CrazyHawaiian

I think it would be a good idea to really look over the ECM/tuning aspect of boosting your 1UZ. Generally speaking higher compression motors are not ideal for high boost applications. You won't have as much "leeway" as guys with lower compression motors when it comes to detonation. Thats not to say it can't be done, but you're either going to sacrafice some ammount of reliability or end up doing alot to prevent detonation (lots of pulled timing, or meth spray, etc). I think having precise control of spark/fuel/timing/etc is going to be essential if you plan to run higher boost levels.

PureDrifter

iTrader: (10)

if ur running <10lbs of boost compression wont be an issue.

there are 3-5mm HG kits available which would solve the problem anyways.

akxx

iTrader: (1)

Turbo is much more difficult to package in the 1UZ engine bay...just ask any of the guys running custom turbos--it is ALL custom fab, and lots and lots of work.

The M90 semi-kits are only about $2500 US, and then you add an M90 from the US for $200-400. No problems with stock hood clearance. Check with Rush Imports in Australia--Neil's a great guy and super knowledgeable about blown 1UZs.

As long as you run 7psi or less on the blower you don't even need an aftermarket ECU--stock computer handles the extra power just fine. Factor about 325-350 flywheel HP with this setup.

You can put smaller pulleys on, and get 9-11 psi, but at that point you will need piggyback and larger injectors. 7MGE or 7MGTE injectors from MkIII Supra are direct swap replacements for 1UZ motors and will provide plenty of overhead. If you're thinking 9-11 psi, water injection is recommended for safety.

It is NOT advised to go with thicker head gaskets on the 1UZ.

akxx

iTrader: (1)

Careful here-- 7psi from a blower is generally considered the limit for stock ECU and injectors.

While you could probably run 9-10psi of M90 boost, it would absolutely require a piggyback and larger injectors and absolutely perfect tuning if you're not running some kind of charge cooler. Turbo is a different story since it produces less heat in the compressed air than an M90 at that boost.

PureDrifter

iTrader: (10)

when i say <10lbs i mean in relation to the strength of the bottom end.

an SAFC and RX7 FC 1000cc injectors (they bolt on ) would easily take care of any fuel issues

and if i was building this up id prolly go for an M112, more potential and reasonable price increase. plus iirc the RI kit comes with a blank top plate that can be requested with certain blower cutouts already (m112 is on the list )

hobojoe

any reccomendations on a aftermarket ECU for a 91 ls400

akxx

iTrader: (1)

Bottom end--no problem--there's 15psi 1UZs running stock bottom end with proper charge cooling and excellent tuning.

1000cc injectors are waaaaay overkill and would result in very poor idling characteristics unless you're looking for 1000HP applications. For even 500hp, you don't need anything over 440cc. You really need to match injectors to the power levels you're trying to achieve--bigger is certainly not always better in this case.

Problem with the M112 setup is that so far, I know of only 1UZ boat motor applications this has run on. I don't know if the M112 would even clear a stock LS/SC hood (almost positive it WON'T clear an SC). A properly ported M90 would still be a better alternative to the M112 up to the ~450RWHP level for the 1UZ. If you're goal is 500+, then I think M112 moves more air efficiently at those levels.

akxx

iTrader: (1)

What are you looking for--piggyback or standalone? What's your power goal?

CrazyHawaiian

My point was it might be a good idea to really look into this to ensure that you're not setting yourself up for failure. Just "slapping things on" and saying "its good to go" might not be the smartest thing to do in the long run. Because it would realy suck to put in all this time and money and then the engine detonates within 20K miles or something. There are a few key things people sometimes forget to consider when they focus on performance. Things like reliability, effeciency, streetability, etc. Its important to understand there is a difference between getting something to work, and getting something to work reliably and be streetable. Having the proper ECM tune and proper fuel system is a very important aspect of reliability and streetability. Here are a few questions I would consider if I were attempting to do this project:

What is my static compression ratio?
What is the VE% of my engine?
What are my cam specs?
What altitude will the car be used at?
What are my dynamic/effective/final compression ratio's on boost?
What octane gas can support that compression ratio and control detonation?
What octane gas do I have thats readily available locally?
If its 92/93 at the pump, what am I going to do to supress detonation?
What am I going to do to control the timing?
Will I have to pull alot of timing to make this work?
How much power can the injectors support at 80% duty cycle?
If its not enough, what Injectors will I need?
Will those bigger injectors be streetable from an idle standpoint?
Will the fuel pump be able to flow enough to meet the fuel demands?
How will the transmission perform with the new power goals?
How about the supporting systems of the car? (brakes/cooling/etc)

And the list goes on and on. Nobody needs to answer these questions, its just examples. And don't get me wrong, I'm not saying this can't be done. We all know it can be done. I'm just saying there are questions that should be asked, research that should be done if you don't want to end up with a broken car in 1 year or something. When I read these threads and look at these products I see everyone focusing on the power and performance aspect. No mention of tuning for reliability or what happens after the fact. Maybe people have already done all the work to answer all the questions, that would be great. But I'm not sure. My point was it might be a good idea to research all aspects of this project before busting out your wallets.

PureDrifter

iTrader: (10)

im pretty sure all the info u need is in lextreme's technical and specs section

PureDrifter

iTrader: (10)

M112 wont clear hood if u use the RI manifold.

15PSI is fine for a normal 1UZ but for higher mileage (175k mi+) would you risk it

1000cc injectors (may be 750cc now that i think about it ) are prolly overkill but id rather have the motor run rich than lean.

akxx

iTrader: (1)

175k is just getting broken in on a properly maintained 1UZ, as they are documented to easily go 300k+. If compression and leak-down show good, then I would absolutely *risk* it. We're talking 1UZ here, after all, and replacements are all of a few hundred bucks!

Trust me, you can run more rich than you could possibly want on 440cc injectors at 500 RWHP on the 1UZ--to the point of blowing nice thick black fuel-rich smoke out the back of your tailpipes at full boost. Running even 750cc injectors at this power level will only result in crappy idling and compromised driveability.

PD--I deeply respect your general knowledge of the LS, and you are one of the most prolific contributors to this forum. However, the advice your are giving regarding engine mods on the 1UZ are not based on the realities of actual experience gained from those who have modified these engines--a quick browsing on Lextreme forums or SoarerCentral or any of the other 1UZ mod forums would show that. Not bashing you, just asking you to be cautious in what you post since many on this forum, including me, look to your advice as near-golden!

PureDrifter

iTrader: (10)

oh believe me i dont pretend to know anything, all this supercharger stuff (aside from teh clearance issues) is mostly hypothetical. its good to have someone around whos actually done it

akxx

iTrader: (1)

To clarify, I haven't done it...yet. I've been gobbling up as much info as possible from the 1UZ gurus (most of them are in Australia) so I can have a better-planned path for my supercharger project!

CrazyHawaiian

Huge injectors like 700+cc might not be streetable on these cars unless you change the Injector driver or wiring to support low impedance injectors. These cars are wired for high impedance injectors, this means low current. At higher flow ratings the high impedance injectors can pose an idle problem like akxx mentioned. The flow size does play a role but its more due to the impedance type. The more an injector flows the bigger the components get (heavier they get), the more "power" it takes to operate them at acceptable speeds. The "power" is actually the ammount of current going to the injector, the more current there is the faster the injector control (pintle or disk) can move/snap. Aside from that, the type of control switch is different between high and low impedance injectors (research peak and hold), mix matching them the wrong way will likely cause damage to the injector and maybe even the driver over time. So if you guys do plan on running the bigger injectors I would definately research the injector drivers and what can be done with them. Remember, difference between getting something to physically fit and getting something that will run right and be reliable.

If you guys are serious about supercharging your 1UZFE I would look into having a custom cam made. The correct cam can make the world of difference in both power and tuning aspects. Usually cam's designed for n/a motors are not ideal for boosted applications, though sometimes there are exceptions. You can also match the powerband of the cam with the powerband of the forced induction type. Since you guys are talking about using roots superchargers you'd probably want to consider a lower end powerband with maximum torque. If it was a centrifugal supercharger like a Vortech then you'd want to consider a more mid-range to higher end powerband. Or if its turbo then you'd want the powerband to begin when the turbo is spooled (so depends on what turbo you use).