FIC2150 tuning notes
Jan 21, 2015, 09:28 PM
#77
Evolved Member
I don't believe its misfire also.
I've had mine on the dyno with headphones on, its definately not misfire on my car, it runs silky smooth, just leans out between 2500-2750 rpm.
I've had mine on the dyno with headphones on, its definately not misfire on my car, it runs silky smooth, just leans out between 2500-2750 rpm.
Feb 3, 2015, 05:07 AM
#78
Interesting but I'll have to try it to believe it. My disbelief arises from several factors. First is that I don't think the stock FPR has a damper built into it. The only thing I see is the spring and diaphragm assembly for setting the pressure. Next is that it's hard to believe that there is insufficient fuel flow to be allowing this to happen. Since its rpm-specific, it would seem to be a resonance-driven issue. Anyhow, I'll log fuel pressure as soon as I get a chance. A 18% fuel reduction will require about a 30% fuel pressure drop. Should be easy to see.
I am now tuning an Evo 8 that exhibits this same scenario but from 3100~3400rpms (higher than I ever seen on my X) so I've wanted to test a dampener on this car. All the Evo 8/9's I've tuned I have never see this issue but it was common to see on the Evo X.
The dampener used from Radium looks awfully like the stock regulator so my presumption is its a reaction time of a large FPR vs the tiny stock unit. Someone logged the pressure over the course of an hour and there is a very clear visual the dampener is working to stabilize.
See this post for logged data:
http://www.boostedforum.com/Thread-A...16349#pid16349
Main thread for informational purposes:
http://www.boostedforum.com/Thread-A...-others-SOLVED
Feb 5, 2015, 10:27 PM
#82
Its a spring loaded diaphram. My guess is that it takes about 32 psi to push it off its seat, and then it probably bottoms out at about 50 psi. It really should have a vacuum/boost reference like an FPR so that the damper pressure adjusts itself to keep the diaphram in the optimal position to absorb and release pressure pulses. Its not the best product for the job, but no one makes a proven one (like I described), and other's have said this one works so I thought I'd give it a try to see if it gets rid of the lean spot. Its supposed to rain for the next six days, so it might not be until next week before I try it out.
Feb 6, 2015, 10:04 PM
#83
Well, the pressure damper didn't do squat to eliminate the lean spot. The lack of any effect matches well with my data logs showing no unusual fuel pressure drops. I suppose it could be argued that it wasn't in an optimal location, so perhaps I'll try it at the rail inlet.
Last edited by mrfred; Feb 13, 2015 at 04:37 PM.
Feb 13, 2015, 04:46 PM
#84
The fuel pressure damper is working. It didn't work at all when it was attached to the FPR, but its definitely working with it T-ed into the fuel inlet at the rail. At low load it has completely wiped away the lean spot, but at higher load (still in vacuum), its only partially removing the lean spot - only about a 10% enrichment is required instead of 25% enrichment. At this point, its quite tempting to try to tap it directly into my fuel rail to see if that works even better. I also need to talk to Radium about whether they'd be willing to make a vacuum/boost referenced fuel pressure damper.
Last edited by mrfred; Feb 19, 2015 at 08:31 AM.
Feb 13, 2015, 06:11 PM
#85
The fuel pressure damper is working! It didn't work at all when it was attached to the FPR, but its definitely working with it T-ed into the fuel inlet at the rail. At low load it has completely wiped away the lean spot, but at higher load (still in vacuum), its only partially removing the lean spot - only about a 10% enrichment is required instead of 25% enrichment. At this point, its quite tempting to try to tap it directly into my fuel rail to see if that works even better. I also need to talk to Radium about whether they'd be willing to make a vacuum/boost referenced fuel pressure damper.
Feb 16, 2015, 05:27 AM
#87
The fuel pressure damper is working! It didn't work at all when it was attached to the FPR, but its definitely working with it T-ed into the fuel inlet at the rail. At low load it has completely wiped away the lean spot, but at higher load (still in vacuum), its only partially removing the lean spot - only about a 10% enrichment is required instead of 25% enrichment. At this point, its quite tempting to try to tap it directly into my fuel rail to see if that works even better. I also need to talk to Radium about whether they'd be willing to make a vacuum/boost referenced fuel pressure damper.
I have mine on the fuel rail between injector #2 and #3 and my near stall-causing lean spot is totally gone.
I'd try at the minimum an inline option like Radium offers if you cannot add it directly to the rail in some form.
Feb 19, 2015, 05:06 AM
#89
Evolved Member
Good news!
I have an AEM rail, I like having the mech gauge on top as I log pressure into the ECU off the reg.
I, like you are contemplating either drilling and tapping the bottom of the rail in the centre for a damper or swapping the rail out.
I have an AEM rail, I like having the mech gauge on top as I log pressure into the ECU off the reg.
I, like you are contemplating either drilling and tapping the bottom of the rail in the centre for a damper or swapping the rail out.
Mar 1, 2015, 06:52 PM
#90
I finally put in a tank of pump gas because several people were asking me to try it. Its actually E20 because of the residual two gallons of E85 in the tank, but close enough. For cruise conditions it was close to perfect with my first guess at injector scaling for pump gas (my E85 value divided by 0.7). Idle was a bit off, but after a few minor tweaks to the pulsewidth linearization table at very low pulsewidths that I could never assess on E85, I have it idling nicely. There's a bit of a lean spot when transitioning away from idle. No time yet to iron that out, but I have no doubt I'll be able to fix it, probably tomorrow or maybe tonight. Goal will be to take whatever changes I make to fuelling tables other than the injector scaling and apply them to my E85 tune.