NetG

Mbodall

I don't have any more details, but I'm guessing you just about nailed it. They probably used the forged internals like the 1UZ had and hooked it up with forced induction. Even 500hp would still be super reliable. It's been well over 10 years, but I remember reading an article about the ridiculously over-engineered 1UZ-FE (our 3UZs are basically the same as the 1UZ but bored out/smaller cylinder sleeves and not using forged internals, among a few other minor changes)... anyway some engineers were trying to see how much power the 1UZ could handle, so they put it on an engine dyno and gave it forced induction to the Nth degree, intake, exhaust, etc, but left the stock internals in place... they progressively added things and kept dyno'ing it after each addition... it reached 2400hp before it bought the farm

NetG

Mbodall

If you're at all curious about how they got over 2,000hp out of the 1UZ, don't be lol. The point of that exercise was to test the engine to destruction with absolutely no regard for every day driveability or reliability. I don't remember it being mentioned in the article I read, but I'd assume they weren't using pump gas to achieve those ludicrous numbers. I'm sure even cranking a little over 1,000hp with the stronger internals of the 1UZ will not get you very far, unless you plan on rebuilding the entire engine every time you drive 1/4 mile like a top fuel dragster lol.

As for being curious about the 500hp 3UZ, I can guarantee that forced induction was involved. I've read a lot on multiple forums and the general consensus is that Toyota/Lexus really did a good job of efficiently squeezing just about all the power and torque out of these engines, and didn't leave much of anything on the table as far as easily attainable additional horsepower and torque. In my research, the most common mods that I've seen talked about are the ubiquitous cold air intake, exhaust including new headers (some custom), and an ECM tune.

As we all know, an intake is probably the least expensive, and an ECM tune as well as a new exhaust can start to get pricey. Full exhaust including headers can run you around $1,000+, especially when going for custom ones. Even with all that done, the gains would be somewhere between 25hp/tq and maaaaybe up to about 40hp/50tq... if you're lucky. I actually saw dyno readouts where people lost a little bit horsepower and/or torque after installing new exhaust systems, headers, intakes individually; and/or impacted their torque and horsepower curves in a bad way. I think the problem is that some of these headers and exhausts were too free flowing/generally improperly designed and negatively affected the exhaust velocity and scavenging. In hours and hours of reading on this topic, there were only one or two people that claimed around 40hp/50tq gains but their dyno results were a topic of debate citing that every car (even the same year, make, and model) will dyno differently, as to whether or not the dyno tech did the temp/atmospheric corrections... correctly lol. The amount of money spent for relatively minuscule gains would definitely not be worth it, unless money is no object to you. The people I read about that did do an intake, full custom exhaust, and tune reported spending somewhere in the neighborhood of $2,000-$3,500+ for everything. Since there really isn't a huge market for hot rodding Japanese luxury cars (go figure), at least here in the states, mods like good full exhausts are usually custom fab jobs = $$$$$. There are a few companies that sell headers for the 3UZ that attach dyno results to the product page, but these results are much disputed. It's a shame too, because if we drove 4 cylinder economy cars *rolls eyes*, there would be a plethora of readily available bolt-ons to turn our angry weed whackers into even angrier weed whackers.

To make our ponies start breeding like rabbits, you'd have to suck air into that engine like Dark Helmet's Mega Maid vacuum sucking the air out of Planet Druidia (not really, but anywhere I can squeeze in a Spaceballs reference... ). Anyway, turbo and supercharger kits for the 3UZ are pretty cost prohibitive (even in SC430s and GS430 which are still rare, but far more prevalent than in LSs) because just like the bolt-ons... very soft market = either lots of custom fab or a very expensive kit since they're not sold in any kind volume that would help bring down manufacturing costs. A couple of people have gone the forced induction route and reported spending $10,000-$15,000+++ to end up anywhere between 285rwhp and 480rwhp. I forget who makes it, but I remember seeing a kit that was selling for $14,000 and included over 30 new components... headers, exhaust, pulleys, fuel injectors, fuel rails, fuel lines, water pump, heat shields... they claimed it was everything you needed to make the whole thing work. Now mind you, that was in a GS430 application, so to make all that work in an LS, more custom fabbing... $$$$$$.

Depending on whether or not your 1UZ has the VVT-i heads, I think I'd probably rather start playing with it. Those engines have obviously been around way longer than the 3UZ and have been being modded for decades now. I'm sure you'd have a much easier time finding good/proven performance parts for it than you would the 3UZ... that is, unless you like a challenge and do a little fabricating yourself, and want to see if you can do it lol.

NetG

Scootymad

Put it this way. In the V8 Supercars championship in Australia, they're getting something like 600hp out of 5 litre engines, but they're highly strung race engines that don't last long between rebuilds. I have a feeling that TRD didn't use forced induction at all, but also had a high;y strung, high compression N/A engine. The general rule of thumb for an atmospheric engine is 100hp per litre of displacement (and that really only is a rough guide until you start taking into account Honda B, F and K series engines or the Ferrari 458 engine, which were designed from the outset to make high N/A power), so a 4.4L making 500hp normally aspirated is not that too hard of an ask when you start thinking about the development potential of TRD. I'll start from the bottom and work my way up. In the sump, it'll likely be dry. Race motors need good oiling so dry sump is the order of the day here (less oil for the crank to pass through = more hp). The crank is likely already a bespoke item to give 4.4 litres, so it'll be knife edged and micro-polished for lower friction (more hp). The rods will be cro-moly-nickel 4340 forged I-beam items for higher strength and lighter weight (less reciprocating and rotating mass doesn't necessarily give you more HP, but it increases throttle response, which makes the car feel faster and snappier when taking up the throttle). The pistons will most definitely be forged oversized aluminium pistons with higher compression ratios (north of 11.5:1 - more compression = more bang = more HP). The cylinder heads will have been ported and CC'd to within an inch of their life, the valves will have a multi angle grind to them, and also likely made of titanium and sodium-filled for less mass. The valve seats will have been recut larger for more airflow, valve springs will be much stiffer to compensate for the increased RPM, and the camshafts will be done to a secret TRD grind (Kelford Cams will likely have similar specs). The injectors and ignition system likely won't be anything fancy as that's pretty basic stuff, likely TRD-spec gear. The key to all this is the induction system, and getting as much air as possible down its throat. Most N/A race engines I've come across use individual throttle bodies with trumpet lengths to suit the track they are racing. It'll be covered by a huge carbon fibre intake plenum chamber and a big snorkel to the front of the car to shovel air into the plenum. With all this gear (and please remember this is the most logical explanation I can give on a race motor that TRD may have built) an engine such as this should be making much more than 500hp when tuned to the near point of detonation. That is when you pair your timing back a few degrees, take a bit of fuel out of it and make less power to suit the regulations, or to ensure your engine becomes more reliable, rather than run on the ragged edge like a lot of old Formula 1, Group B rally and Group 5 sports car engines, where it didn't matter if an engine was no longer useable at the end of the weekend, you just banged another one in, wound the boost up and just sent it.