Guest bastaad525 Posted July 15, 2004 Share Posted July 15, 2004 Anyone have any dyno numbers or have a good idea just how much a few extra degrees of timing (over stock) increases power? In an N/A motor. Sometimes it really feels like a big increase. Bumped the timing by three degrees on my Sentra yesterday and it really felt like a big increase in power. Quote Link to comment Share on other sites More sharing options...
Guest 305240 Posted July 15, 2004 Share Posted July 15, 2004 Be careful you don't get the dreaded pinging, or start to overheat. I don't know beans about these newer computered things. But, back when I used to run the point system mustangs, they would take all the advance you could give them without pinging. I never had an overheating problem either. Quote Link to comment Share on other sites More sharing options...
Savage42 Posted July 15, 2004 Share Posted July 15, 2004 Usually you will gain HP with more advance. General rule of thumb is that you don't want more than 36 degrees of total advance. Hope that helps. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted July 15, 2004 Share Posted July 15, 2004 Now I dont know about the Sentras but on some newer vehicles your not actually advancing the timing by moving the distributor.....your actually adjusting the fuel injector timing. (Just mentioning it because this is the way it is on some Dodge/Chysler vehicles). Guy Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted July 16, 2004 Share Posted July 16, 2004 nah... this is a '91, and I checked in the haynes, rotating the dizzy moves timing. I bumped it up 3 degrees from stock. I did seem to notice a little increase in throttle response, and yeah the car feels peppier. Temp gauge stays steady at just below half, as it always has, and I heard no ping. This one has a knock sensor anyways and from what I hear it's pretty obvious when it does it's thing. Of all the times I've been to the dyno with my Z's I've always meant to try adjusting timing and seeing how much effect it had but never get around to it. Surely someone here has tried this on a dyno and can accurately say "well you gain around x hp for x degrees advance"? Quote Link to comment Share on other sites More sharing options...
Clifton Posted July 17, 2004 Share Posted July 17, 2004 Off boost I adjust it till I get a little spark knock from to much timing. Not detonation as it will still happen at cruise. Then I back it off a few degrees. On my Toyota truck I can't even run it at spec in the summer as it will knock. So basically as much timing till it knocks. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted July 26, 2004 Share Posted July 26, 2004 I was messing with my carbs and timing this past weekend, but I dont know where the timing is set right now as I don't have a light. I just kept turning it till it told me "AGGHHHH!!! NO MORE!!!" and backed it off slightly. I'm thinking it's probly a bit too far advanced right now, as it idles just above 1000 rpm, and I'm full out on all idle stop screws/adjusment at the carbs. But WOW does she go like stink! Like a kick in the pants after 3500! BTW Im running an 81' zx dizzy with the 'black box' on it, and no vacume advance (the vac. pot doesnt work anymore) so I just set more initial advance.. just curious though.. how much mechanical advance (if any) is my dizzy going to have? I plan on puting a light on it this week (if I get my dang air filter) and tuning the thing properly.. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 26, 2004 Share Posted July 26, 2004 An '81 ZX dizzy should have 17* mechanical advance, as stated here: http://home.att.net/~jason510/dizzy_specs.htm. Here's the other great dizzy page, since I always give them out together: http://www.jrdemers.com/280ZX/distributor/distributor.html Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted July 27, 2004 Share Posted July 27, 2004 I'd get the vacuum advance thing fixed/take care of... I used to run my SU'd N/A motor with no vacuum advance... I would get lean pops from the carbs every so often, and had some other small issues... when I finally replaced the vac advance canister and hooked it back up I noticed a decent improvement in off idle response, and mid throttle performance, a small increase in gas mileage, and no more popping from the intake. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted July 27, 2004 Share Posted July 27, 2004 So thats what those pops are coming from.. Kind of annoying.. but the screw that holds the vac advance to the dizzy is well.. stuck/rusted in place so it's gona be a chore to change out.. plus I'll have to buy a canister.. stupid old car parts wearing out over time.. Oh yes, and thanks jmotensen for the info. Matt G Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 27, 2004 Share Posted July 27, 2004 I never ran vacuum advance on my Z's (SUs or Mikunis), because they've always been broken when I got the car and they'll start advancing on top end runs, which is really bad. Never had the popping either. Plug the vacuum hose that comes off the intake to the dizzy, and set your timing at ~18 or 19 degrees BTDC and see if it still pops. If you use vacuum advance you'll get a little bit of in town driveability, but when you do a long top end pull like on a long straightaway at the track you won't have any vacuum at first, but then as you get into the higher rpms the vacuum starts to creep back up, which then advances the timing and can cause pinging. Of course, it won't if you set the timing to the factory level of 8* or whatever, but then you won't have your 36 when you need it. Quote Link to comment Share on other sites More sharing options...
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