1998 SC400: Third Time's the Charm
 

Bit of an impulse buy this week... I joked with the seller of a 1998 SC400 that he needed to hurry up and sell it, because after 4 days of seeing it for sale, I was feeling compelled to travel up and take a look. He lowered the asking price as a result... It didn't take long before I had talked myself into it, and the asking price was quite fair so it was the easiest no-negotiation deal ever.

I did my homework beforehand, determining that it had been driven a consistent 30k miles/year it's first 4 years (regional sales?), then only 51k over the next 13 yrs with the second owner who pampered it and passed it on to the friend/family I bought it from. It didn't come with any maintenance records, but I have most of what I need to know from the Lexus dealer service history. It's not due for a timing belt change for another 20k (now that I have the supplemental owner's manual that confirms the 90k interval), which is reassuring given the interference engine. Seeing it in person, little details like a very new looking OEM radiator indicate it wasn't cheaped out on.

I had very high hopes for the VVTi engine and 5-spd A/T, but I was blown away by how responsive it is! I can now, finally and happily, cross the M/T swap off my wish list.

Things I wasn't fully expecting include: Nakamichi sound system, no cracks in the center and pass. vents, no HVAC LCD bleed or lights out, no gauge needle flicker or back lighting out, all steering wheel tilt/tele works, no cracks in pass. window trim and only one small one in the driver's trim that was repaired before it split, no cracks in rear seat belt trim, all seat motors work, main engine splash shield intact, no broken headlight tabs (highs and lows look like they were replaced recently), original jack and tools, non-faded exterior B-pillars, new windshield, good steering wheel leather, windows work, A/C blows cold (45° @ 92° OAT), and all inner/outer handles intact. Whew. The list of things it needs is laughably short, with just a few missing weatherstrip clips, carpet spills, tired trunk struts, and worn shift knob. Even the sunroof is quiet at highway speeds.

I bought it with the thinking that, if it was as good as hoped for, I would transfer as much as possible over from the '94, such as the black & tan interior swap, the Supra rear sway bar setup, and the wheels and LS400 calipers, then begrudgingly sell the '94 since I don't know what to do with that many cars. It's 10x better than I dared dream, so barring any nasty surprises, it'll be full speed ahead with the conversion.

I haven't settled on a name yet. This is my third and hopefully final SC400, with the middle one being a '95 parts car. Three Strikes has the wrong connotation, but I sort of like it. Hmm. Wait, it's obvious... Son of Goodkat = Slevin!

https://cimg0.ibsrv.net/gimg/www.clu...cae85ca211.jpg

Summary Section, much of it inherited from Goodkat:

The car is currently at 3428 lbs (227+ lbs removed, 5.51% reduction from 3655 lb stock), a calculated 53.6%/46.4% (0.9 percentage points better than stock) front/rear distribution, and is running like a dream. I haven't taken it to the mechanic yet to have it combed over, but nothing of concern has popped up. I haven't seen even a drop leak down below, and I've been under it a few times.

Creature Comforts:

• Permanent Fix for the Window Trim Cracks - Just gluing the breaks won't do anything long-term. It's not a weak seam, as some have suggested. There is no seam. The issue is a lack of bracing along the full length of the trim piece -- the cracks develop between the thin braces every couple of inches -- easily solved with expanding foam to support the entire backside evenly.
  
• 6.5" Rear Deck Speaker Upgrade w/ No Modifications - Pretty self-explanatory, but defies conventional wisdom that the deck openings must be modified to accept a speaker that large. Rounded out with 5.25" door pod speakers. The stock 4" speakers are undersized and surprisingly heavy, although the Nakamichi component tweeters seem to be quite good. The Nak speakers aren't nearly as cheap as what the Pioneer system was spec'd with, but it's evident they're still pretty weak when compared to a modest upgrade.
  
• Aftermarket Subwoofer in Rear Deck - Following the lead of others, upgraded the system without compromising trunk space.
  
• Stereo & Cubby project.
  
• Black & Tan 2-Tone + Mazda RX8 Driver's Seat - Partial interior conversion. The RX8 seat weighs 30 lb less than stock while retaining the power functions (loses the manual recline lever). It's significantly more supportive, especially in the bolsters, while sacrificing only a small amount of the plush comfort. I don't have the corresponding passenger seat, but I've got a "matching" '02 Celica GT seat modified to mount up. Its shape and fit couldn't be much more similar to the RX8 seat, and it's also 30-35 lbs less than the SC passenger seat.
  
• Matrix XRS 3-Spoke Steering Wheel - I thought the smaller wheel might make for twitchy steering, but it actually does just the opposite, damping the overly power assisted input. (Less leverage from closer in.) Smaller diameter and better hand grips make it an all-around sportier experience.
  
• Vent-less Dash Vents - Yeah, I went there.
  
• Remote Key Programming

Performance and Wishful Thinking Performance:

• Alternative BFI Air Intake - or BeeFI, as I like to call it. I truly believe this is an improvement over the traditional BFI design and has the advantage of being all but invisible for Cali modders. All of the benefits (and more), with none of the drawbacks. You can still access the headlight as normal, and there's no danger of a "normally open" design suddenly becoming "normally closed" in the event of broken plastic bits like with the traditional BFI.
  
• M2 Performance / Manzo axleback exhaust - Dropped nearly 9.5 lbs, sounds better, looks better (more so in filling out the '97+ body kit than it did on the '94), and possibly performs better. Deleting the center resonator and two rear resonators and adding an improved downstream y-pipe (along with bigger 2.5" in and 2.25" dual out tubing) dropped another 9 lbs -- closer to the additional 10-15 lbs I was hoping for than the 1994's 5.5 lbs savings with the smaller resonators. But boy does it sound mean now!
  
• '95+ LS400 Front Brakes with Modified Dust Shields - Improved braking but not nearly the 13+ lb alleged weight savings, coming in at less than half that. Techna-Fit stainless steel brake lines.
  
• MKIV Supra 22mm Rear Sway Bar - I thought it would be an easy swap from the '94, but the subframe mounts won't come off the '98 so it's on hold until getting it up on the lift and tackling it with higher powered tools.
  
• MKIV Supra A/T Limited Slip Differential - awaiting installation.
  
• A650E Pressure Regulator Mod - The equivalent of the A340E 4th solenoid mod? In theory, at least... In practice, I can't say I noticed much of a difference.

Factory Frankenstein status: '97 black interior elements for 2-tone look, '95+ LS400 front calipers, LS400 inner door handles, SC430 cargo net, Matrix XRS steering wheel, MKIV Supra rear sway bar (pending), MKIV Supra LSD (pending), '05 RX8 Shinka driver's seat, part-time '02 Celica GT passenger seat, '04 Mazda6 shift knob, '07-09 G37 Enkei donut spare, '98 front / '95 rear Mustang Cobra summer wheels & '93-97 MKIV Supra TT winter wheels, and '00 Elantra stubby antenna. Just because.

moved pictures to post#4...

Those are nice! Probably one of the best combos for the SC. Pretty much all the latest options and the best out of the box drivetrain that these came with in the US.

Do these have electronic throttle control or a cable/mechanical throttle?

If electronic, I would highly recommend getting the Blitz Throttle Controller for it. It was one of the first and best mods I did to my GS430. Plug and play and gives you several responsiveness settings to choose from so you can set it to either stock responsiveness (when it's not activated), or choose between ECO (even more laggy than stock to settings 1-3 which are far more responsive). Also, if you can find an SRT intake and ECU mod, that also makes a world of a difference in sound and some performance (claimed up to 30whp). They're out of business so might be tough to find on the used market.

LS400 bbk, high quality coilovers, and catback exhaust is a MUST for these. Makes the car feel completely different and much more fun/safer to drive.

Here are a few pics after driving it home and a bit of interior cleaning plus quick exterior rinse.

https://cimg0.ibsrv.net/gimg/www.clu...6923042b31.jpg

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And here's the engine bay after removing the silly cover, doing some cleaning, and most recently, replacing most of the vacuum hoses (all but the PS pump and brake booster) and changing up the routing a bit:

https://cimg5.ibsrv.net/gimg/www.clu...2254a9b735.jpg

Without the engine cover, there's no need for the heavily shaped hoses to squeeze into the tight contours. The PCV valve and crankcase vent hoses are significantly easier to remove now, and there's less strain on the plastic barbs of the purge solenoid and air intake.


Yeah, people definitely have not overstated the improvements. '99 gains the perforated leather and 3-spoke steering wheel, but I'll be putting my RX8 seat and a different steering wheel in, so '98 is as good as it gets for all intents and purposes.

Mechanical. I was expecting electronic at first, too. Thanks for the Blitz suggestion, though. Sounds like a nice option for that configuration. :)

Swift Racing Technologies? I can't help but think Dodge when I see that acronym... I found several search results, so that gives me some stuff to read up on. I had planned on transferring over my alternative BFI.

I'll be swapping over the LS400 calipers and axleback exhaust. I'll call the exhaust shop and see if the custom stuff they did up from the front y-pipe back to the mufflers, eliminating the center and rear resonators, can be swapped over, as well. It's welded to the front y, so it would require several steps of cutting and re-welding between the two cars, or unbolting at the cats and moving the whole thing over if everything's the same.

I had started reading up on Gixxer Drew options before buying the '98, figuring the shocks would likely be toast. They seem to be in pretty good shape, though, so that's not a pressing need.

I tried swapping over my '95-96 tail lights this morning, having read that they're compatible without the '92-94 hyperflash issues, but the bolt holes and locator pin don't quite line up. I thought that was only for '97-00 tails on '92-94, but since '92-94 and '95-96 are compatible, that makes sense. I put the '98 tail back in for the time being, since I don't really care to modify the housings and/or body to fit.

Congrats on the upgrade. :thumbup:

Thanks!

I got it registered today and did more cleaning of the carpet spills, following a friend's advice and scrubbing with Simple Green. A couple more rounds of that and it should be presentable. I picked up an '04 Mazda 6 perforated black leather shift knob to replace my worn one. It looks quite nice as-is, but should really work well once the black interior bits are added around it. I also got my alternate BFI transferred over and swapped headlight/parking bulbs. While in there, I discovered this mysterious box in the passenger fender/grill:

https://cimg2.ibsrv.net/gimg/www.clu...d5067641d5.jpg

'98 on the left, '94 on the right.

Any idea what that is? It says Toyota Denso 7740-24060 on the bottom, but I can't find anything for that. It has a couple hoses running to it in back and an overflow hose in front. Some sort of reservoir? It's an extremely heavy mounting bracket, whatever it is, so it would seem to be of some significance.

On a related note, I'm still looking for some sort of factory service manual for 1998+, since the one floating around all over the internet is only applicable to non-VVTi aspects. So much about the 1UZ is suddenly foreign to me, like whether it has an IACV, whether it's possible to adjust the TPS, why the vacuum and coolant lines both connect to what look like hard fuel lines, etc. My hood sticker is missing, so I don't have any hose/belt routing hints there. I'm not all the way through the owner's manual yet, though, so maybe I'll find some answers in there.

Also, here's a side by side shot of the '97-00 vs '95-96 tails, with the latter just set in place since the holes and pegs don't line up:

https://cimg2.ibsrv.net/gimg/www.clu...535735eda3.jpg

Sure would be nice to put the earlier ones on and do away with the chrome trim, but I'll sit on that for the time being. Gotta tackle brakes, wheels, exhaust, Supra rear sway bar, and interior first. :)

The box on the 98 is the charcoal canister. They relocated it for the vvti. The 2 hard lines running by the intake plastic are evap lines that go to that canister.

As an fyi: the vvti is electronic throttle. The cable actuates the accelerator position sensor. The long metal motor on the drivers side of the throttle body is what actually opens the butterfly. The cable also acts as a failsafe as well. It will open the throttle manually to 30% if the throttle motor fails so you can limp home.

Your engine is also has returnless fuel system. The tank and pump assembly is different from the 92-97. What used to be the return line to the tank on the earlier cars is used for evap now. It runs across the back of the bay and over to the canister.

I am of the opinion that the vvti motor is much easier to work on from a maintenance perspective. The only thing I can't figure out is where the heater valve vacuum line plugs on to the motor. The intake doesn't have the nipple on the back like the older engine does.

Hope this helps.

^ That helps a ton, thanks! The lack of a charcoal canister in the usual place was obvious, but never having owned an OBDII and/or VVT car, I assumed it was somehow eliminated along with the EGR system. The '98+ box looks so different from the old one, I never would have guessed that's what it is. That explains the hard lines running down that direction, disappearing below the intake. I figured they were headed toward the PS pump or something. I could've sworn one connected to a coolant bypass, but maybe I followed it wrong and it was actually a vacuum solenoid for the canister.

Er, okay, make that electronic throttle. :) Again, I've only worked on cars with a traditional throttle cable, so I figured the presence of such a contraption meant that's what it is. I'll have to follow it around back with daylight tomorrow and see what it is you're describing. The cable had quite a bit of slack in it, so I tightened it up this evening but haven't gone for a test drive yet. I'm thinking now that that wouldn't make a difference, though, if it's just a fail safe.

I noticed the fuel rail is configured quite a bit differently. Fuel pressure loss was one of my biggest headaches on the '94, so anything that operates differently is okay by me!

I'll take a look at the HCV and see if I can figure out where it ties in... It helps having the two cars close by to check what's different. At first glance, I've found it odd how few vacuum lines there are compared to the older 1UZ. You don't by any chance have a picture of your hood sticker?

I don't have the hood sticker from the donor car, it was wrecked. I transplanted the vvti into my 95.

My 98 SC300 has the charcoal canister in the same location.

The 98-00 vvt-i cars are always a little harder to find information for. I would recommend searching for a service manual from the 98-00 GS400 since the basic engine specs will be the same.

I took another look at it today, and boy is that deceptive. It sure looks like a throttle cable running through the firewall to the pedal. :)

There's a vacuum barb on the top of the intake plenum, dead center toward the back. The HCV runs to a tee just off of that, with the other end of the tee running under the resonator box and down toward what I'm guessing is the PS pump. That's how mine is set up, at least.

Oh wow, so you're really the expert now on the ins and outs of the VVTi, having transplanted it!

Ooh, good call! I was actually just reading some GS400 intake manifold stuff when you posted that, but hadn't thought to venture down that road for general engine documentation, as well.

Well, it technically *is* a throttle cable. I know when I first got the donor car, I thought it was 100% drive by wire. Needless to say, the gas pedal assembly is the same for all cars, just has a different cable.

Took me a second to wrap my head around what you were saying, but I get it now, and it makes sense. By the way, you are correct, it runs to the power steering pump.


I swapped everything that was necessary over with the least amount of "hacking and cutting" possible. That included, but is not limited to:

• Dash
• Cowl wiring
• Dash Wiring
• Steering column
• both airbags
• fuel tank/pump assy.
• tank hard lines
• all relevant ecus (and their respective mounts)
• engine, trans, rear
• instrument cluster
• shifter
• ABS pump and hard lines (front only, rear did need to be changed)
• all EVAP stuff (which included the passenger tow hook from the 99)

My goal was to have a really clean swap, that could be seen as seamless. The only real wiring changes I had to make were swapping out the foglight connectors, and had to purchase the relay set that mounts under the fender for the DRL (so I can have high beams). The only other real wiring I had to do was swap out the blue body connector in the passenger rocker panel so my fuel door would pop. I also was fortunate enough to get 2 keys to the car so I could not have to worry about the immobilizer.

I made sure to do timing belt, etc including all new seals and gaskets for the entire engine and trans.I even used the full 99 exhaust. It just sounded better to me. Less noisy (well, it *does* have 2 large resonators in place of the cans that the 92-97 has).

The engine i put in has 174K on it. My dad (who lives to hate on toyota) can't believe how good it sounds.

My ultimate goal for the car is to make it a bit more modern. 290hp helps toward that goal ALOT. I'm actually planning to tag her and take her out for her first battery of shakedowns early next week.

Now that my diatribe is over, yes, throughout this process I have learned so much about the VVTi. Expert level? That's debatable, but i'd be happy to answer anyones questions that they may have. It's not the easiest of swaps, that's for sure, and it's also not cheap. You really have to have a passion for the UZ (sadly, nobody really does). I'll never sell this car for what it's worth to me from a time standpoint, plus, having something that not a whole lot of other people have is sweet too.


I don't have the full FSM, but I have the full TEWD for the 99, which is pretty much going to be the same for you (with a few small exceptions).

Manuals

Oh yeah, I almost forgot. You will rue the day you have to put cam seals in it...

The lack of a picture is worth a thousand questions. :)

You know, it might have been easier to swap a '95 body onto a '99, rather than everything you moved over to the earlier car... J/k. That's a helluva undertaking.

Did they change which wires that connector carries or something?

That's a big bonus, to be sure. I got one Master and one Valet key with the '98, but the Master has a broken key ring loop on the handle, making it somewhat worthless. As soon as the title is in my name, I'll see about getting the key code from the Lexus dealer (inconvenient, being a ~3 hr drive) and then get a new Master cut, swap the remote/chip over to it, and set the original aside as a spare. That should cover my needs with minimal expense, considering the cost of new remote keys.

I had planned on doing the timing belt ASAP, given the unknown maintenance history, but it turns out it was done 70k ago, so I don't have to worry about it for awhile. They did it at the 120k service, oddly, instead of the 90k the manual calls for. I guess that supports the notion that the 90k interval is very conservative.

How does the '98-00 exhaust differ from the earlier ones? I was under there today, swapping my axlebacks (TBD if I can get the custom midsection transferred over), and I didn't see anything obviously different. The rear resonators might be situated differently, but I'd have to line the old ones up to be sure of the angle.

Awesome, thanks! I'm guessing TEWD stands for Toyota Electrical Wiring Diagrams? I couldn't find the acronym anywhere, but that fits them all looking to be electrical PDFs. All the GS400 service manual links seem to be long gone.

That fun, huh? Like, 1UZ starter bad?

The three connectors that come up the rocker panel from the rear are different. The blue one iirc has a single blue wire for the fuel door, and also has the wires for the TRAC ecu if equipped. For 98 they moved the Trac ecu to under the passenger rear quarter window next to the wireless lock ecu. My 95, as well as the 99 donor, we're not Trac cars, so my blue connector had just a single wire in it. Was a simple pop the tab and slide the wire into my old connector at the appropriate position.

I wanted to retain my 95 keys because of missing the door locks, etc from the 99. I cut the key end off and attached it directly to the immobilizer ring, then stuffed it back behind the radio. I plan on adding a manual kill switch for extra security to kill the signal to the ecu.

I would recommend popping the cam sprocket covers off and looking at the condition of the belt. Also check for oil anywhere around the sprocket. The sprocket is the vvti gear, and it can leak oil. The "nut" on the front of the gear is actually a cover, and it has a gasket.

The cats are different. The resonators before the mufflers are not straight through like the 92-97. They are larger rectangular units that actually 90 degree out to the mufflers. They did it for quietness over the old style.

You are correct. Overall, a 92-97 FSM will cover 85% of the same material that the 98+ would. The vvti is not a while lot different to work on than the pre-vvti. The a650e is essentially an a341e with an extra gear slapped in it.

Have to take out the intake cam on each side. Can be tricky to get set back correctly. Fortunately toyota did a good job marking the sprockets and whatnot. It's something to do if you do the timing belt.