4efte map sensor on 4AGE NA ecu

[jacobrjett]

firstly I dont plan to do this to mine I just wanted to put it out there for discussion

on a 4age smallport (or any 4age with a MAP sensor) the theory is that the factory map sensor is rated to 1 bar (15 psi) before it maxes out. It puts out a voltage signal from 0v to 5v.

atmospheric pressure is roughly 15 psi dependant on elevation and temperature etc. so as soon as the NA map sensor sees more then a few psi of boost it will error

swapping it for a 4efte map sensor which is rated to 2 bar but puts out the same voltage, 0psi = 0v, 15 psi atmospheric pressure = 2.5v, amospheric pressure + 15 psi boost = 2 bar = 5v.

this means exactly half the signal. factory injectors are 182cc and 4agze are 365cc. almost exactly double.

so at 15 psi/atmospheric pressure, where the NA map would be maxed out at 15 psi, it will be putting out 5v to max out the 182cc injectors.
4efte map with 365cc injectors will be putting out 2.5v and have half the injector flow rate but having injectors twice the size should even it out.

obviously there are problems. it will not retard the ignition automatically once the boost comes on. This means a need for retarded base timing. also the closest thing you have for tuning for a good a/f ratio would be a wideband and a fuel pressure regulator. a rising rate regulator could be of help here, not sure.

but it does sound like a way to get an NA ecu boosting temporarily. running in diagnostic mode will eliminate any fuel cut but it shouldnt cut out with boost until the map sensor maxes out anyway.

at first i dismissed the idea thinking that the NA ecu will read the vacuum from the map at lower revs then it will switch to boost and just turn everything upside down or inside out. but then i thought about it and its really only a voltage from 0v-5v telling the injectors how much to open/close, the 4efte map will just put out that voltage so it should work. the injector size has to match the map size though. (IE double the map range, double the injector size)

is this a temporary way to get an NA 4age boosting on the factory ECU?

[jacobrjett]

http://forums.club4ag.com/zerothread?id=982&page=3

This setup is good to run a turbo 4AGE with stock ECU up to a boost cut of around 14psi. It may or course need adjustment of the fuel pressure to do so safely, but that's best done on a dyno, or with a wideband O2 sensor. I've been in contact with a dude from Turborolla website, who is running the same setup as I'm going use, even the same turbo. He's using the 4EFTE sensor and the 4AGZE injectors.
Use a Toyota MAP Sensor, as the plugs are the same three pin plug. Use either the 4EFTE one or an early model 3SGTE one, as they are both 2 BAR sensors (fuel cut will occur at around 14psi

The 182cc injectors use the stock MAP sensor from max vacuum up to 0 vacuum, (no turbo, so no boost). That will go full scale of the MAP sensor voltage 0-5v.

With the 4EFTE MAP sensor, it will run from max vacuum to 0 vacuum in a scale that's 0-2.5v, then boost to 1 BAR (~14psi) 2.5v to 5v.

The voltage range might go the other way (0v for max load on the N/A sensor), but the theory is still sound...

So, now as you can see you have half the voltage scale in the vacuum range, so thus the reason for using injectors that are twice the size of stock (182cc vs 365cc).
This works because the basic trend for fuelling of an engine is linear (take away compensation of water temp, air temp.... and stuff like that). I've been looking at fuel maps on my mates Hondata S300 and a stock 4AGE MAP someone had posted on the intenet.

It all works out quite nicely, except when boosting high, where you might need to use a rising rate fuel pressure reg, as the differential pressure in the plenum will lower the effective fuel pressure. Eg 10psi boost and 50psi fuel pressure, will effectively be like 40psi fuel pressure due to the pressure differential. Well that's my theory anyway. I'll be testing this with and without a RRFPR on my car.

[DexGT]

Well for a start 4EFTE injectors are 295cc , possibly a 4EFE might be 183cc but thats not going to help you much .
As for the rest of it , who knows but if they can't even get the injector sizing right it's probably dubious .

[evil_si]

Cant remember which map sensor to use, but yes it does work,

I did a turbo conversion on a customers 4/5afe car a few years ago, we used a rising rate fpr a bigger intank pump and he used a toyota turbo map sensor and did around 40,000km with no issues

[Stu-]

Yeah works almost perfectly on a 4afe

[jacobrjett]

Well for a start 4EFTE injectors are 295cc , possibly a 4EFE might be 183cc but thats not going to help you much .
As for the rest of it , who knows but if they can't even get the injector sizing right it's probably dubious .

im talking about turboing a 4age smallport, not a 4afe/4efte

with 4agze injectors and a 4efte map sensor

I will dummy it out for a bit in a few weeks hopefully just to see if it really works or not.

[Shrike]

Wouldnt a 4agze map sensor and ecu be more suitable ?

[jacobrjett]

if i wanted to change ECU entirely, why would I swap to a GZE ecu I would swap to a standalone (which I plan on anyway)

this pretty much means stock 4age smallport, swap the MAP sensor and injectors, and its ready to boost 14 psi without changing the ECU and no/minimal wiring

[Shrike]

I thought the 4agze ecu was a direct plugin (could be wrong)

And your swapping to bigger injectors anyway so just run a 4agze setup on the 4age

[jacobrjett]

as i said from the start i dont plan on using this to run my 4age i am just putting the theory behind it up for discussion

matching injector sizes to a 2 bar map sensor on a NA ecu etc. how much its going to have to be retarded to compensate for boost, whether the fuel maps will still work etc.

[QikStarlie]

smallport injector are 235cc are they not? so you would need something around 470cc rather than 365's

who knows what the factory ignition map looks like. but will be somewhere between 25-30degrees, most likely closer to 25deg. at wide open throttle (na). will want to get that back down to around 15degress at your max boost (14psi) on hi comp engine. so knocking the base back to 0 should work. will be a bit more lazy and probably use more gas cruising

/ short version: retard base timing to zero.