Temp related knock
 

It's not news that our FA20 engines are sensitive to high temps and seem to be a bit knock prone. I wasn't sure where to post this so I started a new thread. Hopefully this will result in some good solutions in tuning software and/or hardware that will not cut into already lowish power and prevent loss of power due to high temps.

I have already taken some precautions to try to lessen knock in my own modified tune using the OFT and Rom Raider. Here are a couple of logs taken at the same road in different temperatures with the same exact setup. Logs start with a 3rd to 4th to 5th WOT pulls with FLKC and Knock Correction being logged.

In 75*f ambient temps:
http://datazap.me/u/solidone/stg1-20...2&zoom=268-590

As you can see, not a lot of corrections going on here. I'd actually consider this good, since the minor corrections is telling me I got the maximum amount of ignition advance in the tune where the computer is only dialing back a little bit in a small area. Not enough for the IAM to be cut back.

IN 100*f ambient temps:
http://datazap.me/u/solidone/stg-1-f...12&zoom=63-368

Here, with only the difference being the higher ambient and intake temps, you see the computer pulling more and more timing as I continue to up shift. I'm sure less power is being put down than the earlier log in cooler temps.

What this data tells me is that under conditions that we see at the track, in hotter than 100*f temps and more continuous aggressive up and down shifting the engine is likely putting down less and less power as the day and on track sessions go on. My butt dyno concurs. And the resulting IAM once I check the status after a few sessions on track also concur. Where do I go from here to try to reduce this degradation in performance without cutting into the already low output of this engine?

Edit: I'm just going to add a few more logs as the earlier 2 at different temps for my own record. :)

84*f ambient:
http://datazap.me/u/solidone/stg1-20...2&zoom=121-386

[*after uninstalling oil catch can from PCV vacuum line, fuel trims and afr's changed and more knock corrections logged without other changes*]
84*f ambient w/high IAT's (+100*f):
http://datazap.me/u/solidone/stg1-20...-12&zoom=8-308

86*f ambient: (12.6:1 afr)
http://datazap.me/u/solidone/stg1-20...12&zoom=52-347

73*f ambient:
http://datazap.me/u/solidone/stg1-20...12&zoom=27-299

You can alter the IAT/Temp compensation tables to pull some timing as temp increases, your still pulling timing but you generally come out ahead if you pull the timing and avoid the knock as the ECU is pretty aggressive in pulling timing once the knock is detected. If you preemptively pull say 1 degree via temp compensation it might avoid the ECU pulling 2 degrees when the ECU is left to detect and correct the knock.


As your on 91 octane for track days it would probably be worth paying some extra dollars for some octane booster or a drum of better fuel for the odd track day its cheap insurance.


below is the IAT/Temp tables you could just make the compensation more agressive by making it start earlier or increasing the values.

The second table I originally interpreted incorrectly. -100% means full compensation applied and 0% means no compensation applied from the prevoius table.

If I was going to the track i'd throw in some octane booster as well just for some added protection.

http://www.ft86club.com/forums/attac...1&d=1408588907

I'm actually considering this. Although I've asked some more experienced track folk like @CSGDavid about this. He seems to think octane boosters don't do shit. Not sure what his experience is with different octane boosters. While I recall reading some material showing certain octane boosters do actually do as advertised, I'm not one just take peoples word on some of these things. There's one sure way of finding out, I always say. :)

I would totally agree that better quality fuel is always better than octane booster, but its better than nothing.

Another alternative is to have a track map and pull some timing out at track loads and RPM. It's a safe option and then add in some protection with the IAT timing comp table. Better fuel is definitely the 1st option though.

On a side note, Steve I can't work out the RR 3D map above. I assume the -100% means 0% is applied (-70% is 30% etc), or is it the other way around?

Tdd conformed it works oposite to what I thought by bad

-100% in the compensation table means no compensation applied
0% means full compensation applied from activation table

The only reason I ask is that ECUtek table is basically a multiplier. This is the stock table:
https://dl.dropboxusercontent.com/u/...20Ignition.jpg


Makes it a little easier to understand IMO. Either that or the numbers in the RR table should be 100% and not -100%

hmmm so are we able to increase ignition advance in cooler temps (below 70*f) on these tables? Winter is right around the corner, maybe we can cash in some ponies with the lower temps while at the same time tune for knock resistance when it gets hot by tweaking these tables.

I think the answer to your question is yes, however do you really want to test it and how would you set it up? Where would your standard temp be and will the lowering of the IAT bring you any further knock resistance? You would need a totally knock free base to test it out on and be willing to induce knock across the whole range. Plus, you'd need to do multiple tests to ensure that no results are "one offs". I don't think the time/effort would be worth the extra degree in timing you may be able to get in there.....

FWIW, on our visit to Cosworth all the dyno figures were stated as at 55C..... potentially this is where most would set their tables up at and work from there.

@Shiv@Openflash can we get some input here? Im wondering this as well

Well, I don't have the luxury and access to a dyno located in a climate controlled temperature adjustable room. I was thinking of just making conservative changes to the existing tables and log what happens once the temperature cools. It still pretty hot in cali so I'll just be working on the hot side of the table and retarding the ignition. While I do that I will apply a conservative amount, like half a degree of advance to the cooler side at 68*f and below and see what happens when it starts to cool down. I know the existing ignition table works pretty well in 80*f and cooler temps, so that will be my starting point with the OTS tune provided by vishnu.

@steve99 @Shiv@Openflash Steve, this chart makes me think that the alterations you've made to the percentages are actually decreasing the amount of timing being pulled.

Correct I had it arround the wrong way :-(

It's definitely confusing though. We just need @Shiv@Openflash to chime in here so we don't blow anything up :bonk: