General Automotive DiscussionGeneral automotive discussion and chat. Honda, Toyota, Chevrolet, Ford. It doesn't matter, just talk about it here.
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Okay, first off a turbocharger with twin-scroll turbine housing is more efficient. The exhaust manifold will be more complicated to manufacture, but the efficiency will go up. Read about it here: eGARRETT.com Here is a T3/4 with a twin-scroll turbine housing for a rather good price: New T4B Turbo (300hp) or New T4B w/T3 flange Turbo (300hp) This is the only comparison chart that I could find: Turbo Summary Chart I'll keep on looking...
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The main problem with the returnless fuel system, besides what others have already stating, is that it is the same pressure the entire power curve, and the stock ECU knows this. If you add boost, you need more fuel, and with the current system, there is no way to add more fuel except for piggyback computers and/or stand alone engine management, but the stock fuel system can only go approximately 27% over stock at low RPM, and as the RPM increase, the percentage actually decreases! With boost, after the returnless fuel system has been figured out, you will also need a upgraded ECU or a stand alone unit. I have been thinking about how to go about replacing the stock returnless fuel system, and this is what I have come up with so far... Input is always welcome....
In order to replace it, obviously we will need to add the return line, and our fuel rail is pretty close (emphasis on "close") to the 6th gen fuel rail. Instead of having a pipe on one end and another on the opposite end, ours just has one fuel line on the right side of the fuel rail. Drill out, tap out, and put a connector for a fuel line on the other end, and run that back to the fuel tank. Granted, this would be to free flowing for 1. The ECU 2. The injectors... because the fuel will simply go to the area of least resistance. We would need to put some kind of restrictor on the new line, to keep pressure built up over the injectors, and would probably need to remove the stock fuel pump and regulator from the gas tank and replace them with higher flowing ones.
The only problem is that there would be no way to have the fuel pressure continously adjust the pressure, thus putting us back to square one, except now at least of have a full circuit fuel system.
BTW... I just happened to remember this... Anyone lie close to XS Engineering? The new Toyota Celica and Toyota Matrix both have returnless fuel systems, and they have figured out how to undo this and make a turbo kit for them with a full circuit fuel system. Someone should stop by and ask them how the hell the did that...
-Dale
EDIT: This is XS Engineering's addy
XS Engineering, Inc.
4030 N. Palm Street, Suite 302
Fullerton, California 92835
Telephone 714-992-4133
Fax 714-992-4534
I don't understand how the stock fuel system works? There's a fuel pump in the gas tank that keeps on pumping the fuel to the fuel rail, right? Then there's the fuel pressure regulator. All that does it keep the fuel pressure steady, right? Then there are the injectors which have a certain flow rate. Then there are various oxygen sensors that the ECU uses in some way. Then there are air/fuel ratio maps that the ECU has as well. Now my question is how does the ECU regulate the flow of fuel to the engine? Does anyone know? Does it turn on and turn off the fuel injectors for a certain amount of time? Does it control the fuel pressure somehow? What happens?
Edit #1: Found something that explains this. Electronic Returnless Fuel System I guess the ECU tells the FPR how much pressure it needs? The FPR can adjust from a certain psi all the way up to the output of the fuel pump? If so, then we'de need the RSX's FPR/fuel pump/filter unit.
With ours, the fuel pressure is constant (to a degree), the ECU changes the injector pusle width to make the injectors inject fuel at a certain rate. O2 sensors are for emissions and by this the ECU can make the injectors flow higher if say it detects the air mix is lean or it can back the injectors down if the car is running rich and/or an cold start up in which the cat has yet to make it to proper operating temp and thus too many emissions are being seen by the second 02 sensor. Unfortunately it all boils down to emissions, not power. The computer does have a set path of what fuel needs to be injected into the engine to make it go, but it also has a little "wiggle" room for different operating temperatures, ambient air temperatures, etc. that affect any car at different altitudes, climates, conditions, etc. Understand, or do I need to break it down further, which I don't have a problem doing so don't have a problem asking.
OR FOR 250 GET A PIGGY BACK FUEL MANAGEMENT SYSTEM THEN THROW IN A HIGH FLOW PUMP FOR ABOUT 150- THEN CALL IT A DAY
EDIT- JUST CALLED XS- THEY SAID THEY HAVE NO KIT FOR THE MATIX- AND THE CELICA KIT ISNT DUE OUT FOR AT LEAST ANOTHER 5 MONTHS- AND I STILL ASKED HOW THEY OVERCAME THE ISSUE- HE SAID- "IM SORRY BUT I CANT GIVE YOU THAT INFORMATION"- PRICK
<< With ours, the fuel pressure is constant (to a degree), the ECU changes the injector pusle width to make the injectors inject fuel at a certain rate. >>
Oh really? How do you know this? What does changing the injector pulse width mean exactly? What happens physically to the injectors to make them deliver more fuel or less fuel. Yes, please keep going...
I'm reading some stuff on the net that explains this a little better. Here's something I found that refers to a returnless fuel system in general:
<< The fuel system is returnless, like most new cars, to lower the temperatures of the fuel in the tank and minimize evaporative emissions. Fuel pressure does not vary with manifold pressure as it did with the old engines; instead, it is now fixed at about 50 psi. This means no tuning simple turbo systems with rising rate fuel pressure regulators... sorry. >>
Edit #1: Wait, how do the nitrous kits get more fuel to the engine? [IMG]i/expressions/face-icon-small-confused.gif[/IMG]
Edit #2: Here's something I found:
<< The fuel system on the 1ZZ-FE is a returnless fuel system. Meaning, I cannot just use a fuel pressure riser or regulator. Sport Compact Car magazine said I have to solve the fuel issue by reprogramming the ECU. I really do not want to go that route. Rather, I'd like to plumb some injectors into the intake manifold or before the throttle body. I would use an aftermarket fuel injector controller such as HKS, to activate under boost. My question is how will I run the fuel to the injectors. Will I have to route a new fuel line with new pump and regulator from the tank? >>
Anywho, a piggyback computer basically tricks the stock ECU into thinking the engine is doing something when in reality it is not. EX. Engne is running normal, the temperature is at par, emissions are normal, etc. A piggyback, if the user say increases fuel by 10% from 5k to 8k RPMs, will tell the stock ECU that the engine is running dangerously lean, at 5k to 8k RPM, and the stock ECU through its various logarithims (SP?) will decide that the fuel needs to be boosted by 10% at these RPMs to bring the engine back up to par, which causes the engine that is already running normal, to become a little rich, thus adding power. But remember there is such a thing as running too rich.
Summary: Through the various sensors that the piggyback computer hooksup to, it tricks the ECU into thinking the engine is running differently than what it actually is.
Good? Bad? Or still confused?[IMG]i/expressions/face-icon-small-confused.gif[/IMG]
BTW often times people will increase the fuel with piggybacks, but will only think it is doing any good, when the only way to find out is to slap the car on a dyno and play with the piggyback.
How many of these piggyback computers do we have to chose from? The one we talk about in the thread I previously mentioned is made by Greddy and it's called e-Manage. What troubles me about this thing is this (quoted from greddy.com):
<< Basic functions will allow the user to slightly alter factory injector duty-cycle(± 20% at 5 preset RPM points), by intercepting and altering airflow or MAP sensor signals. >>
This sounds like there is a limit on how rich we can run. Would the limit be taken care of with higher flow injectors, and the RSX's in-tank setup?
WOW- HAHAHAHAH- OK GUYS YOU ALL GOT TO KISSA MY BUTTA- I JUST TALKED WITH REV HARD- THEY ROCK- JUST GUESS WHAT TURBO IS GOING TO COME WITH THERE KIT FOR OUR CAR????- A T3/T4- HE SAID AROUND 7 LBS OF BOOST- AND AS FAR AS THE FUEL ISSUE- THEY ARE RUNNING A HI FLOW FUEL PUMP- EITHER 370 OR 440 INJECTORS- AND A GREDDY E-MANAGE SYSTEM- AND APPROX COST OF KIT IS $4600!!!!!!!!!!!!- SOOOOOOOOO I GUES MY T3/T4 TURBO IDEA AINT THAT BAD EH????
Or still confused?[IMG]i/expressions/face-icon-small-confused.gif[/IMG]
