Ignition Timing on NA-ts

[Ravan17]

Ok ive been sitting here and killing myself tryin to figure this out, i need some one to explain this to me, b/c i think im either really stupid, or there just isnt a way that this can work. ok, here is the deal:

I have a 95 5spd NA-t, boostlogic t61 kit , apexi gt-spec exhaust, 2.5 mm headgasket, 525cc injectors, lexus v8 maf, and some other things, my fuel managment is the apex safcII, when i went to get tuned a month or so ago the tuner (who is AEM certified) asked me wat PSI i wanted to run, i told him 18, he asked about my ecu, i told him stock NA ecu with SAFCII, he then was like well the problem is pulling so much fuel to run 18 psi and advancing the timing blah blah, so we tuned at 15 and it made about 370 at the wheels with shitty bosch plugs that kiept blowing out, he told me if i got the AEM EMS i could fix the ecu advancing the ignition timng when i pull fuel, but my question is HOW???????? i have a distributor, so what does the ECU have to do with the ignition if the distributor is mechanical and will still fire when it is supposed to, is that not right? i mean its spun by the exhaust cam and when the contact is made inside of the distributor the spark is sent to the designated cylinder.....so some one please expain that to me, i just dont get it, and what are some of you other NA-t guys doing about fuel managment with safcii? can more fuel be pulled?? i need answers.....i just dont get it...lol thanks

[Ravan17]

nobody......?

[Jaxsc3]

well lets put it this way if your ecu doesnt like what its seeing it will retard the timing and it will retard it alot ive gone threw this many times of going back and setting my timing at 10 degrees over top dead center ... few days later throw the timing light on and its a couple degrees below TDC but i also had no fuel tuning what so ever and im obd2 its very possible that your ecu will continue to retard timing. one of the first things i would suggest is speed density conversion and most deffinatly an egt gauge when your car retards timing obviously your egts shoot through the roof and ........ get some ngks for a turbo soupora i believe they also have a step colder than stock tt plugs. as for what im running for fuel tuning aem ems ... if you decide you want to get an ems shoot me a PM i can hook u up

[DaveH]

I think the simple answer you are looking for is that the ECU can adjust timing "inside" of the distributor. You adjust the distributor externally to get it generally in the right position, and the ECU will make the coil fire, which will time the spark exactly when it wants, and is not really related to the position of the distributor.

[Ravan17]

makes sense in a way......but the distributor still only makes contact with the wire contact at one timed point, which is timed by the exhaust cam....but i gue sthat makes a lil bit of sense since it only takes so little time for the degrees to change when the engine is rotating

[MikeS10]

I have been asking myself that same question ravan17, how if its mech. does it adjust the timing?? thanks for the insight dave. its still a bit fishy to me though.

ravan just a lil side note i'm running almost the same setup as you except for my exhaust and choice of electronics. i think going speed density will def. help you out a bit. i was able to get 436rwhp at 14psi (thanks to BLcrew)- i'm hoping with a small amount of tweaking i can daily drive it forever at 14psi and 450rwhp i'm not sure if any timing adjustments were made though.

sorry for the late azz reply hahaha - boring business trips lead to forum surfing galore

[SuperRunner]

I have been wondering the same thing as well. In vacuum advance motors, it actually moves the rotor...or does it?, I am not sure what happens with this distributor. Actually, the more I think about it, the more this makes sense below:

The rotor is not a point, it could be a "T" shape. This allows the ecu to control when it sparks along the "T". I am pretty sure this is how they do it. I am still thinking about going Emanage Ultimate to avoid this problem. I know I can get quite a bit more power doing this...if I can make it work.

[Bean]

makes sense in a way......but the distributor still only makes contact with the wire contact at one timed point, which is timed by the exhaust cam....but i gue sthat makes a lil bit of sense since it only takes so little time for the degrees to change when the engine is rotating

Have you ever taken your distributor apart? The ECU controls timing by controlling the coil (just like DaveH said); it knows the position and can advance/retard at will.

There IS NO "point" for the wire contact; if you look inside your distributor, you'll see there is a face to the rotor connection; its not a little point here; its a wide face.

Bottom line, if you want to really control the ignition timing; get an AEM ECU. All the piggyback bs has a drawback when tuning. Lean the fuel? then you've advanced the timing. Then you have to retard the timing to make up for that. It gets old.

[legendboy]

Sorry if I sound like an ass for my first post :) I am a new Supra owner. I came from the world of honda fi. I build custom turbo kits and tune (honda)

This thread sounds a bit like the blind leading the blind.

The ecu controls ignition timing. It will add and subtract timing from the static base timing, which is set at the distributor, based on sensor/load conditions. You cannot adjust for boost by adjusting the static timing.

First of all, you want to retard ignition timing under boost. This is also not linear. You can always advance timing back up after peak torque to recover hp lost by the retarded spark. A stock ecu will run 35+ degrees of ignition advance at WOT/high load, even higher in other conditions. Basically the stock n/a ecu isn't programmed to deal with any load greater then atmospheric pressure ie. No boost (Sorry, I’m a speed density guy lol) It will continue to think that it is under WOT (full load) and use the appropriate ignition advance value. (or throw a code and your car will die/choke/stall...etc..)

Using piggyback fuel computers like the safc will allow you to control slightly larger injectors and or run more fuel, but all its doing is intercepting sensor signals and fooling the ecu into thinking its at different load conditions and to add (or subtract) more fuel. This is very bad as the ecu normally will throw large amounts of ignition advance into the mix.

By retarding the distributor you can add or subtract a couple degrees of ignition timing but nothing substantial enough to warrant safe boosting. Also, when you retard the dizzy you are decreasing performance all the way across the power band, and your EGT's will go up.

This is why standalones are really the only safe way to do it. (Unless you are using a factory turbo ecu, which is programmed to handle spark under boost)

Basically:

-Too much ignition advance + boost = detonation
-Too much ignition retard + boost = heat = detonation

Now i do realize that some motors are tough and can hold up to abuse that ignition advance + boost create. I don't know enough about supras specificaly yet to really comment on that too much, this is just general information. Hope that helped a bit.

[SuperRunner]

Yes, this most of us already knew. The question was about other ways you can retard your timing since on the distributor, you only have so much time for the spark to arc accross the points.

The solution was that there isn't just a single point, but a rather large surface that the spark can jump from the rotor. This allows the ECU to adjust when the coil actually fires and the spark will still go to the correct contact on the distributor cap.

[Bean]

Sorry if I sound like an ass for my first post :) I am a new Supra owner. I came from the world of honda fi. I build custom turbo kits and tune (honda)

This thread sounds a bit like the blind leading the blind.

The ecu controls ignition timing. It will add and subtract timing from the static base timing, which is set at the distributor, based on sensor/load conditions. You cannot adjust for boost by adjusting the static timing.

First of all, you want to retard ignition timing under boost. This is also not linear. You can always advance timing back up after peak torque to recover hp lost by the retarded spark. A stock ecu will run 35+ degrees of ignition advance at WOT/high load, even higher in other conditions. Basically the stock n/a ecu isn't programmed to deal with any load greater then atmospheric pressure ie. No boost (Sorry, I’m a speed density guy lol) It will continue to think that it is under WOT (full load) and use the appropriate ignition advance value. (or throw a code and your car will die/choke/stall...etc..)

Using piggyback fuel computers like the safc will allow you to control slightly larger injectors and or run more fuel, but all its doing is intercepting sensor signals and fooling the ecu into thinking its at different load conditions and to add (or subtract) more fuel. This is very bad as the ecu normally will throw large amounts of ignition advance into the mix.

By retarding the distributor you can add or subtract a couple degrees of ignition timing but nothing substantial enough to warrant safe boosting. Also, when you retard the dizzy you are decreasing performance all the way across the power band, and your EGT's will go up.

This is why standalones are really the only safe way to do it. (Unless you are using a factory turbo ecu, which is programmed to handle spark under boost)

Basically:

-Too much ignition advance + boost = detonation
-Too much ignition retard + boost = heat = detonation

Now i do realize that some motors are tough and can hold up to abuse that ignition advance + boost create. I don't know enough about supras specificaly yet to really comment on that too much, this is just general information. Hope that helped a bit.

Goost post. But I've seen no evidence that OBDI 2jz-ge ECUs will compensate AGAINST whatever timing you place the distributor at... you can retard your static base timing on the distributor and IT WILL make a difference... the ECU only compensates via maps based upon the difference between base timing and timing on the map, not absolute timing.

Now on OBD2, I'm unsure. But I've known MANY people that have turbocharged NA Supras and SC300s... many of them chose to remain with stock compression levels, and still many of them retarded the base timing so they can raise the boost levels without any issue, myself included.... and it works.

[legendboy]

Well basically if you set your dizzy at 10 degrees btdc (retarded all the way type of thing) you are reducing the amount of total timimg at WOT by a couple degrees, maybe 8 or 10. The problem is that since the map in the ecu is probably throwing 35+ degrees advance at that point you still could be in trouble.

i think yours and others success may be due to the fact that the stock 2jz is pretty damn tough! i have a feeling however if you had these cars on the dyno and were using a listening device on the block you would be able to hear detonation. at least this has been my experience.

make a full run with the charge pipes disconected and listen, then do a boosted run and listen to the difference.

I can't comment on the obd2 comment as i really don't know jack shit about toyota yet LOL

[legendboy]

also, to add, i can't imagine how bad part throttle boosting is when boosting on a stock ecu, i imagine thats where the real damage takes place.

a quick question to you guys, how many guys here have melted pistons?

[soarerflame]

what about the MSD Boost Timing master gadget thingy has anyone used that?

[SuperRunner]

also, to add, i can't imagine how bad part throttle boosting is when boosting on a stock ecu, i imagine thats where the real damage takes place.

a quick question to you guys, how many guys here have melted pistons?

I havn't heard of too many people damaging their pistons this way. Thost that are, are running 24+ psi, and ditched the stock ECU long ago.

[SuperRunner]

what about the MSD Boost Timing master gadget thingy has anyone used that?

This seems to be a pretty commom mod, I am thinking about doing this if I don't use my Emanage Ultimate.

[Ravan17]

what is this speed density converter, how much does it go for? and wat does it really do? its xmas time and im making my xmas list: ) , so yea, makes sense to me now how the ecu pulls ignition timing, and i cant say for sure, but i dont see how running a piggy back at low boost levels( 15-17psi) will detonate ure engine....atleast on a supra, there are a couple of members running NA-t for ove 2 years with no problmes

[Dramon]

though the thing you have to remember about part throttle boosting is that the load is a lot less on the engine as well.

[Ravan17]

what is this speed density converter, how much does it go for? and wat does it really do?

[Bean]

what is this speed density converter, how much does it go for? and wat does it really do? its xmas time and im making my xmas list: ) , so yea, makes sense to me now how the ecu pulls ignition timing, and i cant say for sure, but i dont see how running a piggy back at low boost levels( 15-17psi) will detonate ure engine....atleast on a supra, there are a couple of members running NA-t for ove 2 years with no problmes


Best I can tell you is READ. Speed density conversion is going from a mass-airflow air-metering setup (stock) to a MAP setup (AEM ECU or MAP ECU). Allows more precise tuning and will make more hp.

15-17psi is not low boost levels.

Those members with no problems have done a lot of research and they did it right the first time.

legendboy: the stock ECU does not throw 35 deg of advance. I doubt it even goes over 20 MAX. Retarding the base timing to 10 degrees will make the car drive like a turd. One can only retard the base timing about 4-5 degrees; after that, its diminishing gains and driveability and gas mileage suffer HORRIBLY.

Timing in the stock maps is VERY laid back in the lower rpm band. There is a significant spike at 4000-4500rpms and then it trails off. That spike is where people have problems; its where the car makes max torque (more vulnerable that way twofold really). Under 4000 rpms stock, the timing is just dead :)

As for the MSD, SC300T on clublexus used one once. I have not spoken to or seen any posts by the guy in quite a while. I have no clue what happened to him. I stopped seeing him post sometime before CmptrWiz died on clublexus. However, from what he said, it worked very well; and he ran 10-12psi on pump gas on a 60-1 with very little base timing adjustment.