Upgrading Injectors - 440cc - 660cc - with programmable ecu

[Kedderz]

I will be upgrading my injectors this afternoon hopefully and Im assuming I wont do any damage to my engine by upgrading my injectors to 660cc from 440cc, it will just run rich due to the current tune?.

I have a autronic sm4 computer and will only run the car to get it down to a dyno to have the mixtures adjusted.

The worst it could do is pop and fart due to the excess fuel and maybe foul the plugs or am I missing something?

[andrew_mx83]

that will be a shitload richer.... introduce some un-metered air to help even things out if its too rich to run

[Shifty]

You will be lucky if it runs mate... as mentioned if you add in some un metered air it will run better... disconnect a BOV recirc line or something.

Change the oil, oil filter and plugs once you get to the dyno place.

Alternatively.. just tow it.

[Kedderz]

Tow might be the way to go then, thanks guys.

[RA35GT]

Isn't there a master fuel trim you could adjust to bring it back? (Something around 440/660 but leave it on the rich side?)

[Kedderz]

I dont have any way/method of altering the tune unfortuantely

[andrew_mx83]

put em in, pull a big vac line off the inlet manifold and see how she goes. if u can easily let air in before the throttle body even better.

[mattysshop]

if it's map sensored i didn't think it would make a difference as manifold pressure would drop...

i'm going to be upgreading 440's to 800's soon on a 3S... but the motec runs a 3 bar map sensor so i don't think doing this would work...

i would be more inclined to take 10psi out of the fuel pressure

[Kedderz]

The car is map sensored.

[mattysshop]

sorry i edited that as you were replying,

try taking out some rail pressure??

sometimes a temp fix smaller injectors is to run a little more rail pressure..

surley you can do somthing similar in reverse??

[Kedderz]

I dont have an adjustable FPR, its a stock fuel system just with a surge tank + lifter pump and a bosh 044 supplying a stock 1ggte fuel rail.

[andrew_mx83]

resister before fuel pump lol.


if its map sensored i dont think inducing more air will help to lean it out

[Duk]

Jamming some 50% larger injectors in an engine and expecting it to able to drive it is bloody hopeful.

Why can't you get the tuning software from Autronic?

If you can't play with the fuel map, then either tow or trailer the car to the people who can.

Maybe get your tuner to come to you and simply reduce the whole fuel map by 40-50% and then drive to the dyno.

[mattysshop]

considering your setup with aftermarket management and big injectors, i would suggest that you do use some sort of adjustable reg

some of them arn't that expensive, you can get decent US stuff at very good prices.. aeromotive, mallory, etc etc can be had for under $200...

my mates 3S motec setup runs a mallory raising rate one from Performance wholesale that he got for about $150.. black billet anodised.. it looks the part!!

[gixer]

Why can't you get the tuning software from Autronic?

Spot on, Autronic has an injector scaler you can mess with this