Ping under boost - air temp or timing

[mikeatrpi]

I am having trouble with occasional ping under boost... I'd really appreciate any advice you all may have.

I marked the log in two places just after I heard the noise in the log. My air temps are getting pretty high. Should I pull timing or add fuel to fix the pinging? Is there some sort of temperature correction that might be affecting me too?


Possibly related to the above issue - I have my radiator fan wired to a spare output. I have it set to turn on at 195 degrees. The fan runs after each hard boost pull, yet the CLT never reads that high in the log. What's going on? Am I right to think the pinging is running lean and heating things up?

VE


Spark


Setup:
MS1 (v3 board, MSnS 029y4)
1982 Datsun 280zx NA -> Turbo conversion
VR distributor signal
Stock coil
BPR7ES plugs gapped 035
Not intercooled
5 PSI boost
Cylinder head temp sensor used as CLT sensor
GM open element IAT sensor in J-pipe mid way between turbo and throttle body

Attaching full MSQ; log is 3MB and too large to attach:
http://z.modeltrainguide.com/msextra/20 ... .12.21.msl

[Dennis930]

I have not looked at your log, but MAT correction has been identified as being too aggressive by MS users. It is possible MAT correction is pulling too much fuel at higher IAT temps - if you are seeing the AFR higher than expected when the pinging occurs. Your spark table does not look too aggressive at high boost levels to me. One way to check MAT correction if your car was tuned in cooler temperatures is with the engine fully warmed up, monitor AFR at idle over a period of time as IAT rise due to heat soak. If AFR's rise as temps go up, then adjust the MAT correction curve to bring the AFR in line. This would have to be done with O2 correction turned off for idle.

[turbo conversion]

If the compression ratio has not been lowered (I'm assuming it has not) then with out an intercooler timing looks a little aggressive to me.

My first install was a 280ZX na converted to turbo with intercooler and my timing was 2* less across the entire boost table.

Your afr table is to lean under full boost also (13) I would try between 11.5 to 11.8 to one.

I would rather gas foul a plug from to much fuel than burn a piston from not enough.

Remember, you can always add timing or take away fuel as needed but once you smoke an engine it is to late.

David

[mikeatrpi]

Thanks for the tips!

Here's my correction table. I think I messed with this years ago.


Here's my current AFR targets. In the log, sometimes I'm spot-on... other times, its VERY different.


I'll drop the "150" row to 11.8 and the "130" row to 12.8 and richen up the VE table too.

Do any of my settings look weird? Yes, I know I need to work on the AE. The log clearly shows that. But I should get the VE table dialed in (richer) and pull some timing too first.
http://z.modeltrainguide.com/msextra/settings.png

[turbo conversion]

I would start with the AFR and timing first and then tune VE as needed.

David

EDIT: I can't help you with the air density correction, I don't have any experience with MS1 and my firmware is different.

[benckj]

Have you tried setting AFR table using the tools? This is a great calculator to set-up table as yours looks very lean at top end.
Also on the EGO control the "controller step' is set to 0% which seems a little odd.

jim

[Dennis930]

Mike,
A 13 AFR is too lean for boost conditions. You should be in the 11.5 - 11.8 range at full boost, maybe even a little lower particularly without an intercooler. You should be at 12.5 getting into boost just above 100kpa and gradually drop down to you full boost.

[mikeatrpi]

I didn't even realize there was a tool to help generate the AFRs. What a difference with my original table!

[benckj]

That looks more like it. I never saw the tool first time I set up AFR table. Once I had some real world torque and power figures it helped dial in the set-points. Like indicated above, need to have rich conditions once you start boosting. Low to mid 11's after 150kpa.

Sometimes its advisable to run sequential injection and add a couple of percent to inner cylinders for high boost values. On some engines these tend to run lean.

jim

[Dennis930]

Mike,
You will have to richen up the idle region, but that looks much better.

[mikeatrpi]

Things are getting better! I adjusted the timing and target AFRs, manually scaled some regions of the VE table, and let auto-tune do its magic. In boost now its getting around 11.7 AFR, but my MAT's are climbing like mad and I still hear a little bit of pinging.

Link shows the AFR and Spark table: http://z.modeltrainguide.com/msextra/stillPing.png


I'm going to try pulling timing > 3500 RPM and > 120 kpa and see what happens.

Also - check out my Gair. Should it rise, or fall, as temps increase?

[mikeatrpi]

Yeah, pulling a touch of timing in the 3000ish area just over 100kpa helped. I don't hear pinging. I still want to figure out Gair and accel enrichment... plus I'm thinking about colder plugs to give myself a little bit of margin.



Thank you all for the advice thus far!

[benckj]

High MAT are due to poor intercooling and heat soak. Might pay to look at upgrade options with IC, fans, water spray or WI mods.

Tables are starting to look better although there is still plenty of tuning required. Why are your MAP scale so odd values? May be better to use round figures and bump up to beyond the highest intended boost (is

Do you have knock sensor settings adjusted and protection enabled? Need that protection when running boost especially when as your getting high MAT's.


Jim

[mikeatrpi]

Hi Jim,

I have them roughly scaled to PSI. I thought 7 kpa is roughly 1 PSI?

I do not have a knock sensor.

I also have a pile of parts - a Starion intercooler, a "log" style air-to-water intercooler, and a pump and parts for a methanol injection setup. I just can't make up my mind which one to install!

[turbo conversion]

Is the engine still high compression (stock na motor) or have you lowered the compression ratio?

David

[benckj]

Install A2W with meth/water injection between IC and TB.

Correct on kpa/psi conversion but strange to see odd values for MAP. If your striving for 15psi boost then want to have 200+kpa on table. As noted above this may be a little ambitious if compression ratio is high and no knock protection.

Jim

[mikeatrpi]

Is the engine still high compression (stock na motor) or have you lowered the compression ratio?

David

Hi David, its still got the NA compression... 8.something to 1 I believe.

[mikeatrpi]

If your striving for 15psi boost

Jim

Hi Jim. Nope, definitely not shooting for 15 psi. At least not until I figure out what I'm doing. The Datsun guys say the T3's max out around 10psi anyway.

My goal is to attend a track day in August and not blow anything up! I'm quite happy with lower boost right now, 5 to 7 psi.

[turbo conversion]

I did this same conversion for my first project at 8 psi with a big aftermarket air to air intercooler.

I would install what ever intercooler you are going to us before doing a lot of tuning, the tune will change with the intercooler.

David

[Dennis930]

Mike,
If you are still running the stock heat range plugs, you should definitely go to colder plug for this setup.