Hi Flow Cats Fitted - NOW Super Lean To Super Rich Instantly?

[BigDaddyCool]

I should post a log as always........ but im on a diff computer.

I had logged my wideband today, if you went WOT it would shoot lean like 20-30% as you get being an instant PE change and not getting there yet, but it settled instantly to like -1%ish area....

Since I got the high flows it now shoots lean and then runs almost half that value rich......... the wideband is also now kinda woobly ........ where do I start.

Do i first need to add timing now I have cut cats from 400 cell to 200? I dont have a dyno dynamics handy to check torque related info.

Is the rule of thumb to add or remove timing when improving airflow here on this mod?

[MikeOD]

Where is your wideband? Before or after the cat?

What is your PE ramp in rate?

[BigDaddyCool]

On the scan jump to about 4:31.... on the scan.

I'm gunna slow down the PE change so I can get a grasp on what's really going on..... Wideband I'm going to double check....... because I think the exhaust guy has moved it given it's yoyo readings. I had it in the header itself just before the cat joined.

I had two high flows fitted and they have o2 ports in the front of them (as well as the header ports etc) and I think he's thrown the wideband closer to the cat now, I'll have to double check he wasn't stupid and did that.

So I have all the gear right. I had my car professionally mafless tuned which sucked so i went back to mafless and fixed some of the timing, I'm still unsure on that tune tho with his original tune (which I use as a ref). His tune has like 14 degree's of timing at WOT (4400rpm area 80g) for an aspirated V8 seems ridiculously low. I run like 23 (4400rpm 80g) .......

[Bill Hooper]

Hi,

Were you able to determine why your wideband was all over the place, specifically at idle and cruise, after you added your high flow cats? If so, what was the corrective action you took in your tune to fix it?

- Bill

On the scan jump to about 4:31.... on the scan.

I'm gunna slow down the PE change so I can get a grasp on what's really going on..... Wideband I'm going to double check....... because I think the exhaust guy has moved it given it's yoyo readings. I had it in the header itself just before the cat joined.

I had two high flows fitted and they have o2 ports in the front of them (as well as the header ports etc) and I think he's thrown the wideband closer to the cat now, I'll have to double check he wasn't stupid and did that.

So I have all the gear right. I had my car professionally mafless tuned which sucked so i went back to mafless and fixed some of the timing, I'm still unsure on that tune tho with his original tune (which I use as a ref). His tune has like 14 degree's of timing at WOT (4400rpm area 80g) for an aspirated V8 seems ridiculously low. I run like 23 (4400rpm 80g) .......

[BigDaddyCool]

Hi,

Were you able to determine why your wideband was all over the place, specifically at idle and cruise, after you added your high flow cats? If so, what was the corrective action you took in your tune to fix it?

- Bill

Not fully yet but so far from what I can tell....... as mentioned in another thread even when using MAF Only it still runs some basis off VE etc...... So I've unhooked the MAF to retouch the VE, and the VE is alot smoother now so shortly when I go back to retouch the maf it should be alot more stable.

That said, I had noticed that running VE MAFLESS or MAF ONLY the idle is jumpy since getting it done........... so my plan ultimately now I think is I need to look at two main things, one being transient ........ primarily I think Im overshooting on it now.......... and second........ Idle Airflow Min.

By fixing the idle airflow min (which you usually dont touch unless necessary as it virtually never works or rather works 'better') to fix what I beleive is a massive idle adapt timing issue.

I think the high flows are driving the adaptive idle nuts...... So I think I need to look at that, first I need to workout on the VE and MAF where stable really is mostly.

I have a great setup for all this, I run openloop but use the 4 stock sensors to read STFT for VE to compare against my wideband AFR as I have all 5 sensors in the exhaust with the wideband on the header in the right spot so it works great now for tuning adjustments.

I hope you follow with all my jargon there. --- Since i got them fitted, I've mostly focused on WOT for the VE table and made smaller adjustments to the VE table in driving area's. Thats almost done, so I'll go back then, do a quick adjustment for the MAF then learn how to adjust the idle airflow and give that a crack.

There is another thread on here for that, the idea is to stop the car having to fight so hard to bring idle inline by using its adaptive timing etc.

PS. That scan above with the point I said went from real lean to real rich take notice of the VE and Dynamic Airflows, because that was MAF ONLY. So it shoots rich and guess what my VE is rich in that same spot MAFLESS.

I have long thought on these cars you cant disable VE, not really..... And honestly I think unless you zero out dynamic, and all the ve tables the car will still run off either somewhat.

[ingsteve]

Have you tried to calibrate again your wideband?

[BigDaddyCool]

Have you tried to calibrate again your wideband?

At the moment I'm correcting my professional tuners "so-called- what i command im getting VE table........... so that 'what I actually command I actually get' in terms of PE.

The professional tune I had done commanded 12.5 AFR @ WOT, it actually was more like 13.1 which tapered down to 12.7-12.5.

So im fixing that first so that my maf will match the ve. ..... and what I command = what I get...... its easier then trying to bodge histograms to match my professional tuners tactics.

I am doing this all by wideband yes