inj. duty % question

[nesmsm]

I was wondering if injection duty % should be at 100% sometime like at WOT a/o high rev, because I can't get mine over 65% when real time monitoring, can someone tell me if that's normal?

thanks

[Magusownz]

I was wondering if injection duty % should be at 100% sometime like at WOT a/o high rev, because I can't get mine over 65% when real time monitoring, can someone tell me if that's normal?

thanks

You don't want the injector duty to reach 100% at any time. Most people don't trust getting close to the max of the injector. Mine now are right around 90% and I'm about to throw in some 440cc injectors.

[nesmsm]

I see, but isn't 65% too low? I was thinking it might have something to do with the TPS because I test it with the multimeter and I'm getting good range with closed throttle but not with wot, it is showing very out of range numbers, do you think that could be possible?

[Magusownz]

I see, but isn't 65% too low? I was thinking it might have something to do with the TPS because I test it with the multimeter and I'm getting good range with closed throttle but not with wot, it is showing very out of range numbers, do you think that could be possible?

What are you modifications? Stock injectors, bolt-ons, turbo?

[nesmsm]

well not that much, k&n sri, free exhaust-de-cat, mwr flat face valves, mahle 13.2:1 and the power fc, stock injectors, but still I'm not getting correct number range on the TPS with the multimeter at wot.

[Magusownz]

well not that much, k&n sri, free exhaust-de-cat, mwr flat face valves, mahle 13.2:1 and the power fc, stock injectors, but still I'm not getting correct number range on the TPS with the multimeter at wot.

ah I'd recommend getting some bigger injectors if pfc is saying your inj duty is at 100%. Your map could just be real rich but I know celica injectors are slightly smaller than ours so your stockies could possibly be close to being maxed out.

[Nachtmensch]

I was wondering if injection duty % should be at 100% sometime like at WOT a/o high rev, because I can't get mine over 65% when real time monitoring, can someone tell me if that's normal?

thanks
It sounds to me like you may not know exactly what injector duty is.

[v3bahumut]

I was wondering if injection duty % should be at 100% sometime like at WOT a/o high rev, because I can't get mine over 65% when real time monitoring, can someone tell me if that's normal?

Completely normal, it means your injectors are working at 65% of their maximum capability.
If your injector duty was at 100% your car would be asking for more fuel than your injectors could deliver.

[TUMASGTS]

Sometimes at WOT i hit 90% with 630cc injectors and AEM fuel return kit..

[Smaay]

Sometimes at WOT i hit 90% with 630cc injectors and AEM fuel return kit..

that number doesnt sound quite right. but it might be correct. on my setup with 750cc injectors, i was hitting 100% duty at about 350HP and 15psi. once i changed over to a return fuel system, that duty dropped down to 60% with no other changes. so it makes a huge difference.

return fuel system FTW!

[kortik]

how do you adjust fuel pressure on MWR FPR?

[Gts*Jason]

There is a set screw in the top of the AEM Regulator, adjust it up or down for more or less fuel pressure.

[xrsfreak]

Not to hijack the thread but if I run 440cc injectors (stock everything else about fuel system) and I see 100% duty cycle at 8000rpms and AFR leaping up what are my options? If I buy 525cc injectors will it be enough? Or do I need upgraded fuel pump or MWR Billet Fuel Rail and FPR ? Thanks in advance.

[xrsfreak]

Off to 525cc injectors and 255lph fuel pump...

[evilthorne]

Bigger fuel pump for sure but you should be able to run the 440's with the MWR fuel return system safely. Smaler injectors are sometimes easier to tune with.

[xrsfreak]

Thanks evilthorne. I contacted Matt at MWR and his suggestion was 525cc injectors for sure and fuel pump will not hurt on top of that. These two things I believe I can swap myself. Now return fuel line is scary since I do not know sh** about it :) Although I believe that is also an option to get return line and stick with 440cc.