Hmmm, something else is wrong here. You aren't making enough power to justify larger injectors, yet your afr's are pretty lean. I'd get the stock injectors cleaned and tested maybe.

 

135rwhp is only 8-9% more than a stock S4. In fact it's about the same as S5, which runs rich on its identical 460cc/min injectors. At that power level, you should definitely not need to add fuel to get those AFR's. In fact it looks like you've taken some out since you never get lower than 13.0:1. Something's not right here...

 

That was on a mustang dyno, when I ran it on a dyno jet dyno i put down 149 hp, and from what I have been told that there dyno was reading a little low saying that it was about 10 hp low.

 

Even if it was 10hp off there is still something wrong... You don't need bigger injectors with that low of power. Something is really wrong with afr's that lean with that low of power.

 

This is exactly why I laugh when people think dyno power figures are so important.

Even if you have 160rwhp (and you shouldn't believe anyone who says their dyno "reads low"), that's still well within the capacity of the stock injectors and the stock ECU. Something is wrong. Have you checked fuel pressure under load? Is the AFM sending the right airflow signals?

 

I just backed off my timing a hair more on my large SP six port NA. Total advance is roughly 10 degrees more than stock now, and I needed to take away more fuel from the top end. Now I'm at -17% at 8k with the 550 secondaries.

Astrochild7 can verify that this badboy pulls pretty nice, like a mild TII. It really doesn't need the 550's at all because I was able to add up to 15% fuel to my old 460's and have it richen up fine.

 

wideband tuned?

 

Seat of the pants! Ask astrochild7, he saw me do it and couldn't believe it, but felt the power increase by leaning it out a little after I backed off the timing.

na's don't need wideband if they don't have a tendency of detonation under lean mixture. Mine never has done so much as a ping no matter how lean I've gotten it. Tuning by feel is an old practice used before the days of wideband o2 sensors. Another way is by pulling spark plugs and looking at the color of deposits on them. When I really want to do it with precision I use my Gtech and set the SAFC correction to where I get maximum instantaneous G's at specific rpm levels.

I don't expect u to believe me, I'm much more intuitive than ur average FC owner......

 

just a question...if T2's make 200hp factory, why did they come with larger capacity injectors? I dont think the factory thought "Ok, people are gonna be upgrading these and boosting the hell out of them, so we better give the T2 bigger injectors!!" 15 years ago. So why give T2 larger injectors, if the 460cc can support 250 horses =\? im not trying to be a dick and prove anybody wrong, i just would like the reasoning behind this.

 

The factory wants the injector to last a long time. A larger injector means it doesn't have to stay open(energized) as long which means it doesn't create as much heat. Less heat means its more reliable over the long haul.

 

Boosted applications need richer AFR's than non-boosted applications is one reason.

 

sex

 

REX,

Chad here with the blue 90 N/A in the NRR club. I find it hard to belive that your car was running anywhere near lean in the RPM range we run on these tracks with stock fuel maps. Even with dirty injectors. My 90 has similar mods (minus the cat) And has 76k original miles. I installed an SAFCII and had it dyno tuned. They found that above about 5500 the car was in the HIGH TENS AFR. VERY RICH. they put it at about 12.8 throughout that range. I imediatly got almost 12HP 3-4 ftlbs of torque. Dump a can of sea foam in the tank before your next fill up and see if it makes any differences. That stuff is great mantinance for our rotaries. Maybe do two treatments in a row and give the car a number of good workouts with that stuff in the tank. It's not like other off the shelf fuel injector cleaners, sea foam actually works.

And if you are really concerned have the car dynoed with a wide band O2 sensor. RS motors in saint paul has the best dyno in town. Mustang AWD and it's almost brand new.

 

ughh, i just want to know when i put in the street port and t4 turbo should i upgrade them? i already pretty much bought them and I don't plan to put them until the street port anyways.

 

Streetported n/a block with a T4 Turbo? Uhhh yah definitely. Probably something like 550 primaries and 720 secondaries to be safe, with an upgraded fuel pump as well.

 

MPM's pretty much answered this one. Pretty much all factory injectors can support a lot more power than stock. Most stock EFI systems run the injectors at 50-60% max duty cycle.

 

I already have a walboror 255 lph pump, so i think i should be good on that.

 

What are your mods? If you have a walbro already and your AFR's are THAT lean on an N/A something is really wrong, depending on your mods that is.

 

Intake
S5 Intake manifold, 6 ports and vdi open
S5 Motor
S4 ECU
SAFCII
2.5" header back split to dual 2", stock header still
RB Pullies
All emissions removed
Polished and knife edge throttle body with cold start assist removed.

Thats all i can remember

 

oh yeah the walbro also

 

Yah somethin else is wrong then, like maybe a couple injectors aren't working fully, because you shouldn't need anymore fuel yet.