SR20DET Running Lean @ WOT.

[daftphunk]

Sup.

Read a lot of the threads on this and nothing comes with a real straight answer, and most of them have different symptoms than I do.

Anyways, so I am running lean at WOT. I have an S13 SR20DET with an S15 T28. Stock injectors, Walbro 255 pump, fmic, exhaust, turbo mani, nismo FPR.

My FPR is set to be at about 38 psi. I just installed my Innovate Wideband the other day, and is on the down pipe past my flex section. The flex section is a little messed up and I am pretty sure I have an exhaust leak. I want to know if that is what is making me run lean though.

At WOT my Wide band will read 13ish. Fluctuates really, 12.5-13.5. I understand that is lean at WOT. I am going to up the FPR to 40psi and see what happens there. But anyways, the car drives fine. Doesn't stutter, doesn't seem like it misfires or anything. I'm just concerned with the wide band reading. I did check plugs awhile back and they were a little white :/ but only one of them was.

Idles at around 14.7. Will fluctuate around a bit. Off the gas It runs at about 15/16 which I understand is normal.

Vac leaks? Exhaust leak? What should I look for to trouble shoot this.

[chituntang]

Your flexpipe may affect wideband reading but how much boost are you running? Stock injectors cannot handle the capability of S15 T28.

But you are not running way lean, just a little.

Get bigger injectors and N62 maf, then head for a tune.

[daftphunk]

Yeah so I have found out. But I have also read some cases of stock injectors handling the S15 T28 fine, but it does make sense since the S15 injectors were bigger.

I don't have a boost gauge/controller setup now, but I imagine it to be stock, if not, then not more than 10 but I'll figure out for sure tomorrow.

[kevmeistah21]

Keep me updated with this.I'm gonna be running the same exact setup.

[!Zar!]

You're running a bigger turbo on a stock tune and injectors.

Am I the only one that sees something wrong with that?

[daftphunk]

^ I also see the problem but I have seen cases similar to mine and cases where it has been fine. However that seems like the most probable cause so I'll just go buy a Power FC and go for the tune with bigger injectors

[!Zar!]

Just because other people do it doesn't mean that they are not running lean. I'm pretty sure you are running those injectors near 100% duty cycle.

[kevmeistah21]

Cant you the run the t28 at low boost temporarily until you supporting mods? I was planning on running it cause I just upgraded went my t25 took a crap on me.. I was planning on running the t28 on low boost until I get injectors and a tune, prolly within the next month.

[HYPNOTIK]

First of all, your fuel pressure is too low. It should be set at 43.5. Secondly, I was hitting 100% duty cycle on a S14 turbo with 370's. If a S14 turbo will max 370's then a S15 turbo should be a no-brainer. Third, 13's is not a little lean. 13's is WAY lean and your lucky you haven't blown a hole in your piston yet. Most tuners that I know tune for a target AFR of 11.5-12.5. My car is tuned at 12 under WOT.

I'm not trying to be a dick, just telling you straight up.

[sd8ted]

12's is lean IMO. Risk of detonation. I always thought 11.5 is ideal power afr, anything more than that is risky. My car is tuned at 11.3.

I ran this exact setup for 4 months. Just upped the fuel pressure a bit to get it safe on the wideband and took alittle timing out to help out too. Had no problems at all.

[HYPNOTIK]

ALOT depends on the timing. I personally would not run leaner than 12.

[norcalslider]

i found out i was running lean as hell when i had my WG line T'd from the BOV and it ran at 4psi so i unhooked the WG hose and it ran 12psi and ran like it was tuned so maybe you have yours setup like that.