Mkiv Supra TT Lifecycle / Progression

[pwpanas]

Here are some of the steps I've gone through and/or learned the hard way as to the 'right' path that grew my driver skills as I owned, drove, and upgraded my Supra.

• I've come to think that anyone should start with the right Supra. For example, I figure if you want to go fast, forget the n/a Supra - you need a real TT. As we've discussed in several other threads, upgrading the n/a into a *full* tt spec simply costs too much...so get a TT right in the beginning if performance is what you have in mind.
• On the other hand, if you just want to look good, get an n/a - spend your time waxing it and cruising for dates - it's still a VERY cool looking ride!
• As I'll get into a bit more below, think about mileage, condition, whether it's already been modded, etc. and don't settle for less than what you want.

Note: From this point forward, I'm going to focus on the TT, since that's all I've owned and worked with. Somehow, I kind of got lucky and ended up with an Mkiv TT long before anyone knew how upgradeable and over-engineered it is.

• Be willing to spend some long, hard time searching for the exact condition of Supra you want. This is a VERY rare car, so you'll often have to put your best offer on the table within hours of it being posted for sale (contingent upon getting it checked out, of course). Be sure it hasn't been modified, and the 2jz-gte compression/leakdown tests are performed..
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• Whether you're starting with a relatively low mileage Supra or one with 200K+miles, I've found that proper maintenance is the foundation of everything you'll want to do with your Supra.
  • Don't skimp on tires - they're the only thing connecting your car to the pavement. Use oem-spec rubber or better (i.e. Z-rated), in the correct sizes. Lower-performance tires will reduce the usability of your horsepower *and* will also reduce the effectiveness of the Mkiv TT's excellent braking system.
  • Use oem-spec fluids or better. Synthetic 10W-30 motor oil, for example. Toyota 'red' coolant. etc.
  • If >50K miles, replace the oem plugs. Use platinum or iridium plugs - copper plugs must be changed every 5K miles or so.
  • Change the timing belt a 60K intervals, per the owner's manual
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• Although the Mkiv TT is an incredible vehicle, there are a few of quite minor, but irritating items that 'wear out'...things not mentioned in the owner's manual:
  • Rear hatch bumpers ('93.5-'95) (annoying rattle) - (easy) 'yota issued replacement bumpers in '96 that fixed the problem, but no recall was issued.
  • Coilpacks above 75K miles (weaker spark) - just get a new set (easy)
  • Oem blow-off valve above 75K miles (leaks boost) - replace with aftermarket BOV that vents to intake
  • Coilpack plastic clips above 75K miles (crumble), can cause ignition misses - replace oem plastic clips (easy & cheap)
  • PCV hoses above coilpacks, past 75K miles - (easy and cheap) replace with new oem pcv hoses
    (they get rock hard, which makes changing sparkplugs / compression test very difficult)
  • Heater hose (coolant) joint above #6 coilpack/sparkplug (pops apart). (cheap) replace with double-barbed brass fitting (5/8" iirc) and two hose clamps
    This item may have to do with how frequently the owner(s) changed/flushed the coolant
  • Harmonic dampener above 125K miles (splits at rubber dampening layer & falls apart) - replace with new oem or aftermarket dampener
  • Rear oem shocks (leak) - *very* simple to replace d-i-y, thankfully.
  • Interior:
    • Console lid hinge(s) a bit flimsy - don't sit on the console! Quite easy to permanently fix with a zip-tie.
    • Targa roof rattles in some Supras (higher mileage). To fix, simply remove the targa roof, completely disassemble it, tighten all bolts (use Loctite), reassemble, and reinstall.
    • Dash trim above odometer and passenger air bag lifts in one spot (both locations) - slight cosmetic imperfections.
  • Note: Other than the harmonic dampener and the coilpacks, these are all pretty cheap to fix...and even those two are only in the hundreds (i.e not thousands). With the coilpacks, the parts are a little more expensive, but you can replace them yourself really easily. A new oem harmonic dampener isn't that expensive, but it's not a trivial job (eg. radiator must be removed).
  • Many of these items relate to the tremendous heat produced by the 2jz-gte (and the turbos, of course). Depending on how hard the Mkiv TT has been driven, most plastic and rubber components anywhere near the exhaust side or center cavity of the engine eventually give up the ghost. Horsepower is a dual-edged sword.

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[warmkop]

Very informative. Thank pwpanas
I definitively agree with wider tires my supra is going sideways all the time.

[pwpanas]

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Now we can finally get to the survey categories!

• Leave it stock ("320hp"+): At this point, you have an Mkiv Supra TT running properly, with all maintenance items taken care of. Like I did, and just as Toyota intended, you need to fun with it bone-stock! This car was under-rated from the factory; a brand-new us-spec 6spd produced almost exactly 320rwhp (376hp at the crank). Even with 100K+ miles on it, as long as your BOV and/or charge-air clamps aren't leaking boost*, you shouldn't be too far off from that number. Consider taking it to a road race track and get some professional driving instruction. Take the time to really learn your Supra's driving characteristics in all conditions with no modifications.
  Note: Replace the oem screw-type hose clamps with T-bolt hose clamps to keep those i/c hoses from popping off.
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• BPU (350rwhp-450rwhp): Bypass the cats with a straight-through 3" downpipe, install a GReddy BCC (to prevent the oem 'fuel cut'), a boost gauge (so you can see how much boost you're running), put a small adjustable clamp on this hose (top right of the photo), fill the tank with unleaded 100+ motor-octane race fuel, and tighten that clamp until you've cranked up the boost to at least 20psi. Be careful! ...when that boost hits you'd better be going perfectly straight, on a dry road with no other cars around. The back end might kick out a bit, so be prepared to counter-steer without overcorrecting.
  • CAUTION: To help maintain traction and control of your car, you may want to go to wider rims&tires at this point. 11.5" wide rear rims and ~9" wide front rims with the correct offsets fit under the oem fenders just fine, and maintain a good balance.
    I know a number of Supra owners that damaged their Supras (not too seriously, thank goodness) because of the change in horsepower to grip ratio. Toyota's engineers did an excellent job balancing the Mkiv Supra bone-stock. Whenever you change anything, you need to reengineer the overall car to reestablish that balance. That includes everything from tires to cooling system upgrades to manage the additional heat generated when you increase the horsepower. Please do not underestimate this responsibility when you start modifying your car.
  • At the higher boost levels, other components will likely need to be 'reengineered'/upgraded to match, like your clutch and blow-off valve.
  • If you find the race fuel thing inconvenient, install a high-flow alcohol injection kit.
  • BPU+++: If you want to squeeze a bit more out of BPU before you go to the next level ("6.", below), upgrade the intercooler, adjustable cam gears, (lightened) flywheel, exhaust system, and fuel controller. About 450rwhp is achievable max, with brand-new oem twin turbos and a brand-new 2jz-gte at BPU++++. Of course, you'll need to spend time on the dyno to tune the fuel controller and adjustable cam gears!
  • Note: An aftermarket exhaust is *not* necessary at 'bpu' level, except for looks. You can wait until BPU+++ or even single turbo level before you upgrade without affecting BPU performance at all.
  • Before any other upgrades, have fun with your Supra and learn it very well at this level. Everything you learn here will apply when you upgrade the horsepower to the next level.
  • If your budget is constrained and you want to optimize your $ invested (including resale value), then don't ever upgrade past BPU. Be sure to use a harness adapter when installing your GReddy BCC.
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• Single Turbo (Small or Mid-Size), Stock Fuel System, Stock ECU, Stock MAF (500rwhp-650rwhp): This next set of upgrades represent a more significant investment than BPU. However, you can get by WITHOUT an aftermarket fuel system or standalone ECU upgrade; the stock MAF (US spec), intake plenum and throttle body are just fine too.
  • To me, this is the level that Toyota *should* have built the Mkiv Supra TT to.
  • You'll need a single turbo kit with relatively small single turbo (67mm inducer or smaller, .80 turbine a/r or less), and a high-flow alcohol injection kit. If you didn't put a fuel controller on in the previous step, you'll need it here. I'd also recommend upgrading your oem fuel pressure regulator to an adjustable aftermarket regulator...and then increase the base fuel pressure by ~10%+.
    Note: Even with that 10% increase in base fuel pressure, your oem fuel system won't handle more than about 525rwhp or so. The alcohol injection kit must make up the difference in fueling requirements for 525rwhp-650rwhp.
  • Now is the time to definitely get yourself a set of the TSRMs (Engine & Chassis at least)
  • You'll benefit from an aftermarket exhaust at this level, if you didn't upgrade it at BPU+++. There's no need to go crazy though - any mandrel-bent 3" exhaust will be just fine.
  • Tuning, tuning, tuning. Spend as much time on the dyno as necessary to tune your air:fuel ratios until they remain perfect throughout the entire rpm+power band.
  • Definitely upgrade your rim widths to handle this horsepower, if you didn't in the previous step.
  • Keep the boost level to about 25psi. Be prepared to supplement your alcohol injection with some race fuel in the tank, to avoid detonation.
  • If you still have your oem clutch, it definitely won't handle this much power. Consider a twin-plate aftermarket clutch.
  • You'll benefit from some aftermarket *shocks* here (note: the Mkiv Supra Turbo has coilover shocks, not struts!). My preference for a cost-effective upgrade is KYB/AGX shocks and possibly some Eibach springs too if you really like that lowered look. You can try a stiffer sway bar on the front, but leave the rear one alone unless you are very well trained in drifting (i.e. your Supra will get *very* 'tail happy' with a stiffer rear sway bar...and not all drivers want or need this, especially (for example) if you daily drive your Supra in the rain).
  • Again, spend time on the track to learn the changes in performance characteristics. Driver training, driver training, driver training. The most important 'nut' to upgrade is the one behind the steering wheel!
  • Don't upgrade past this level if your budget is moderately constrained. You can still more-or-less break even on the whole Mkiv Supra 'deal' at this point. Past this point, you're investing $$$ for pure fun and entertainment with little chance you'll get your $ back. You have to decide if your budget can tolerate the 'hit'.
  • Drive your Supra as OFTEN as possible at this level! You'll have lots of fun here. You'll kick the tail of many other performance street cars at this level, including some 'exotics'.
    

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[pwpanas]

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• Single Turbo (Large), Aftermarket Fuel, Aftermarket ECU, Stock engine internals (800rwhp-1050rwhp): Still want more? Time for an even bigger turbo, a full fuel system upgrade, aftermarket cams w/double valve springs, an aftermarket ecu, a bigger intercooler, an aftermarket intake plenum & throttle body, a triple plate clutch, and a shot of nitrous to quickly spool up that big turbo. I hope you've been saving some $$$ - each step of this journey gets significantly more pricey than the previous one. However, these parts are all 'off the shelf' - little to no customization is necessary at this level. It's the customizations that cost the really, really big $$$ amounts. By restricting your mods to stock internals, off-the-shelf parts, and a large but not huge turbo (eg. 72mm or 76mm), you can still contain the costs to a semi-sane degree.
  • It's probably time for pure race-compound (R-rated) tires, and a widebody kit or fender flares to handle 13" wide rims and 335+mm rubber.
  • Use pure high octane race fuel (eg. at least 110 MON) in your gas tank to avoid detonation at this 30+psi boost level. About 850rwhp (1000hp) is achievable at this level. Above 850rwhp you'll need to use a more exotic fuel, like c16 or vp120 import.
  • Instead of alcohol injection and race fuel, you can consider E85 if it is readily available in your area. This is still an off-the-shelf fuel system, but the injectors are much larger. Get an aftermarket ecu that can dynamically adjust your fuel curve and your max boost level based on the (often-inconsistent) alcohol:fuel ratio in E85.
  • You'll benefit from a mild port & polish on the head at this stage. Might as well get the valve seats re-cut too - don't skimp: make sure you take it to a head shop with a Serdi machine, 7-angle on intake and full radius on exhaust.
  • A standalone ecu takes a significant amount of time for an expert to get right for your exact setup, in all driving conditions. As with the previous step, don't skimp on tuning.
  • If you didn't upgrade your suspension before now, it's time for (at least) some Tein or HKS coilovers, adjustable swaybars...unless you're drag racing. For drag racing, you'll want to disconnect the front sway bar, and run slicks + skinnies.
  • Get ready for the real fun. At this level, you'll be able to embarrass most motorcycles and high-end exotics.
    
    You can now literally ignore most performance street cars (unmodified or mildly modified, foreign/domestic it makes no matter), because they're not even remotely any challenge - it really seems like they've stepped on their brakes when your boost hits.
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• Hog Wild - 1200rwhp-1500hp+, but still amateur: Above about 1100rwhp (6spd), you'll need to "build" your 2jz-gte's internals. It's only the connecting rods that can fail at the 1100rwhp level, and then only with nitrous usage. I have reliable reports of the oem pistons being good to at least 1300rwhp (6spd). The $$$s are 'hog wild' too at this level, so if your budget is restricted in any way shape or form, I'd suggest you stay in the previous category.
  • Go for the best connecting rods (Carillo), pistons (JUN), bearings (Clevite), head studs (ARP L19, or oversize), etc. You'll need to find a machine shop *experienced race-building the 2jz-gte* in order to not have things fail. If you experiment with inexperienced builders, you're essentially overpaying to educate them.
  • For 1500rwhp+, you'll need to think 3.4L stroker, and aftermarket main caps.
  • You'll need full head porting and oversize valves (Ferrea). 1mm oversize can be done with the oem valve seats (272 cams, 1300rwhp-ish), but 2mm oversize requires aftermarket valve seats (280 cams, 1500rwhp+).
  • Massive turbo (88mm+) - depending on application. For extreme high-end roadracing, a current-technology ~72mm turbo will be fine, but you'll need much more suspension work (Penske/Moton/Ohlin/etc.) and cooling mods.
  • This fuel system is custom (i.e. not 'off the shelf'):
    • Triple fuel pumps in-tank, or large-flow external (race) fuel pump.
    • Huge fuel lines and fuel injectors. Direct port nitrous.
    • Ultra-high flow fuel pressure regulator
  • Race fuel, race fuel, race fuel. Think VP Import or C16 - either of which is probably about $25+/gallon. Also think 35 to 40psi of boost, and beyond. The only way to run those boost levels without blasting your pistons...any brand of pistons...to smithereens is by using the very highest octane race fuel.
  • Triple or quad plate, triple-carbon clutch...or fully built race transmission (non-Toyota)
  • 4"+ exhaust (preferably titanium - ultra light)
  • Fully tunable suspension (Penske, Moton, Ohlin).
  • etc., etc. (lighten the chassis, install a roll cage, aftermarket LSD, etc.).
  • Tuning, tuning, tuning. With the right race fuel and 40psi+ of boost, timing and your air/fuel curves have to be as close to perfect as humanly possible in order to get the 1300rwhp+ results you're looking for. You may need to fly in an expert tuner from out of town, and be prepared to shell out the cash needed to put your car on the dyno for at least one more full days.
  • If you have any specific questions about specific configurations at this level, please ask.
  • Unquestionably, assuming your driving skills are well-honed, you'll rule the streets and many (amateur) race tracks (in the same class of car as the Mkiv Supra Turbo - 'GT Sportscar'/hatchback). No bone stock car except $500K+ ultra-exotic 'supercars' or pseudo-street cars (eg. Porsche GT3) will even come close. You'll also have fun with other highly modded Supras, highly modded Vipers, highly modded Vettes, highly modded Skylines, and modded Lambos. I can't guarantee you'll win every race, but I can guarantee you'll be competitive - most likely it'll be the driver and not the car that holds you back.
    
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• Pro race series: Almost everything at this level is proprietary, if the race team is currently competing. Why would they share anything with their competitors?
  • Most (but not all) of the mods at this level are only a few percentage points better than the top amateur mods in the category above. However, those few percentage points often mean the difference between winning and 2nd place.
  • Many of the mods at this level are practically useless for a daily-driven street car. For example, you'll never get 300,000 miles out of a set of titanium connecting rods.
  • All that said, I'm sure we're all interested in anything any pro race team member that previously or currently raced/races anything equipped with a 2jz-gte is willing to share with us!!!!

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If you've carefully studied the categories above, you'll see a bit of a gap between small-to-mid turbo (650rwhp) and big single (800rwhp). If for some reason you want 725rwhp (specifically), of course an Mkiv Supra Turbo can be built to that level, basically using a mix-and match process from those two categories of mods. However, you'll likely find that you may not end up spending very much less at 725rwhp than you would have for 800rwhp...which is why I essentially skipped over it in the modification categories..

Auto transmission: Subtract about 10% more rwhp (for the same crank hp vs manual trans.)...depending on whether it's a built or oem transmission, and whether or not it's a high stall torque converter (TC, with or without lock-up). The oem auto TT tranny can hold about 500rwhp to 575rwhp...depending on how hard it's driven and how wide & soft the tires are. Drifting with (for example) 13" wide R-compound rear tires will limit the auto tranny's holding power to ~500rwhp, reliably. Oem-spec rubber and no 'hardcore' racing it'll hold 575rwhp reliably. A 'fully built' mkiv oem tt tranny (eg. by Sound Performance or Boost Logic) with aftermarket high-stall TC will hold up to 700rwhp reliably. Past that point, you'll need a purpose-built TH400 or 4L80E customized specifically for the Mkiv Supra Turbo; a TH400 built for a large-displacement V8 (same rwhp) will fail 100% for sure.

Hopefully you found all of that interesting. In short, the Mkiv Supra Turbo really is an incredible vehicle that will allow you to compete at almost any level of performance. As it is with any other motor sport (bikes, cars, boats, planes, etc.)...it's mostly a matter of how much $$$ you throw into it (especially at the highest levels)...as well as how much time the driver has invested in increasing his/her skill level. If you start with an Mkiv Supra Turbo, I sincerely believe you will not be disappointed in the outcome, regardless of your ultimate goals.