2JZ-GTE VVti in VVti SC300
10-02-15, 10:50 PM
#1
Driver
Thread Starter
2JZ-GTE VVti in VVti SC300
so I bought a super clean 98 SC300 (vvti of course). Just curious, I know the in's and out's of the mechanical aspects of doing a 2JZ-GTE vvti swap done. What I am curious about is what ECU can both run the engine and interface with the SC300 body connectors? From reading it appears that the Aristo ECU might be able to do everything, though the body connectors, which are broken up into 5 separate connectors are, are one large connector on the Aristo.
I am not into this for some crazy drag strip monster I just wanted something that is close to as quick as my IS350 is, perhaps 300-350whp, which means at MOST a set of USDM twins or reworked Aristo's if I get bored with the stock Aristo's. I see that most people do piggyback setups but that looks like a huge pain in the a$$. So I was hoping that I could either run the Aristo's ECU or perhaps somehow reprogram the stock SC300 to work with the Aristo 2JZ-GTE (yeah, probably impossible).
I understand tuning, though have sadly no experience actually doing it, and an AEM or other standalone is completely out of the question, just way too much money involved in a side project/hobby.
Last question, was thinking of going NA-T if money gets short and I can't go 2JZ-GTE, the big question is, even with a thicker head gasket installed I still have domed instead of dished pistons, not ideal for FI, plus the rods on the VVTI motors are weaker, so that may be a concern. Though what boost levels have NA-T guys reliably maintained?
I am not into this for some crazy drag strip monster I just wanted something that is close to as quick as my IS350 is, perhaps 300-350whp, which means at MOST a set of USDM twins or reworked Aristo's if I get bored with the stock Aristo's. I see that most people do piggyback setups but that looks like a huge pain in the a$$. So I was hoping that I could either run the Aristo's ECU or perhaps somehow reprogram the stock SC300 to work with the Aristo 2JZ-GTE (yeah, probably impossible).
I understand tuning, though have sadly no experience actually doing it, and an AEM or other standalone is completely out of the question, just way too much money involved in a side project/hobby.
Last question, was thinking of going NA-T if money gets short and I can't go 2JZ-GTE, the big question is, even with a thicker head gasket installed I still have domed instead of dished pistons, not ideal for FI, plus the rods on the VVTI motors are weaker, so that may be a concern. Though what boost levels have NA-T guys reliably maintained?
10-03-15, 04:14 AM
#2
so I bought a super clean 98 SC300 (vvti of course). Just curious, I know the in's and out's of the mechanical aspects of doing a 2JZ-GTE vvti swap done. What I am curious about is what ECU can both run the engine and interface with the SC300 body connectors? From reading it appears that the Aristo ECU might be able to do everything, though the body connectors, which are broken up into 5 separate connectors are, are one large connector on the Aristo.
I am not into this for some crazy drag strip monster I just wanted something that is close to as quick as my IS350 is, perhaps 300-350whp, which means at MOST a set of USDM twins or reworked Aristo's if I get bored with the stock Aristo's. I see that most people do piggyback setups but that looks like a huge pain in the a$$. So I was hoping that I could either run the Aristo's ECU or perhaps somehow reprogram the stock SC300 to work with the Aristo 2JZ-GTE (yeah, probably impossible).
You don't need a piggy back to get into the 400rwhp. A stock Aristo ECU will bring your there.
You cannot reprogram or no way an SC300 ECU work with an Aristo 2jzgte / TT transmission setup.
Last question, was thinking of going NA-T if money gets short and I can't go 2JZ-GTE, the big question is, even with a thicker head gasket installed I still have domed instead of dished pistons, not ideal for FI, plus the rods on the VVTI motors are weaker, so that may be a concern. Though what boost levels have NA-T guys reliably maintained?
Boost levels depend on your overall setup. Type of Fuel plays a role too. Make sure every component on the setup match every other components with your overall goal in mind so it is a reliable and efficient setup.
People complain about high hp cars being unreliable ... these are the people who cheap out . They don't use the right parts and do not let the right people work on their cars then complain having an unreliable car. Newer sport cars now are making North of 500-600rwhp and are reliable but pricey. Even some freaking Kia or Hyundai now does more than a stock muscle car of the past. GT-Rs and Lambos are tweaked to make over 1500rwhp and you see them all day on the streets . One just has to spend money to play.
Last edited by gerrb; 10-03-15 at 04:24 AM.
10-03-15, 03:05 PM
#3
Driver
Thread Starter
Wow...so much good info here, thanks so much. I wasn't sure if the Aristo or Supra TT ECU's were capable of changing the LTFT/STFT's, AF, and ignition timing as to warrant such high gains. I know with most stock ECU's you get a little "wiggle room", glad to hear that the Aristo ECU will get me there 
Also, good to know that I can use the Aristo twins to get to my goal I still like the idea of steel compressor wheels though, as they are much tougher than the JDM ceramic ones. If I can find a set of USDM's for cheap (that aren't trash) I might still go that route...though I think the flange might be different on the manifold, which means getting a USDM manifold (more money). Either way, I will cross that bridge when I get there, I could even do the aristo twins upgrade someday (rebuilding them with GT28RS wheels) if I get bored of 350-400whp 
As far as the harness goes, I was planning on going the Dr. Tweak route as I want a plug and play solution that is solid, not that I don't trust myself to do it right, but having someone that knows the in's and out's of wiring and has done it many, many times, as well as has access to replacement connectors if/when something unexpected happens is just excellent peace of mind
Your comments bring up an interesting point, going NA-T might not be a bad idea, I might look into that further. One thing is FOR SURE though, this car HAS to be able to run reliably on pump gas, which is why my goals are relatively modest.
Now this will show my lack of knowledge here, but having no EGR on the Aristo motor would seem to be somewhat a problem as EGR usually cools cylinder head temperatures and is factored into many cars' ignition timing mapping so that the engine can run advanced timing and leaner fuel trims b/c the EGR is active. Considering Japan has higher octane gas standard over there, am I going to run into problems with pinging on 91 octane here in the states? That's probably a stupid question for those of you that are very knowledgeable. Either way looks like this is going to be simpler than I thought it would be, looks like the harness is really the big "key" to getting this all to work, all the rest of the stuff, like piping, intercooler, fuel pump/fuel pump ecu, oil pan replacement, etc.., are pretty straightforward and not terribly expensive.
Also, good to know that I can use the Aristo twins to get to my goal
I still like the idea of steel compressor wheels though, as they are much tougher than the JDM ceramic ones. If I can find a set of USDM's for cheap (that aren't trash) I might still go that route...though I think the flange might be different on the manifold, which means getting a USDM manifold (more money). Either way, I will cross that bridge when I get there, I could even do the aristo twins upgrade someday (rebuilding them with GT28RS wheels) if I get bored of 350-400whp As far as the harness goes, I was planning on going the Dr. Tweak route as I want a plug and play solution that is solid, not that I don't trust myself to do it right, but having someone that knows the in's and out's of wiring and has done it many, many times, as well as has access to replacement connectors if/when something unexpected happens is just excellent peace of mind
Your comments bring up an interesting point, going NA-T might not be a bad idea, I might look into that further. One thing is FOR SURE though, this car HAS to be able to run reliably on pump gas, which is why my goals are relatively modest.
Now this will show my lack of knowledge here, but having no EGR on the Aristo motor would seem to be somewhat a problem as EGR usually cools cylinder head temperatures and is factored into many cars' ignition timing mapping so that the engine can run advanced timing and leaner fuel trims b/c the EGR is active. Considering Japan has higher octane gas standard over there, am I going to run into problems with pinging on 91 octane here in the states? That's probably a stupid question for those of you that are very knowledgeable. Either way looks like this is going to be simpler than I thought it would be, looks like the harness is really the big "key" to getting this all to work, all the rest of the stuff, like piping, intercooler, fuel pump/fuel pump ecu, oil pan replacement, etc.., are pretty straightforward and not terribly expensive.
10-03-15, 05:16 PM
#4
Driver
Thread Starter
Damn, I just realized that although this method is great, I will lose OBDII compliance. What are my options? Run a USDM GTE ECU? Which comes with it's own set of problems, no EGR in the JDM head/manifold and it will be expecting to see 550cc injectors AND a different set of cams.
Does this mean that the only way to retain OBDII compliance is to use my GE ECU with piggyback or standalone?
Does this mean that the only way to retain OBDII compliance is to use my GE ECU with piggyback or standalone?
10-04-15, 04:44 AM
#5
JDM twins are ceramic but the only reason they will fail is overboosting them beyond their capacity. You don't have to overboost them to get into your 350rwhp goal... even at 15psi which is well within their range , you are already above your 350rwhp goal. Thus for your power goals I really don't see the need to spend more and get other turbos cause you will have to replace a lot of stuff on that exhaust side. It is not just a matter of taking out your JDM turbos and slapping the USDM turbos.
if truly you want a 2jzgte , then your only choIce is use the USDM 2jzgte engine ODB2 version from 1997 to 1998 toyota supra mkiv. Good Luck finding one. They will be very hard to find.
Running just the USDM ODB2 ECU will produce error codes since certain engine components needed for odb2 compliance are missing from an Aristo 2jzgte.
your other option is go NA-T with odb2 compliance for which your 350rwhp is still very doable ... rods on non vvti short block are stronger so you might want to use that short block. But for 350rwhp power goal , I truly believe the vvti rods will survive.
if truly you want a 2jzgte , then your only choIce is use the USDM 2jzgte engine ODB2 version from 1997 to 1998 toyota supra mkiv. Good Luck finding one. They will be very hard to find.
Running just the USDM ODB2 ECU will produce error codes since certain engine components needed for odb2 compliance are missing from an Aristo 2jzgte.
your other option is go NA-T with odb2 compliance for which your 350rwhp is still very doable ... rods on non vvti short block are stronger so you might want to use that short block. But for 350rwhp power goal , I truly believe the vvti rods will survive.
Last edited by gerrb; 10-04-15 at 05:12 AM.
10-04-15, 07:10 PM
#6
Driver
Thread Starter
Damn, I really wanted to go GTE w/VVTI. I am a big fan of VVTI plus turbo. Looks like that T in GTE is the most expensive letter in the alphabet.
So what do guys do? I mean there must be some people that have gone GTE with OBD2 cars? Run both computers? Piggyback to run the engine? Surprised that someone hasn't created a JOBD translator (and no I don't simply mean language). Maybe I could swap a GTE head, piston and rods, make it USDM...probably expensive and difficult.
Btw, Gerrb, your garage looks impressive. Maybe my college education will pay off someday and I will be able to afford half of what you have got there, wow!
So what do guys do? I mean there must be some people that have gone GTE with OBD2 cars? Run both computers? Piggyback to run the engine? Surprised that someone hasn't created a JOBD translator (and no I don't simply mean language). Maybe I could swap a GTE head, piston and rods, make it USDM...probably expensive and difficult.
Btw, Gerrb, your garage looks impressive. Maybe my college education will pay off someday and I will be able to afford half of what you have got there, wow!
Last edited by soloist3; 10-04-15 at 07:27 PM.
10-05-15, 05:30 AM
#7
Thank you Soloist ! One day you will be able to have the toys you want. It is a matter of time. Work hard while you are young and reap the harvest in the future. Maybe retire early at 50 just like I did and have a lot of time to play with your toys. You never know.
There are a lot of odb2 compliant GTE cars. You just have to use the right engine components and ECU. With your power goals there is no problem at all. Just use the USDM Toyota Supra MKIV components and odb2 ecu. As I have said your power goal is easy and still odb2 compliant.
It is when you are going beyond the power of what the stock odb2 ecu can handle that you start getting away from being odb2 compliant. When you want more power , you start taking away exhaust restrictions like cat converters , that alone is enough to fail you from being compliant. And there are a lot of other things associated with making power that won't allow you from being odb2 compliant.
So there is a trade off... the more power beyond what a stock odb2 ecu can handle then forget about being compliant. Otherwise stay within what the stock odb2 ECU can do. Like you mentioned using piggybacks so you can use bigger injectors.... you know that your exhaust gases level goes higher with more power that would not pass emissions so no piggybacks or aftermarket ecu might be able to help you.
a USDM ODB2 2jzgte ECU can even help you get into the +500rwhp so I don't see any reason to use any other ecu when your power goal is only 350rwhp.
I don't get what you said about swapping the GTE head, piston and rods to make it USDM. Note that JDM and USDM short blocks 2jzgte (non vvti) are exactly the same so no point of swapping the rods and pistons. Not unless you are talking about your 2JZGE engine.. putting in GTE pistons and rods and using your GE vvti head. Note that if you use GTE pistons and rods with GE vvti head, depending on the head gasket , your compressions changes. Also before I forget 2JZGE and 2JZGTE stock rods are exactly the same.
There are a lot of odb2 compliant GTE cars. You just have to use the right engine components and ECU. With your power goals there is no problem at all. Just use the USDM Toyota Supra MKIV components and odb2 ecu. As I have said your power goal is easy and still odb2 compliant.
It is when you are going beyond the power of what the stock odb2 ecu can handle that you start getting away from being odb2 compliant. When you want more power , you start taking away exhaust restrictions like cat converters , that alone is enough to fail you from being compliant. And there are a lot of other things associated with making power that won't allow you from being odb2 compliant.
So there is a trade off... the more power beyond what a stock odb2 ecu can handle then forget about being compliant. Otherwise stay within what the stock odb2 ECU can do. Like you mentioned using piggybacks so you can use bigger injectors.... you know that your exhaust gases level goes higher with more power that would not pass emissions so no piggybacks or aftermarket ecu might be able to help you.
a USDM ODB2 2jzgte ECU can even help you get into the +500rwhp so I don't see any reason to use any other ecu when your power goal is only 350rwhp.
I don't get what you said about swapping the GTE head, piston and rods to make it USDM. Note that JDM and USDM short blocks 2jzgte (non vvti) are exactly the same so no point of swapping the rods and pistons. Not unless you are talking about your 2JZGE engine.. putting in GTE pistons and rods and using your GE vvti head. Note that if you use GTE pistons and rods with GE vvti head, depending on the head gasket , your compressions changes. Also before I forget 2JZGE and 2JZGTE stock rods are exactly the same.
Last edited by gerrb; 10-05-15 at 08:27 AM.
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10-05-15, 01:49 PM
#8
Driver
Thread Starter
Actually yes when I was speaking of swapping rods, pistons, and cylinder head, I was thinking of converting my GE engine to GTE, though it's a LOT of trouble to go through for "potential" gains over NA-T. My thought was that because the Aristo motor doesn't have EGR and some other USDM OBDII emissions systems (you might need to help me out with this one) it may be easier to buy a GTE cylinder head and GTE head gasket and MAYBE the rods (the pistons don't bother me too much as I can now see from reading and seeing pictures that most of the difference in compression is due to the head gasket than the pistons themselves). Finding a USDM GTE is probably NEVER going to happen, I mean it's very rare that I will be able to just set aside $3-4k cash in hopes of getting an engine that even when/if it shows up online might be gone in 20mins, or be too far away to justify the freight cost (new england states).
So start with the USDM Supra TT Auto OBDII ECU (probably the least popular of all the Supra ECU's, save for N/A). Pick up a USDM GTE cylinder head/intake/turbo parts, bolt them to my GE block OR pick up an Aristo GTE motor and use the short block (for the lower mileage and better rods/pistons) and put a USDM cylinder head/intake/turbo's on top of that. Either way, to stay legal I will have to have to keep the emissions equipment which means I can't use the Aristo cylinder head and intake without some serious machining work done to install EGR equipment. Curious to know if any machine shops do this kind of work with the JDM cylinder heads and intakes...could probably make a killing as a machine shop once you make an appropriate jig to route out EGR ports in JDM motors.
Then again, even if someone did machine the JDM cylinder heads I would still have vvti to deal with, which personally I love considering how much more torque is available down low, BUT the USDM GTE ECU wouldn't know what to do with it and I am not sure how the USDM GTE ECU would react to having a piggyback activating VVTI, it would throw off all the fuel/ignition timing maps designed for the non-vvti motor.
All that, OR go NA-T...which sounds boring as hell but is unfortunately my best option
So start with the USDM Supra TT Auto OBDII ECU (probably the least popular of all the Supra ECU's, save for N/A). Pick up a USDM GTE cylinder head/intake/turbo parts, bolt them to my GE block OR pick up an Aristo GTE motor and use the short block (for the lower mileage and better rods/pistons) and put a USDM cylinder head/intake/turbo's on top of that. Either way, to stay legal I will have to have to keep the emissions equipment which means I can't use the Aristo cylinder head and intake without some serious machining work done to install EGR equipment. Curious to know if any machine shops do this kind of work with the JDM cylinder heads and intakes...could probably make a killing as a machine shop once you make an appropriate jig to route out EGR ports in JDM motors.
Then again, even if someone did machine the JDM cylinder heads I would still have vvti to deal with, which personally I love considering how much more torque is available down low, BUT the USDM GTE ECU wouldn't know what to do with it and I am not sure how the USDM GTE ECU would react to having a piggyback activating VVTI, it would throw off all the fuel/ignition timing maps designed for the non-vvti motor.
All that, OR go NA-T...which sounds boring as hell but is unfortunately my best option
Last edited by soloist3; 10-05-15 at 01:57 PM.
10-05-15, 02:16 PM
#9
You give me headaches with all the options you are throwing in ... lmaol , just kidding !
you have very low power goals at 350rwhp. So KEEP IT SIMPLE ... NA-T ... cheapest route and be ODB2 Compliant which is a requirement of yours. No point of bringing in all the other power making stuff when they are not needed with your power goals.
Don't complicate things. BTW, compression is affected by both the thickness of the headgasket , what head you will use (the amount of recess on the GE and GTE head are not same), and the Pistons themselves.
you have very low power goals at 350rwhp. So KEEP IT SIMPLE ... NA-T ... cheapest route and be ODB2 Compliant which is a requirement of yours. No point of bringing in all the other power making stuff when they are not needed with your power goals.
Don't complicate things. BTW, compression is affected by both the thickness of the headgasket , what head you will use (the amount of recess on the GE and GTE head are not same), and the Pistons themselves.
10-05-15, 10:01 PM
#11
Driver
Thread Starter
Yeah, I am definitely grateful he is on here, for awhile I thought I was posting in the wrong section with as few replies as I was getting. Still thinking about putting a GTE cylinder head on my GE block though, the GTE head and gasket will get my compression ratio closer to a stock GTE which is probably better to run with the GTE ECU. It also benefits me by giving me more choices for manifolds and parts (ok, that might be debatable), though, with the GTE ECU I have a factory reliable solution that is guaranteed to run the motor pretty damn well until well beyond my power goals. I really don't like the idea of a piggyback for a car that's under 500whp.
I suppose I should read up on ALI's ECU mod for NA-T, so at least I know what I am getting into when/if I go NA-T w/o the GTE ECU. I am so stuck on getting at least a GTE cylinder head/intake mani if not going full NA-T, I have always wanted to see that motor in my SC (well, took me long enough to find a clean SC to actually do this with), seeing the top end of the GE just pisses me off, it's like this tease, I mean having the NA version of one of Toyota's best motors in a car that is essentially the luxury version of the MkIV Supra chassis. Even with turbo's feeding it, it still looks GE which is trivial and ridiculous but for some reason bothers me.
I suppose I should read up on ALI's ECU mod for NA-T, so at least I know what I am getting into when/if I go NA-T w/o the GTE ECU. I am so stuck on getting at least a GTE cylinder head/intake mani if not going full NA-T, I have always wanted to see that motor in my SC (well, took me long enough to find a clean SC to actually do this with), seeing the top end of the GE just pisses me off, it's like this tease, I mean having the NA version of one of Toyota's best motors in a car that is essentially the luxury version of the MkIV Supra chassis. Even with turbo's feeding it, it still looks GE which is trivial and ridiculous but for some reason bothers me.
Last edited by soloist3; 10-05-15 at 10:07 PM.
10-06-15, 01:37 AM
#12
Driver
Thread Starter
Hmm...thinking about it, the Aristo has the same ETCS-i that my GE motor has, which means I shouldn't have an EGR (I will have to double check). This means that I SHOULD be able to run the stock ECU plus an AEM F/IC or similar piggyback and retain OBDII compliance. Might be a pain to work with (using a piggy back) but boy do I ever like the idea of just swapping in the Aristo GTE motor. This might involve merging the GE/GTE harness, not sure what might be missing on my factory GE harness. It also means having to go with a single OR bypass the sequential mode on the factory twins (should they remain attached to the motor). This is looking better and better. This means I can retain using my weak but free auto transmission without having to search for an SC400 driveshaft. Not sure how well the GE trans will hold up at the 350rwhp mark; perhaps I could use the parts in the Aristo auto trans to fortify my auto trans (it is my understanding that those transmissions are electronically controlled using the Aristo ECU, whereas the 1998 SC300 still uses a mechanically controlled transmission).
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