, but the VVTi ones are by far the worst, and the non VVTi 2jz are the best for making power stock. To get them to really pull big numbers you need extensive porting with oversize valves. if you are interested have a look here you may need a logon but its worth it.

[FLAWLES]

what do you base vvti heads are the worst at flow capabilities?

i would like to here your reasons?

[Rookie]

Because they have been back to back tested against non VVTi heads and have flowed worse?!?....

[sergei]

I don't think that how much can head flow on bench is completely related to how much head flows in real life.

What all these bench flow tests are missing is the dynamics of the flow.

Correct me if I am wrong here:
The problem is that they flow in a single uninterrupted stream. In reality because of the interruption from valves the dynamics of the whole system becomes very complicated:
certain restrictions that have been in uninterrupted stream could be very beneficial in interrupted stream.

I think of engine as musical instrument as first, and only second as air pump.

I think it is a bit of arrogant (no offence) for a guy with a flow bench to say he knows better than yamaha/toyota that spend millions in research and development. Although I must admit they haven't designed the head for 600+Hp but that is another story.

[Rookie]

Yes Sergei you are wrong, flow bench testing is very representitve of what goes on in real life, if you do it correctly. And Yes I would say that TK can make a head flow miles better than stock, the results are there in the link I posted. You would be deluded if you think that you couldn't do a better job on one head than yamaha/toyota do in a production line of a million. Read the link and then decide.

[sergei]

Yes Sergei you are wrong, flow bench testing is very representitve of what goes on in real life, if you do it correctly. And Yes I would say that TK can make a head flow miles better than stock, the results are there in the link I posted. You would be deluded if you think that you couldn't do a better job on one head than yamaha/toyota do in a production line of a million. Read the link and then decide.

I did read the link, but remember the gas flow in ports is not continuous, in fact there are times where the flow reverses. Of course you might need bigger ports to support double the power, but what if you are after nice torque curve, and power near the factory figures perhaps 30% more power? There is no point in messing with ports on a modern toyota engine, unless you are after enormous power, which at that stage makes vehicle undrivable.