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Discussion Starter #1
Not that I have any inclination to boost my is (have a turbo supra already), but I thought I'd post this link up for those who are as a starting point for a custom setup. I know that there's a shit ton of tuning issues and this that and the other, so please keep the hating at a low, this is just for other people to reference.

Squires Turbo Systems - Universal
 

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I guess this is helpful for fitment issues but space was never exactly the issue with the IS's anyway. We're more worried about the ECU encryption, the high compression ratio and the difficulty of tuning the injectors (particularly with the 350 having a two separate injectors). But thanks.
 

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ethanol thing is just like water meth injection. Only problem with that is that the new is engines use the direct injection for gasoline. Also on the is350 it used the direct injection only on high load demands. the port injectors are only used for start up, light throttle, cruise applications.

The main tuning issue that people are complaining about is the relatively high compression that the 2gr-fse engine has. This will cause a problem with tuning when it comes to controlling detonation. Ignition tuning becomes very difficult at higher compression levels if the fuel cannot burn slow enough. 91octane or 93 octane does not burn slowly enough to control timing at high compression level. The most "boost" these high compression engines can handle will be determined upon how well ignition can be controlled.

I am looking into a stand alone for my car for a turbo build. I too have looked into the squires turbo systems. I have installed these in customers cars and have seen impressive results. As far as the stand alone it will be more of a piggyback. It will be used to control the port fuel injectors and timing beyond what the stock ecu can control. Basically during high torque demand "boost" when the port fuel injectors are not used by the stock ecm the stand alone will take over and supply the ground and control the port fuel injectors to supply more fuel, beyond what the direct injectors can supply. Since the stock ecm is not providing the ground for the port fuel injectors it will "think" that the injectors are not being used. Timing will ultimately be controlled by the stand alone. This is all theory for now. The IS350 having both port fuel injectors and direct injectors may be a blessing in disguise.

I am currently looking for a salvage is350 to start playing with.
 

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Yes you can but you will be limited to the extent of correction that the stock ecm can control for now. Do not know of any ems systems that can control the direct injectors. I will be asking my diesel buddies as to what they are using. Anything is possible as long as one has time and money and willingness to learn.
 

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All good points guys. I would want to know how big the IS350 injectors are in regards to the capacity to supply enough fuel for the engine. They may be sized smaller based on the use of two injector systems with the DI being the main. I found a SAE article about the 2GR-FSE engine. It has some numbers for the injector dimensions - FYI.

Does anyone know what type of pistons are in the 2GR-FSE and 4GR-FSE engines?

So far in have read that the connecting rods are forged steel but have only read that the pistons are 'light weight type' and that the piston rings are 'low friction type'. I am hoping to discover that the pistons are forged aluminum instead of Cast Hypereutectic.
 

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The port fuel injectors should be somewhere between 289cc/min-300cc/min. As for the direct injectors there is no real way to test these without specialized equipment so no specs were given except for a resistence check. supposed to be around 2.1-2.31 ohms at 68F. I will look for my Toyota course books but don't think we went too in depth on it.
 

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Discussion Starter #11
As for engine management, I was talking to a friend of mine, that had his own company where he did custom built megasquirt ecu's. They're really inexpensive as far as stand alones go, but according to him, they are capable of controlling direct port injection, and up to 12 or 16 injectors independently. He said it would take a bit to get one to work for the isx50s, but it could be done-however, the the question then would be having that ecu talk to the other supporting systems (tranmission, brakes, stability control). coming from PLC programming background, that part should just be some inputs/outputs from the ecu. figuring out the pinout would be the next task.
 

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The engine managment seems to be a real problem with these cars. The injector driver and other control modules are separate from the main ECU. I am pretty sure that the MIL light would be triggered if you try to bypass or unplug the wiring. Also that's just fuel but timing should be adjustable as well.

My crazy idea now is just to have a piggyback fuel system based off of a N20 system & progressive controller to add fuel based on boost pressure. It is still just a dream but ya got to start somewhere.
 

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I'm probably going to get flamed for this, but this is how I look at it. You modify a car to perform way past factory standards and most likely non-legal emissions system. What's the obsession with keeping the CEL off? Most of the 1st gen IS guys run all day with a CEL and it doesn't bother them. In my own car I just pulled out the damned CEL bulb lol. If I hook up the scantool I have about 8 codes in the stock ECU. But my car runs a good 450-500whp and drives awesome with no engine problems at all. The way I see it, if the car runs awesome...then to hell with the CEL.
 

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Many states will fail your inspection if a CEL is on.

Apart from that though, it depends why it's on.

If it's on because it can't see your rear O2s (the ones that don't really do anything useful) then who cares.

If it's on because it can't read what the injectors are doing however it'll likely put the car into limp mode, and it'll run like complete crap until you fix it.


But honestly, the CEL on or not, it's still currently impossible to do much for power adders on the 2IS for any reasonable amount of money.

With a 1IS it's actually pretty easy... do the same crap the supra guys have been doing for 15 years now, just tweak it for the particulars of the car.

But the 2IS is a completely different powertrain, it's a MUCH more complex engine and computer setup, with a whole lot more sensors it cares about, a whole lot more to control, and no way to even know -what- the factory programming is really doing due to encryption. Add on a 12:1 compression ratio with all that other complexity and it's a pretty tall order to get anything done, even if you couldn't care less about the CEL.
 

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I'm probably going to get flamed for this, but this is how I look at it. You modify a car to perform way past factory standards and most likely non-legal emissions system. What's the obsession with keeping the CEL off? Most of the 1st gen IS guys run all day with a CEL and it doesn't bother them. In my own car I just pulled out the damned CEL bulb lol. If I hook up the scantool I have about 8 codes in the stock ECU. But my car runs a good 450-500whp and drives awesome with no engine problems at all. The way I see it, if the car runs awesome...then to hell with the CEL.
JeffTsai,

I just noticed that your newer lexus is running on E85. How did you decide that the fuel system was compatible for higher concentrations of ethanol? I plan to have a look at my 2007 IS so see if the fuel lines are SS vs. aluminum etc... and would like to know what you did.
 

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Hey guys, this forum thread has been inactive since 2008 but I wanted to send a reply just in case.

Ive been searching all over the forums and the web with regard to building a FI 4GR FSE engine and I have seen so many idiots yammering all over Club Lexus about how it's impossible, and make their claim with very little factual information.

I was curious if you folks have figured out how to boost this engine with the complex EMS and high compression ratio. Have any of you had luck with superchargers? Any thoughts or suggestions you can pass along?

With regard to the pistons, I too was wondering if they were forged or not. What are the specs around the hypereutectic pistons? From my understanding, if the material grade is strong enough to withstand heavy pressure / combustion, it shouldn't matter if it's forged or cast. Since I know too little about hypereutectic pistons, I was wondering what your thoughts were.
 
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