kismetcapitan

replaced all earthing leads, misfire is gone.

I had never had this problem with my BNR32. I have a completely new ignition system, all looms, earthing kit, HKS DLI twin power, Splitfires. But I had my engine rebuilt, and since getting it back, I get this damned hiccup/stumble at around 2500rpm at light throttle. It usually misfires once, but sometimes twice. I question whether its an ignition problem because I have wideband logs. If it were an ignition misfire, the AFR would spike rich, and ignition cuts are smooth anyways. This hiccup is a slight jolt, and if you've ever hit a fuel cut limiter, you'll know just how bad a fuel-cut jolt can be!! Anyways, when it misfires, the AFR spikes LEAN. Meaning, the ECU is cutting an injector or two...implying a software bug. But the thing is, it hadn't done it before. Only after getting rebuilt, and my earthing wires did get moved around to different locations. I'll try to put them back where I had them, see if that makes any difference.

so what do you think about my oil setup.... Tomei oil pump, Trust sump extension, Tomei oil baffle, Canton 2qt Accusump (fitted into Trust remote oil cooler), Tomei 1.5mm oil restrictor...and that's it. No head drain. It's all coming together this week. I figured a 1 liter overfill, plus the 1.5 extra liters with the Trust sump extension should help out in case I get a head overfilled with oil. Mines cam cover baffles should keep the oil in, and I've got a Nismo oil separator as well to help return oil thrown out of the cam covers. I've basically done everything possible except the head drain (short of going dry sump of course). Should I have done the head drain? Are there any track GT-Rs in Australia that run without a head drain?

same with my R32 GTR. The clicking relay is on the left side of the boot, rear wall, hidden behind the trim. IIRC correctly it's the leftmost one of the pair sitting there. I wonder if it's simply electrical, or if a proper bleed of the ATTESA system will cure it?

Ten months of ownership of a 1991 R32 GT-R. The car has been drivable ten weeks of that period. First engine - bad map, bad knock took out piston#6. Second (old, cheap worn out) engine, I drove the old, stock fuel pump into the ground by running 700cc injectors and 4~5bar fuel pressure. Det-based preignition during the pump failure took out all six piston rings in a meltdown. Now on it's third engine (completely rebuilt, refreshed, rebored, repistoned, re-bearinged, re-everything) which is making over 600bhp at the flywheel, but just lost its oil pump. In a highly tuned car, small mistakes end up causing BIG problems, and the vacuum lines are still not sorted out, causing a mysterious fuel pressure drop over 6000rpm. At this point (by my choice), the car is more "restored" than simply "repaired". I've spend USD40,000 on the project so far, and I am hoping mightily, praying actually, that the end is in sight and that I can just drive the damned thing. Expensive, but if all goes well, about $2-3000 more will see the car finished, and I'll have a car faster than a 911 turbo for a tiny fraction of the price (they cost about $250,000 in Korea). I guess it just depends on how you look at it

just wrapped up my BNR32 rebuild two weeks ago or so, and the car is mostly sorted, except for massive explosive misfiring under WOT load at 6000rpm and above. main bits of the car: Tomei Poncams 260/260, 9.15mm lift/Garrett 2860-5 turbos (like HKS 2530s), and all supporting mods. The fuel pump is an Apexi in-tank model, spark plugs are NGK Iridium grade 8 gapped at 0.6mm, about 2000km on them but they've fouled three times in the past two weeks. New Splitfire coilpacks and stock fuel rail with Nismo fuel pressure regulator. The charcoal fuel vapour canister up front was removed and the lines blocked off or rerouted. The overfueling has been sorted and the plugs aren't fouling anymore (a fuel tank breather hose was misrouted). Now however, fuel pressure will not fully rise with boost. No matter what I set the base pressure at, during driving, it will follow boost up 0.7bar, then start to gradually, and then rapidly (depending on rpm and rate of acceleration) fall 2 bars. Below 3bar fuel pressure, the engine starts to misfire. Boost is set at 1.5bar at the moment. During dyno mapping, the fuel pressure ran normally (climbing in sync with boost) and I made 496rwhp. But I can't replicate this ever since they "sorted" the breather line problem, which would cause the car to massively overfuel when the tank was topped off, but run normally on 1/4 tank or less. I suppose I could just set the rev limited to 6000rpm and live with it. But then, that wouldnt be much of a GT-R now would it?? Any thoughts/ideas would be appreciated!

I ran 700cc injectors at 4 bar (60psi about) at idle on my RB26, stock fuel pump. It lasted about a month before dying, and taking the pistons along with it. US$13,000 later, I'm back on the road....

yep I want one - I'm not in Australia though. Paypal + some extra for shipping and fees? This thing can't be that bulky - a DPDT switch and some wires...I can do the schematic but my soldering is shite

I had a chance yesterday to compare some pistons. The first were some N1 pistons - they had a bunch of little holes on the sloping sides - clear sign of detonation. Then I took a look at my old pistons from my melted RB26. What I thought were black melted holes were actually thick carbon deposits built up on the piston surface. The only surface distortion was at the piston edges, where searing hot gas made it's way down to melt the rings and took a bit off the pistons edges as well. What causes heavy carbon buildup in a four-stroke engine? Is it from running rich, or just crappy, dirty Korean fuel (even if it is 100RON)? Or something else? Avoiding knock is pretty straightforward - retard timing, higher octane, running rich, etc. But what about avoiding runaway preignition? Highway cruise, 5th gear, then suddenly without warning, everything melts down, you get the white smoke of death, and it's all over. I'm not the only one to have lost an engine this way. If the cruise portion of the map is lean (for fuel economy), perhaps dangerously lean, how would that in itself blow your engine? A hundred times on the freeway without incident, then on the 101st you get a nasty surprise. Is the safe course of action to simply run rich all over the map? Wouldn't that exacerbate carbon deposit buildup? I thought I was the only one to have such "bad luck". Turns out I'm not. I have thoroughly studied preignition and know what causes it (glowing spark plugs, glowing carbon deposits, glowing sharp edges). With the flamefront igniting as far as 160 degrees BTDC things get too hot in milliseconds. Would running fuel detergent additives help, I wonder? I've always viewed that rack of bottles in the shop as nothing more than snake oil. Or does that crap actually worsen things?

does anyone have their office number in Japan? would be much obliged...

which wouldn't normally put me out, but I wired them 5000quid before Xmas. They then sent half my parts, then went on holiday. 3000 worth of parts still haven't been sent, and unfortunately that part contains all the important bits to *start* my engine rebuild, like the pistons - without which I can't bore and hone my block. They haven't answered a single email I've sent since xmas time, and now I'm getting worried - not only is the rebuild held up, but my tuner is breathing down my neck as my car is collecting dust on his lift. Has anyone run into a similar situation? I've had delays from Nengun before but they always kept me up to date with emails. It's the silence that's killing me...

have you heard anything from Greenline/Jason after the holidays, i.e. recently?

I've done it once, as it's one turbo and pretty easy to access, it should be rather straightforward. Most of the muss anfd fuss comes from the oil and water lines, but as long as you can sort those properly, then it's really just a matter of getting the intake out of the way, pulling the heat shields, then unbolting the turbo. tying the exhaust in place with some wire will make the other end of the turbo easy - forgot to do that, then was wondering why the turbo weighed so much more than I had remembered

I've got an Apexi N1 4" catback mated up to a decat pipe and a Mines downpipe. I love the sound, but it's got the 3000rpm resonance something awful - in any gear, so long as the engine is pulling any sort of load. Had stock turbo elbows but those are getting replaced with Tomei units that will flow a bit better, I wonder how much they'll change the overall sonic character of the exhaust. Oh, and JUN B.L is a Korean company. Not familiar with their products so can't vouch for them.