larger injector characteristic

[TheToyman75]

Renxun,

What engine is it you have fitted the 800cc injectors into ?
What size were the original factory injectors ?

Controlling an 800cc injector with an Emanage will never give you a good result. As a guide its not recommended to use a signal bender with an injector any more than 20% bigger than the original item.

And Rochesters are designed for owners of dragracing V8's. No matter what ECU you use you wont be happy iwth them at light throttle.

The fact your changing your fuel pressure was the first MAJOR sign your doing it wrong !

[MWP]

Large sized injectors with low impedance are hard to tune correctly when using resistor packs as the injectors open too slowly making tuning at idle & cruising (low duty) very difficult.

The only way to fix it properly is to use peak & hold injector drivers (they are in the ECU) and no resistor packs.
This normally means changing ECU to a good aftermarket unit with P&H, or if running a megasquirt, some extra circuits.

The other way to get around the problem is to run staged injectors.

[The Witzl]

i skipped the part about using low impedance injectors with resistor packs!!
Yes MWP is right!!

[renxun]

Renxun,

What engine is it you have fitted the 800cc injectors into ?
What size were the original factory injectors ?

Controlling an 800cc injector with an Emanage will never give you a good result. As a guide its not recommended to use a signal bender with an injector any more than 20% bigger than the original item.

And Rochesters are designed for owners of dragracing V8's. No matter what ECU you use you wont be happy iwth them at light throttle.

The fact your changing your fuel pressure was the first MAJOR sign your doing it wrong !

im using a 1jz engine
original injectors are commonly known 380cc
now im using msd (rochester) 1008cc

wilbo- the thing u show me is emanage blue, the correction done there is actually bending the airflow signal. not the injector drive signal. so the e manage blue isnt actually capable of deducting fuel. unless the airflow voltage had been pull down which will affect timing too.

toyman- yupe i realized that tis is a major problem if i had to alter the fuel pressure for my application. thats why im trying to find out what is going wrong there. thanks for reminding there pal..

i tink the only best solution is to wire back my previous lt12 to it... i was running it previously b4 i got fedup of it and run back the stock ecu wid e manage instead. you guys been very helpfull.

[MWP]

What is this car for?
I doubt you be able to use injectors that large on anything but a drag/dyno-queen car.
If you really do need that much fuel, but want drivability as well, you need a staged injector setup.

Going back to the LT12 with those injectors probably wont help either, Microtechs dont have the best resolution.

[wilbo666]

wilbo- the thing u show me is emanage blue, the correction done there is actually bending the airflow signal. not the injector drive signal. so the e manage blue isnt actually capable of deducting fuel. unless the airflow voltage had been pull down which will affect timing too.

OK, just reading your below post wasn't sure if you knew it could take fuel out at all

the e manage blue cant take out fuel but e manage ultimate can..

Cheers
Wilbo

[renxun]

What is this car for?
I doubt you be able to use injectors that large on anything but a drag/dyno-queen car.
If you really do need that much fuel, but want drivability as well, you need a staged injector setup.

Going back to the LT12 with those injectors probably wont help either, Microtechs dont have the best resolution.

its actually for my drag car..i ran 50% meth and 50% petrol hence the need of injector this big... but not all the time i ran on fuel mix like this. i do bring it to street wid 100% pumped fuel... but i kept it at sleeper mode to compete in the street car category. meaning to say it has all the interior and legal documents. i only bring it to the street once every week or 2 for a warm up or to check on the tune.

im very new to tuning however when you mentioned about staged injector setup meaning to say i need 2 sets of injectors. smaller injector for the lower part and staged the larger injector at midway. is that what you meant?

and if microtech dont have the bst resolution, what does?

[MWP]

Yes, staged = 2 injectors per cylinder.
Only one (a smaller injector) works below a certain load, then one (the larger injector) or both work at higher loads.
Your Microtech can do this, so this would probably be the best option at the moment.

See: http://www.microtechefi.com/forum/viewtopic.php?t=3

[TheToyman75]

Renxrun,

To control an fuel injector that large you need to have a good quality Injector like the Sard Items you mentioned AND an ECU that is capable of controlling them. The Autronic ecu's have great control of fuel injectors, especially at idle and if you went for there latest offering, the SM4 it will give you benefits like the 2 step rev limit and launch control staright out of teh box if you set it up right. Its not the cheapest ECU around (CHeaper than an equivilently optioned Motec) but it will do the job you need very well.

How much power does your 1J Make ? They really are some huge ass injectors.

[renxun]

dont have dyno machine here in my town ... the nearest one will be like around 550km away from my home...

before i get any further, i would like to ask back regarding the very main basic. Usually. lets say we idle at 14afr. by raising the fuel pressure, theoretically the afr will turn richer. and backed up by evidence wid the previous set of injector.

However, with the sard low impedence and this msd, i faced the opposite. whenever the fuel press is bumped up, i get leaner afr. this is a problem that need to be identified first. my fuel system is alright as whenever i plug back the high impedence injector, it gets normal. which means whenever i bump up the pressure, the afr get richer.

the tune wont be right if the basic isnt correct

[TheToyman75]

You are clearly not driving the injectors correctly as has been stated by other in this thread.
Your problem is the combination of tune, ECU and settings you are using. There is very little chance the injectors themselves are at fault.

[MWP]

However, with the sard low impedence and this msd, i faced the opposite. whenever the fuel press is bumped up, i get leaner afr. this is a problem that need to be identified first. my fuel system is alright as whenever i plug back the high impedence injector, it gets normal. which means whenever i bump up the pressure, the afr get richer.

Sounds like your fuel pump or fuel lines are not up to the job.

Get a constant rate FPR (not rising rate), set it at 60psi and forget about it.
Tune with the ECU, not with fuel pressure.

[renxun]

toyman 75 - i guess thats the main issue.. if i face this issue, i believe others should have too. but i felt weird that why some of the emanage write up that i read at etuner or even here can get away wid the low impedence injectors

MWP- my fuel pump is dual bosch 910 parallel setup wid 10mm inner diameter fuel line. my FPR is a constant rate FPR frm sard.

[TheToyman75]

renxun,

If your engine actually needs injectorsthe size you have then a 910 is not going to keep up when under high boost.

The 910 is the Baby Bosch pump. The 044 is more like what you need if your engine is actually using the fuel you are attempting to feed it. When looking atthe flow figures, dont forget to reference them to the fuel pressure. The more pressure the less they flow and each pound of boost you add is matched by the FPR.

[renxun]

renxun,

If your engine actually needs injectorsthe size you have then a 910 is not going to keep up when under high boost.

The 910 is the Baby Bosch pump. The 044 is more like what you need if your engine is actually using the fuel you are attempting to feed it. When looking atthe flow figures, dont forget to reference them to the fuel pressure. The more pressure the less they flow and each pound of boost you add is matched by the FPR.

Sorry if i created any misunderstanding. Im actually using 2 unit of bosch 910 in parallel . Should be around the capacity of a 044