This is what on the car, Crower stage 2 cam, Crower spring/retainer, oversize vlve .5mm and vafc, aem pullies, cai, and planning on puting 11:5 endyn piston that is it, everything else is stock. can this be done, how will he car idle and stuf on OBDII until i get more money to replace it with EMS. Suggesting please
As long as you can tune it with the VAFC on a dyno, you should be fine until you get a standalone. You just need to make sure you get enough fuel in there... and make sure you use high octane (Im sure you already know that).
You might want to look into upgrading your rods as well, either by having your stock rods shotpeened, or putting in aftermarket rods.
well the reason I ask its b/c 525 piston +500 labor that is what i like but if i get rod then i have to spend more like another 600 on rod. I think i'll not go that way and save a little more and get EMS since i'll do the block later. Thanks a lot for the info guys
what do the rods have to do with it? if your motor is detonating, it will break, forged rods or not.
obdii doesn't really have anything to do with it either, you can retard your timing if necessary with any of several piggyback devices, and a vafc + b&m fpr will do an adequate job of adjusting fuel delivery for a low budget setup.
Yes, but I think the point is that he doesn't want to spend the money on that stuff right now, or at least wants to run it prior to doing anything like that.
I think 11.5:1 CR on 91 is a bad idea. It's not like he's in California, he can run 93 octane which *should* be OK. I would be hesitant to say 91 would be fine with stock timing.
DEFINITELY need a VAFC with that setup. You might need to add a bunch of fuel just to prevent detonation.
Originally posted by marcucci ....he can run 93 octane which *should* be OK. I would be hesitant to say 91 would be fine with stock timing.
DEFINITELY need a VAFC with that setup. You might need to add a bunch of fuel just to prevent detonation.
i would agree that the line for this setup is somewhere between 91 and 93. i personally wouldn't run it on 93 without some assurance that it wasn't detonating, but that's just me (having blown a motor that NOBODY could hear detonating!)
he'll need something for fuel pressure in addition to the VAFC, i don't think adding 5% fuel (about the max with a VAFC) is going to be enough. i like the B&M retrofit to the stock fpr myself.
you can put it up to +50% if you want, but somewhere around 5% (depending on the weather and the mood of your ECU) is where the MAP signal exceeds the limits of the ECU's fuel tables. it's around 2.95 volts : anything past that and you get massive bogging and a check engine light.
since these cars weren't designed for boost, you can't simply increase the map signal beyond atmospheric pressure (which is what you should have at full throttle already) by very much at all.
Only 5%? The stock ECU is supposed to be able to handle fuel requirements +/- 20% from what I remember reading. Then again, that doesn't have a lot to do with the MAP reading, soo...
Originally posted by marcucci Was this based on your (or others') experience?
mine and many others... the stock ECU will definitely have a cow if you sent it a 3.3v map signal... (2.8v * 1.2). it's a very common problem when people think they can use the vafc to supply fuel for a boosted motor just by putting in "+25%" or whatever. on my car, i'd get bogging and codes somewhere around 6% iirc, others have reported being able to go a little further, others a little less. if you look at the helms there's a range limit for the map signal (i believe it says ±2.9v, but it may say ±3.0v). you could check the output of your map sensor when exposed to atmosphere, and the difference (plus a little bit) is your max positive vafc correction right there.
the ecu probably can provide 20% more fuel based on long term trim values plus short term trim values plus warm up conditions (low ect & iat), but that doesn't mean you can trick it into doing so by sending it a map signal equivalent to a couple psi of positive pressure.
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