BAd gas detonated my kat!!!!

[chillmieste]

I just finished installing evrything about a week ago. I was going on one final tune on the highway for my hi throttle points on the safc. Got it tuned perfectly 11.8 12.2 afr. I pull up to a stop light and ther car started to put put like a go kart. Im like my car doesnt usually sound like this. I pull back into my shop and oil all over the valve cover, it looked like it all came out of my valve cover breather. Car felt kinda sluggish, did compression test cylinder 1,3,4 80 psi...... After all my hard work the fukin gas at this mobil station was s***. after this happened i was talkin to My fabricator, he was like man that gas station made his scion knock like crazy. he put in fuel stabilizer and went to another gas station and the noise went away. Im assuming my ring lands cracked pressure built up in the cracnk case and came all out my valve cover... Im in south florida in pompano. dont know how ur mobil gas stations are in other stated or around florida, but BE CAREFUL WHAT GAS UR PUTTING IN UR CAR!!!

[AZhitman]

I feel your pain, brother. Popped 2 KA's before I got it right.

Not to say it WASN'T bad gas, but I've gotta say, that SAFC may have had a LOT more to do with it. Don't spend another dime on that motor until you get a proper engine management system.

[eazye2000]

I'm up near Tampa if you need help, or any parts.

[ss82480]

Yeah I feel your pain, just got my KA-T running and it lasted less than 24 hours. More than likely from bad gas. I had a JWT tune and wideband, everything looked ok until I had the exact same thing, oil spewing from breather.

[chillmieste]

thanks eazye luckily i found a bottom end from a auto zenki. any suggestions on what i should do with that gas. just filled it to full. u think like an octane booster would help or should i jus drive it slow till the gas runs out?

[AZhitman]

Like I said before, don't be so quick to condemn the gas. I'd be looking at the SAFC first. You have nothing to control for ignition timing, and an SAFC is, in my opinion, foolish to use on an engine you've put so much effort nito.

[chillmieste]

tis be tru but i had maunally turned the distributor and set it to 13 degrees. wouldnt this have helped?

[AZhitman]

Ummm, not necessarily.

All an SAFC does is fool the ECU - it adjusts fuel/air ratio by modifying the MAF signal, telling the ECU to add more fuel, and its capacity is usually maxed out at +50%.

For a car like mine (KA-T), adding 50% of max injector flow STILL would have been insufficient, creating a lean condition.

[Spring Break '92]

I would say the SAFC had just about everything to do with it. Leave those things to the Honda boys who use fish tank check balls with their MAP sensors and rising rate FMU's.

[CTS13]

How did you come to the conclusion of bad gas?

[GEO]

I just finished installing evrything about a week ago. I was going on one final tune on the highway for my hi throttle points on the safc. Got it tuned perfectly 11.8 12.2 afr. I pull up to a stop light and ther car started to put put like a go kart. Im like my car doesnt usually sound like this. I pull back into my shop and oil all over the valve cover, it looked like it all came out of my valve cover breather. Car felt kinda sluggish, did compression test cylinder 1,3,4 80 psi...... After all my hard work the fukin gas at this mobil station was s***. after this happened i was talkin to My fabricator, he was like man that gas station made his scion knock like crazy. he put in fuel stabilizer and went to another gas station and the noise went away. Im assuming my ring lands cracked pressure built up in the cracnk case and came all out my valve cover... Im in south florida in pompano. dont know how ur mobil gas stations are in other stated or around florida, but BE CAREFUL WHAT GAS UR PUTTING IN UR CAR!!!

11.8 - 12.2 is NOT safe ...

you should have been more in the 10.8-11.2 range at WOT... Also what was your timing and spark plug depth?

[GEO]

I feel your pain, brother. Popped 2 KA's before I got it right.

Not to say it WASN'T bad gas, but I've gotta say, that SAFC may have had a LOT more to do with it. Don't spend another dime on that motor until you get a proper engine management system.

Well.... I know plenty of people who were running 450rwhp+ on just the SAFC-2.

[AZhitman]

Yeah, and I know a guy who fell out of a 12th-story window and lived.

Means nothing. SAFC is crap.

[WDRacing]

FMU is better then the SAFC IMHO. Cheaper too...

ROM tunes are to cheap not to buy these days.

[Blown240sx]

I just finished installing evrything about a week ago. I was going on one final tune on the highway for my hi throttle points on the safc. Got it tuned perfectly 11.8 12.2 afr. I pull up to a stop light and ther car started to put put like a go kart. Im like my car doesnt usually sound like this. I pull back into my shop and oil all over the valve cover, it looked like it all came out of my valve cover breather. Car felt kinda sluggish, did compression test cylinder 1,3,4 80 psi...... After all my hard work the fukin gas at this mobil station was s***. after this happened i was talkin to My fabricator, he was like man that gas station made his scion knock like crazy. he put in fuel stabilizer and went to another gas station and the noise went away. Im assuming my ring lands cracked pressure built up in the cracnk case and came all out my valve cover... Im in south florida in pompano. dont know how ur mobil gas stations are in other stated or around florida, but BE CAREFUL WHAT GAS UR PUTTING IN UR CAR!!!

11.8 - 12.2 is NOT safe ...

you should have been more in the 10.8-11.2 range at WOT... Also what was your timing and spark plug depth?

Im sorry but 10 A/F is WAY to rich. 11.5-12 is perfectly fine to tune on. I tune all my cars to this area. anything less than 11s and your just wasting fuel. Maybe on a big HP build Id stick closer to 11-11.5 but Ive tuned many cars to 11.5-12 and they make great power, still running fine to this day (over 3 years on some of the tunes), and they dont detonate at all.


Also addressing what AZHitman said. I dont totally agree that the SAFC is crap its just no the best option for larger power motors. Especially if you build the motor. For your standard KA-T or slightly higher modded KA its ok.
The SAFC does fool the ECU and this does make timing issues but only for cars running larger injectors such as 740cc (which is the theoretical limit of the SAFC).

Better explination of what it does, the SAFC intercepts MAF signals and changes the output voltage to change the amount of fuel added, well the thing you have to realize is the ECU also uses that MAF voltage to tell the amount of timing to add.



Kind of hard to see but if you look across the top, the "LOAD" is what the ECU sees from the MAF. As you pull voltage to get less fuel the ECU reads from a different cell. This directly corresponds to the timing map. It reads the exact same way, the problem is though on most factory maps the less load (MAF Voltage) the MORE timing it adds. So when you use a 740cc injector you have to pull a lot of fuel = a lot less MAF voltage ("LOAD") = MORE timing.

MORE timing = Detonation

[s13drifter88]

an safc is only good for making minor correctios, not for a full tune. if your ecu cant handle it stock then an safc really wont help much either. ideal afr's should be between 11 and 11.5 max (safe). it sounds to me like by pulling fuel you increased timing and therfore it detonated, especially being up into the 12's. btw, if your so worried about the gas, add 3 or 4 gallons or 110 unlead, dont bother with octane booster. itll only boost about 1 or maybe 2 gallons of gas to its advertised ratings but not the capacity of your tank.

[chillmieste]

Ok guys thanks for all the input. I pulled out some fuel from the rail and found it was like a dark du du brown. I totally listen to hitman and the others bout the safc (more than likely had most to with detonation + gas). Drained gas tank added whole can of sea foam to the tank with some 93 gas. Ended up getting a bottom end locally from a 95 auto 240 for 50 bucks! woot. After a nice week and a half engines back on the road. I got a megasquirt 1 ver 3 and its working so fn good. Cant wait for the dyno tune hopefully in the next 3 weeks or so. Driving good for the street, keeping my afrs in 11-11.5 range, no fn around this time. Thanks for all help everyone! Ill keep ya posted o yea kat probably one of the funnest cars ive driven yet. Its so nice to have a place where we all love our babies.

[Razi]

Proper!
Glad the KA-T is back on the road