timing maps/strategies for old-school turbo engines

[chris davey]

It seems that I am running a bit more timing than you at 1bar and around boost areas. I don't know how the different types of engines and efficiences makes thing differ though.

I got quite confused after looking at Lance's 3rz turbo maps as he is running WAY more timing than I am. It was something like 29deg at 14psi. Never quite got my head around how he could do that. No knock though.

What are you using to detect knock? I think you probably have a bit more timing to put in but would be very careful with knock detection. I have never actually heard any in my car so it is difficult for me.

What sort of fuel is this tuned for?

[gearb0x]

However, afterwards we were still guessing as to a good reference point (and a tuning strategy) for improving the timing map.

Just advance it till it blows up, then back it off and rebuild the motor


I kid i kid

have u played with any of MS's autotune features now you have the wb02? i guess on an turbo it might not be a good idea

Id be interested in having a sticky beak at the logs. My MS install wont be till later this year unfortunately

Phill

[thechuckster]

oldcorollas: when i set it (the LC1 controller) to instantaneous repone, the logs show the O2 sensor responding within 1 or 2 log events. My engine still misses a bit at idle (dodgy intake and bad placement of injectors) and accell tuning is needs much improvement so it can wildly swing about. The O2 sensor is about 2" after the turbo.


Chris: my engine is more prone to knock/detonate under boost, but being an older head design i can run more off-boost timing (or so Msefi crowd thinks). My knock detection is my ears in the cabin, it rattles pretty loudly when the timing is too high. Plus my zorst is pretty quiet

Also, that timing map on boost is quite conservative.

I've been using standard Caltex fuel and been quite good (surprisingly) so it should be a safe tune for PULP. I normally run BP premium fuel.


gearb0x: odd that you suggest that... i do have a 1GGTE (just missing a new clutch and a W58) in storage for this very situation

I'm going to try autotune when the overall map and accell settings are good - but it's only for polishing a tune, not setting up from scratch. Plus it only kicks in when the actual versus mapped settings are within close distance of each other.

I'll also post the proposed AFR target map as this will also guide autotune.


edit: i forgot to include a link to my MSQ file.

[oldcorollas]

for the accel, i found that too rich as just as harsh a cut (if not more) as too lean.... and the time was very short also. don't be afraid to pull fuel out of the accel enrich.

[thechuckster]

stu: it's like the initial burst of accel enrich helps at the start of the accel curve, but then runs out of puff until the map signal stabilises.

I think we're going to change it to MapDot accell instead of TPS as that's supposedly a better method of accell enrichment when on boost.

[The Witzl]

Chuckie - you are running a lot of timing on idle.... this is something i thought you wouldnt really want to do?

I'll try to post up my (non-boost) ignition curve thus far.... i still have a lot of tuning to do - i'll be borrowing Wilbo at dubbo

[thechuckster]

low compression = big idle advance

[thechuckster]

two log files for folks to view/analyse.

- driving with O2 correction on (max of 5% change to map values) - oddly enough, this setting make it cruise poorly - like it's missing. XLS file (1.9Mb)

- driving with same map but no O2 correction - runs smoother bud the accel stumbling seems a little worse. XLS file (2.0Mb)

Samples of the log being viewed with Megalogviewer - you'll need a web browser that displays PNG fies.

O2 correction on - Accel/boost when on freeway:


O2 correction off - Accel/boost to enter highway:

[chris davey]

Is the max and min numbers the max and min achieved or the top and bottom of the section?

Crazy that the second one drives better as the AFR varies a lot.

Datalogs are a hell of a lot easier to decifer when you are in one gear only like the top one.

[thechuckster]

chris - most of the max/min numbers are set by me - anything no ending in a 10 (e.g. rpm, map) is the max/min value for the log.

yeah - not sure why that's happening (O2 off equals better result). I'll try to get a log doing the hill run for better comparison... just needs two people to do it easily.

[30psi 4agte]

looks like it is leaning out a bit in 4th to me ???

is it possible that the map settings are a little lean for that particular boost range / rpm? The car mabe surviving off of the acc pump settings in the lower gears which arent held as long to achieve a richer AFR reading and then tapering off when the longer gears are held because it relying solely on the map settings which arent sufficent

[oldcorollas]

why does the MAP signal have so much noise? it'S being reflected in both the spark and PW, although it doesn't show up in the AFR..

if you can't get rid of the noise, i'd be tempted to take the upper and lower MAP values of the boise, and make them the same VE, so that even if you get the fluttering noise (which may or not reflect the air getting in), you don't have varying fuel input (which would feel like a misfire from the varying power)... perhaps...

got a fuel filter/restrictor before the MAP sensor?

[30psi 4agte]

Do you think a restrictor would help that ?

CHUCK: where is the map sensor vac/ boost line coming from on the engine ?

[thechuckster]

Am pretty sure the MAP line comes from a port just after the throttle. The throttle connects to the (under-sized) plenum via about8" of 2 1/2" pipe.

I fitted ports for every vacuum need (MAP sensor, BoV, FPR, boost guage) rather than having them share one small port. The brakes have the own much larger port and there's as larger-again port for the idle-up valve and PCV valve.

am wondering whether that too is adding to the noise - i must source a turbo-engine PCV valve for comparison.

I was thinking of putting a restrictor in to cut down that noise - am not sure whether that's a feature of the poor plenum design or the valves copping more damage from the red-hot turbo event from 3 years ago.

[30psi 4agte]

FWIW
I think my MAP sensor gives a similar reading on the log......IE noise.
I cant be too sure as i dont have the a log handy as i had to re-format my lappy and lost them.

From memory it is fairly similar ------ but maybe not as bad.

Chuck :like you mentioned it mabe worth trying OC's suggestion (restrictor) to see if you can soften the noise.