scheides

iTrader: (10)

^I had a setup like that on my 1G, its a bit much IMHO since I have a BBK w/stock size inlet. Cool as hell setup though, too bad I JUST sold my 4"-2.25" coupler FP sells with it

So, on the jitter thing, async TPS table doesn't seem to make a lick of difference for me, so I changed it back to stock. EGR Timing advance tables are now stock as well, and I also tried full-time open loop, as someone mentioned to me that getting the cruise AFR in the low 14's high 13's had helped for them. I tried afrs from 15.5 down to 12.9 w/o any difference (other than it smelled like gas a lot more LOL!).

Bump for anyone knowing if the MAF Scaling tables actually doing anything on this speed density patch.

l2r99gst

iTrader: (2)

Yes, they do. They act like VE tables. You can read John's 'easy speed density' thread for more info.

The jitter that you are experiencing may be a jumpy IPW that I had noticed in a specific map/RPM range. Log your IPW to see if that's the case.

clockworktoy

Yeah i had tons of space so i got a pretty big aem dryflow and my turbo has a 3.5" inlet so a 4" filter was a perfect option to match up to my 4" intake pipe.

scheides

iTrader: (10)

I'm sure my IPW does, I'll try and log it.

Thx for the info on the MAF Scaling, I had left it stock and it may have caused me some problems when changing over.

scheides

iTrader: (10)

IIRC that 'easy speed density' thread was only on evo-tech.net, which is apparently dead at the moment

l2r99gst

iTrader: (2)

Nope, it's right here.

scheides

iTrader: (10)

Gah, thx. I was looking for the one by JohnBradley, not jcbanks, doh! I get the concept though, I'll update mine, I'm sure it will make everything line up.

binky

iTrader: (11)

Yeah whats up with that? Looks like the domain name ran out...? There's just an ad up now ;[


-Bink

mrfred

iTrader: (50)

A subtle but probably important difference with the "MAF smoothing" and "MAF compensation" tables is that they only affect IPW and not load whereas the MAF VE tables in the SD patch will affect both load and IPW.

scheides

iTrader: (10)

Oh wow, really? So altering the MAF tables will likely affect fuel trims then, correct?

mrfred

iTrader: (50)

Yes, it will only affect IPW and not load. IMHO, I think its better to first tweak the VE tables so that SD load matches MAF load, and then if needed, tweak the MAF IPW scaling tables.

Slo_crx1

iTrader: (9)

So how exactly does the MAF smoothing table effect the IPW? I understand how the MAF compensation table works, but what exactly is the other one smoothing? I tried scaling the smoothing table once to see if it would run smoother with better trims, and the trims seemed to stay in check within the +/-5% range, but it also seemed to effect the stutter i.e. make it more prominent the more I changed the MAF curve.

mrfred

iTrader: (50)

I've been thinking for a while about how to make sense of these tables. The code says that both tables do a lookup vs MAF Hz, and the lookups are both scaling factors for the IPW calculation, i.e.,

IPW = MAFComp*MAFsmoothing*other_stuff

So, both tables will have the same effect on IPW. Why two tables? I think the MAF compensation table sets the ideal relationship between MAF Hz and airflow while the "MAF smoothing" table is meant to be trim adjustment, and is not a smoothing table at all.

scheides

iTrader: (10)

Very intriguing. I agree mrfred, if your calculation is right it would have to be sort of a trim and not 'smoothing' at all. It would be nice to get this figured out fully, I'd think both the MAF and SD guys could benefit.

So I loaded up alky/alt-map stuff last night and tested it this morning. Fuel is spot on, high 11's just perfect. Timing however, is pretty far off, 4-5°. Thankfully they were LOW, otherwise I might be crying right now Going to have to adjust the scaling a little to bring it up to where it should be.

I'm taking baby steps, and it is just amazing to me how much power 2° of timing adds on alky, the car just feels like it is waking up! 2-3° left to go. I'm working out what I want to do for a new intake, and still contemplating a new COP ignition setup before I throw it on the dyno for shane@DB Performance to dial it in.


I have a question: let's say I get everything nice and dialed in on my current setup. Then I upgrade turbos. Assuming I keep a similar boost profile, I assume AFRs at WOT will go lean and I will just need to adjust the VE tables for either high rpm, high load, or both? BBK XL wut? :P

mrfred

iTrader: (50)

The part of the code where this calculation is performed is very unambiguous. Its just a straight calculation with no conditionals on the terms that go into the calculation, so my formula above is definitely correct. If you like, you can prove it for yourself. You can first try 1.1*(MAF scaling + MAF scaling offset) in ECUFlash [both MAF scaling and MAF scaling offset need to be multiplied by 1.1], get an open loop AFR log, put those values back to stock, and then try 1.1*("MAF smoothing"). Both will make AFRs go 10% richer.

The turbo upgrade scenario is interesting. The XL should be more efficient than the standard BBK, so it would make sense to first try tweaking the MAP VE values to bring AFR back into line.