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The Wilwood Brakes Dude
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228 Posts
Discussion Starter #1
Just like the title says. Anybody hooked up the SAFC-II to display Knock sensor.

Im about to put the motor back in the car and I dont want to have the issues I had before. "Chuncks of the side of my piston missing" from detonation. check my post "Off to show the Z car guys the 7M-GTE is the S#!T" for the whole story.

The Short story is, I think the car had a marginal stock HG to start with I (retardedly) decided to go for a top speed run (well over 150 mph any ways) 4 days after I got it on the road and the car was so loud I couldnt tell if it was detonating. And I think I had bad gas.

Anyways tonight I will have the motor all buttoned up with ARP studs and a 2mm MHG and I really dont want this to happen again. Hell I want to guarntee it dosent happen again. So here are the items I plan to combat it with.

1. 2mm MHG
2. SAFC-II with knock sensor enabled (if possible)
3. H2O injection
4. 55 gallon barrel of toluene in the garage (if possible)

P.S. anybody know who sells 55 gallon barrels of Toluene in AZ?

Seriously I will drive to CA if I have to.

but first things first, you guys know about this Knock sensor function on the SAFC-II.

Maybe I can rig it to a maniquin hand and a bimba cylinder so it will bitch slap me every time it detects knock.
 

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TheFastCoonAss
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6,083 Posts
Just curious as to why you went with a 2.0 MHG? Was the intent to lower the compression ratio?

On your subject, if your timing is not way out and you run good gas you shouldn't have any detonation issues. Water/Alcohol injection works good on these cars for running higher boosts because it cools the intake charge. I have a freind that builds them and runs a dual nozzle, one before the IC inlet and another right before the throttle body.
 

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The Wilwood Brakes Dude
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228 Posts
Discussion Starter #4
2mm MHG? yes that is why, plus I really plan on turning up the boost in the future.

I always thought you didnt wan to run the H2o injection before the IC because that would cause vapor to loose velosity and density and it could possibly condense out of the atmosphere and leave a puddle in your IC. All H2o injection should be done post IC.

Least thats what I thought. I will read the links.

Thanks

but still I am looking for feedback on the SAFC II and the Knock sensor hookup
 

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Registered
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2,148 Posts
Your correct about pre IC injection, its not ideal.

From what I understood about the knock sensors, the safc basically cant read them. The problem is that there is a terrific amount of electrical noise that is generated by them in normal operation, and that the safc is unable to differentiate between that and knock.
 

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No One Ever Listens To Me
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5,467 Posts
mullenc525 said:
Your correct about pre IC injection, its not ideal.

From what I understood about the knock sensors, the safc basically cant read them. The problem is that there is a terrific amount of electrical noise that is generated by them in normal operation, and that the safc is unable to differentiate between that and knock.

this is VERY true...EXCEPT...that is the case with the stock knock sensor wiring or any normal wiring for it...if you use shielded cable and rewired it i would think the results would be better...

as of now i have a regular wiring to my knock sensors with that option setup on safc2 and the "knock" noise it actually reads i dont even pay attention to because im pretty sure its all engine and electrical noise its picking up.... i would think with a 250+ knock noise count its getting i would hear the knocking ;)
 

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Tired of being sexy
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IdealSupra said:
this is VERY true...EXCEPT...that is the case with the stock knock sensor wiring or any normal wiring for it...if you use shielded cable and rewired it i would think the results would be better...

as of now i have a regular wiring to my knock sensors with that option setup on safc2 and the "knock" noise it actually reads i dont even pay attention to because im pretty sure its all engine and electrical noise its picking up.... i would think with a 250+ knock noise count its getting i would hear the knocking ;)

Awesome, I was worried about my measley 20 knocks on idle every once in a while.
 

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greasemonkey
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3,126 Posts
highest i get is in the 40's on a hot ass day here in fla with no audible noise. funny thing is apexi cant even tell us what the number is , or what number is damaging to the engine.
 

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Senior Member
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2,279 Posts
I always thought you didnt wan to run the H2o injection before the IC because that would cause vapor to loose velosity and density and it could possibly condense out of the atmosphere and leave a puddle in your IC. All H2o injection should be done post IC.
Pressure precludes puddles.
 

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Registered
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IdealSupra said:
this is VERY true...EXCEPT...that is the case with the stock knock sensor wiring or any normal wiring for it...if you use shielded cable and rewired it i would think the results would be better...

as of now i have a regular wiring to my knock sensors with that option setup on safc2 and the "knock" noise it actually reads i dont even pay attention to because im pretty sure its all engine and electrical noise its picking up.... i would think with a 250+ knock noise count its getting i would hear the knocking ;)
stock knock sensor wiring is shielded. THe electrical noise comes from the sensor itself, basically a little microphone, that is attached to your block. About the nastiest thing I can think of for making elec noise.
 

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Madd Tyte JDM yo ®
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7,014 Posts
the stock knock sensors generate the noise. the SAFC2 picks up ALL the noise. including stuff the ECU doesnt pick up. tahts why the SAFC2 has to be calibrated. you have to hold the engine in neutral at a specified RPM and set the SAFC2 to recognize that amount of engine noise picked up at that RPM and disregard iit. its like setting Tare on a scale when weighing stuffs.

once the SAFC2 is "tared", it will show you any noise ON TOP of that which is inherent with the engine's mechanical noise. you basically zero it out to avoid getting "phantom knock" displayed or picked up.
 

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No One Ever Listens To Me
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mullenc525 said:
stock knock sensor wiring is shielded. THe electrical noise comes from the sensor itself, basically a little microphone, that is attached to your block. About the nastiest thing I can think of for making elec noise.
yeah it is shielded...but not very well IMO....using coaxial or ethernet cable in correct fashion will yield better results....

and chris even with it calibrated like we did mine it will still pick up a lot of stuff...cause it only has two calibration points...one around the 1500rpm mark and one around the 3500 rpm mark... if you go past 4k it will pick up stuff and consider it "noise" thats how my peak readings show me at like 200+ sometimes are i do some redline runs....

IMO its kinda a useless feature especially considering NO ONE can tell you what the "numbers" actually correlate to in terms of knocking. :dunno:
 

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The Wilwood Brakes Dude
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228 Posts
Discussion Starter #13
Awesome, thanks everybody. Great info, this is exactly the kind of stuff I wanted to know, Anybody know how many degrees the factory ECU can pull from the stock baseline timing?

I will get into this SAFC install as soon as I get the motor back in. I was up till 1:00am last night putting the motor back in but I will have it running later after work tonight.

Since the SAFC only controls Air flow inputs it CANT control timing exclusively (via the knock sensor function)???? Is this correct.
 

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TheFastCoonAss
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6,083 Posts
outofstep said:
Pressure precludes puddles.
That is correct, he builds them with 150 psi pumps, and also nozzle sizes have an effect. He mainly builds them for Turbo Diesels.
 

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The Wilwood Brakes Dude
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228 Posts
Discussion Starter #15
Hey, Outofstep. IF
Pressure precludes puddles.
then why does every (garage) air compressor on the planet have a petcock? Answer to drain the liquid that has condensed after slowing it down and cooling it. Remember it was just pressurized when running thru the compressor motor.

In your A/C on your car (every car) What is that thing right in front of the radiator? Its a CONDENSER its only purpose in life is to turn VAPOR in to LIQUID by slowing down and cooling the hot vapor.

By introducing water vapor in to an enviroment pressurized or not, the function of making it a vapor is whats decreases the temperature of the liquid and the vapor itself will be the intercooler (the greater the water ammount and vapor atomization has the same effect as a larger intercooler with more cooling fin surface area). Once you introduce this vapor to a cooler enviroment and slow it down (the IC) it will try to condense. Extended periods of high velocity will keep some of the water still in vapor form but it will definately condense just like your cold soda can on a hot humid day or your A/C condenser. An intercooler "is a condensor" for the vapor "AIR" its just that the ambient temperature on the outside isnt enough to condense "air" into a liquid.

Misting nozels should never be placed up stream on an intercooler. Why do you think you cant run an intercooler on a carburated draw thru turbo system? The fuel would condense out in the intercooler. That would be a very exciting back fire.

Guys did I miss anything? I have never heard of h2o before the IC. but I have been wrong before.
 

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Republican
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8,421 Posts
IdealSupra said:
this is VERY true...EXCEPT...that is the case with the stock knock sensor wiring or any normal wiring for it...if you use shielded cable and rewired it i would think the results would be better...
Even with my usb wiring thier is still significant electrical noice in my knock sensors (info from the power fc) and I know it isnt detonation.
 

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Registered
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so does anyone know the procedure to set the knock feature? maybe a link or something like that to help this guy out with his problem(also those that lost their manuals like me)?
 
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