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Discussion Starter · #1 ·
im looking more for a technical answer on this one, eg.-from a mechanic...etc. i know this is subject matter on various other forum topics, but it is mostly opinions. as far as aftermarket mods with the trd supercharger, i want to know facts. i was debating to get a sc for the tc if/when i got the tc, but after reading the news that toyota will offer it as a trim from the factory this is a deffinate in my opinion. but heres my issue, the last two cars ive owned: 95 v6 accord, 98 svt contour, ive done my fair share of diy'ers. espeicially on the accord. i replaced almost every part on that car and it was b-e-a-utiful. no rice involved. but the thing i always hated is the risk that comes with aftermarket performance parts. the fitment is not an issue and neither is if it adds horsepower. the thing is is if one of those parts affected the engines life by shortening it, or looses some of its everyday driveability, oh well, its a 95. but if i buy a new tc its because its new. for the money i could get a pretty sweet used car, but its used. so, if i buy it new, i want it to last. this means i will only put the cream of the crop parts on it so it runs as close to stock as possible with the added benifit of power. this means ABSOLUTLEY NO chips, or homemade mods. a supercharger from the factory vs an added one after production means that the tc was built for FI, meaning more reliabilty and a computer with new calculations for increased fuel under boost. where it is true the aftermarket headers, full exhaust, intake, etc will significantly increase the engines airflow, thats out of the question, of course it will add power. but whats going to happen to its life an drivebility? CEL codes are commonplace for me with past mods, even though theres really nothing wrong with it, its still not driving like the manufacturer intended. like the newest performance part for the tc, the engine head (cant remember the exact product name) thats dated for soon release: of course it will add a good amount of power. or how about the intake, tb, and intake manifold. aftermarket versions of these will all add power, but how will that afffect a computer that already programmed for boosted conditions? will it smile and approve or make drastic changes and try to compensate this unexpected and unwanted increase of airflow? the answers im looking for i want to include if mods that increase airflow are harmless or conflicting? it would be a lot different if there wasnt a computer trying to be the boss, sometimes they are open to change, sometimes they wont even stand for a new filter. basically im scared to mess up a perfectly new car that i want to do 100% right for a change. someone please enlighten me.........
 

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If you are planning to add the supercharger I'm assuming you want to know about mods that will compliment that. As their is little information around the new head as of yet, I cant give you an opinion about it. As for your basic boltons, intake, exhaust, header, throttle body, the tC should be able to compensate for these changes in a benificial way.

the tC uses a MAF system to measure incoming air, therefore the ECU knows how much air is in the intake. Therefore the extra air that will be entering due to your added mods will be counted and extra fuel will be added. This is opposed to a speed density system, like your accord had. A speed density system uses a MAP sensor to sense changes in manifold vacuum along with engine RPM to calculate how much air is coming in. There are preset algorithims or "maps" that the ECU uses to know how much fuel to add. Since manifold vacuum is an indicator of engine load, not actual air coming in, it wont compensate as well for mods like i/e.\

hope that answers your question.
 

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Didn't someone on here say that the tC has a preset fuel pressure system and that the ECU is unable to adjust fuel when more/less air is detected. This being one of the hurtles Toyota had to overcome in developing the TRD S/C.
 

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the tC has a returnless fuel system which means it does not use a fuel pressure regulator to raise fuel pressure under load. it simply opens the injectors for more or less time to get the proper amount of fuel.

the reason this is a pain for trd or any of us looking to easily get more fuel out of the stock system is there is no fuel pressure regulator to work with.
A fuel pressure regulator more or less pinches off the fuel return line, therefore increasing fuel pressure. the more fuel pressure you have behind the injector when it opens, the more fuel that will enter the intake. These regulators use manifold vacuum to determine how much fuel pressure is needed. when u put an FMU (fuel managemnt unit) like the ones that commonly come with turbo kits, this fmu works with the fuel pressure regulator to up fuel pressure more and more for for how much boost you are introducing into the intake.
 

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What do the experienced think about an intercooler for the SC? From my (FI newb) point of view - this should be the safest mod for the SC imaginable. AFAIK all the intercooler does is lower the temperature of the air going into the engine, and since the ECU is "trained" to work with a very wide range of air temperatures it should be able to safely adjust for cooler air - thus making it free safe power for the cost of the IC and some piping. How about them apples?
 

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That sounds right to me, Zoltiz, but I don't really know $}{!T.
 

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Originally posted by ZEROmotorsports@Feb 21 2005, 03:21 PM
when u put an FMU (fuel managemnt unit) like the ones that commonly come with turbo kits, this fmu works with the fuel pressure regulator to up fuel pressure more and more for for how much boost you are introducing into the intake.
Got a link to a FMU that changes fuel pressure? I've never seen one.
 

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Originally posted by zoltiz@Feb 21 2005, 03:58 PM
What do the experienced think about an intercooler for the SC? From my (FI newb) point of view - this should be the safest mod for the SC imaginable. AFAIK all the intercooler does is lower the temperature of the air going into the engine, and since the ECU is "trained" to work with a very wide range of air temperatures it should be able to safely adjust for cooler air - thus making it free safe power for the cost of the IC and some piping. How about them apples?
For the amount of boost the S/C is planned to make, an IC is of marginal value. It's easier to just run a little rich and use the fuel's heat of vaporization to cool the intake charge.

The other problem is the intake air temperature sensor is in the MAF, not the manifold. Although I have seen a blow through MAF in a custom application, I've never seen a factory run boost through a MAF. I am told the blow-through configuration has better tip-in response once it is properly tuned, but many tuners opt for converting to MAP because it is easier to adapt to high boost and doesn't have issues with blow-off valves discharging metered air and making the engine stumble or stall completely from a rich spike when you close the throttle under boost.
 

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Originally posted by chrisl311@Feb 21 2005, 06:24 PM
seriously, youalll havnt even answered my question yet about the life. LO BUX RACER, this is for you.
Are you talking service life? I'm not understanding what you want me to address.
 

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Then I'm totally confused. All pre-returnless regulators are vacuum/boost modulated. The idea is to keep the pressure differential across the injector pintle constant so the injector flow parameters are constant. If the fuel pressure doesn't rise and fall with manifold pressure, then the flow characteristics of your injectors change. It's possible to tune for this, but very few do it this way.

Standard regulators operate 1:1. 1 psi boost, 1 psi fuel pressure increase to keep the diferential constant. Rising rate pressure regulators don't go 1:1, the rate rises in a curve so at 1 psi boost you might get 1 psi fuel pressure increase, but at 10 psi boost you might get 15 psi increase from the same regulator. The idea here is to allow the tuner to use smaller injectors for better idle response and atomization while providing the flow of a bigger injector while on boost. If the injectors are good, they won't lock up under high pressure (one of the big advantages of side feed injectors), and they will perform like much larger injectors at WOT.

But this is just tech talk. How is a FPR an FMU? My understanding of fuel management is controlling the injector pulse width with an electronic device connected to the OEM ECM or using an aftermarket ECM that allows you to modify injector pulsewidth directly. Changing the fuel pressure to change the amount of fuel delivered isn't the way I've seen it done by any manufacturer or aftermarket supplier. They all use electronic controls. Sure you could do it with fuel pressure, but nobody I've seen does. Got a link to this?
 

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Discussion Starter · #16 ·
i think you might be confused because they are taking it off topic. my original inquiry was about puting on aftermarket headers, a new intake, intake manifolld, those new heads tctunerz is promoting. those will all change the way the engine makes power. on an NA engine i wouldnt be concerned, but ive never owned a forced induction car before. the way ive always thought of it is turbos are more mod friendly than superchargers?? thats the way ive come to see it, but not reallybased on fact. basically i want to clear up some fuzzy understandings of mine. you can skip all the descriptions im familiar with how every thing works, just how engines react to mods under forced conditions. i just want a better understanding to make better, wiser descisions about adding power. im not trying to, for example, replace the heads and it not work right without trial and error. i want the extra power, but dont need it for a race that im entering next week. my car is strictly going to be a daily driver, all i want the power for is for driving fun, and the occasional off-the-line race. plus i love cars. about the intake/exaust, i want to know how the engine and computer will take these mods with the supercharger, since the system is obviously more complex than natural, and the fact that the system wasnt set up for these mods like a custom set up. thats all
 

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jms001 is the screenname for scionspeed here he's the only person who can answer the kind of questions you have about engine management i haven't dug into the tc's engine management, my engine mod money is being spent on my supra i understand how the tc is set up, but i don't see an easy way to get the ecm to understand boost and i don't see an easy way to get the injectors to provide more fuel as boost increases with the oem design it is different because it's returnless the oem injectors are barely good to 180 hp without boost so you'll be starting with more fuel for any serious mod dc sports has a header for the tc, there is a discussion about it on this board it does not run without tripping the cel, but dc has no intention of fixing the problem because it is being sold as a race only part the trd supercharger is currently not available it is expected april 1 their kit will contain everything necessary to make 200 crank hp reliably and with full toyota warranty. it is your best bet for a daily driver flow gains with a reworked head may or may not work well with obdii some guys have reported constant cels with ported heads because the engine is operating out of the expected parameters for obdii the actual results remain to be seen any mod that is effective for na is also effective for fi, with the exception of ignition timing tuning fi likes less advance and is more likely to have detonation issues other than that anything increasing flow in an na engine will also increase flow in a fi engine does this answer your question?
 

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Unless Toyco has completely changed their ECM philosophy, it will need a piggyback. It comes with bigger injectors for sure, they're in the picture of the kit.
 
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