Is this normal? (timing belt marks)

[TheMAN]

very interesting... this further convinces me that the CA can benefit from an external knock/ignition controller... the J&S safeguard can react faster than 99% of all road vehicles today... it not only retards timing from knock detection PER cylinder, it also advances timing up till the knock threshold to maximize engine performance... it also can detect knock up to red line, unlike most stock systems

I can tell you from experience that the CA's knock sensor is pretty useless once you do something extreme, like shoving hot air through the engine (major heat soak)... but I'm not surprised at all considering this is more than 20 years old technology, and given that ECUs even 10 years newer have crappy knock detect algorithms, it isn't out of the ordinary that audible pinging is observed during extreme conditions

bottom line is, for those of you who want extreme performance from your CA where margin of errors are slim, a J&S is cheap insurance considering the big picture... I have seen it keep engines running insane amounts of boost from blowing sky high, and I've also seen it prevent catastrophic failure when something stupid happens, limiting damage considerably... to me it is a peace of mind against stuck/bad wastegate actuators, bad injectors, bad fuel pump, bad fuel, etc

the way I see it... stock works fine for stock or mild upgrades, but once you go balls to the wall, you need better safety measures, just like how people install standalone EMS (however, my personal research shows that none of them beats J&S's knock detection algorithms) to allow better tuning of their engines

[mr_ca18det]

Very true and the ca ecu does not retard timing if it senses knock .

[dash]

"tuners" have wrung amazing power from a wiiiiiddeee variety of setups, using this slow old ecu, with many surviving the rigors of track use repeatedly

a J&S is cheap insurance considering the big picture... I have seen it keep engines running insane amounts of boost from blowing sky high, and I've also seen it prevent catastrophic failure when something stupid happens, limiting damage considerably...

and what have you seen this on ?
r u gonna pump "insane amounts of boost" thru your "J&S safeguarded" ca18 ? I wanna watch

J&S safeguard can react faster than 99% of all road vehicles today... it not only retards timing from knock detection PER cylinder, it also advances timing up till the knock threshold to maximize engine performance

that and more, has been their advertisement from way back. Sounds great, but...... if it is such a fantastic piece of equipment, with aforementioned capabilities, why has it not caught on yet.... even what, some 12 years later ?

[mr_ca18det]

I've never delt with the j&s but i'm not knocking nistune just pointing out it has its flaws but its also extremely easy to use and install and for the money well worth it also the forums for it your very unlikely to get flamed for event the dumbest question they support it extremely well . Any aftermarket tuning program or system is only as good as whose using it.

[Buddyworm]

Due to the ca ecu being older than the Sr its slower to respond to what's programmed in the maps. For example when i had my s15 turbo lets say i had my timing at like 30 before spool up and if you try to taper it down to say 16 when in full boost the computer cant adjust fast enough and your timing will drop down to like 8 degrees then when your in the higher load areas it stay in longer it will come back up to where it should. Does that make sense. But i'm not the only one with this problem its not the end of the world and its not a nistune problem its just a slower computer so fast adjustments arent possible. And megasquirt can control everything boost luanch control. I'm almost possitive ca ecu run a 128 bit system as opposed to the sr is 256 maybe. But if your running it stock or light mods nistune works its just fast spooling turbos dont work very well. There is ways to get rid of a lot of the timing drop just takes alot of messing with. But its super easy to use and is user friendly

I disagree entirely. I had zero issues while running a TD05-14b with a 6cm^2 hotside and anybody who's run one with those specs knows how quickly that little huffer winds up. Spooled hard from ~0.2 to 1bar in something like 500rpm and my final timing matches the tables exactly in all load conditions. The ECU is not the problem. Did you use the knock copy function to copy your timing map to the knock map? One thing that IS quirky with the CA ECU is it averages the High Octane and Low Octane maps to determine final timing.

Edit: Also, 128bit is not the speed of the system it's the size of the rom image, SR's use a 256bit rom. Furthermore, the ECUs require a minimum access speed of 100ns from the chip they reference for the map tables. If the ECU accesses the chip once every 100ns (and I've done the math right), then at 7500 rpm the ECU is referencing the tables over 79,840 times every 360 degree rotation of the crank. Ergo, no, it's not the speed of the ECU that causes your timing to drop when you're motor is seeing increased load because it's impossible for the motor's state to change faster than the ECU can read it.

[biosehnsucht]

Re: size of ROMs, it's 128kbit and 256kbit actually, or 16 and 32KB. The 128 and 256 confusion comes from the part # 's being for example 27C128 or 27C256, respectively.

[Buddyworm]

^Good call. Haha, I've even seen the filesize in windows now that I think of it.

[mr_ca18det]

Yeah i run both maps copied thats what mine does even with the holset same deal during spool that s*** drops then when in boost back to where it should be. There is someone else with the problem on the nistune forum maybe you just got lucky with it or maybe we have somethin wrong with our cars.