JoeYabuki

Whats up guys,

Currently going in on my r154 swap. Car is an Auto 1995 CA spec Sc300. Super indecisive on build, sitting on some OEM supra twins but may go single turbo. 400hp is my goal.

(Kahn if you are reading this, I think single turbo is the best way forward budget wise lmk if you come to so-cal we can work out a trade or something for the TT's.)

These are the parts I have currently sourced (2023 pricing for anyone trying this in the present day.)

mk3 supra r154 non tripod - $1000
Currently looking to get a jzx-90 tripod mount. Anyone know if this a compatible length?
The R154 I bought came with the shifter, can this be used once I extend the shifter to the tripod style?

Mk3 supra driveshaft - $250
My understanding is that the front half of the mk3 will mate to the auto rear and I need to transfer over the sc300 carrier bearing. From what I read this will fit in nicely.

Oem clutch(? i assume) assembly and break pedal - $80
Brake pedal is in, thats definitely an OEM part. Not looking forward to installing the clutch pedal assembly. Ive read the horror stories. I have the clutch master cylinder too but it might need to be replaced.

To all that have done this, did you need to relocate all the steering wheel tilt ecus etc? I want to keep mine for now (they all work )

I am probably going to buy a JZ bell housing from Driftmotion, shifter extension too if the Jzx-90 doesn't fit. If anyone has a bell housing lmk.

Question: Am I looking for a MK3 flywheel/clutch or with the JZ bell housing am I now sourcing a JZ flywheel etc?

I'll post a spreadsheet I got going with parts and pricing for visibility to all the dudes(and girls) doing this now in 2023.

For the time being, I am just cleaning up all the used pieces and planning my build. I know this subject has been covered countless times but I wanted to track my progress.

Pics to follow once I am home and am not pretending to work.

KahnBB6

iTrader: (5)

Hey Joe,

Being in California you already know what I am going to say: build the engine with reconditioned stock twins and get a fully working USDM EGR system on there, USDM 550cc injectors and a USDM 93-95 6-speed ECU. And cats. I agree with you completely regarding the cost and complexity being more straightforward and easier with a modern single turbo but.... you're in California. If I had no plans to take my car back there I probably wouldn't have built it with stock sequential twins. It's not about budget but rather what won't be a legal issue.

Further, it is much easier to use a stock twin setup with a 2JZ-GTE short block since the turbo oil feed holes (two of them) are ready to bolt right up on the exhaust side and the GTE oil pump has slightly more capacity than the GE to feed both the two turbochargers as well as the built in piston oil squirters.

Also there is some logic to retaining OEM 2JZ-GTE pistons and rings for a CA legal build. Since they are hypereutectic (just like the 92-97 2JZ-GE Non-VVT-i pistons) they have expansion and contraction properties that better control oil blowby. The pistons themselves are good up to a ceiling of 700whp and even the OEM 92-97 GE and GTE rods just need ARP rod bolts to make them strong enough to handle up to a ceiling of 700whp themselves. But common forged 2618 pistons, for all their strength, will have a little more trouble with cold start emissions and a little more blowby than the OEM GTE pistons.

And the those stock twins DO need to function in sequential mode for testing purposes:

This is because when the EGCV (Exhaust Gas Control Valve... right before the #1 cat bolts up) has exhaust flow to the #2 turbo closed off below 3800-4200 rpm it causes a condition of high back-pressure and low volumetric efficiency. This is actually one of the things that allows the stock setup to put out its normal emissions numbers.

When the EGCV has either opened up in sequential mode or is perpetually open in the 5min TTC or permanent TTC configurations there is now full exhaust flow to the #1 and #2 turbos. This creates high volumetric efficiency in the exhaust stream and much lower back-pressure... which is good for higher RPM power but not good for passing emissions at lower engine speeds.

A few MKIV TT owners on Supraforums have confirmed in the past that most of the time their stock twin cars would not pass smog while in TTC mode but would in sequential mode.

So over there it pays to be able to switch between a functioning sequential system and TTC mode. Although around the city even with a manual transmission I still prefer sequential mode.

.....

As far as parts go I appreciate the offer but I already have a spare set of USDM twin turbos in case I might need for future servicing. I recommend you hang onto those however. Are yours JDM or USDM twins? You should be able to make a set of rebuilt (with upgraded steel wheels) JDM stock twins work with a swap but it's much easier to use either version with a GTE short block since the turbo oil feed holes bolt right up. Then you just need to get a custom fitted #1 cat and #2 cat. #1 is the hardest to have made for you since the USDM and JDM turbo outlet flange designs are different. You can buy raw flanges for an exhaust fabrication shop to use from Driftmotion.


I am not 100% on this but I think the JZX110 toploader upper shift housing and extended arm will work on an MKIII R154 transmission at the same extension length as a later R154 Tripod extension. BUT.... do some more reading here on the forums. I know that some members have experimented with either the JZX100 or JZX110 upper housings but I am fuzzy as to whether this actually worked for them on an R154 or an R150 or an R155. There are some very subtle bolt mounting hole spacing differences up top for one or more of those R-series transmissions.

A tripod shifter assembly will require that you swap on an entire R154 Tripod rear tail-shaft housing. That's difficult to source and a lot of trouble.

Alternatively you can use XCessive Manufacturing's Soarer 154 extension housing and shift arm replica service... but the shifter outlet placement is further forward in the 1992-1994 5-speed manual SC style. Depending on how you want to modify your transmission tunnel that may or may not work for you.

Also if you will stick with that MKIII R154 consider getting it rebuilt with new heavy duty bearings, a Marlin Crawler 1st gear chromoly thrust washer, Marlin Crawler chromoly front bearing retainer plate and all billet aluminum shift forks from either Marlin Crawler or Driftmotion.

It is a *close and tight* fit yes... but what you should really do is take that MKIII R154 front driveshaft and your SC's rear driveshaft with the SC center bearing swapped onto it to a professional driveline modification shop and have them shorten the barrel section by approximately -3/4". NO MORE. That adjusts its length to be exactly the same as a JZZ30 Soarer R154 front driveshaft. It all needs to be rebalanced as a full two-piece system on a two-piece driveshaft balancing machine by the shop.

You have to remember that the Supra MKIII with a 7M-GTE and matching 7M bellhousing makes the R154 stick out 3/4" shorter within the MKIII chassis at the tail end than an R154 sits in an SC300/400/Soarer chassis. Hence the need to shorten the MKIII R154 front driveshaft approximately -3/4" for an SC application. I went through this myself with my own MKIII R154 front driveshaft fitment.

Alternatively you can have your stock SC300 Auto front driveshaft barrel section *lengthened* by approximately +50mm (aka +1.96"). That will make the SC300 Auto front driveshaft the same length as a JZZ30 Soarer R154 front driveshaft. The splines fit perfectly in your R154 but in stock form this driveshaft is dangerously too short. Actually since the SC300 Auto driveshaft has a uniform barrel it should be the easier of the two front driveshafts to have modified for length and re-balanced by the driveline shop. It will also look 100% the same as a genuine Soarer JZZ30 R154 front driveshaft when you're done getting it lengthened.


The manual SC brake pedal is direct bolt in. The clutch pedal assembly can be used OEM or you can go with XCessive Manufacturing's aftermarket SC manual clutch pedal kit.

You can also install the MKIV Supra LHD clutch pedal bracket and pedal parts. They are of a different design but function just the same minus the helper spring on the side which only the SC/Soarer OEM clutch pedals have.

No need to change or relocate anything with the stock SC tilt column assembly or its ECUs.

Get the 1JZ-R154 bell-housing from them. You need that for any R-series swap. Shifter extensions again see my comments above.

For a JZ engine with an R154 transmission you will need the 1JZ-R154 flywheel. The OEM steel version is fine and worth it as they last a long time. You do not need or have much benefit from any lightweight aluminum flywheel with these engines in such a heavy chassis.

RudysSC

I can't ever add much to Craig's awesome posts, however, I'm very much lookin' forward to watching your build come together! And the CALI legal builds always intrigue me - a lot of detail and jumping through hoops involved but the finished product is always awesome.

joewitafro

Pretty certain the tripod will not bolt onto the early transmission. They used to sell an OEM extension from toyota with a swan shifter for an early model soarer before the swap to tripod, but those parts have since been discontinued so you'll find shops like driftmotion that extend your inner linkage rod, and extend the top aluminum mount to fit a standard MK3 supra shifter; this is what I recommend you do.

KahnBB6

iTrader: (5)

^^ This. The tripod shifter setup WILL NOT bolt up to an MKIII R154.

I managed to buy one of the OEM 1991-1993 JZZ30 Soarer R154 shifter housing extensions and the OEM internal extension arm back in 2013... when they were already getting close to being discontinued. I converted my MKIII R154 with that. However... this made the most sense for me because I have an early 1992-1994 style original 5-speed SC which has the correct transmission tunnel opening to allow that housing to line up perfectly where it should be as-is. The early SC300 5-speed "swan bend" style shifter has to be swapped over to make it work. Or an original Soarer early style swan shifter or one of a couple of swan bend aftermarket short shifters (an old SupraSport V2 or V3 short shifter or an old C's short shifter).

This early style style setup has a shifter opening that is still a few inches further forward than an R154 Tripod transmission has its shifter sit in the tunnel.

XCessive Manufacturing does make a replica of this extension housing with a service to extend your MKIII R154's internal shift arm to match.

A solution might have been to order and swap in the OEM 1992-1994 Lexus SC300 5-speed transmission top sheetmetal... but that part has been discontinued. The MKIV/SC/Soarer Tripod style M/T transmission tunnel top sheetmetal is still available however.

Both Driftmotion and XCessive Manufacturing also offer extension housing custom lengthening services to bring the toploader shifter out to the distance that all tripod transmissions have it sit at. That is another option.

....

If you stick with an MKIII R154 you need to go with one of these two shifter extension housing options. The replica housing that XCessive sells is the closest to how Toyota did it in 1991-1993 5-speed manual Soarers. But you do need a "swan" style shifter for that.

joewitafro

I actually have both of these R154's; my original early model chaser/soarer R154 that i picked up for $400. You can really see shifter position based on those upper 6 bolt holes.



And my brand new tripod R154 that cost me ~$3000

KahnBB6

iTrader: (5)

Ah!! That is very cool! Well in your case there is NO need to modify either shifter setup. They are already exactly as they need to be in stock form.

The early toploader Soarer R154 could probably do with a case cleanup and repainting (masking off the center steel plate when spraying) and it would be a good candidate for a full rebuild and upgrade with Driftmotion and Marlin Crawler parts.

The brand new tripod R154 shouldn't need any of that out of the box unless you want to throw the kitchen sink at it horsepower-wise. Also it has a revised and more reliable 1st gear thrust washer that needs upgrading in the earlier R154 versions.

....

What you need to decide now is which shifter setup you want to commit to.

Honestly? I would buy the OEM top tunnel sheetmetal for an MKIV (P/N 58261-14010, McGeorge Toyota)

Or the SC auto to manual tunnel conversion plate kit that is sometimes available on ebay from one fabricator:

https://www.ebay.com/itm/16494114354...Bk9SR_Ct9ZDvYQ

Use either tunnel conversion solution, buy the OEM tripod rubber dust boot parts (which are essential). Then install your new Tripod manual transmission.

The early toploader Soarer R154 version will need the earlier 92-94 SC/Soarer style manual tunnel top sheetmetal to make for the most OEM-like install and I believe that part has been discontinued already. You can alternatively do a custom cut of your auto transmission tunnel to fit the older style toploader R154 but to do it right you would still need to drill and fit on the rubber dust boot isolator to keep out heat, noise and extra vibration coming into the cabin.

In your case you just bought the newest and most updated R154 version so I think that is the one you should focus on preparing the car for, just my feeling on it.

You only need to add the OEM metal deflector cover to the rear of the tripod R154 (P/N 33146-30020 "Deflector Extension"). $25 part. Just paint it before getting it installed (it has to be hammered on carefully and uniformly using a block of wood to protect it while doing so). Your older early Soarer R154 already has that deflector on it.

JoeYabuki

aaaaannnndddd, I'm back. This is going to be a slow-moving build. The goal is to have everything prepped before swapping. Trying to aim for two weekends of actual labor on the swap.

I cleaned up the Mk3 R154. Currently getting it ready to remove the shifter housing and send it to Drift Motion for the extension service and pick up a 1jz bell housing. Thanks, Kahn, I'm going to add those Marlin Crawler parts to my little spreadsheet. Hoping to get the transmission built now so I can worry about the clutch and general stuff.

Looking into shifter options now as well. If anyone reading this has had the extension done, what aftermarket shifter assembly have you gone with?



I was able to pick up another SC300 Auto drive shaft today. I figure having an extra one would be good peace of mind. The plan is to mate the Auto SC rear w/carrier bearing to the front MK3 now and send it in the have the MK3 front shortened by -3/4" Thanks again Kahn.

I'll put them together and take a before and after (length adjustment photo)


If for whatever reason I don't like how the Mk3 SC combo mates, I will have the parts available to lengthen the Auto drive shaft to Soarer specs.

Currently, waiting to pick up a drill bit for the clutch master and start the clutch pedal process. I said it before, and I'll say it again, I'm a little intimidated. Deciding if i want to keep this, OEM clutch master cylinder, or get something aftermarket.

I need to reassemble some of the clutch pedal, I pulled it out of a junkyard SC in the pouring rain so I was a little haphazard when removing.

I did, however, get the manual brake pedal in. A little incentive to just install the clutch pedal already and not have to worry about it.

KahnBB6

iTrader: (5)

Excellent work and planning all around, Joe! Your plan to shorten the MKIII R154 front driveshaft will work out just fine and if you so choose to you will have the spare SC300 Auto front d/s to lengthen.

Yes, since you have an MKIII R154 (I do too) it is a good idea to have a rebuild done and upgrade the 1st gear thrust washer, front bearing retainer plate and all the original shift forks to stronger billet aluminum Driftmotion and Marlin Crawler replacement upgrades. That will give you a very strong R154 that will be good up to its known 700whp or so power holding ceiling. 3rd gear is the one weak point of all R154 transmissions at VERY high power levels beyond that but so long as you aren't absolutely thrashing the transmission and slamming all the gears into place there will be no problem. It is a strong gearbox.

There is always the option to upgrade it with straight cut gearsets for even more power holding but that's really something you'd only want to do for a racecar.

....

When I picked up my MKIII R154 (in 2013) the OEM early Soarer R154 shift housing extensions and matching internal extended shift arm were still just barely available new. I bought both parts and had them installed with my transmission rebuild. For me this was a good choice because this allowed my R154's shifter to sit exactly right in the original tunnel opening of my 1993 original 5-speed (all 1992-1994 OEM 5-speed chassis have this shifter opening placement).

As such I first just re-used my OEM 92-94 SC300 5-speed swan neck shifter but I quickly switched to the (now long discontinued) SupraSport V3 short shifter made for Supra MKIII W58's and R154's. It is also a swan neck bend and works perfectly with 1992-1994 SC300 5-speeds using either the original 92-94 SC W58 or a converted MKIII R154 or an original 91-93 Soarer R154. All non-tripod.

....

But since you don't have the same transmission tunnel shifter hole placement that 92-94 SC 5-speeds have your install will require modification to or replacement of the tunnel no matter what.

What extension housing length you go with is up to you. And that will determine whether or not you'll need to scare up a swan neck shifter or use one of the R154 shifters made by Driftmotion. Cube also makes an aftermarket shifter but the round mounting section seems more appropriate to me in the DM aftermarket shifter offering (the old discontinued SupraSport V2 and V3 "swan" short shifters also use a round mounting boss.... as do the extremely old and discontinued C's "swan" short shifters for early type non-tripod R154's).

Driftmotion's shifter has a single angle bend reminiscent of classic American muscle car shifters and I am not certain where that lets your hand fall onto the shifter ball or leather wrapped end depending on what extension length you get.

The way the shifters are supposed visually to sit in the center console with the leather boot on is straight up... even if underneath it all there is a "swan" bend.

With Tripod R154's (and Tripod W58's and V160/161's) their shifters are all straight and pointing up naturally.

JoeYabuki

Testing Testing...


Clutch pedal test

Quick cruise control delete to free up space and got the clutch pedal assembly mocked up. Looks like things are going to be pretty straight forward from here on out.


Did a quick run through off all the clutch assembly parts. Order some new bushings and plastic bits that have gone all brittle. The pedal itself was sitting weird so I figure a modest rebuild wouldnt hurt.

Stoked for the Chase Bays / Wilwood Clutch master I got.

Bore Diameter is 35.6mm bore. Got myself a 37mm Hole Saw bit for some precise fitment. For the bolts, the drawings say 8.6mm so I picked up a 9mm drill bit.

Crude approximations of the template diameter (Bolt Holes)

Crude approximations of the template diameter (Bore Holes)

Behold. The template. Top most bolt hole was filled with seam sealer, scraped it out with a flat head.

Cruise control ECU delete helped a ton with space. Considering trying to remount the tilt steering module to where the CC sat. CC sat clear of the clutch.

Carrier bearing swapped over.

MK3 front compared to the Sc300 Auto front D/S.

JoeYabuki

One thing I noticed is that there are no obvious bolt holes for the bottom of the clutch pedal mount. Am I correct? Or just insanely blind?

The next time I check in, it's drillin' time. Also, plan on getting the driveshaft over for a balance and 50mm chop.

Thanks all for weighing in, I really appreciate being able to bounce around ideas and getting responses. Very Motivating!

May is lined up against me. My daughter's birthday, Mother's Day, and my Wife's birthday rolled into one. I can for sure say I am not rolling around in car money.

R154 modifications will happen slowly.

RudysSC

You're absolutely killin it man. I've never had my clutch pedal removed from my car so I'm uncertain about the holes, however, check out a few manual swap threads as of late and hopefully they mention if there are existing holes (I believe there are...).

Good things take time - can't wait to see this come together for you! Rowing your own gears in these big bad coupes is an awesome feeling.

JoeYabuki

Finally found the time to get back in there. This round was the final fitment of the Clutch Pedal assembly and Master Cylinder.


37mm center bore to fit the Chase Bays master cylinder. I used an 9mm drill bit for the two mounting holes. I had a tough time staying centered when drilling the mounting holes. I self taping punch would be a good thing to have.

Deburred and smoothed out the holes using a cheap harbor freight rotary. Test fitting the ChaseBays master before a bit of paint on the exposed metal.

Ran into a small fitment issue. The ChaseBays rubber boot is beefier than the stock Aisin boot. I removed about 3mm of material from the cylinder hole of the pedal assembly so everything sat flush.

View of the ChaseBays Master from the engine bay. I'm pretty stoked, it looks nice and clean in the engine bay.

Bonus shot my wife took of my struggle. Tip: Get a small LED light with a magnet mount. Helped a ton under the dash.

I always wondered why people don't have to many actual pedal install photos. Now I know. It's a b*tch. For ease. I removed the cruise control ECU last week. I ended up mounting the tilt/steering ECU to the CC bracket. This freed up alot of room for the clutch pedal itself.

This is where it is sitting at the moment. It feels a bit off to me. However, I did not attach the pedal itself to the master just yet. So this is full lock up.

Everything all buttoned back up. I need to take a second look at pedal placement next round. Super stoked all together. I wanted to put the pedal in now as motivation to continue the project. Can't wait for seats and steering wheel.

JoeYabuki

Thanks, Rudy!! Documenting the process here and getting feedback has been great motivation.

JoeYabuki

Now that the clutch pedal is in, it's time to get the drive shaft shortened. I need to compile a list of the parts needed now.

Slowly recharging the wallet for the eventual shifter extension and 1jz bell housing from Driftmotion. Also shopping flywheel, and clutch setups. That seems to be the last two major expenses.

I estimate about $750 to get the transmission ready to plug in. If I could find a clutch and flywheel for roughly $450 I would be stoked. Then I would have some budget for a KAAZ LSD. Scouring FB marketplace for some used bits. If anyone has economical recommendations, I am all ears.

On a side note, I have been thinking about interior shift boot options. I don't think it's worth going OEM for the bezel. I have it in my head to go Old School and source a rubber accordion-style one that would fit.

AE86 Shift boot for reference.

Has anyone ever seen this done in an SC? Debating if it would translate at all or just fall flat and look goofy. I guess its all about final execution. I'm going to give it a shot.