injector upgrade

[kurt fuhlbrigge]

Most of the time my injector duty on the dsm link maxes out at around 80% but once in every tuning run I get a spike to 97-99%. I believe the injectors are 650cc using a fp68 turbo at around 21psi . Car runs around 400hp .I would like to try to turn the boost up just a couple more psi.Car ran a 12.20 and id like to hit 11 sec. Car had a little blip @ 6000rpms in 4th gear but I did not have the dsm link on it so i dont know.I thought maybe time to step up the injectors.What do you guys thing?

 

[bryanwheat]

I would get some 1,000 cc injectors.

 

[NHerron]

When you have link, people usually get the biggest injector they think they'll ever need since link has no problems tuning in big injectors. That way you dont need to buy injector after injector ...and the prices of bigger sizes don't differ significantly anyway

 

[kurt fuhlbrigge]

well the car is just about maxed out for that turbo and the stock block.I just bought the turbo and the mtr .So Im not looking for much more out of either one.Im pretty happy with the way it turned out .It runs great on the street which is what is was for.Heck a 12.2 sec street car aint bad.But now that I saw that I want to call it an 11 sec car.Im spraying a 35 shot of nitrous to give it a little kick which should put it near 435hp and from what I read i dont want to go much farther on a stock mtr.I could bump up the nos jets to 50 for a run and see if that gets me the 2 tenths im looking for.Ok so say I stick with the car the way it is.Does seeing the injector duty jump to 97 once in a while tell you that the injector size needs to be increases?Or is this ok ?Thanks

 

[NHerron]

That's an awesome daily driver!

If the spiking happens a lot you might want to upgrade for fear of burning out the injector coils or the coil drivers contained within the ECU. Not a guaranteed thing but it's possible.

Also, and someone correct me if wrong here but I believe a 'normal' IDC will result in more consistent/predictable AFR's over an injector with higher than recommended IDC's


You probably wouldn't be out too much money if you sold yours on the classifieds and got some bigger used ones from someone

 

[gofer]

If you're running DSMLink why don't you post a log and let us take a look?

The injector IDC value being logged is calculated by the ECU based on engine fueling requirements that are being pulled by the ECU based on injector globals, MAF Hz sliders, the VE table (if you're running speed density), and the OLMax/MinOctane tables in direct access. So, to say the least, logged IDC's are always accurate unless you've got injector wiring/injector issues so the "jump" you're seeing from 80% to nearly 100% isn't a tuning issue in ECMLink. What happens to your AFR when the "jump" happens? I'd be leaning towards a fuel pressure issue, whether that be the pump or the fuel pressure regulator.

If you could post a log it would tell us more than you could ever try to explain, it's hard to help by guessing.