scoobyfury

I have a '98 uk car with a td05 front entry turbo & I'm looking to upgrade to 440 injectors to get max benefit for an eventual fmic.

I've been told that my Hks afr will be able to increase the fuel enough for the injectors but thought it best to check that this is right ?

Cheers

Martin

RICH WILD

In a word.....no.

What ECU are you running? If it is standard, then 440s should not really be fitted.

The AFR simply fools the ECU into increasing the amount of time the injectors are open, so the injectors will add more fuel than they would normally.

The injectors add more fuel themselves bu nature of their larger size, so to say it will "increase the fuel enough for the injectors" is basically misunderstanding how the fuelling system works.

Your injectors are open for a set time determined by the ECU which varies dependant on how much fuel the ECU "thinks" the car needs. By fiitng a bigger injector, the ECU still "thinks" there's a 380 there, so pulse the injector for as long as it takes to add the required fuel. if the injector is larger, in thart given pulse it will add more fuel so your car will overfuel across the whole rev range automatically. If the AFR is backed off this will redress the balance, but that kind of defeats the object.

For bigger injectors, you should remap the ECU, but why do you want bigger injectors? What boost are you currently running?

scoobyfury

Thanks for taking the time to answer

The car has a full decat system running 1.1 bar of boost using an Apexi AvcR boost controller, with both HKS FCD & AFR with a TD05 front entry turbo & standard injectors running at 90% duty which I've been led to believe is too high. The car was however dyno'd 3 weeks ago at 293 bhp with a nice torque curve & no detonation apparant.

I'm intending on fitting a front mount intercooler & have been given to understand that I will need larger injectors to get full benefit/safe running but also believe that I am crippled by my current '98 standard Ecu.

What in your opinion would be my options regarding fueling ?

Thanks again

Martin

RICH WILD

Well,

I run the same turbo as you at 1.45 bar on the standard ECU and injectors, albeit with an uprated pump and regulator and an uprated TMIC and using booster. The most I get is the odd green on the knocklink. I have been dynoed at 386bhp at Well Lane.

So, I'll leave you to draw your own conclusions from that one.

Larger injectors and a FMIC with a mappable ECU will obviously allow you to get the most from the car but don't feel like it is a "must do" straight away.

My next step is an Apexi ECU but I'm still sticking with the standard 380s for now.

scoobyfury

Cheers Rich,

I think I'll probably go the same route for now then. Fmic with uprated pump & reg and see how we go from there.

What pump & reg are you using ?

Martin