TypeIsCheap

The SD tuning guide mentions multiplying the stock VE table by 1.15 before starting to tune the VE tables (to protect against a too lean condition). I assume this is so you can tune from the rich to lean direction instead of vice versa.

Forum wisdom indicates that the VE tables need only minor tweaking for bolt ons (intake, headers, exhaust in this case) if at all and several of the "headers only" tunes I've reviewed from the repo confirm this.

I'll be tuning with a wideband and applying the AFR Error % to the VE table, does it make sense to start with a more reasonable VE bump, 5%-10% instead of 15%? Or log with the stock table first?

I'm only a "book learned" tuner at this point, looking for some real world experience here. Thanks!

(Also posted on the HPTuners forum.)

LSX Power Tuning

iTrader: (4)

15% on a bolt on car will be pretty rich.

JakeFusion

iTrader: (7)

You're adding probably 10-12% power to the car. So you need to add similar fueling. However, the stock car most likely is running rich to begin with, so I'd do 10% and see where you are.

TypeIsCheap

Thanks for the feedback, 10% sounds more reasonable, I'll start there.

redtan

iTrader: (5)

You're not going to run that lean with bolt-ons that you're going to hurt anything. The o2 sensors respond very quickly and bring in fueling to where it's needed nearly instantaneously. Just go out there and log your trims and then adjust. I never found it necessary to pre-adjust the VE table for mods even with a cam and heads. I just went on a light drive right afterwards and started from there.

JakeFusion

iTrader: (7)

You know redtan, I increased my fueling across the board for my heads/cam... and when I tuned with the wideband, I ended up taking fueling out everywhere. The 60lbs injectors I have didn't need any more fuel in the VE table. Some places I was taking out like 10-20%. So it may not be needed, but I'd rather be safe, at least on a WOT run.

But if you do part throttle logging, it's mostly at stoich anyway without any PE enrichment, so you can see how close you are pretty fast without any real danger.

redtan

iTrader: (5)

Exactly, I actually also found quite a few spots in the VE table (mainly over 2400rpm) that were running quite a bit rich and was pulling 6-10%. So blindly just adding fuel without scanning first is only going to put you further away from your goal.

JDMC5

iTrader: (3)

if it has boltons......use the stock table. pay attention to the wideband at WOT and make sure it doesn't lean out too much. Also, it wouldn't hurt to pull some timing at WOT initially.

TypeIsCheap

The stock table was very close. Other than a few outliers like the deceleration zone going rich at closed throttle almost everything was -1 or -2% AFR error with a few -3/-4 around 3-4k.

Oddly enough there was an -7% AFR error around the idle zone. Patching this up in the VE table overshot it and made it run lean on the next log so I just put it back to the stock VE for now. Still planning on more logging when time permits.

Thanks all for the great discussion.

JDMC5

iTrader: (3)

do you plan on running a SD tune?

Idle has a tendency to do that. When I scan I always make sure I drive the car around for a minute before I log to let temps stabilize, then when you return to the driveway collect data for idle.

TypeIsCheap

No, I'm planning on enabling and tuning the MAF as well. When I logged with my NBs a while back I saw LTFTs in the +8ish range so I'm guessing that's from the MAF transfer function being a bit off due to the modified intake tract.

Good info on the idle, searched around a bit for that today too and that was the consensus, heat soaked IATs can skew the data. I will definitely remember that the next time I log.

LSX Power Tuning

iTrader: (4)

Another thing to use to help out smooth out the data is filters. Make it where you have to hit a cell count of 25-50 or whatever you would like to help smooth out the bad data you're getting in quick throttle movements or transitions.

TypeIsCheap

Oh yeah, I've been playing with filters and cell counts quite a bit with the data I have. This is where experience comes into play I assume. I'm getting more familiar with the tool and interfaces and trying to connect what I see to the theory/physics at some level, quite interesting stuff really.

Slowhawk

iTrader: (12)

Well, to me a VE tune requires both the maf and 02's to be shut off. Dial in the VE and then turn on the 02's. I wouldn't add anything on the base VE to start.

TypeIsCheap

That's my understanding as well, and both the MAF and fuel trims are disabled while I'm working on getting the VE table calibrated.

JakeFusion

iTrader: (7)

The more things you turn off and the more tables you set to an EQ of 1, the better your VE tune will go. Ask me how I know.

01ssreda4

iTrader: (96)

That's how I do it as well.