cygnusx1 Posted December 4, 2004 Share Posted December 4, 2004 OK guys it has been about two months (1200miles) that I have been running 14psi boost, 55psi fuel pressure, and 27btc timing on the stock motor and stock FI. The only FI upgrades: a walbro pump and FMU or (RRFPR). It even has 45 miles of road course time on it with these settings. I checked the plugs and they do show signs of pre-ignition. I've never heard it ping once and the power has been phenominal but it's time to back off the timing and boost about 3 degrees and 1psi until I get a better fuel system. I do keep it under 5000rpms but lean is lean. I think we can call this the limit of the stock FI. Ths plugs have a gray flaking on them...probably coated with aluminum It has been fun though. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 5, 2004 Share Posted December 5, 2004 um... okay why is this the 'limit' when you haven't even really pushed the FMU nearly as far as it can go? Last time I dynoed I was running about 14psi of boost, at 70psi of total fuel pressure at WOT/full boost (this is only a 16psi increase over if I was just running the stock FPR) and I had plenty of fuel to maintain low 12:1 a/f ratio all the way to redline. I've been tellin ya I didn't think you were running enough fuel pressure I forget how long I've been running it this way but I've had no problems and it seems that 70psi is still within acceptable limits w/o blowing hoses or injectors. This is with the FMU set to three turns in from full out. Remember even as low as two or two and a half turns out made a huge difference and was way too lean even at only 12psi of boost. This was at 60-65psi of fuel pressure. The only problem I have with the setup is the rich dip when boost first comes on, but you already know that problem may very soon be solved as well. Anyways, though you can see that rich dip on the dyno, you don't feel it... there's no bog or anything to suggest it's running real rich. My plugs have never shown any signs of preignition or anything, no metal flakes, no nothing, and always a nice dark brown color when I check them. I'm also running a couple degrees advance over stock. Never a ping or any erraticness on any of my dyno charts either. I'd hate to see you give up on the FMU so easily like that... being the only other person I know of on here using one... I only bought it because I saw you were using it and having good results. And now with Trey over at BEGI being interested in this and helping me with some 'tuning options' it may become an even better alternative to standalones and big injectors. Anyways... before you go just 'tossing it out' why not take it to a dyno with a wideband and see what it's really doing and to fine tune it, instead of looking for the next solution? Quote Link to comment Share on other sites More sharing options...
Sean73 Posted December 5, 2004 Share Posted December 5, 2004 Are you running 27 btdc at idle, or is that full advance? If it's the former, that seems very high. Stock is 20 degrees at idle. I think you should be able to run 14 psi with the right fuel pressure and timing combination. Sean 73 240Z Turbo L28ET, 8.8:1 CR, NPR IC, Z31 ECCS, 10 psi Quote Link to comment Share on other sites More sharing options...
Afshin Posted December 5, 2004 Share Posted December 5, 2004 I second what Sean just said. 27 btdc at idle, while being way fun for initial response, is way to high for that set up. On my set up with 440cc injectors and a nicely reprogrammed ecu by Bernard and BPR 7 plugs I most certainly get pre-ignition with 26-27 degree timing. I need to set mine at 20-22 btdc to avoid all pre-ignition and be safe (e.g. hot day, racing engine and california 91 octan gas). So this is more likely a problem of too much timing for the boost set up as opposed to fuel. My guess if you where overly lean with that timing and boost the engine would have blown by now. Personally I would not exceed 23 btdc even with better gas... Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 5, 2004 Share Posted December 5, 2004 keep in mind guys he is running an '83 EFI setup. The '83 timing is already set to 24* BTDC stock, so he's only running 3* more advance, not 7 Still... with 14psi out of an upgraded turbo this still seems it might be too much advance. Most people will retard the stock timing when increasing boost... me and cygnus advance it instead Well you could always either a) drop the timing back down a bit, or get a boost timing retard unit. BUT... dont count the FMU out just yet... personaly I really feel that unit should be working just fine and is capable of giving you more than enough fuel than you need for what you're running. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted December 6, 2004 Author Share Posted December 6, 2004 Well, actually, the first thing I did after the post was turn up the FMU. With the timing at 27adv initial, the mid range richness spike was not as much of a problem as it was at stock timing. So, I think I need to bring the timing back 1-2 degrees, bring the fuel up around 60-65psi and leave the boost at 14psi. With the spark plugs looking like they have gone through nuclear war, it is time to back off a setting or two. Bast. IF we get those "discs' sorted for the FMU and get rid of the mid range spike in richness, I will gladly use the FMU for more fuel. Right now to get good mix at 14psi@5500rpm I need to dump raw fuel through my turbo at 14psi@3500rpms. That makes for a cherry red exhaust housing! Today was a first. One of my cousins has a brand new M3 and he is a car nut and fell head over heels for my Z when he saw it. Sooo to make a long story short, I drove the M3 around and later he drove my Z. I have to tell you, the M3 is tight! I mean literally. In sport mode, it feels so right. If only it had my Z motor in it The motor did feel a little lazy compared to my Z although it was very easy to drive fast in it. After he drove my Z he had a grin from ear to ear. He called it a rocket ship....I particulary was proud to hear that from him because he also drives a 1996 Porsche Twin Turbo (996) Carerra. He took my Z up to 120mph uphill! It had plenty left in it too. I convinced him to come to the track with me next spring...with the TT 996 Carerra. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 7, 2004 Share Posted December 7, 2004 I know my current setup does run really rich in the midrange, but no more so that it ran when everything was all stock and I had just upped the boost to 10psi. Actually, if you overlay the a/f ratio graphs from my 10psi, bone stock efi, no I/C run, over my 12-14psi, I/C'd, FMU fueled pulls, they are 99% identical. In each trim level, I saw a rich spike of about 10:1 from about 3500rpm as well. I've never seen my exhaust manifold glow, by the way Really i dont think it runs rich enough long enough to do that. You said you usually shift around 5000rpm... so should always be in the 4000-5000rpm zone while racing or whatever and shouldn't be running overly rich there, I would think. At least, mine doesn't. It really is just a fuel 'spike'. Anyways, it's tuesday now and I'm still waiting on the discs... he said he mailed them out on thursday, so they should show up today or tomorow at the very latest. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted December 7, 2004 Author Share Posted December 7, 2004 My exhaust expands when it gets real hot and touches the rear valence making an awful creeking noise. Usually when I hear that creeking and open the hood, the turbo is glowing good. Since I advanced the timing a couple of months ago, I have not had the exhaust get hot enough to creek; even at the track. Since I saw the plugs the other day and put in some more FMU, the exhaust started creeking again; getting the turbine red and hot. I know this is all guesstimate since I have NO EGT and no WBO2 to document or quantify any of this. I am going by seat of the pants, smoke in the mirror, ear calibration, and visual cues here (dont try this at home). The proper will scold me for going this far without the proper tools. In a small devious way, I am waiting to burn a piston hole in this 120K mile motor so I can rebuild it bionic strong...meanwhile, the other little guy in my head says: "keep it alive, back off man!" Anyhow, I can only deduct what is happening with combustion by virtue of the "cause and effect" method of tuning...or since it affects my butt dyno, is it "cause and affect"? I do know, I ran near overtemp combustion for a couple of months by plug inspection and when I add 10 more psi fuel FMU, I run a HOT turbine...so do I burn the turbine or burn the pistons? Thar's the pickle I'm in. I can't seem to find the sweet spot by chance....not that I ever expect to without the proper tools. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 9, 2004 Share Posted December 9, 2004 Really odd... I wonder how I've found a happy medium between the two with such a similiar setup? I have never experienced either problem. Question, did you do both, richen the mixture AND retard the timing? I would have done only one or the other first. I'd have richened it up and kept the timing where it was and see what happens. Really that FMU should not be running so rich so much of the time to cause it to glow red like that that's really, really odd. You know... you really, REALLY should make it a point to get down to a dyno. It should be less than $100 for three baseline pulls with WB/O2. Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 9, 2004 Share Posted December 9, 2004 bastaad525 and cygnusx1 one thing your are forgetting is that you both have different turbos than each other. The turbos make boost at diff times and have diff efficiency's. So that could be the reason cygnusx1's turbo glows and bast's doesn't. I will be getting to the dyno withing the next week or so probably with 370cc injectors and stock fuel pump. Hopeing to get 12-14psi. Also I want to try to keep it above 11:1 and below 13:1 I know know good luck but a man can dream right Ted Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted December 9, 2004 Author Share Posted December 9, 2004 I fattened the fuel at the FMU and adjusted nothing else. The short term result has been a hotter turbine and hotter exhaust. It still runs strong all over the powerband, but backfires a little more. I don't know if it put my combustion temps in a safer spot or not...but more fuel should be safer than it was...at least for the pistons and the head gasket. Any word on the FMU parts yet bast.? Oh and good point about the Compressors being different. My powerband certainly moved up in the RPM range after installing the new turbo. It takes a bit longer to spool but it hits like a sledgehammer. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 10, 2004 Share Posted December 10, 2004 Yeah the discs showed up in the mail today. I'm anxious to try them, but need that WBO2 and a way to make the fuel pressure gauge visible while driving. I've been going over the diagrams and descriptions sent to me by them, looking at how the thing works, and asked Trey over the phone why he thought this would do the trick. Maybe I"m not understanding something, but to me it sounds likely that using the smaller disks would have the same effect as just turning the bleed adjustment out. not what I'm after at all. But, only testing will tell. Soon Quote Link to comment Share on other sites More sharing options...
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