TRex

iTrader: (3)

I've started trying to tune my VE table using the methods generally posted, man am I having a hard time filling the high rpm, high load cells on public roads. Filtering is set to hide any cells that don't have 30 hits in them

Car is geared with 4.30's, so that does not make it easy to load the engine for any length of time above 3000 rpm. I haven't tried it but I am guessing it wouldn't be much better even if I was going 130 mph

Anyone have any hints they want to share ? What's the going rate for dyno time without the tuning work ?

horist

4.30 gear? so Im guessing you're a 6 speed?

If so... just use higher gears from a stop... 3rd gear or 4th gear start will hit lots of load cells

tricky part is... when you start to hit the higher RPMs PE is going to activate (since it'll take > x% throttle to reach that) and at that point you can throw those cells out because they're useless then (PE is open loop)

If you have a wideband, then use the AFR % correction histogram (not sure what EFI Live calls it, but they have a built in histogram for it)

If you don't have a wideband then you have to be careful because if you disable PE mode then you're going to be commanding 14.7:1 AFR at high load areas which is bad...

TRex

iTrader: (3)

I have a wideband, and I scaled the VE table so that I would be rich during the tuning, and set PE ratio to 1.0 so it does not affect AFR.

I tried the starting in 3rd or 4th, but she still doesn't stay at the rpms very long once I'm above 3000 rpm. Top speed in 4th is only about 115, and she's still pulling pretty hard even at that speed. I've been trying to do it staying below 75, which is damn near impossible. I just don't seem to be able to stay at the rpm cell with the throttle not moving and the engine loaded above 40 KPA long enough to get 30 counts ?? I must be doing something wrong.

I guess I just need to do lots of high rpm blast - I'm getting cell counts of 4. 5. 7, etc. at the high load, high rpm cells. This is with maybe 4 or 5 high rpm blast. Probably getting like one count per run

Hope I don't lose my license doing this

Billiumss

iTrader: (11)

Here a trick that I use for M6 cars:

- Set cell count to 4
- Use 1st and 2nd gear
- As you give it gas, use your brakes to make it harder to go faster, you will hit more load cells

It's a little hard on your brakes but it works!

MeentSS02

iTrader: (11)

...or find a chassis dyno. As for the PE thing, if you have a wideband, you might as well tune in open loop. Leave PE enabled, and set the OLFA table to 1.0 across the board. When you get to areas where your PE enables, it will automatically kick in and keep your engine from blowing. Plus it will give you a more realistic picture of what is going on if you go back to closed loop operation, since there is some sort of back calculating done with the different commanded AFRs.

SSpdDmon

iTrader: (10)

Sounds like you're flooring it once and calling it quits.?.? You need to make about 10-20 WOT runs to get some good data for the upper-RPM cells. That way you can get a decent average to work from. As mentioned before, a little pressure on the brakes will help keep the car in those cells longer. My advice would be to take some time (and a radar detector) up to MI. We have 70mph highways up here. Find a 'good' spot between a couple exits and make a few laps. I would guess somewhere near the border might be best due to potential jurisdiction complications. Just make sure you're on your way out of the state. Then again, even John Force can't get points on a dyno.

12secSS

iTrader: (30)

I use a pretty similar technique, but I do not use the brakes. I look for a canyon type enviroment with hills and so forth. You can stay in the 1st or 2nd gears much easier, plus the incline grade will add loads to the table. You also do no want to floor it or aggressively accelerate through the rpm band, you want nice and easy transitions. Also, I would recommend you tune the VE table exactly as you drive it on any given day, then the tune will be more precise to your driving requirements. One finaly thought, you can delay PE mode to come on after any RPM you would like.

Ragtop 99

iTrader: (7)

I'm trying to understand the theory for those w/o a wideband. If I disable PE when tuning my mid to high MAP cells, won't reenabling it make the car too rich?

Also I'm still waiting on HPT to arrive, but I thought I saw in Edit that PE was enabled based upon MAP and rpm. Is that incorrect?

MeentSS02

iTrader: (11)

MAP, RPM, TPS, and it blends in at a specified rate.

RedHardSupra

iTrader: (1)

do NOT set PE to 1.0!!!! especially when you're tuning higher rpms.
think about it: do you really want your mixture to be at 14.62 at 6000rpm and higher (even if not WOT) load?
yes, it's very annoying trying not to trigger the PE mode, i delay it, but i never turn it off completely, think of it as your insurance.
just be very gentle with the throttle, long slow steady inputs, and a lot of trial and error and repetition. it takes a while to get it down right, but it's totally worth it.

TRex

iTrader: (3)

That's the conclusion I am coming to ! I'm thinking I might go up to Wisconson, also might try Jennibella's suggestion and locate an incline, although that is somewhat hard to do in the midwest

I've got most of the typical daily drive cells filled in, but I wanted to tune the VE closer on the high load cells before I start tuning the PE, since really all the PE is doing is changing the target AFR.

As far as your question Ragtop 99, although I am new to this, I think I have a pretty good grasp on the theory and mechanics, which goes something like this:

You adjust the VE so that the VE in the table matches the actual engine VE - thereby allowing the computer to accurately predict airflow based on MAP and RPM. Then, the PE ratio is adjusted so that the target AFR is achieved. To my understanding, if you are running MAFless (which apparently adds another factor) or if your MAF is calibrated correctly, and your VE's are very close to accurate, then your PE table will be very close to 1.13. PE's drastically different than PE suggest a VE table or a MAF that is way off.

My understanding is that PE is enabled based on MAP, RPM, and temperature. We disable it by changing the enable temp, and also set it to 1.0 so it has no effect on the commanded AFR. However, to keep the engine safe during the VE tuning procedure, before we start we adjust the OLFA table or the VE (depending on your software version) in the rich direction, measure the error from target, and then adjust by the error amount.

Maybe if I have this wrong one of the experts will jump in here and correct me.

MeentSS02

iTrader: (11)

I take it that the people disabling or hampering PE mode are tuning closed loop off of the trims?

TRex

iTrader: (3)

Should be ok as long as your OLFA is at something like 13.0 right ?

MeentSS02

iTrader: (11)

Are you tuning with a wideband?

TRex

iTrader: (3)

Yep

TRex

iTrader: (3)

Yep

MeentSS02

iTrader: (11)

Okay...just making sure you weren't causing yourself any unnecessary grief. Damn I'm glad I got my wideband...

MeentSS02

iTrader: (11)

Wait a second...which one is it? You are tuning in closed loop WITH a wideband?

TRex

iTrader: (3)

No, I am tuning in open loop with a wideband.

BTW, for those that do not have a wideband, I just looked at my NB voltages - .842 v = 13.0 AFR on the Wideband. 12.6 = .877, 12.5 = .894

Use at your own risk, your results may vary !

I might make a chart for giggles later.

MeentSS02

iTrader: (11)

Okay...try this method:

1. Set the OLFA table to 1.0 across the entire board.
2. Set PE to whatever you want to shoot for as your final AFR across the entire RPM range. Make sure the PE entry values are what you want as well (I have mine kick in around 35% TPS or so).
3. Set PE enrichment rate to 4.00 (so it comes on instantly).
4. Put your car into open loop, and make sure the MAF is disabled. Easy way to disable the MAF: Set the fail freq. to 0, AND 0 out the entire MAF table. It'll send it into SD mode in a hurry, so there will be no guessing whether or not your MAF is having any input on your tune at the time.
5. Do the standard AFR % Error histogram until you get your VE table in line. Smooth it, but make sure you are only smoothing the cells that are being hit regularly. You don't want your data skewed by some of the outlying VE table values.

If you don't want to use the MAF, just re-enable closed loop operation.

If you want to use the MAF, leave it in open loop, but re-enable the MAF by resetting the fail freq. to the factory value, and put in the MAF table of your choice. Then make yourself a nice MAF % error histogram, and do some more runs. This will bring it back in line with the VE table so they aren't conflicting with each other.

Then you can re-enable closed loop and be on your way.

What this does for you:

1. It keeps you from wasting an extraordinary amount of gas by setting your entire OLFA table to 1.0 instead of the really rich 1.13 (well, not really rich, but for cruising, it is overkill).
2. It gives you a more real world tune since PE will be enabling when it normally would be during normal driving conditions.