Gents,

I have a 1993 MB touring that I purchased from Ebay back in 2010 - have been slowly removing/replacing/fabricating since then to build a reliable street/track toy. Car has a PFS rebuild with 3mm seals, likely a small port, and an Rx6 single kit with my custom v-mount. Started her for the first time in 18 months yesterday - fired up and ran, idled a bit rough (chasing a vacuum leak I think). Managment is via PFC with datalogit - using the PFC base map right now, waiting for my wideband to come in the mail this week for some tuning. I'm starting from zero but have learned a bit through the helpful docs on this site and others. I've tweaked the base tune a bit based on my research to date - changed a few of the specs as per Wargasm's article from 2004 and then increased the split to +2 in the non-boosted areas and retarded to a max leading of 41 across the map (for smoother lift off throttle at high RPM as per a friend).

Was wondering if the gurus could take a look at my tweaked PFC data file (attached) and comment: I'm hoping to use the PFC to control the Apexi wastegate via Apexi solenoid (car had an AVC-R which was conveniently stolen the day that I was to pick it up). Thinking that I can do this at approx 1 bar via boost control setting of 1.0 on settings tab 1 ? Planning to seriously richen the mixture (30-40%?) at 22000 (approx 17.6 psi) so the 14.7psi+ range will act as safeguard in an overboost situation instead of fuel cut. Since I'm running the factory MAP which maxes at 17psi, I'm expecting that I wont hit the PFC fuel cut (1.0 bar + 0.25 bar = 18.3 psi). My rationale is that if I lost wastegate control or something and overboosted, the result would just be an engine bog due to too much fuel.




Thanks,

Aaron

 

Yeah you can only go so far without a wideband.

You can play around with it. What really determines smoothness of tip-out is the decel fuel cut control. I've never seen a standalone which allows the tuner good control of this. It needs to be staged based on rate of change of TPS voltage, engine load point, etc. Sometimes it should cut fuel to one rotor, sometimes to both. It's the same with piston engines that cut fuel to half cylinders at times. Here's how it works on the stock ECU:





See this thread

https://www.rx7club.com/single-turbo...ontrol-900599/

For this kind of overboost protection strategy, you should retard the timing (both leading and trailing) in that area as well.




Thanks,

Aaron[/QUOTE]

 

Thanks Raymond for the info - I'll change the turbo control settings and then start logging some data (got my wideband installed last night).

Before I jump right to tuning though, I'm still sorting out and idling and driveability issues:

Car wants to idle at 1600 rpm+ even when fully warm. Only way that I can drop the idle towards 900/1000 is to actually grab the throttle plates and manually twist them a back towards closed (they dont move perceptibly, but the idle drops). Mixture screw is 1/8 turn from full in, and idle screw is backed out so it's not touching. When I tap the throttle, it returns to the high idle. Secondly, if I touch the throttle, it immediate bogs (will die if i do more than toe it). If i'm gentle with the throtte application, it will then rev in response normally after about a .5 second lag. Any thoughts? I've adjusted some of the accel. pump type settings as per wargasms PFC tuning guide...They didn't seem to make any difference with this issue. I also tried an old stock twins map from Brian Cain with zero split timing in vaccuum. That didn't help either.

Thanks in advance,

Aaron

 

Need to see logs and the map. Then we can look at your TPS voltage, idle speed control valve duty cycle, and ignition timing.