Hey guys, i'm getting ready to start my 4g64 Turbo project, and i have a question. How many of you guys are running a knock sensor or Turbo ECU (has built in knock sensing)? I think i'm going to stay SOHC, and thus converting to a Turbo ECU would be somewhat difficult. If any of you *aren't* using knock and you're turbo....are you having reliability issues, and what kind of boost levels are you hitting? I know Curt (4g64T Spyder) is using the J&S UltraSafeGuard, but for the cost of that, i might as well just do the DOHC conversion.
Comments?
Thanks
you dont HAVE to use the turbo ECU. you can get an safc (which you should anyways) and tune it from there. i'm only missing a few parts before i go turbo and i dont plan on running a knock sensor before i turn the boost up beyond 8psi. after that i'm gonna install a knock sensor and lower comp forged pistons and then turn the boost up.
i know i dont *have* to....SAFC is definitely in the works...but the question was more about knock. I'm buying an extra motor and putting low compressoin pistons to start with to avoid the risk of detonation, but i'm still worried about blowing up the motor because i dont have the proper precautions (i.e., knock sensor to pull timing)
i say just get the ecu & do the head swap. you will move up to distributerless ignition, be safer with knock control, and be able to push more power with timing. besides, how were you planning on tuning it otherwise? a knock sensor just makes everything so much easier.
I agree with sabzi completely, but I have been turbo for almost a year now w/o the turbo ecu or knock sensor.
dohcstunr brought up a good point, but I don't think anyone's tried it... install the knock sensor and just wire it directly to the AFC and monitor it there. The ecu wouldn't be involved, so timing is still an issue, but at least you'd be able to see it happening.
how are you tuning your car man? just wideband and egts?
i doubt wiring the knock sensor directly will work, from what i understand, the knock sensor just shows noise levels, and the ecu interprets sudden spikes in the noise levels as knock. i don't know how effective a human would be at trying to interpret the knock sensor output directly.
The only tuning I've done is via the AFC and pocketlogger, trying to get my fuel trims close to zero.
my theory is to hook up the knock sensor. just giving it signal voltage and ground. of course it wouldn't roll bak timing on the fly.
but if you tap your safc2 into it. and then calibrate the safc2, so that it knows what noise levels are acceptable.
then, you could set a warning level on the safc for what is too much knock. it wouldn't save your motor by pulling timing, but it could give you a heads up on whats going on in your motor, and help a bit with tuning for more boost.
the major issue about tuning a car without a knock sensor and knock dependant timing, is that you can tune it the best you can on one day at this temperature, atmospheric pressure, boost level, octane level, etc. and get no knock, and then the next day when conditions change, you your knock count will go up. and your car could be running in the danger zone. theats right i said danger zone.
of course its not going to fix your timing, but just like any other gauge(boost, egt, oil pressure) its going to give you a better idea of how your engine is perfoming, and how its accepting the changes. allowing you to know if your engine is operating under safe conditions.
i agree with sabzi. if you are going to have another motor anyways, why not just do the headswap. it will be much easier, and safer.
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1994 Galant GS-Turbo
you aren't getting what i'm saying about the knock sensor. even if you wire it into the safc, you won't know what it means. knock count isn't based on what voltage is displayed, it is based on how quickly the noise rises. the ecu basically looks for something out of the ordinary to decide if it is knock or not. you won't be able to look at the voltage and figure out if it's knock, and neither will the s-afc.
so why would the safc even have a knock monitoring mode if it wasn't at all useful? what would be the point of it? the safc is designed to recognize what the acceptable noise levels are at every rpm. thats why you calibrate it for your vehicle. couldn't you just set the warning levels after calibration so the safc can alert you when everythings going to shit?Originally Posted by sabzi5858
it was just an idea i had.
i myself would have done the ecu swap if i went 4g64t, i was just trying to find an option for those who don't want to or can't spend the money to do it right.
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1994 Galant GS-Turbo
ahh, sorry, my fault. i was thinking s-afc not s-afc II, i don't have any experience with the new one, but i looked it up on their site and sure enough it displays knock. hs anyone in the dsm world tried this yet? it would be interesting to know if this works.
(it was me who misunderstood, i thought you were saying to hook it up in a "ghetto" way to disply the voltage coming from the knock sensor. i was unaware of this feature of the s-afc II.)
edit:
"After extensive testing and work, we have found that no, the unit will not monitor knock signals from a OBDII vehicle."
taken from: http://www.prostreetonline.com/pso/pages/h....asp?sessionId=
so it looks like the s-afc II gets the knock signal from the diagnostic port of an OBD I car, which means it is the signal from the ecu, so looks like that's a no go.
the afc2 has a knock sensor input, with an entire process to calibrate your knock sensor. you can also set it as one of the channels to be displayed on your display. i'm sure wiring in your own knock sensor could provide a knock monitor that the afc2 can work with.
yeah, but the AFC still can't pull timing....so its more or less a just warning (like an Pyrometer or A/F meter). I guess i'll just bite the bullet and do it right. It's gonna cost more than i wanted to spend, but i'd rather not be building another motor in a year when i blow mine up because i didn't do it right this time.
After sifting through a few posts on dsmtuners, it looks like DSMLink is the only way to monitor knock on a 2G.
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