JZX100 V's MX83 auto Q's

[TTMX83]

OK, I need some help/advice with a project I am considering.

In a nutshell, what are the differences, electrically, between the JZX100 (A341) and the MX83 (A340) autos. I have done a non VVTi 1JZ conversion into an MX83 using the MX83 auto and the JZX81 ECU had no trouble conrtolling it. Would a JZX100 1JZ and ECU be able to control the MX83 auto?

I am 90% sure it will bolt to the motor, using the MX83 convertor, 1JZ flexplate and bellhousing.

Cheers Brad.

PS: I know the MX83 auto isn't the strongest thing compared to the auto the engine comes with. But thats not the question

[Cuts]

the autos behind the vvti 1j are a heaps different to the older style ones, im no expert but they are more electronically controlled or something, i doubt you could run the older box on the newer ecu (or vice versa for that matter).

[TTMX83]

Yes, they seem to be quite different, although I am only going by the EPC. It appears that the JZX100 auto has only 2 solonoids as opposed to 3 in the MX83 auto and all the part numbers for every sensor are different and possibly in different locations too.

Oh well.

Cheers Brad

[TTMX83]

OK, so would one of them auto controllers work, like MV's of a Suprastick or whatever they are to get it going?

Cheers Brad.

[jzk25]

VVt auto has 4 solenoids. It has electronic line pressure control where early 1JZ is cable line pressure. the clutch packs/case etc is the same though, you can swap the cable valve body over. There is no speedo drive in vvt auto's either.

What are you wanting to do exactly?

[TTMX83]

I want to put a VVTi 1J into and MX83 using the Cressida auto. I was hoping they didn't change the electricals over on the auto. I have been given a budget from the 'boss' and that does not include another auto So I am trying to do ot as cheap as possible.

Does anyone have a picture of the plugs on a JZX100 auto?

Cheers Brad.

[jzk25]

The whole thing is different from a control point of view. You'd be better off with a non vvt 1jz anyway.

[TTMX83]

I have been there, done that. I know from a conversion point of view it is easier.

The only easy way is to use the right auto for the engine then

How is a non-VVTi one better? Surely a VVTi one is newer, less klm and makes nicer power.

[jzk25]

VVt engines struggle to make power. Everything is undersized and the engine management is not very flexible.

[TTMX83]

Standard Vs srandard? Not everyone is trying to make uber power....

[J0RD0]

i think you may run into troubles using torque convertors out of other boxes, some of the splines are different between the A340's as i found out the hard way. Honestly you can pick up a jz auto box fairly cheap. Just run a shift box from whoever and everything will be simple.

[jzk25]

Std vs std with basic mods like exhaust I would still pick the old 1JZ. 2JZ is better than any of them and cost the same. Done deal.

[gtfloor]

I can't see your reasoning jzk25 have you actually owned a 1jzvvti? the 1jzvvti is harder to make power from that is crap, the engine is much newer, turbo setup is much simpler, spools up heaps quicker than old twin ct12a setup, takes up less room in engine bay, vvti makes turbo lag almost non existent compared to twin turbo. I have owned 5 1jzgte twin turbos and all have been modified to some point, the vvti, with exhaust, cooler and boost is definately worth the extra bang for your buck, compared to the old twin arrangement.

As for engine management you can buy a jzx100 power fc for automatic for $1100.00, that seems like a decent choice to me, just giving people the heads up, these engines can make decent power and start spooling around 2600rpm vs 3300rpm for stock twins, 220 to 240rwkw with stock injectors, boost, exhaust, cooler.

[jzk25]

I have some experience with them, I wouldn't post if I hadn't.

The turbo on a VVT spools faster because it is smaller. Therefore it runs out faster and the turbine falls off it faster. The head ports are tiny, this also helps it spool faster but chokes the top end. This is just how it is, the engine is built to deliver a flat torque curve and boost low in the rev range and the pay off is limited topend when compared to the other JZ turbo engines.
I've got 3 of them on my mezzanine floor at the moment if you would like to see how small the ports are.

You can buy a powerfc for $1100 then another $1k for tuning and not get far, the guys with non vvt's can buy an SAFC for $100 and some 2JZ injectors for $100 and make 350hp atw.

I wouldn't bother with any 1JZ to be honest, a 2JZ is far far better in every way and the cost difference is negligible.

[TTMX83]

They are interesting points.

I converted an MX83 a few years ago as a 'repair' for the 7M's blown the HG. I used a twin turbo 1J. It made maximum torque at 2600 rpm on the dyno. All standard but with a 3'' exhaust. This was for a daily driver.

Once again I have an MX83 but this one got rod knock and spun a bearing. Once again it is a daily driver and I came across a VVTi 1J that I hoped would be able to control the Cressida auto. This was to be the 'repair'.

I am certain that the VVTI 1J would be better to drive than the twin turbo 1J, standard for standard, why would Toyota design something that wasn't an improvement on the old model......

If I wanted to go out and spend a farkload of money on something that was no longer streetable but powerful, sure I would get a 2J with a big turbo. But that's not my intention.

Cheers Brad

[jzk25]

Go over to JZX100 forums and you should find an auto. People often convert from manual to auto because the auto cars are a lot cheaper to buy. The auto has a slip joint extension housing so is not a big PITA to fit either. You'll have to fit a speedo drive to it though, the casting is there from memory, just needs drilling out.

[CrUZida]

Errr, am I reading this correctly?
You are planning on running the original Cressida auto behind a 1JZ?
And you are expecting it to last more than a few months?

[TTMX83]

Sure, have a mate running one behind a TT 1J. Just has a shift kit in it. Two years now and counting. It's only 3rd gear that is weaker on the Cressida one right? Either way it's not happening now. By the time I got it up and running properly, I'd be better off buying my old JZX83 back...

Cheers Brad.

[Nilezy]

http://wiki.jzx100.com/index.php?title=VVTi

The turbo on a VVT spools faster because it is smaller. Therefore it runs out faster and the turbine falls off it faster

1. VVTi 1J turbos (CT15B) are not smaller than twin turbo 1J turbos (CT12A)
CT15B
Impeller 46/65mm
Turbine wheel 60/48mm
CT12A
Impeller 37/54mm
Turbine wheel 52/42mm

2. The turbine doesn't fall off faster, the CT15B is a more efficient turbo than the CT12A. Of course if you increase boost pressure, the ceramic wheel doesn't like to overspeed so will be damaged. Look at Diagram 6 when comparing both CT12A's against the CT15B

The head ports are tiny, this also helps it spool faster but chokes the top end. This is just how it is, the engine is built to deliver a flat torque curve and boost low in the rev range and the pay off is limited topend when compared to the other JZ turbo engines.

The head ports are not smaller, look at diagram 13, the exhaust ports are shaped better in the VVTi head when compared to the earlier 1J heads:
"The shape of the exhaust ports, combined with making them smoother increases exhaust flow efficiency"

Smaller ports don't increase exhaust flow.........

I would not recommend running a standard A340 behind a VVTi 1J motor.
The older 1J does not produce the nearly 400nm of peak torque in the same part of the rev range as the VVTi 1J. 80% of peak torque is produced at 1800rpm from a VVTi 1J

This alone would be enough to damage a standard A340. The torque convertor and the clutches in the A341 behind a VVTi 1J are way more heavy duty than the standard A340, the torque convertor steel thickness is greater and the A341 uses kevlar clutches and uses the Type IV fluid for that reason.

[TTMX83]

PS: I know the MX83 auto isn't the strongest thing compared to the auto the engine comes with. But thats not the question

Read the first post?

Cheers Brad.

OH, an Simons MX83 auto is still fine behind the TT 1JZ..... Although I guess that isn't proof enough