The Tuning Talk Thread - Forced Induction EFI & JZ Tuning.

[The Real Roadrunner]

if the cam/sync signal varies by as much 15 degrees as Mazman's quote suggest, then you'd have to be really concerned about how much stretch/slop is in the timing belt and whether the tensioner is correctly placed.

Ive never seen 15degrees as that would scare the crap out of me but i have seen up to 10* at the crank, it was on an SR20 and the only time it would do it is if you were giving it hard hits of the pedal and essentialy "pedalled" the car, it had a plugin Haltech on it at that stage and we removed it to go back to the power fc, problem disappeared. seeing as the car was built for the Drift Australia series and your not driving overly smoothly so we needed an ecu that would cope with it.

Its all to do with the amount of slack in the belt / chain, then factor in that its driven by a gear or some form of keyed arrangement, then add in accel and deccel to the mix and with a slow ecu it can all start to get very weird.

id try to explain it in engineering terms but alas im not that skilled.

cheers
linden

[JZA70 R]

ok so ive just had a debate with my mate on exhaust temps at lean afr's at low loads for example cruising.

Im under the impression after a certain point past stoich, the less fuel you add the cooler the exhaust gas becomes. not the cooler the flame becomes.

I used the analogy of a oxy torch. when you get the mixture right you have a blue flame (hot) but if you keep adding o2 (or removing ace) the flame gets shorter and shorter until its extinguished. i dont think it matters how hot the flame is i think the fact its heating effect on a given area is less and less as the flame is smaller. therefor exhaust gasses produced are cooler and cooler?

Is this right?

what would yeild a hotter gas (not flame) at cruise
stoich or 16:1
and
15:1 or 17:1

as you can see we are both too lazy to invest in o2 temp sensors haha

[Disturbed1]

not necc higher gas/exhaust temps but higher cylinder temps as well

[chris davey]

What ECU & engine you have
1jz, lt12s


How you are tuning that ecu
laptop. have done hand controller as well, it sucked. no graphs.


What wideband o2 and knock detection you use and how its intergrated with your ecu
Techedge WB02 is used for datalogging through ecu. Knock sense is also there and is also logged however as yet never had any knock so not doing much

Are you using a Dyno or street to tune, or both?
When car was registered did street tuning and dyno. Now just dyno.


Are you tuning from blank maps or using a 'base map' or someone elses hard work
started from microtech base map

Your opinion on withholding tuning tips or secrets or even your own data and maps from persons and for what reasons?
I prefer to share

What modifications you have done to your engine and how they effect your existing tune, or how they are have increased/decreased difficulty to perform further tuning
Changing from a big laggy turbo to a smaller more responsive one, nitrous also. Basically changed the whole timing map at that stage.

Your experience from tuning timing.
Haven't pushed it. I got a lot of info from other people's setups and worked out where I wanted to be to start off safe. Put a few more degrees in on the dyno and didn't make any more power so didn't want to run any excess timing for no gains. also, 2deg retard for 50shot of nitrous is my rule of thumb however some people say that the more nitrous used you can actually reduce this to 1.5per/50 as the amount of nitrous cools the intake charge that much.

Your experience from tuning fuel.
Pretty easy No great gains to be had unless your map is totally off to start with. Correct timing will yield higher % gains IMO.

Your experience from tuning around knock.
Never got any.

How intimate you are with your ecu, have you learnt every feature and what it does?
Yep, isn't too many which is how I like it. Simple and effective.


Also have 1jz with Autronic SM4. Don't like the software so much. Hell of a lot of things it can do but IMO probably excessive for a street car. Haven't worked out all the software for this.

BTW 1jz-rolla, I only have 17deg at 6500rpm at 20psi with 98 plus 30% toluene mix. I am a pansy

[Disturbed1]

anyone on here willing to share there timing tips - even if its in a pm

curious to see the trends for a turbo inline 6 running a decent sized turbo

heres mine but i think it needs alot of work so feel free to comment

motor is a 7mgte with t78 and 3mm hg so faily low comp ratio. running 18 psi up top and hits full boost at around 4800-5000 rpm

the innovate log at the top right hand corner is a tiny bit out in rpm (rev limit on ecu is 7000rpm) and boost is about 1psi lower then what the ecu sees (not sure why on either)

the afrs were very rough and quick tune and has since been smoothed out on pc but yet to be uploaded onto ecu and relogged.

have got access to knock headphones but requires mounting nissan knock sensors to block so woul drather just keep it on the very conservative side and avoid the hassles.

ideally woul dlike the t78 to come on a bit earlier so hopefully theres somethign in my tune which could be imporved apon to make a slight difference

cheers

[chris davey]

Looks like you might be pulling the timing a bit early to me. ie. at 0psi, theoretically you should have to be pulling any yet.

Also, up top you can probably "ramp up" a little after peak torque which will probably be about 5000rpm. ie. I run 17deg at 4500-5000rpm at 16psi and by 7000rpm it is running 21deg. Ramp up rate is 1deg per 500rpm. This usually helps to keep the torque up in the upper rpm's.

[JZA70 R]

This is my own timing map. I created this myself and it works for me however Im always learning. Its obviously suited to my internally stock 1JZ running factory turbos and u98 fuel.
The entire powerband sits on my knock threshold as this map was used just for drag racing recently.



sorry i couldnt be bothered plotting all the vacuum points for you, the powerfc uses its own unit instead of psi or kg/cm2 ect...

keep in mind the powerfc overrides your specified timing at idle and runs a flat 10' advance regardless. as soon as it detects any tps it uses your map.

according to my logs and a number of other people, the powerfc also adds 1' advance to every cell in the map. strange but something you have to keep in mind.

in summary i run lots of ignition timing around idle, low rpm and low load. ive found this gives excellent throttle response perfect for blipping the throttle and low speed driving. makes the car feel like it has more cubes than it really has.

i decrease timing with rpm and with load. i keep decreasing timing on a linear scale until peak torque is reached. i then hold timing and after peak torque i start adding timing again.

i found out the hard way why you need to add timing after peak torque or towards the end of the engines rev limit, if you dont add timing power drops off quicker than it climbs onto powerband! the result is a flat feeling after peak hp has been achieved.

despite advice that you can add timing as rpm increased, i found this not to be beneficial in my instance. 1 example is if i was around 5000rpm and low load, and put the foot down it would knock because of all the timing on the bridge between no load and full load. this comes back to the insane response from the factory turbos.

there are heaps of other reasons my map is the way it is, if you have any questions feel free to ask.

[Disturbed1]

Looks like you might be pulling the timing a bit early to me. ie. at 0psi, theoretically you should have to be pulling any yet.

Also, up top you can probably "ramp up" a little after peak torque which will probably be about 5000rpm. ie. I run 17deg at 4500-5000rpm at 16psi and by 7000rpm it is running 21deg. Ramp up rate is 1deg per 500rpm. This usually helps to keep the torque up in the upper rpm's.

does this one look any better. admitt it might be foolish messing about with timing values like this but would like to get the basic profile and trends sorted on a conservative scale before worrying about pushing the knock threshold.

[JZA70 R]

at a glance it looks ok, go out and test it.

[Disturbed1]

dont have a laptop to write to ecu

[30psi 4agte]

Looks pretty good but until you see what the engine really wants on the dyno its hard to say. My maps look fairly similar.

The only noticable thing that i do different is in the 0-500rpm range. I usually put the same value across the board here. Say 20deg through all RPM (0-500) and all PSI values.

This gives a more stable base when starting the car esp when it cold. you will prob notice on crank that the rpm and "float/jump" around abit. Even the PSI reading can vary...... Its not just a EMS thing. Peter from EMS tells me it due to current draw on crank. I cant put it down to anything else either. Anyhow

Having the same values in all of the tune points can help as even if the engine is seen to be jumpin around by the ecu the tune doesnt vary because ECU values are the same and will help starting.

It will have minimal if no effect on the rest of the engines operating range a a engine will very rarely if ever see RPM below 500rpm.

[Drifty Midship]

Great thread... My install is a couple of months away and I've been learning heaps about the ecu.
Plan on doing the install and a basic road tune myself.
But i'll be checking this thread for tips...

1. What ECU & engine you have
Adaptronic and 4AGZE

2. How you are tuning that ecu
Built in rapid learn feature for road tune, tuner for power tune

3. What wideband o2 and knock detection you use and how its intergrated with your ecu
TechEdge 2J1 straight into the 2nd com port on the ecu... Factory knock sensor to ecu knock in.

4. Are you using a Dyno or street to tune, or both?
Both

5. Are you tuning from blank maps or using a 'base map' or someone elses hard work
starting with a base map from a 4AGE

6. Your opinion on withholding tuning tips or secrets or even your own data and maps from persons and for what reasons?
Anyone who holds back tips/secrets in the car enthusiast community only does so cause they have some other deficiency and they think that it gives them some kind of lame competitive edge. "Oooh, I'm not telling you what cams i'm running (thinks: they might be better if they use the same as me)".

7. What modifications you have done to your engine and how they effect your existing tune, or how they are have increased/decreased difficulty to perform further tuning
50% engine mods done now, get ecu in to unleash whats there and retune as the other mods go in.. basically just headwork.

8. Your experience from tuning timing. No

9. Your experience from tuning fuel. No

10. Your experience from tuning around knock. No

11. How intimate you are with your ecu, have you learnt every feature and what it does?
About 85%.

[thechuckster]

i vaguely recall reading some posts (here? msextra?) for adding a row (both in fuel and spark tables) below your normal idle to help 'bump up' the rpms when the idle speed got too low.

In essence, the 'bump came form extra fuel (to simulate a light tap on the throttle without the need for an acceleration enrichment addition) that both enriched the motor and allowed you to cope with a possibly transient power supply. The spark went the other way (e.g. slightly less advance than idle and fairly constant over the MAP/Load range) so you weren't fighting any strange spark timing.


Most ECUs these days can simulate a dashpot (which deals with a sudden throttle closure by briefly opening the aux-air valve and also adding fuel) and also do closed-loop idle control. The latter can (if tuned correctly and suitable for the motor) does away with the need for a 'bump' section in your fuel/spark maps.

Also - some ECUs will do some predictive 'smoothing' of transient inputs like MAP or RPM - so things like random spikes at low RPMs can be filtered out or ameliorated somewhat.

[JZA70 R]

my powerfc flicks open the ISCV in between gear changes and when you get off the gas, so thats interesting as you were talking about simulating a dashpot...
under normal circumstances if the idle gets too low (below preset) it again opens the ISCV...

[The Real Roadrunner]

little trick that not many ppl use is to pull out 8degrees of timing 500rpm before the rev limit to stop you bashing the limiter hard during hard acceleration, it prolongs the life of bearings, timing chains/belts and stops your balancer from trying to go two piece.

the other thing i do is bump the timing 5 degrees up at 300rpm below your idle setting, it helps to maintain a steady idle by ramping in timing as the engine slows essentially speeding the engine back up. just dont do it at 0vac as it can make the car harder to start.

cheers
linden