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You actually get more out of turbo one, so maybe its working turbo one a little more and turbo 2 will come on with less pre spool (normally that extra exhaust pressure is used to prespool turbo 2, but turbo 2 will still prespool to some degree).
long term how it affects life of turbo, not sure but If you have US twins there is nothing major to worry about, jdm twins well that might be a different story as they can come apart.
I dunno once you drive it around alot its really annoying and starts to bug you, after we spring modded a bpu supra it was breaking the tires loose on turbo 1 before 4k rpms and changed the car completely, before it was rather tame until the 4k rpm mark, it would hold like 6 psi or something (cant remember exactly)... and then it would rocket to like 16 or whatever it was set on between that and redline (lame). if you drive in the city you will prolly want to look into it, after wards it seems like it pulls straight to max boost with just a tiny pause sometimes, I want to say turbo 1 on that was pulling like 11-12 psi on its own but that depends on the spring you use.
We are running the stock Lexus setup ( with a SUPRA pump ) right now the fuel pump controller is bypassed so full 12 volts to the pump all day long. It's REEALLY noisy ( fuel in the lines pumping round ) no the pump itself.
Currently David is just FRUSTRATED with the car… so more … later
Hmm. So you're saying the sound is actually coming from the LINES themselves? Interesting. I have a USDM TT fuel pump and TT Fuel ECU. I'm going to get that ECU wired in with the EFI2 connection it requires. I'm trying very hard to resist the common 12V Mod but that all depends on getting the EFI2 signal to work
I'm sorry to hear he's that frustrated with the car :/ Other than the fuel line noise, maybe we can help here to get any minor gremlins diagnosed? Yes, please keep us updated.
You actually get more out of turbo one, so maybe its working turbo one a little more and turbo 2 will come on with less pre spool (normally that extra exhaust pressure is used to prespool turbo 2, but turbo 2 will still prespool to some degree).
long term how it affects life of turbo, not sure but If you have US twins there is nothing major to worry about, jdm twins well that might be a different story as they can come apart.
I dunno once you drive it around alot its really annoying and starts to bug you, after we spring modded a bpu supra it was breaking the tires loose on turbo 1 before 4k rpms and changed the car completely, before it was rather tame until the 4k rpm mark, it would hold like 6 psi or something (cant remember exactly)... and then it would rocket to like 16 or whatever it was set on between that and redline (lame). if you drive in the city you will prolly want to look into it, after wards it seems like it pulls straight to max boost with just a tiny pause sometimes, I want to say turbo 1 on that was pulling like 11-12 psi on its own but that depends on the spring you use.
Hmm. I do like that aspect of going BPU and I really do want to. Ideally I'd like to do a spring mod possibly with an HKS EVC to get the car to a maximum of 15-16 PSI. However I'd also like the ability to detune back to stock boost, including on the #1 turbo for inclement weather conditions.
This is why I was toying with the idea of repurposing one of the seat heater switches to function as an E-TTC ON/OFF button-- to turn on very linear parallel (and laggy) power delivery for rainy conditions. It's hard on the pressure tank over time so I wouldn't plan to use it too much. I'll probably just use a generic aftermarket switch at this point.
For city drivability I do agree that a basic spring mod will probably get the engine right where it should be, especially once I swap out my current 4.27 rear end ratio for the original TT Auto 3.77.
I love it that both twins are water cooled as you pointed out to me some months back. Very durable it seems although mine with 150,000 miles have just a little bit of shaft play and I still will have to get them rebuilt. I know they were run at 18psi some of the time.
Aside, I know it's not just the shafts and wheels that are different on the JDM twins but those can now be upgraded with steel wheels that greatly improve their reliability. Actually the JDM twins are far cheaper to do a normal rebuild and steel wheel upgrade on. They're also cheaper to do a STU GT28 upgrade with.
thats good to know about the JDM twins, I did not realize it was cheaper to rebuild those. that should get them right where they need to be if you have a set of those. I am sure you guys will figure it out, lots of ways to adjust the twin turbo system.
thats good to know about the JDM twins, I did not realize it was cheaper to rebuild those. that should get them right where they need to be if you have a set of those. I am sure you guys will figure it out, lots of ways to adjust the twin turbo system.
I have the USDM versions. However, vigman's son has the JDM's in his BAR'd SC. I don't recall the prices offhand but it is actually more common to see steel wheel rebuilds offered at semi-reasonable costs compared to any type of rebuild or upgrade on the USDM's.
Yeah, there will be plenty of options for mild boost adjustment Neither of these cars have demanding builds other than the obscure originality and cost.
Originally Posted by CatManD3W
Kahn you should upgrade those factory twins...
It will appear stock but really it isnt....I was reading a thread on SF and guy made over 700hp on upgraded twins
Believe me I really would like to. They do look mostly stock. I've even heard they add almost 50whp more than normal twins even under normal BPU tune, though I do not think that is with OEM cats. They certainly would be awesome peace of mind but considering that I am building for only 15-16psi on 91 pump gas WITH factory cats (or the Magnaflows vigman used) and an MKIV or Soarer side mount intercooler they are a bit overkill.
The 700whp+ tune with USDM GT28 hybrids that you've read about was on probably on one of Stu Hagen's Supras. He's the original co-developer of much of the R&D on the twin upgrades. His twins easily run 26-28psi and have gone well into 35psi for track runs. And that's in sequential mode! He gets there by running a Vipec or possibly now a ProEFI 128, a specific twin boost controller setup to tune turbo #1 and #2, E85 fuel and big injectors, big front mount intercooler and undoubtedly a very free flowing exhaust system. It's a very impressive machine (excuse me, *machines*-- he has two of them) and other adopters of the hybrid twins both in USDM and JDM spec have put out similarly impressive numbers though maybe not into the 700whp range.
A standard rebuild for USDM twins is $1500 (with a parts refresher kit added) with a simple GT28 wheel upgrade. NOT the same thing as STU hybrids.
The USDM STU hybrid upgrade is about $3200. Used to be a bit more-- they've lowered it recently. Then there is also a new $1K high flow manifold in USDM and JDM versions and a $300 turbo #1 to #2 transition upgrade kit.
It's VERY cool stuff. I'd love to do it even though taking advantage of it in CA would be a challenge. In the future, who knows? I still have a lot of major work just to get the GTE swap into stock tune first.
Last edited by KahnBB6; 02-17-16 at 03:21 PM.
Reason: Grammatical fix.
Usdm twins with a little bit of shaft play... just toss em in and crank up the boost =)
most turbo's have a little bit of play especially with no oil in them, so it might be within spec.
if it was JDM twins then I would be more worried but those usdm twins wont come apart unless the play is so bad its marking the compressor housing.
usdm twins flow quite well, you probably do not need to upgrade them to achieve your goals, what helps them alot is freeing up the exhaust, cause with the stock downpipe/exhaust/cats its rather restrictive and you loose power. I know you are in cali trying to get it barr'd so you will likely be using mostly a stock exhaust, so I wouldn't go crazy on the turbo upgrades honestly I would just find a set of USDM twins that does not need rebuilt somehow (they are getting rarer though) or just throw the ones you have in there and hope for the best.
While I'm in the middle of diagnosing a Code 71 EGR issue on my stock engine I double-checked my EGR parts for the TT swap and discovered that I only had a used TT EGR Valve. I put in an order for one with a dealer and got the word back that it had been discontinued.
Then I learned that Toyota had actually discontinued the USDM 2JZGTE EGR Valve as far back as 2012:
So far, that's used-only TT EGR Valves and used-only TT EGR VSV's. I haven't yet checked on the TT EGR modulator or TT EGR Temperature sensor (EDIT: the OEM temp sensor appears to still be available and Airtex-Wells and Standard Motor Products list aftermarket replacement sensors). I do have all of these parts used so far and a spare new Modulator but I really do wonder what MKIV owners are supposed to do when one of these components fails. So far I have found aftermarket alternatives to be few.
For NA engines there are some aftermarket EGR system alternatives or remans available.
It's a bit annoying to learn.
Last edited by KahnBB6; 03-01-16 at 12:39 PM.
Reason: Updated info
No news on the USDM GTE swap yet other than getting some $50 of turbo side OEM hose clamps in the other day from Japan (cheapest OEM source for so many of them).
I also picked up a new imported GTE TPS sensor because I used the one I already had to cure a TPS issue on my stock 2JZ-GE engine.
This thread is what has been taking up the majority of my available time for car-projects for the last five months:
A lot of issues suddenly came up one after another and they have taken precedence over the swap since my registration renewal and smog are coming up next month. As of the time of this writing I still have a CEL Code 71 I've been diagnosing and correcting step by step.
I also had to get a new OEM 7MGTE clutch and new SC clutch master and slave cylinder installed since my original clutch master cylinder was wearing out and causing premature pressure plate wear. Should have just had that replaced back in 2013 when I put in the R154.
I'm still doing the GTE swap project but the recent slew of maintenance (and having to replace my rare NA ECU after Fedex "lost" it) has been a diversion both with time and finances. I didn't expect to have to do an exhaustive tuneup and overhaul to everything on my 2JZ-GE right now.
There are some remaining parts to get for the swap and then I can begin tackling the full rebuild of the USDM GTE cylinder head, prepping the totally stock 6-speed USDM wiring harness and finally send the twin turbos off to be rebuilt.
Don't expect speed on this project, sorry I'd love nothing more than to be done already, call it a day and enjoy it in stock form but I can't afford to do it all fast
I don't have any garage space right now. Because I am not converting from a fully dressed Aristo 2JZGTE or other engine and I'm collecting every piece I need hose by hose, bolt by bolt, sensor by sensor it's pretty tedious between each step, finding parts and alternative aftermarket direct-replacement equivalents to some things and locating a couple of the discontinued pieces.... like the critical TT EGR VSV. I've got a couple of them now but they are not available new which concerns me.
....
I've learned recently that Dorman Products actually makes some aftermarket direct-replacement Toyota specific VSVs. None for our cars. I contacted them asking if they might have considered making an aftermarket replacement for some of the VSVs Toyota has discontinued for the USDM 2JZ-GE and USDM 2JZ-GTE... including that TT EGR VSV part number. I gave them all the pertinent P/N's. I'm not holding my breath but I imagine the more they get contacted about something like that the more they might consider it.
I've seriously thought of making a thread with their "give us ideas" contact page and the part numbers for at least the EGR and EVAP VSVs for both USDM engines on our SC forum and on Supraforums to see if people feel like contacting them about it themselves.
Couldn't hurt? Toyota and Denso certainly aren't doing anything to help Supra TT owners in that regard. For now we can still get new EGR VSVs for the USDM 2JZ-GE. I know because I just bought one after my original checked out as failed (on the 2JZ-GE engine).
I should note: no April Fools jokes in this post
Last edited by KahnBB6; 04-07-16 at 12:40 AM.
Reason: Gramatical correction
Not directly swap related but I think I've finally found some potential 1-DIN aftermarket stereos I might be happy with down the road since I'm still planning to get my LXCC installed again for gauges.
Jensen Heavy Duty JCV1640BTB:
Jensen Heavy Duty JHD1635BTB:
Jensen Heavy Duty JBR550:
These head units are all designed for work trucks and big rig semi trucks but all three look very normal, mostly clean and best of all they aren't 10-15 year old aftermarket used units. Finding a used Nakamichi CD-400 or CD-500 or MB-VI has been near impossible.
I might also install something like this to put in 52mm VDO gauges for Volts, Boost and Water Temperature (since Vigman has said the SC dash water temp gauge isn't 100% accurate when switching to a GTE engine):
i understand fully the slow build process. although i haven't actually built a car as meticulously defined as what you are doing. down to hose clamps and such being exact lol. I am just curious because it wasn't too long ago that i considered a USDM obd2 build because of emissions. I have since backed off from that based on the difficulty of finding parts and the price. I still haven't decided if I am going to go gte or na-t now. getting the chassis set how I want it before I dive into the engine.
jimmymac30, it really comes down to having no space for a spare engine and thus no JDM 2JZGTE fully assembled engine set that I am converting. All the little systems on the engine have to be replicated from scratch via exploded diagrams. It didn't start out that way but it became that approach after a while. Most of the hoses and such were still able to be obtained.
If I were to start on this swap from ground zero today I might have some pause myself. Somehow I was able to find all these parts one by one in the last three years. Some things I've bought new and some used. Some were already discontinued (engine hooks for instance) but most of those would be more easily obtained today by starting with a fully dressed JDM non-VVTi 2JZ-GTE engine and working back from there.
Does Illinois have emission regulations like California's?
Your approach of chassis first is what I did. If your state only cares about the tailpipe numbers and won't ding you for visual (or better yet exempts you after 25 years) then you might want to consider the 1JZ-GTE VVT-i engine. In theory it should run fairly clean with the VVT-i system and cats although no one has posted emission test numbers with one to my knowledge. If you need a USDM engine with EGR then a swap like mine is unfortunately the only way to go.
An OBD2 GTE version is not that different. It's some minor wiring differences in the engine harness, a 96-98 TT ECU (no 6-speed ECU for 96, fyi) and cats being the same bolt-in shape but perhaps slightly different internally.
If anyone has been wondering why there has been no progress on this swap in the last few months, this thread below has been the reason, mostly because a multitude of things began to go wrong beginning in October-November of last year and my smog test was coming up:
After spending far too much time and money fighting to solve those issues, I finally passed smog and the car was in good shape.
Right after the test I got my rear differential pinion seal replaced since there was a leak there. A leaking exhaust gasket is being replaced today. Phyrrhic victory for me... but I figured I'd done what I had to and could rest easier for a while.
I have been sending in regular oil analysis samples to Blackstone Labs since early last year. This morning I got a call from one of their technicians who was calling ahead of my results even being formally published to warm me that sometime between my last oil change and now (maybe less than 500 miles on religious 3500 mile intervals of Mobil1 10W30 Synthetic) I now have a major coolant leak and some very minor extra wear has already occurred.
Though he told me that so far my engine seems fine it's recommended I don't use it extensively and change oil every 500 miles to keep the wear to as much of a minimum as possible.
It's likely the head gasket I would guess given the 240K+ miles on the engine. We also couldn't rule out some minor amount of coolant getting into the engine while I took the intake manifold off and on many times to service the EGR system. However I was very, very careful and I do not remember any instance where this could have happened.
At this point I have just had the oil changed and will send them another sample. I am going to order a GE head gasket from Driftmotion and see how much replacing the old one will set me back.
But... I really don't know what this means for my 2JZGTE project. I got very ambitious and did a mountain of research and got almost everything I need but from the cylinder head to wiring harness to turbos to the oil pan turbo drain tap to the oil pump needing to be changed to the 2JZ-GE VVT-i crank sensor type.... I'm still not prepared to just jump into all of that at a moment's noice. I've still needed a few more parts that aren't rare.
The original GE head on the car could probably do with a full rebuild itself... if I wanted to. It has no issues other than long term wear but any rebuild of the GE head would make no sense if I have the GTE head already needing a full rebuild.
After my recent very pricey smog ordeal I am in no position to rush the swap.
Currently this has been my only vehicle. The most logical no-brainer choice would be to abandon the swap, repair the head gasket (or whatever is causing the coolant leak) and accept defeat. California wins and I lose. The engine might have already been replaced by now if they'd only focus on tailpipe emissions and didn't have a visual inspection here.
Or I could just park the vehicle and be without a reliable car for quite some time. And given my work and the nature of Los Angeles, that is not really an option.
Rock and a hard place. I've been at my wits' end over the last eight months and this morning's phone call was a very bittersweet pill to swallow.
The car drives just fine for now. You'd never know there was a coolant leak but the lab results show that the trouble is brewing. I am thankful for that early warning and very glad I decided to pay a bit extra for oil analysis on every change. But it's been one thing too many lately.
I'll be doing a lot of hard thinking and soul searching about where things will go from here. At the end of the day I am better off with a healthy and working SC300 than a broken one with heaps of unclaimed potential.
Sorry for the downer after such a lack of updates. It's just where things are at for me and this car. I've long given up asking it to be nice to me and not break anything else. Alas.
02-15-16, 08:10 PM
