EvoTuned

Hello, I’m relatively new to the forums. I’ve done a good bit with audio systems but I’m ready to move on. I would like to eventually improve every aspect of my car and to help to represent customized Lexus cars at their full potential! I have a 93 SC300 with a manual trans with about 55K on it. I’ve done some mods already but for this post I will concentrate manly on performance. I’ve looked into turbo charging and NOS kits. Epik Motorsports out of South Carolina will convert my SC’s engine to a Supra TT for about $5,500. Unfortunately that is a lot of $$$ and it’s more than what I need. I honestly seldom race. Maybe 6 times a year. So what I’d like to do is to get a descent NOS kit in a package that would include everything needed for hookup. I have a custom catback system with Magnaflow Turbo mufflers. (Our exhaust may be a little to LOUD without those resonators.) I’m also getting a Weapon R intake. I really don’t plan on doing any more performance add-ons to my engine unless I have to because I would like my car primarily for show. I’ve honestly never dealt with NOS kits before so it will be professionally installed. What I’d like to know is where I can purchase a kit for my car at a good price. If I knew what exactly I need, I’d buy off eBay Believe me, your help is greatly appreciated!

Lex Luthor

Evo, if this shop is talking about swapping in a 2JZ-GTE engine for $5500, you've found yourself what appears to be a great deal. These motors sell for $7500 ballpark, so be sceptical. If it's legit, jump on it. As far as juice goes, the 2JZ can take a bit hit, given enough fuel to go along with it, sufficient spark, exhaust, etc. These are notoriously strong motors, so if you're just looking for the occasional KoolAid smile, N2O is the way to go. Take a look at the Nitrous Express kit, as well as NOS, and the hopefully soon to be offered Venom computerized system. A local guy here runs a jumbo 200-shot (guess his secret is out) in an IS3 (same motor essentially as your SC3) and runs 13.0s bone stock with just a Pro Torque converter and little 26x8.5 ET Drags. While a wouldn't recommend that to you (especially with the catalysts intact), you can definitely add a healthy shot to the car, Clint sc300tt will back me up on that one.

Keith13b

iTrader: (3)

Intake and exhaust need to be optimized, and you need to beef up your fuel delivery system.

If you plan on going more than a 125 shot, make sure you look into direct port "wet" setups. They will be the most reliable for the motor.

Lex Luthor

I agree, Keith. Anything more than a 125-shot, and you'll need more volume of fuel than the excess in the fuel rail can provide, definitely an NOS inline pump, or an upgraded in-tank pump, such as a Supra TT unit. If your catalysts are intact, you'll eventually fry them with any decent-sized hit, and you'll want to upgrade the exhaust anyway, to reap the rewards of juice. Keith, as i'm sure you know, intake work is suggested but not nearly as important as exhaust/fuel/spark. After all, the N2O is packing the engine with a cool, dense oxygen-rich mixture anyway, better than any ram air could do. Like most other things, Evo, juice is not a slap it on and forget it kind of mod, the entire package must be thought out for everything to perform up to your expectations, and reliably so (unless you're pondering a little 50hp hit, less to worry about). Any decent-sized system will have to be accompanied by certain peripherals, i.e. Hobbs pressure switch, WOT switch, fuel enrichment, spark retard, and a sufficient ignition to spark the mixture. You'll probably want to add an MSD-6AL box, fresh Lexus wires (or Magnecor), Iridium plugs, at least one heat range colder, and i'd close the gap up a bit, plus an MSD rpm switch, a bottle heater (or at least a blanket), nitrous press and temp gauges, high-flow catalysts (or 'test pipes'), and a few other bits.
Keith, did I forget anything? (ever popped any rotary Apex seals on the hit?). Evo, nitrous is addictive like boost, gotta get that fix!

Bean

iTrader: (1)

2jz-gte motors hardly sell for $7500... they are only that expensive if you want to get anally raped by a dealer

around $3500 is the norm...

I think when they convert to the TT engine, they aren't doing a full swap, they are just swapping the head, exhaust manifold, turbos, and intake manifold, etc...

To clear some stuff up, I don't think the volume of the fuel rail has anything to do with how much fuel gets mixed with the nitrous in a wet kit... the fuel pump is the only thing you really need to worry about...

if you go over a 100shot I'd make it a direct port kit... which isn't all that expensive, but its a ***** to install and tune correctly

CmputerWiz

I've got a 93 5-speed. I use(d) the Zex kit, worked like a charm. $500, includes EVERYTHING you need... You can buy it at summitracing.com.

SR

Keith13b

iTrader: (3)

Lex Luthor,

You pretty much covered the basics. One thing though; our motors (like the rotary ) will require 2 MSD boxes - pricy! As for the intake, yes, the N2O packs its own quantity of air - and chills it nicely too....but nothing like collapsing the intake hose after the Nitrous shuts off, but you pulling mad RPM's. All sorts of bad things happen to associated hoses still connected to it. I had a friend w/ a stock mustang - stock intake - 150 shot of NOS [talk about asking for trouble]. At around 5500 rpm the NOS shut off w/ an rpm switch, but he kept the gas down. About a split second later, BOOM!! The sudden change in intake pressure caused the intake charge to flutter, and detonation followed. Head gasket was fine, but needed a new MAF and intake box. Moral of the story- some open-ness in the intake is needed w/ NOS.

Lex you are correct; Don't plan on keeping cats after a long hard hit's. They burn up nicely, but still keep their restrictive nature - so you get the worst of both worlds. High backpressure and high emissions.

The biggest thing to worry about is timing retard and fuel supply. Get a good timing adjustment box and buy a fuel pump thats too big for your needs. You never want to run lean - NEVER!

(ever popped any rotary Apex seals on the hit?)

YEP!!!!! The rotor housings arent too cooperative when that happens. No matter how hard you try - that friggin' rear rotor housing always fails first. And thats why God invented ceramic A-pex seals. I never had a problem after I switched. After the ceramic seals were in place, just keeping the coolant O-rings to stay in one place was the biggest challenge. Man - rotaries can take soooooooooo much nitrous it insn't funny (when built right that is). I ran a 275 shot in my 85 SE. Kept snapping ring and pinion gears; but it was fun! Engine was asking for more!

Sorry, back to the question -

Evo :
Read Lex's last post, and I would recommend everything he mentioned, but would add a progressive rate computer or a complete Nitrous computer all together. Carb'd engines can just inhale NOS, but once you start having everything monitored by sensors, things get tricky. A good NOS computer will manage you ignition timing and fuel pressure, starting RPM and ending rpm....everything. Also, a remote bottle opener is a nice accessory. NOS'ing a motor isn't cheap. It will cost a good amount of money to do it right, so be prepared and be patient.


Bean,

To clear some stuff up, I don't think the volume of the fuel rail has anything to do with how much fuel gets mixed with the nitrous in a wet kit... the fuel pump is the only thing you really need to worry about...

Be careful and keep in mind that what Lex said is quite correct in some sence. The fuel rail will become quite restrictive very quickly in larger applications (operative word is -LARGER applications). For a 100 shot, no it isn't, but larger apps, the entire fuel delivery sys needs to be upgraded. Seperate pumps, regualtors, and fuel lines need to be run. The NOS jets flow some serious N2O, and the fuel jets need to keep up. You can't use a garden hose to do a fire hoses' job. Check on the forums of other Turbo'd or compression enhanced cars, and look what people making over 400 hp do to their fuel systems. (Yes, I know, Evo isn't dropping in a 250 shot - at least I hope not). The reliable and consistent ones usually upgrade the entire cars factory fuel system to a larger set up. Larger hoses and rails - everything.

Now I don't know about the Lexus fuel rails and their characteristics and flow rates, but there is a possibility if you fire out a high enough shot for a long enough period of time, that flow rate of the rail might not meet the demand of fogger jets AND the injectors. The pump may be able to keep the pressure and flow behind the rail, but the rail itself might not flow everything equally. Thats when detonation occurs. But for Evo's needs, the fuel rail isn't an issue.

Remember, I don't know specifics about the Lexus, but I am quite fluent in NOS usage. Now the Totota Rail might be designed to flow carzy amounts of volume, but it is something that should at least be looked into.

Anyway, I'm rambling - Good luck on the install. Just keep in mind everything that has been brought up so far. I see a lot of great info on this forum, so listen to everyone and hear what they have to say. Sometimes weird things happen, but uderstanding all the concepts involved might help diagnose the problem before engine damage occurs. Don't get weired out about my fuel rail comment, but keep it in the back of your mind for when you drop in a 500 cheater shot!!!!


Later,
Keith

P.S. a lot of info on this topic has already been around on the forum - do some searches.