Ali SC3

iTrader: (10)

so your whole reasoning on this is...
US 2JZ-GE-T would run better on:

JDM ECU (w/map sensor) with fuel controller

than,

US ECU (w/MAF/KVF) with fuel controller.

if you have to use a fuel controller anyways what would be the advantages of haveing the JDM ECU? Also isn't the JDM ECU tuned differently?

I am a bit confused but very interested. what I seem to got out of it was you might be able to use just the jdm ecu to run a na-t by matching the injectors and putting in a map sensor. all stock and happy? JDM happy?

Bean

iTrader: (1)

Well with the OBD1 ECU, you're stuck with KVF. There are virtually NO piggybacks that definitively work well. Those that do support it don't run very well. Just ask the horde of MAP ECU users that have pulled their hair out trying to get it to run like stock (it never will). The stock ignition maps are nasty vs boost and even with a thicker hg, the stock GE ECU isn't safe ignition-wise past 15psi or so. You have to manually retard the ignition or hook up a piggyback to do it for you. GE-T cars running the stock ECU will NEVER drive like stock cars.

The common quote has been: "Go AEM, you won't regret it." Well a lot of us that enjoy these cars, dont have an extra $3k to drop on a damn computer. Especially since the hardware that goes into it costs maybe $150 in production value. But then those same people that have more cash than brains say: "You gotta pay to play"; but then I say, "Well yeah, but IF you're smart enough, you can find new ways of doing things". I'm so sick of that "you gotta pay to play" line being the de facto standard of ignorant car enthusiasts. Yes there comes a point where you do have to pay; but ignorantly tossing your money about and just assuming the only right way is the way you did it is very irresponsible to the community. Seems more like personal justification over a lot of cash for something that has less computing power than a bargain-model laptop made 3 years ago. Better reasons are told by the more responsible members: "I did it this way because I felt AEM was the best choice for me, but there are other ways"

With the JDM ECU, you get MAP functionality right out of the box; I hope you understand the potential power increase by eliminating the very restrictive KVF sensor. MAP sensors are also FAR easier to tune than KVF since their output voltage is completely linear vs a KVF/MAF which is logarithmic and the gain of that logarithmic function varies from sensor to sensor. It has timing maps that are friendly to boost. They are readily available and relatively cheap. The stock 2.3bar JDM sensor is calibrated for 440cc injectors. Well guess what? The JDM map sensor is the same model that comes on USDM model SupraTTs as a turbo pressure sensor and feeds in on the same exact wire! Oh and look! MK3 440cc injectors are a drop-in upgrade for GE cars using a resistor pack. It is also extremely easy to run larger injectors with new maps sensors.

You can take that as a constant/linear relationship: 191.3*MAP sensor pressure limit = new injector calibration. Finding exact injector sizes aren't doable, but using something like an SAFC would allow one to tweak it just enough to get it working (we're talking about very minimal adjustment here). Eventually you go past a point where the injectors are too large to really handle well or running a bigger map sensor isnt so feasible; but there are proven piggybacks to work with 0-5v systems (like greddy emanage blue) that can modify actual injector pulsewidths and fix that problem.

Those that have been in the NA-T for a while know the headaches involved when modding the KVF car. This may allow them to bypass all of those problems for much cheaper than they ever imagined. Cheaper than a MAP ECU and with better driveability and quite possibly equal power potential to an AEM

5sp_jzz30

iTrader: (2)

^^^^completely agree with your mentality. i will quote American Gangster...."My Man"

i want to hear more info on this. my solution was to get an Electromotive Tec2 6cyl version and make a an adapter to put a trigger wheel on the crankshaft. i machined custom brackets when i did that on my sr20.

exceptional work Bean. keep it up.

Bean

iTrader: (1)

Slick idea on the trigger wheel btw. Can the TEC2 read reluctor inputs? The G1 and G2 signals can function as cam position sensors while the NE can function as a crank position sensor. As for information goes, I've already sent a preliminary harness layout to get built. We're talking plug and play capabilities here.

5sp_jzz30

iTrader: (2)

^^^^well i was actually referring to the Electromotive Tec2. this is a full standalone ECU. it has coil packs built right into the ecu. you mount this one piece assembly under the hood. it can run via MAP, MAF, or both. it has launch control, and built in wide band compatibility with any wideband 02 sensor. it works with any windows from DOS to XP. i picked up the 4cyl version fom my sr20 for 400 used and complete with all sensors and GM 3bar MAP sensor.

my SC is a daily driver so i didnt want to go through all that trouble to install it.

keep us updated on the progress.

Ali SC3

iTrader: (10)

OK, kinda what I was thinking as well. Changing out the injectors and adding a sensor shouldn't be too big of a deal.

This is exactly the type of thing I was looking for, as after reading pages and pages of na-t guys on piggyback having all kinds of wierd problems has been the only reason im delaying my turbo project. I want my turbo car to act like a stock car and not have wierd idle, unmetered air going places it shouldnt, etc etc...

Im not sure why you are talking about getting a harness made if all that needs to be changed is one wire. couldn't you just take the wire from the KVF on our harness and reroute it to where it needs to go if that wire goes to the right pin?
or do you need a harness because its from supra ==> sc300?

also, would the small differences in the engine need to be adressed. such as headgasket.
would it be advised to use a tt headgasket or run it like it is

In a little while i might even offer to be the guinea pig.

Bean

iTrader: (1)

small differences in the engine may cause a tuning issue; its not something that would be spot on without any electronic aid; but it would be close enough to tune it with a SAFC and DD it for a long time.

It is only one wire, but the GTE ECU adds in several new ones (mostly for ignition) and has negative connections for the reluctor circuits in the cam and crank position sensors that have to be tied together on the -G from the distributor.

Prototype harness cost is $275 and i'm about to purchase it. This can be done with stock wiring, but 5 or 6 wires would need to be added to tie in the ignition signal and several would need to be bridged together. But yeah, only one wire actually has to be moved: MAF input on GE to PWM input on GTE and then run the map sensor input into the same wire in the engine bay that the stock MAF uses (off the maf plug). An IAT mounted into the engine bay can use the same wire the stock MAF uses and it will not need to be moved on the ECU harness since the GE and GTE share that one.

Ali SC3

iTrader: (10)

sounds fantastic.
please take some notes/pics along the way and keep us updated.
maybe a list of all the parts you need to install it.
this seems to me like the most ideal route for those of us wanting to start a reliable na-t setup.

dejacky

iTrader: (2)

nice brain storm

DryBlaze

Wow, you just made my day. Keep up updated on how this goes. If everything goes well and the price is considerably reasonable I would be in line to buy it.

NoLongerA13bFan

iTrader: (2)

Interesting thread Bean. I would like to hear more about adapting a larger MAP sensor to work with the JDM ECU. I read about some stuff on SF about this but nobody had any real good info (that I saw). I have a aristo powered SC running from the best of my knowledge a JDM MAP ecu and would like to throw more boost at it but the stock sensor keeps me worried running higher boost, so throwing say a 3bar on there would be sweet.

isc300t

what's the limit to the jdm ecu with the stock map sensor and a set of 440cc?

Bean

iTrader: (1)

I dunno about the power level, but the stock JDM MAP sensor will read up to about 18psi.

If you toss in a 3bar sensor instead like a GM MAP sensor, then swap in the SupraTT 550s (they are side feed also); then you just need a mild tune with an AFC and can run up to 28psi of boost. 550s might not be enough fuel for that depending on the turbo; but 28psi is the new theoretical limit.

The 3bar would be looking for about ~574cc injectors, so with 550s you would probably run a little lean. You could raise the fuel pressure a few psi if you had an aftermarket FPR. Or just richen up the airflow map on an SAFC about 2-3%.... in all reality, for daily driving, you wouldnt see a difference because its within the realm of the ECU's power to account for that under closed loop driving.

I'll bust out a fancy graph in matlab for anyone who might not understand whats going on

5sp_jzz30

iTrader: (2)

matlab is sweet

post the graphs!!!

Bean

iTrader: (1)

Here you go!