Guys,

Help me decipher this please. It was with 310 injectors, 289 pulley and a 255 Walbro. Tuned with a SAFC2.



My guy thinks I need bigger injectors because he could not get enough fuel in there - even when he went +50% fuel.

Your thoughts??

Jonny

 

Yeah Jonny. I think the people running the 2.87 pulley are using the 370cc injectors. You're running a bit lean top end. Did you ever install the headers yet? Congrats on the numbers though!!!

 

Well it looks like the guy has no idea what he is talking about. The car is PIG rich from 4600ish to 6000ish.
You want that A/F graph to be as straight as possible at about 11.8
You need to pull some fuel out in that RPM range. Its SO rich I'm sure you'll find at least 20-30 RWHP when you get it dialed in.
I'd also think about putting new plugs in it if you have driven it for any length of time at that tune.The plugs even if fairly new, will foul VERY quickly with that much fuel.I'm surprised you are not seeing tons of black smoke coming from the exhaust.

If you have any questions, feel free to PM me.

 

looks like a bad tune. They need to lean out from 4600-5800 like what LMSguy said. And richen up after 5800.

Try to get as straight of a line as possible on 11.5

 

Jonny,
Can you post just the Air/fuel ratio on two graphs? Maybe put dyno #4,5,6 on one and #7 and 8 on a 2nd chart. This will help see the whole range of the A/F nunbers
Looks like your running as rich as 9.5:1. or more also post what your S-AFC setting werer on your last run. example:

1800rpm 2200rpm 2400rpm 2500rpm etc........
+22 +20 +32 +18

 

If I remember right...the guy had pulled about 19% fuel in those ranges, he didnt want to pull more fuel to be on the safe side. Also is timing an issue? He had mentioned the spiky power curve and said most likely the ECU was sensing detonation and retarding the timing. As far as the high RPM lean...no amout of fuel addition would richen it up.

 

my guess is that he may not know how the SAFC works. It does lookk like it has had fuel added but to the wrong RPM level.

With the SAFC you have to choose the particular rpm range you want to add the fuel too. It looks like he added a but load of fuel to the middle rpm range where you see it drop off the screen. He needs to add some to the top end.

If he left it with all that fuel in the middle I would question if he knows what he is doing.

I have a old post with a Dyno chart and 310's with the rmm on this site, I will try to find it for you.

 

You guys say high RPM lean condition. I wouldnt call it a lean condition.YES, its a tad leaner than optimal, but its in no way dangerous lean yet.
I would love a piggy back that allows us to control fuel AND timing precisely.It would be nice to hook up a scanner and watch it as you made the runs to see if it was running into the knock sensors.

 

here take a look at the chart on this post
https://www.clublexus.com/forums/sho...highlight=dyno

Notice how the fule mix is for the most part flat?

 

I was there at the dyno run and he had 19% fuel pulled in the midrange and added 50% fuel at the high rpm range. The guy doing the tune also uses the safc on his twin-turbo 350Z, so I would think he knows what he is doing. He mentioned the fuel injectors were maxed out at the end of the run, I would guess he means the max injector pulse had been reached and would no longer flow anymore fuel. As far as the midrange richness, i have no idea how to fix that...I have the same idea that running about 11.5 and not off the chart would help. I would have to talk to jonny and see what he remembers about the conversation.

 

well to be honest I dont have any personal experience with the SAFC but I do with other tuning devices and stand alones.
You say he added 50% up top so am I correct in assuming he can pull more than the 19% in the mid range?
If so I would definately do that and might want to try bumping the Fuel pressure a few LBs to get the required fuel up top.A FPR is cheaper and easier than new injectors.
But if he did that he would DEFINATELY need to pull more fuel out of the mid range.

I bet the car will be a WHOLE lot more responsive once that added fuel is out of there, and probably more fun to drive as well.

 

Hmm...thats a very nice power curve. jonny was hoping to see the same and we dont know why. Its the same setup. I know the injectors are 310, walbro fuel pump, apexi safc, lsd, 3.76 gear, 2800 tc, and 2.89 pulley. Why the difference?

 

Also how did he add 50% fuel on my unit it can only go +/- 20%
Just curious.

And LMS may have something there, assuming that he did everything right with the SAFC I would check the fuel pump fuel filter and pressure regulator before shelling out 700 bucks for injectors

 

Without trying to be a pain, I would say tuning

Even if he couldnt add fuel to the top end I dont see how he didnt see a problme with the excessive richness in the low to middle.

Thats not safe that is excessively rich.

 

yeah i had mentioned to jonny about bumping up the fuel pressure, I saw a post on how to do it...just gotta find it again. But it really does boggle my mind how rich it ran on the 310s with no tuning. Hell it wouldnt even run...barely started and would stumble bad. The first dyno tune was the partial throttle and thats where he started pulling fuel and you could tell instantly that the car was running better. We started tuning to WOT and the belt was slipping, the dyno run flat lined and there was nothing we could do. So off to the shop the car went, the guys replaced the belt and tightened up the belt tension. The next dyno session, we saw the car running rich as shown in the graph and he pulled fuel to lean it out and it didnt seem to move the A/F. I think we did 5 runs, each with more tuning and ended with 355 hp. We did do 360hp but that was lean and to be on the safe side with the spiky curve and possible detonation he moved af richer. Oh yeah...it was running about 5-8 psi from start of WOT thru end of run....really cool to see the guage...