MAFT and MPI Tuning Pros i have a question...

[importwarrior]

Question:

does the primary injector fire from IDLE to MAX RPM?

 

if YES Then

 

Disclaimer:

this is just a question and some remarks are just for example dont shoot me for examples....

 

 

if yes then whay cant we splice in an injector clip from the primary

get 2 larger injectors like 1000cc or bigger but same size.

use only the primary injector and the spliced clip from the primary injector.

secondary injector clip is not used. well more on that later.

 

TUNING:

you can tune with the MAFT or any other device like it or MegaSquirt

 

now dont verbally beat me up this is just food for thought.

 

with megasquirt or MS you can batch fire the injectors the

injectors are ran off of 2 banks also.

 

so why not run the injectors off of one primary injector harness

from the quest and tune with a MAFT or similar tuning unit.

 

i cant see how this would not work and for the MAFT sake make it

easier to tune. dont have to worry about the transition of the

secondary injector and boost pressure bumping the fuel pressure up.

 

i think it would be a better running car and tuning would slightly be easier.

possibly more consistant.

 

 

again only a thought,

 

Edited October 30, 2013 by importwarrior

[scott87star]

I don't believe the MAF translator would be able to translate that far, meaning it wouldn't have the range to tell the ECU to get the fueling correct. If I read your question correctly you're talking about going from a 600 cc injector to two 1000 cc injectors or 1400 cc more fuel which is over 3X what the ECU thinks is being injected and the translator has to compensate. I'm sure the translator can deal with 10 or 20% changes but not 300%.

 

And if you're going to use MS or another standalone then you may as well wire it correctly.

[Shelby]

I be leave all the translator is doing is lieing to the ecu about air flow and NO the pri inj turns off at aprox 2500 rpms or when the throdle is moved quickly

 

[importwarrior]

Scott,

i was just using the cc size just to show larger CC,

that % adjustment difference makes sense to me for sure.

 

shelby i didnt know that the primary was ever turned off.

i guess that is why the car falls dead on its face when the

secondary is not plugged in at like 2800 RPM. i first thought

it was just severely lean.

Edited October 30, 2013 by importwarrior

[Scotty Dont]

There is no way the primary injector turns off, 950cc is not enough fuel for the motor to run.

[jszucs]

If your going to use MS why would you ever use MAF when you can use MAP?

 

Really your still limited with the 2 injectors, and bad flow of the air and fuel in said mainfold regardless of what injectors, how you fire them, what size they are ECT. This can be compensated by having the spray pattern modified for better atomazation but you are still limited by inconsistant flow to all 4 cyl.

[importwarrior]

This was just to see if it was possible to do with a MAFT, APEXI or other tuning device that was all.

Injector size was irrelevant I know the CC was off it was just used as an example not

permanent or what I would use.

Edited October 30, 2013 by importwarrior

[jszucs]

This was just to see if it was possible to do with a MAFT, APEXI or other tuning device that was all.

Injector size was irrelevant I know the CC was off it was just used as an example not

permanent or what I would use.

 

Yes injector size and everything else aside, your not solving the real problem. The real problem being 2 injectors, and poor distrobution of incoming air and fuel. It's why direct injection can make so much power and be so fuel efficient. Percicse contorl of fuel to each cylinder.

Edited October 30, 2013 by jszucs

[Shelby]

There is no way the primary injector turns off, 950cc is not enough fuel for the motor to run.

 

well do a little testing for your self , wire up two inj testers one to each inj and see for your self , you may learn a little some thing you didn't know

 

no one said it never turns back on but it's much later and under boost

[importwarrior]

I be leave all the translator is doing is lieing to the ecu about air flow and NO the pri inj turns off at aprox 2500 rpms or when the throdle is moved quickly

 

i am just trying to understand this.

ok so if the primary turns off at about 2800 RPM when does it turn back on?

also if the primary turns off, then one secondary injector kicks in only supplying 950cc for the entire engine?

seems like that is not enough fuel unless the injector fires for all 4 cylinders.

 

 

http://www.fullthrottletech.com/showthread.php?t=894

[StarquestRescue]

The transition from the primary to both injectors is based on the airflow signal or the tps movement. After the transition the primary is delivering approximant 40% of the fuel is was before the transition and the secondary picks up the rest of the load. Both increase at similar duty cycles from there as the airflow signal increases. The correct way to do air flow correction tuning is to upsize both or all injectors the same percentage. Lets say 20% bigger injectors, then the airflow signal is reduced approximately 20% with your tuning system..........................It does not matter if the car is a 2 injector starquest or a 4 injectors dsm. The tuning principle is the same. In the dsm world 40% bigger injectors is considered a limit for what air flow correction tuning can do a decent job with.....................This is what the primary duty cycle change at the switch to both injectors looks like on a data log..................http://i237.photobucket.com/albums/ff45/StarquestRescue/Data%20logs/Secondaryonsetatlightthrottle.jpg

[importwarrior]

That's great info.

Thanks for the help

[StarquestRescue]

That's great info.

Thanks for the help

I would suggest you read the first two links in my signature abut 3 times each. Data logging is the most important tuning tool a person can add to there car.

[Shelby]

The transition from the primary to both injectors is based on the airflow signal or the tps movement. After the transition the primary is delivering approximant 40% of the fuel is was before the transition and the secondary picks up the rest of the load. Both increase at similar duty cycles from there as the airflow signal increases. The correct way to do air flow correction tuning is to upsize both or all injectors the same percentage. Lets say 20% bigger injectors, then the airflow signal is reduced approximately 20% with your tuning system..........................It does not matter if the car is a 2 injector starquest or a 4 injectors dsm. The tuning principle is the same. In the dsm world 40% bigger injectors is considered a limit for what air flow correction tuning can do a decent job with.....................This is what the primary duty cycle change at the switch to both injectors looks like on a data log..................http://i237.photobucket.com/albums/ff45/StarquestRescue/Data%20logs/Secondaryonsetatlightthrottle.jpg

 

isn't that exactly what I said

 

is it rpm or air flow or boost that signals he pri to turn back on

[StarquestRescue]

isn't that exactly what I said?

No, not even close.............................................Transition to both at 390 hz, back to primary only at 290 hz.

[Shelby]

No, not even close.............................................Transition to both at 390 hz, back to primary only at 290 hz.

 

 

your chart shows exactly what i said , oh well no use argueeing with you

[Scotty Dont]

 

 

 

your chart shows exactly what i said , oh well no use argueeing with you

 

You said it turns off, it never does. I ran a megasquirt setup on the stock TBI manifold and configured the ecu to turn the secondary injector on at 2500rpm and drop the pulse width to the primary injector nearly In half. It ran quite well, I should have never switched that car to an mpi manifold.

[Shelby]

 

 

You said it turns off, it never does. I ran a megasquirt setup on the stock TBI manifold and configured the ecu to turn the secondary injector on at 2500rpm and drop the pulse width to the primary injector nearly In half. It ran quite well, I should have never switched that car to an mpi manifold.

 

his question was concerning a stock ECU

[jszucs]

You said it turns off, it never does. I ran a megasquirt setup on the stock TBI manifold and configured the ecu to turn the secondary injector on at 2500rpm and drop the pulse width to the primary injector nearly In half. It ran quite well, I should have never switched that car to an mpi manifold.

 

Really? Why do you say that? MPI and direct are where it's at. On that topic anyone ever think of using a jet valve hole to run direct injections?

[Scotty Dont]

 

 

his question was concerning a stock ECU

From his first post "you can tune with the MAFT or any other device like it or MegaSquirt"

 

And I was just sharing some of my experiences, do you really feel the need to be a jerk?

 

 

 

Really? Why do you say that? MPI and direct are where it's at. On that topic anyone ever think of using a jet valve hole to run direct injections?

 

Because I live in Cali and could have smogged the car with mega squirt and TBI.

[Shelby]

From his first post "you can tune with the MAFT or any other device like it or MegaSquirt"

 

And I was just sharing some of my experiences, do you really feel the need to be a jerk?

 

 

 

 

Because I live in Cali and could have smogged the car with mega squirt and TBI.

 

ok this is his first line in his question --

Question:

does the primary injector fire from IDLE to MAX RPM?

 

if YES Then

 

BUT THE ANSWER TO THAT QUESTION IS NO it does not fire from idle to max rpms

that is the question I was answering,,

now as to whom I being a jerk, , even the posted chart shows i was right

 

can't you guys ever just go along and not have to prove you are the last word and start calling names , it gets old

[jszucs]

From his first post "you can tune with the MAFT or any other device like it or MegaSquirt"

 

Because I live in Cali and could have smogged the car with mega squirt and TBI.

 

HMMM well guess you should get a driver car, and plate the quest under historicals then. That's what I had to do with mine but can get collectors in OH.

[StarquestRescue]

Well I could have marked that chart a little better, 0 duty cycle is at very bottom 100 at the very top............................ This screen shot shows duty cycle of the primary and secondary during acceleration. The two lines nearly on top of each other above where I marked duty cycle are the primary and secondary, with the secondary being the darker one. If they are followed to the left it can be seen how the ecu modifies the primary duty cycle as the darker secondary line jumps up from 0 at the bottom of the picture. Where they come together was probably about 26% duty cycle. .........................http://i237.photobucket.com/albums/ff45/StarquestRescue/Data%20logs/Changeat1350Hz.jpg

[importwarrior]

Well from what I see in the chart posted they both run to what I was hoping for

Thanks SQR for the information.

I am reading the links in your Sig.

[Scotty Dont]

 

 

ok this is his first line in his question --

Question:

does the primary injector fire from IDLE to MAX RPM?

 

if YES Then

 

BUT THE ANSWER TO THAT QUESTION IS NO it does not fire from idle to max rpms

that is the question I was answering,,

now as to whom I being a jerk, , even the posted chart shows i was right

 

can't you guys ever just go along and not have to prove you are the last word and start calling names , it gets old

 

You are wrong plane and simple, the primary injector runs the entire time. As the graph shows above and can be conclude by understand that one 950cc fuel injector cannot supply enough fuel for the engine to run all the way to redline.