If I can learn how to do this and make it happen then you can too, Barbary! : )

Everything on engines and vehicles and anything electrical once seemed daunting to me too. I’ve been very lucky to learn from great friends here who have taught me many things over time and who have given me the know-how and confidence to tackle things I never thought I could before

Vehicle projects big and small all look daunting and alien until you break them down and learn the “how“ and “why” of them just a bit at a time.

Sometimes not always being able to find a rare part can be really frustrating but even then I’ve found there is almost always another alternative solution if that becomes a road block.

You absolutely can to do it too, Barbary : )

 

Absolutely great advice, you can do it just hang in there. I have learned so much by being a member and reading everything I can.

 

For some reason I thought these were getting the machined housings and bigger wheels, I don't know why! Regardless, it'll be so nice to get that thing back to 100% so that you can enjoy it to it's full potential. Shoot, on a cold day up here at altitude my car will still spin them in second from a roll all the way up an on-ramp! The stock twins in sequential form are just so much damn fun.

 

Bill-- Absolutely! That's exactly what I did when I first became a member. Lots of reading and learning from others and a lot of asking questions and advice. Learning from others is an ongoing process honestly

Rudy-- Oh I wish they were! Those hybrid stock twins cost a lot more than I paid for these basic rebuilt set (about $750 each!). Maybe because I've mentioned the STU hybrid twins a few times? I have to agree that the sequential mode (stock) for these turbos makes them a lot of fun!

I've got 80 miles on them now. I'd have put more on them but I had a little setback with my cooing fans. One of the two OEM relays (which I had bought used and cheaply off ebay just to see if the circuit would work before spending more on new ones) began to fail and some tests with a multimeter and alligator clip wires confirmed it. I have a brand new one coming in within a few days.

I've also got a 2003-2010 SC430 130 Amp 6-phase alternator on order (P/N 27060-50280-84) to finally get some better and more stable power into the SC.

When all three fans, my turn signals and brakes are pulling current at the same time with the engine on the voltmeter sometimes gets as low as 12.5V which is not good! Recently it has made me avoid using my turn signals sometimes just to not draw that much current at stoplights. The 100 Amp 3-phase TT Auto alternator is good and reliable but it just doesn't put out enough current to keep up once the three fans kick in.

I'll need to follow the guide on the big JZ alternator thread on SupraForums, mark off the areas that need to be modified on the casing and take it to a local machine shop to cut those areas so that it will fit on my engine. This alternator has the same style oval plug that we use. I believe only a fused 1-gauge or 0-gauge size additional alternator positive to battery positive wire should be needed in addition to my already upgraded block and battery to chassis grounds.

I know that most of the SF people use Tundra or Sequoia 6-phase 1UZ-FE alternators but the 03-10 SC430 6-phase alternator has been documented once and seems to be just as successful.

...

The used fan relay dying on me and that ongoing issue with the factory alternator just not putting out quite enough current have now been the only things really holding up driving the car more.

I will get the DIY write-ups published soon. Things have just been hectic.

 

Craig, what's that old saying Rome wasn't built in a day. I am still telling my wife that after 49 years of marriage. But as I know from all your postings (which I read everyone of them faithfully) if anyone can do it you are the man.

 

Have you considered switching to LED bulbs? I never had a power issue but I went to all LED bulbs in my rear taillights on my Tundra for safety reasons. I planned to do it on my SC when I get to the point of installing the 97+ taillights into my 93. I don't have specific data on the SC chassis but I have seen LED bulbs using less power on other cars so no reason it wouldn't help us too.

 

Bill, it's a very true saying and thank you for the kind words! Honestly though I'm still just a novice at all of this, lol! Gerrb, Ali SC3, O.L.T., LeX2k, Beezupra, Stu Hagen, Wreckless and MANY, MANY others who have taught and helped me over the years between Clublexus and Supraforums all far outclass me with their knowledge, skill and experience

And 49 years of marriage!! That's beautiful!!

 

Actually yes I have! I'm just not ready to yet. Combined, all the bulbs in hazard flasher mode on SC's draw 216 amps watts per pulse.... which is quite a lot. Just engaging a left or right turn signal is just 108 amps watts (what’s wrong with me, lol?!) per pulse. Still a lot.

LeX2k actually tackled a way to do this for 1992-1994 SC300/400's which from the factory use a unique 5-spade signal flasher relay that houses two relays inside it. After extensive R&D on his part he found a solution involving the modification of an OEM Generation 5 Camry flasher relay unit wired to a standard Bosch 5-spade connector. A couple of internal modifications to the Gen 5 Camry flasher unit were needed to make it LED compatible.

The full thread and his R&D and solution are published here:
https://www.clublexus.com/forums/per...0-24020-a.html

For now it's not yet known of the long term reliability with standard bulbs pulling 216 watts through his modified relay solution but with a full conversion to LED bulbs used in conjunction with LeX2k's relay it should be a perfectly fine solution.

1995-2000 SC300/400's use a much more common three-pin factory turn signal relay and those cars are much easier to convert to LED using an off the shelf aftermarket flasher unit.

The tail light bulb failure warning ECU has to be disabled in both cases when using LED bulbs.

...

I want to get the alternator upgraded first because once the engine (and alternator) heat up I'm still getting a voltage reading of between 13.5V and 13.1-13.0V. It's right at 13.0V usually with the cooling fans engaged with no turn signals or brake lights activated.

It's the idle amperage output of the factory 90's 2JZ alternator design that's the biggest issue. A full conversion to LED bulbs will definitely help on top of an alternator upgrade though.

I still haven't found all the bulbs that I want to use. Good ones tend to be pricey as I've found and with SC's using so many for turn signals and brake lights they add up.

 

Watts! lol.

I'm have a set of these they are fantastic, nice orange not yellow.
But since you will be running 3 per lamp way too bright. Daytime it would be okay but at night it would be blinding. A solution is run them through a buck converter

For your car this would be perfect if you can live with the yellow output instead of amber/orange. I've posted about these before they about match the incandescent output and have the best diffusion you will find.

I've been running a set of the above for about 3 years now still going. With any LED outside of the top name brands expect them to fail on a regular basis I just live with it.

 

Thanks for those options! I’m still floored by the number of LED brands that are available as I try to figure out which ones are the best to use.

The buck convertor sounds like it will be necessary. It also looks like I’d need to build a case with gasket for each of them that I use.

What’s still weird to me is how the longevity of many LED bulbs for vehicle reportedly isn’t very good while it seems to be the opposite case for common household LED replacement bulbs or LED fixtures with the bulbs wired/soldered in.

And I don’t know where my mind was last night confusing amps with watts, lol. I’ve corrected the post now

 

I learned the hard way, bought a bunch most were complete trash.
Could cover it in heat shrink and tuck it up with the wiring harness, those things are tiny. I've found you can go down about 40% on most LED bulbs before they turn off. And it will make the bulb run way cooler since MOAR LUMENS is what sells apparently but means they push the LEDs to their limit.

If you don't want or need the LED voltage readout get this instead should be able to run 3 bulbs off one of buck converter.
Has to do with form factor/footprint an auto LED has a very small surface area. When looking at the various versions/brands pay attention to the casing the more metal surface area the better. Most of these use the 5050 or 2835 LEDs (name is from the physical dimension in mm) what makes them better or worse is the design/casing and of course the LED arrangement. COB LEDs are easily the best when you need to as closely as possible match the original bulb, but they are generally not super bright. I find they run much cooler.

 

LeX2k, thank you! I'm sticking with your recommendations. I've already saved those bulb links on my Amazon account. When the time comes I'll order one of the buck convertors if needed. Good to know they are very small and easily secured in heat shrink tubing. Yeah, I think bulb manufacturers do pay more attention to endlessly upping the light output rather than creating reliable bulbs that better mimic the incandescents they are meant to replace.

Generally I do look for LEDs with well designed metal heat sinks. The COB (Chip On Board) LEDs sound like the best way to go.

An LED bulb conversion will have to wait a bit longer. I wasn't planning on getting into another alternator upgrade attempt so soon but that seemed to become necessary after rewiring the aux fan circuit.

 

I promised I would come back to this and do a proper DIY. A lot of things got in the way and some more subsequent SC repairs took precedence before I could get to it.

...

This is not going to be a full blow by blow breakdown on how to remove the USDM or JDM 2JZ-GTE stock turbo system. The factory TSRM actually covers this surprisingly well (mostly with just a couple of exceptions) and also in this excellent breakdown guide here by SF member 94 Canuck:
https://www.supraforums.com/threads/...how-to.573456/

But some of its picture links are broken so here is an alternative hosting for the same DIY:
https://www.diyauto.com/manufacturer...al-by-94canuck

And if that link doesn't work I have included a PDF version of 94Canuck's guide in the this post in his thread on Supraforums:
https://www.supraforums.com/threads/...#post-13936092

Also, 94Canuck made an addendum thread on MKIV.com which covers the removal of the factory TT cats and downpipe if that is needed:
http://mkiv.com/techarticles/downpipe/downpipe.htm

And this is a good pictorial guide focused on the JDM 2JZ-GTE CT20 twin turbo removal:
https://www.mkivsupra.net/topic/5275...-installation/

Finally, the factory USDM Toyota Supra MKIV TSRM which fully covers the standard method for removing and re-installing the factory twin turbochargers is attached at the end of this post. That is primarily the guide that I used when it came down to doing this entire job.

With the standard Toyota manual pages I took some visual aid help from the 94Canuck guides (and his suggestion to do a couple of the upper level procedures in a different order than the manual says to) and with an extremely crucial guide for the "b*tch bolt" removal and re-torquing that Beezupra @ SF came up with:
https://www.supraforums.com/threads/...#post-13937661

....

First off, this job requires a few special tools to do it right. Also, if you're planning to remove old worn out or blown turbos and install a new factory set you'll either need a safe space for the car or engine to sit until your turbos are rebuilt and sent back to you or you will need to acquire a second set to have rebuilt and ready on standby if you want to make the entire removal and replacement go faster. If you're only going to remove them and go with a single turbo then there's no need to focus on more than just the full removal process.

Lastly it REALLY helps to have a garage to work in. It's even better to have a hydraulic shop lift to put the car onto. I had neither and did all of this in an open driveway with jack stands, a hood mounted engine bay LED light bar, flattened cardboard boxes to lay down onto and while checking the weather reports every day to avoid rainy days.

Even while having 95% of the parts, gaskets and tools that I required beforehand I still had a few times where I had to wait a week or more for something to come in the mail and other times I could only accomplish 1-2 steps any day that I had free to work on the vehicle.

No matter how prepared you are, removing the stock twin turbo system takes a lot of tedious effort and it'll wear you out. I recommend not rushing and commending yourself for each step completed carefully and methodically. Just get it done at your own pace.

Next post I will cover the tools and parts needed.

 

For the removal and reinstallation of the 2JZ-GTE USDM TT or JDM TT twin turbos you will need a few specific tools in addition to your usual set. Most of this stuff you'll need to order in advance. You just won't find them at your local Autozone, Lowes or other tool store.

In addition to short and long 3/8" sockets in 10mm, 12mm and 14mm, and a short 8mm 3/8" socket you will also need:

--Wrenches in 10mm, 12mm, 14mm and ratchet 12mm and 14mm wrenches as well as the longest 14mm wrench you can find.

--For the very long 14mm wrench (which I used as a breaker on the nuts holding the turbochargers to the exhaust manifold) I bought a VIM Tools DPW1417 oil drain plug wrench. About $30.

--Yet another very long 14mm wrench I bought was an EZ-RED #NRM1214 12mm and 14mm angle-adjustable ratchet-style wrench. This was suggested by a Superforums member and it came in handy many times. I never used it to break hard to reach 14mm nuts loose. For that I used the VIM Tools 14mm wrench.

--A Gearwrench 3/8" drive 18" long extension (model #87804). Around $16 or so.

--A Neiko Torx E4 to E24 socket set (Model #04300A). $25 or so. This is needed for removing and re-installing various size factory studs with the correct socket type.

--At Beezupra @ SF's suggestion, it is HIGHLY recommended that you purchase a Power Torque Bolt Extractor set (Model #PTT0022). There are other similar kits but I could only find this sold online through O'Reilly's Auto Parts (you know... that one auto parts chain with the infuriatingly annoying commercial jingles that never leave you alone while you're browsing youtube? Ugh... yeah, order it from them).

Contains extractors for: 10mm (3/8" SAE), 11mm (7/16" SAE), 13mm (1/2" SAE), 14mm (9/16" SAE) and 16mm (5/8" SAE).

That bolt extractor set is absolute GOLD and is required to remove the Exhaust Gas Control Valve housing's difficult to reach bolt... along with a couple of other bits that will go with it.

--A 2" long 1/4" drive extension

--A 3" long 1/4" drive extension

--Various other 3/8" drive socket extensions. "wobble" versions are helpful sometimes.

--A 3/8" socket to 1/4" drive adapter (to the extension and socket wrench)

--A 1/4" socket to 3/8" drive adapter

--A short 1-1.5" socket extension (like a Duralast #73-801)

--A good calibrated 3/8" torque wrench capable. Something in the 1-75 ft-lb range is good. Like a CDI Torque model #752MFRMH.

--A FULL can of PB Blaster penetrating oil.

--A Lisle #66580 23-1/2" Flexible Magnetic Pick-Up Tool. $12 or so. This thing will save you if you ever drop a bolt, nut or small stud while working around the turbochargers. A longer magnetic pick up tool that is non-flexible can be useful too but you should have this one in your tool kit.

--A 14mm 3/8" drive "torque adapter". This is needed to torque down the stock twin turbochargers to the stock exhaust manifold at the correct torque. The clearance is so tight that you absolutely need this. A common "Crows Foot" adapter in 14mm will not do (believe me, I tried one) and will cause stripping of the nuts.

The annoying thing about a 14mm 3/8" torque adaptor is that several tool companies make them... but you WON'T find one listed for sale on Amazon and you WON'T find one for sale at ANY common auto parts stores. No matter which manufacturer's version you choose to buy, they all need to be special ordered and may take up to a week or more to arrive in the mail.

That being the case, order these (and the other listed tools that you don't already have) early. I ordered one from Snap-On. They're all around the same price.

Available 14mm 3/8" drive torque wrench adapters (prices current as of 2021):
Napaonline — Carlyle-NAPA Carlyle Hand Tools P/N CHT-TA38114M — $16.00
TETools — 14mm x 3/8” Drive 2” long torque adapter P/N TA014M — $32.72
Snapon — Snap-On 14mm torque adapter P/N FRDHM14 — $31.00
MacTools — Mac Tools 14mm torque adapter P/N XB214MMR — $28.99
Matcotools — Matco Tools 14mm torque adapter P/N BTA14M — $30.20

Aside, you should also have a 12mm version of one of these in your toolbox for torquing down your main 2JZ mechanical cooling fan nuts (and the 2JZ-GTE M/T accessory belt tensioner shock absorber if you have that on your engine).

And with these you'll need to use a calculator to determine the extension length and adjust your wrench's torque setting to get as close as possible to the TSRM manual required torque for a given bolt/nut: https://www.tekton.com/how-to-accura...rowfoot-wrench

You also want that torque adaptor to stay straight while the torque is being applied. It's not going to be accurate used at an angle.

 

This should be a short list. Other than the turbochargers themselves and the gasket kit (assuming you'll be installing a rebuilt set) there are just a few extra things that are worth doing while all the hardware is out so that many things are easy to access.

--First, the factory Toyota Supra 93-98 USDM turbo gasket kit is P/N 04175-46031. Some gaskets are no longer available individually but this kit includes everything you need for the turbos and immediate hardware attached to them. Depending on where you buy it from it will be $150-$225. There is a different part number for the JDM 2JZ-GTE twin turbo gasket kit which I do not know offhand.

--90179-08101 nuts

--Driftmotion's aftermarket USDM 2JZ-GTE Exhaust Gas Control Housing gasket (which you will use in addition to the OEM gasket that also goes in this location). With as crusty as these cast iron housings can get I think this extra heavy duty custom designed gasket does a lot to help sealing in that location.

--Sometimes one of the studs on the EGCV housing's lower area (which connects to your factory #1 catalytic convertor or down-pipe) can break off. In this case you can either extract the broken stud and then re-tape for a larger diameter stud that still clears the hole on the other side or you can use a slightly under-sized Grade 8 bolt with threads on either end and torque it down with a closed end wrench on the back and your socket (use the Power Torque Tools extractor socket to torque down) on the other side. The latter is what I did even though I'd have preferred to tap the housing for slightly larger studs.

--Any vacuum, air hoses or coolant hoses in your twin turbo system, especially the one that are hard to reach, should be replaced at the time of re-installation. The ones at the very back are especially critical. Same for the OEM clamps going to them.

Notably:
Hose, Air No.8 (x2) 17348-46010 and the clamps 96135-51100 (x4)
And the larger coolant bypass hose right at the back of the rear turbo plus two new clamps for that. That is 16282-46010 with x4 clamps 90467-21010.