Orignal conversation between myself and gtsnissanb on Spike's thread:
Originally Posted by Spike11 - why is yours goin to fail lol
Because I have a 4-1 decat manifold, decat pipe (but no replacement cat), 2" Ashley midpipe, 2" Jap style backbox with 4" outlet, heat proof exhaust wrap from manifold to backbox, cone filter, 1.3 fuel rail/injectors, and a disconnected lambda sensor. It bangs like a shotgun on overrun or when I redline it because I've set my fuel pressure regulator to run slightly rich as well. I guess I'll have to find a friendly MOT garage that will "accidentally" put the sensor up the tailpipe of the car in the next bay
Originally posted by gtsnissanb - Why in the hell have you unplugged the lambda?? You don't want your car to run rich it looses power! Your not running anywhere near enough to need to worry about det! Your basically making your car slower, more polluting, #### on fuel?? Why not to mention the chance of bore wash, knackaring plugs, blocking up the exhaust! A car runs best at stoich you seem to be doing your up most to kill it
2 of the connectors on the sensor are broken, and I'm missing the seal that does inside it. Plus I think the rubber on the outside of one of the wires has snapped. Just haven't had a chance to replace it yet, so I've got no choice but to leave it disconnected. I only run it rich when I go to my local car cruises, just haven't had a chance to adjust is back. And I recently bought new plugs, so surely I don't need to worry about them? It doesn't feel sluggish at all
Originally posted by gtsnissanB - An overly rich car will not produce as much power as a car at stoich FACT you are most definitely not sucking in enough air to make the car run lean, so the fuel system mods you've made are just going to run it rich. Hence the popping on over run! You need the right AFR you can't just guess these things it only needs to be richer to prevent det. You won't have to worry about the plugs no if you don't mind changing them very regularly
Like I said, it only pops on overrun when I adjust the fuel pressure regulator. If I run it normally, it doesn't pop, and I actually get half decent mpg out of it. And as for spark plugs - I can get them for free, so I'm not worried about having to change them regularly
Originally posted by gtsnissanb - You obviously had a faulty lambda meaning you never had experience of it running right. You can't say unplugging the lambda will make your bone stock engine run better when all you have in the way of afr increase is the air box which the lambda would notice and alter the ecus fueling accordingly the mods you've done have taken the control away from the ecu which trust me knows better about fuel pressure and afr and now are running the car rich which is not good it's potentially deadly to a engine! Get it on a dyno get the AFR checked. I'm not being funny with you mate but things go very wrong with cars very fast I've built enough engines to know this. It makes me laugh as I've said in the past about the tards that stick resistors in their ect sensor, the Internet tells you more fuel=more power so you buy these things! But it's not the case there is more to combustion than fuel and go!
I'm not saying it runs better, but I did notice a slight change when I ran it with the lambda sensor uneplugged. When it was plugged in, it wasn't really sluggish in any way. Then it started to feal like it was running pretty lean, so I unplugged the sensor to check and make sure everything was ok with it. That was when I noticed one of the wires was snapped, and when I unplugged, I saw that 2 of the connectors were bent slightly. Tried to push them back, and they snapped. So now I have to run with it unplugged until I get a new one. I did think about putting an Almera airbox back in, but it feels like I'm getting more from my cone filter and cold air feed. I daresay I'll end up getting it dyno'd when I get 1.3 cams and skim the head, just to be safe, an maybe a re-map if I can afford it.
Originally posted by gtsnissanb - When the cams go in and the heads skimmed an increase in fuel will be more relevant. As running higher CR increases your risk of det so I'd imagine if you don't want to retard the ignition then your going to need higher octane fuel and more of it to keep it all cool and handle the longer duration and lift from the 1300 cams
Aha, so when I fit the cams, I'll need an increase in fuel anyway, which should make it run better? Along with maybe a second cold air feed, and running on 97 octane fuel instead of 95?