Put on an aftermarket rising rate fuel pressure regulator/fuel pump and retune.

I've seen some single turbo guys use the stock injectors and those two aftermarket parts and their injector duty goes down.

 

Ya if your still running stock twins you shouldnt need injectors, adjust your injector duty to fit your needs. BUT you shouldnt even have to do that, im on a To4E and im running stock injectors.

 

two ways to do it. install bigger injectors, or a rising rate fuel pressure regulator, acually or both.

I went with larger injectors, but I woudln't do it again. i woudl only go larger injectors if I raised the pressure. larger injectros require higher pressure to get good atomization. for stock twins I would go with RRFPR, if going single you can just stick on some 1050 or 1200 with higher pressure.

 

Ryan,
What is your target RWHP? Depending on your answer, my response might range from 1200 - 1600 cc/min.

Regards,
Brian

87 TII
93 R1 T04S

 

How much boost are you running? I have been running 1 bar with the stock injectors and only an rp pump. I've been told this is way too much and I need larger injectors to run that much boost. My plan was rrfpr, and a fuel rail with 1600 cc injectors. Thats probably overkill for the twins but one of these days I'll have a single in there and don't feel like dealing with the fuel issues twice. Anyone know what is needed to run 1 bar with the twins?

 

Get your car tuned with a wideband, you should have plenty of fuel for 340 rwhp with the stock injectors. My guess is your mixture is far richer than it needs to be. If you adjust your mixture your duty cycles may go down.

Wade

 

You are one crazy man. Off topic sorry but what single are you looking at?

 

Rikki -

I recently installed the denso too, then hit the wideband. With basemod map on the PFC (and mods listed below) my A/F was like 9:1 across the 3.5k - 7.5k range.

You are likely overworking your injectors for no reason other than to waste fuel (and maybe toss a few flames out the tailpipe!).

I pulled 10 - 15% out of the PIM's between 3k and 8k and was still running low 11's:1 a/f (still too rich). Injector duties did as expected and went from 90+% to the low 80's%.

I'll be back on the dyno w/wideband after FMIC/Pulley's, Airpump removed, etc in a couple weeks and should easily hit 330hp @13.5psi with good a/f and < 90% inj duty cycles on stock injectors.

K

 

As other have mentioned, tune with a wideband to make sure you are not just running pig rich.

The only way to reduce duty cycle is to change the fuel maps (or run less boost). Changing the fuel pump, injectors, fuel pressure, etc. will ALLOW you to run lower duty cycles after tuning, but just installing the parts alone will not change your duty cycle at all.

-Max

 

dumb question but Ill ask anyhow.
are you guys looking to go rising rate FPR to raise the base FP... if so what are you looking to rise it to?

 

I am in the same boat. I have hit 100% Duty Cycle a few times when running WOT in 3rd and 4th. It seems to run richer when it is colder out. I am constantly running mid-high 90%'s any time I race it though but I don't like when it says 100%.
I have the Desno fuel pump and stock injectors on a Streetported Twin Turbo motor. I am kind of worried about tuning my own car but there is noone around here that can tune the PFC for me so I will have to try myself on a wideband. What numbers should I be looking for because my PFC was tuned by XS for my mods but it is still running rich as hell.
I am only boosting at .86 on the Commader, whatever that equals, 13-14lbs. I am not sure what. My Pettit Boost gauge shows around 13psi. I want to turn the boost up a little and lean the mixture out some as well. I don't want to risk anything with agressive tuning but I think I am a little too far on the safe side right now. Any help would also be great. Thanks.

 

I've hit 100% duty cycle at 13 psi and I have upgraded my fuel pump. Also, my PFC was tuned on the dyno using a wideband. I strongly suggest upgrading the inj, it's extremely easy. 1300cc will work great for the twin turbo setup and a single turbo setup.

 

Tune it on wideband Ryan and adjust the fuel maps.I know you haven't done this yet .I bet that get's the duty cycle down into safe ranges. My .02