Does your AFR go rich during spool-up?

Some people have reported that their car runs rich when it's spooling up. Mostly it's people with FMICs that complain about this, but TMICs are not immune to it - it's just not as bad. If it dips rich enough, it costs you power. It cannot be tuned out with MAF scaling or with the fuel table, so it's kind of annoying.

 

I have found some previously-undocumented parameters and tables in the ECU that are contributing to the rich dip. With my car, the rich dip is now reduced by about half - it dips from 11.2 down to about 10.5, instead of down into the high 9s. Basically there are tables that add fuel when load is increasing rapidly, and subtract fuel (but not as much) when load is decreasing.

 

It seems pretty promising. So, if you do your own tuning, I have some new tables to play with. If you're willing to be a guinea pig, that would be great, because I would like to know more about how much of an issue this is with other peoples' cars. So far I've only been testing with my own car.

 

All I ask is that you post up two datalogs that include these parameters:

 

* Engine Load (2-byte)

* Throttle

* RPM

* Boost (there are a few parameters for this, just choose one - I'm not picky)

* Wideband AFR (the factory sensor won't suffice)

* Primary Open Loop Enrichment

* Final Fueling Base

 

(Add more parameters if you want - those are just the ones that I'm interested in for this little project.)

 

Log one pull from 2500 RPM to redline, and log one from 4500 to redline. Stomp on the throttle, don't ease into it. Preferably in third gear.

 

If your car behaves like my car - and I think they all do, but I am looking for evidence - you'll see the Primary Open Loop parameter tracking your fuel table, and you'll see the Final Fueling Base parameter dipping about a half-point richer, and you'll see AFR following the Final Fueling Base.

 

If your are running the A2WC522N ROM (05 LGT), I can post up the tables soon. If not, post up those logs anyway, and let me know which ROM you do have. I can find the tables in other ROMs too, it'll just take a bit longer.

 

Why am I not just posting up the tables? Because I want more data - I want to see how significant the rich dip is, from a couple of different setups - TMIC, FMIC, stock turbo, big turbo, etc. Then I want to see how much of it can be tuned out with the new tables. If you'll post up some 'before' pulls, and promise to post some 'after' pulls, I'll help you tweak these tables so we can both see the difference.

 

Thanks!

I can post up some logs later this week. Just need to take some new logs for the open loop enrichment and final fueling base. One thing I have noticed from logging multiple cars is that if you have too soft of a BPV/BOV spring, it will crack open, contributing to a rich dip. I run a super stiff spring in my Forge BPV and the rich dip is not nearly as bad.

I am assuming a stock BPV is considered soft?

 

The reason I ask is : I am getting ready to head to Cobb/Plano for a tune at the end of August, and am contemplating an aftermarket BPV. I have read that they are not helpful and I have also read that they are needed.

 

I will be tuning a BNR 16G on 93 and E85. I am assuming the E85 tune will see @ 20lbs of boost. Do you think an aftermarket BPV is needed, helpful ?

 

Input appreciated

My stock BPV cracked open at around 18-19 PSI. On E85 you could push the 16G to 22-23 PSI peak if you want. I really like the Forge BPV. Doesn't crack open early with a proper spring, sounds great, and is a nice quality piece. My car has better throttle response than most other cars I've driven, even ones with smaller turbos. YMMV of course

I can post up some logs later this week. Just need to take some new logs for the open loop enrichment and final fueling base. One thing I have noticed from logging multiple cars is that if you have too soft of a BPV/BOV spring, it will crack open, contributing to a rich dip. I run a super stiff spring in my Forge BPV and the rich dip is not nearly as bad.

 

I forgot - Do you have a TMIC or a FMIC? I'm happy either way, just curious.

 

Also, what's your ROM ID?

 

If a BPV opens, it would cost you some boost, but since it recirculates I wouldn't expect it to cause any richness. That sounds more like a plain old leak, maybe around the mounting flange, maybe through the BPV itself.

Perrin TMIC currently.

522N Rom ID since I'm running the fuel pump patch. Thanks for that

If it's recirculating, less air is still flowing into the engine than it expects at that point in time, right? Then it gets recompressed and "recycled" if you will.

The air that recirculates will re-enter the intake stream after the MAF sensor, so it's a closed system between the MAF sensor and the intake manifold. The flow past the MAF sensor will equal the flow into the motor.

 

I'm glad to hear about the TMIC. All I have so far are logs from my FMIC'd setup so I'm really curious how much difference that makes.

Not a log, but here's a dyno pull. Cobb stage 1 93 Oct. stock TMIC. As you can see my A\F's are in between the high 9's to mid 10's.

 

Mike

 

http://i99.photobucket.com/albums/l293/HAMMERDOWNGT/Subaru/2007-11-07-1643-52.jpg

Not a log, but here's a dyno pull. Cobb stage 1 93 Oct. stock TMIC. As you can see my A\F's are in between the high 9's to mid 10's.

 

If you get those up into the mid 10s - low 11s I bet it would give you more power. My car used to dip into the high 9s just as it was reaching peak boost, and you could feel it losing power and then getting more power as the AFR got back into the 10s.

 

My fuel table never gets richer than 11:1, and part of the reason for my car's dip into the high 9s was the ECU feature that adds fuel when load is increasing. After tuning that out I still have a rich dip but it only goes to the mid-10s now.

Ok, I do have ATR & taking my LGT to stage 2. This weekend, GS cross-pipe. GS Up- pipe, Invidia high flow Cat Down pipe & Invidia V2 CBE. Next week my Racer X FMIC will be here.

 

The original motor, turbo & stock air intake with K&N panel filter. Over 173.5k, compression check is good, 1) 145psi 2)145psi 3)150psi 4) 147psi. Do you think Cobb's Stage 2 93 Oct. will work good enough as a base map after up-grading the exhaust. As I wait for my FMIC, before the tune needs to be tweaked?

 

Mike

Very interesting, NSFW. Just stumbled across this thread. I've got some comp days coming up in a few weeks and I'll hook up my WB02 and get some fresh logs.

Do you think Cobb's Stage 2 93 Oct. will work good enough as a base map after up-grading the exhaust. As I wait for my FMIC, before the tune needs to be tweaked?

 

It'll probably work fine. You should do some logs just to be sure, but start another thread for that.

Thanks, no problem

 

Mike

Im having a similar problem but not as bad. I cant get mine to lean out Me and Clark Turner have been trying to figure this out for 2 weeks now.

 

Im on stage 1 93oct with an aem cai

Post up a log that includes the parameters listed in the first post in this thread. If you're talking about the same thing I'm talking about, I will get you some new table definitions that should help.

 

No hurry though, it will probably be at least a couple weeks before I have time to dig up the new tables.

Subscribed.

Im having a similar problem but not as bad. I cant get mine to lean out Me and Clark Turner have been trying to figure this out for 2 weeks now.

 

Im on stage 1 93oct with an aem cai

 

 

Hey,

 

Clark Turner will be out here for a dyno and tune day with Dave Brown on Oct 1st if your interested. (Would be about 2.5 hour drive for you) It's easier to work out those issues on the dyno rather than an etune. I didn't know you got another Subaru. Congrats!

So your just talking about acceleration enrichment.

 

It's mostly because the lag from maf. To what's actualy going in.

When you have fmic there are huge dynamic differences where the intake tract is bigger and it will change in density. So yea acceleration enrichments is where you gotta play.

It's about 50/50 MAF lag and ECU enrichment. Previously I was dipping from about 11:1 to just below 10:1, and with this enrichment turned off I dip to about 10.5 or so.

Hey,

 

Clark Turner will be out here for a dyno and tune day with Dave Brown on Oct 1st if your interested. (Would be about 2.5 hour drive for you) It's easier to work out those issues on the dyno rather than an etune. I didn't know you got another Subaru. Congrats!

 

 

Thanks. Yeh I finally got my finances back in order and got a nice deal on a 2011 WRX that I couldnt pass up...

Post up a log that includes the parameters listed in the first post in this thread. If you're talking about the same thing I'm talking about, I will get you some new table definitions that should help.

 

No hurry though, it will probably be at least a couple weeks before I have time to dig up the new tables.

 

Heres a log I took yesterday of my COBB STG1 + AEM HWG 93 octane map. What are your thoughts? I dont have a WB02.

COBB_STG1+AEM_HWG_93oct_Pull.csv

NSFW very interesting! I'm switched over to Cobb, and see lots of fun fuel enrichment tables I don't remember seeing in RomRaider. An entire section IIRC of a sort of tip-in that is load-referenced, not throttle-referenced. I coppied all my RR tables to Cobb, and that entire defined Cobb section was unmatched in the RR definitions. But sounds like you found them

 

I look forward to supporting this effort in a few weeks when I have my FMIC on.

 

*Yes, I'm doing Cobb for my 3 goodie reasons: 1) live tuning, 2) Switching maps without laptop (E85 blends, 93, 87, idiotic vallets going WOT in parking lots here in Dallas, etc.), 3) Tuning 5EAT timing pull while shifting, and other fun tables RR doesn't have in the big release download.

SO PLEASE DON'T MAKE FUN OF ME FOR SUPPORTING THE MAN. I BOUGHT IT USED AND I WILL SELL IT USED LATER FOR THE SAME $$$.

 

 

 

In for a solution that doesn't require me to buy a WBO2...

 

With your mods its impressive you haven't already.

Heres a log I took yesterday of my COBB STG1 + AEM HWG 93 octane map. What are your thoughts? I dont have a WB02.

 

The stock O2 sensor will only read down to 11.2, so without a wideband it's almost impossible to measure this. You could move the sensor to the downpipe, and retune to run 12.5:1 and then you'd know if you were dipping rich by 1.3 or so, but that's more trouble than just getting a WBO2 installed.

 

Plus you need to log Final Fueling Base and Primary Open Loop Enrichment in order for me to know how much richer (if at all) your AFR is, compare to what the tune calls for.