VE question

[NBMLS2TA]

I have a 98 TA that I swapped an LS2 into, I recently installed milled LS3 heads and and LS3 intake. It has a 226/230 EPS cam and I have normal boltons, LT headers, 85MM MAF, 92MM TB, and 98MM FTP lid. I am just curious if it is normal for my VE table to be up to -24 from stock? I am low to mid 20s lower than stock around the 25 to 50kpa and 800 to 1600 rpm. Is that normal? I know that with a cam the low rpm areas are usually lower than stock but just wondering if it is normal to be that much lower? For instance, the stock tune has 56 at 1200 rpm and 35kpa. My tune is at 33 in that same cell.

Thank you for any input.

[charcoal03silvy]

For first startup of a cam I typically multiple the 400 rpm cell by 0.6, the 800 by 0.8, and 1200 by 0.9 and then do a little smoothing. Did a 4.8 with a 226/229 cam and boltons, the VE in the idle areas are down by 32 in some areas.

[NBMLS2TA]

For first startup of a cam I typically multiple the 400 rpm cell by 0.6, the 800 by 0.8, and 1200 by 0.9 and then do a little smoothing. Did a 4.8 with a 226/229 cam and boltons, the VE in the idle areas are down by 32 in some areas.

Thanks for the reply. I did lower those areas like in all the write ups but I wasnt sure if it was normal to end up that low in the end.
Thanks again!

[MikeOD]

The changes in your VE table should look exactly like the way the engine changes power curves when you cam it...if it has no power down low anymore, the VE will drop a LOT down low too. Midrange and up top where the power comes up is where the VE will go up...similar percentages to change in power.

[JamesLinder]

Post your tune or your VEs in excel spreadsheet so I can take a look at them. Did you change compression ratio, intake manifold, heads, anything else? What is duration at 0.050 lift for intake and exhaust?

[JamesLinder]

I do not support wild ass guessing VE tables; they need to be correct as does your MAF table. Obtain a wide band oxygen sensor, install it and
connect it to your HP tuners software and tuning is then very simple and 100% accurate. you will then see what your actual VEs should be
and you will be surprised at the differences, and will then understand that it simply is not possible to guess at these values, that it is not
possible to tune VEs using PCM fuel trims, and that it is not unusual for a modified vehicle to perform better if left in open loop after properly
tuned because LTFT's do not tell the truth after headers are installed. It is not difficult to install the wide band sensor; it will fit in one of your
rear O2 sensor bungs and you can easily hook it up to HP tuners with two wires from the O2 sensor controller to HP tuners. Logging lambda
error gives you correction factors to apply to VEs and MAF tables for each cell. You will be amazed at the improved throttle response and
acceleration; it is almost hard to believe!

[THE CHAD]

When I tune cam set ups etc on our AUS cars(commodores), on start up I tend to get my instant fuel usage(litres/hr) on dashboard down to 2.4-2.6ltr/hr...when you first attempt to start after cam install you will notice it will be in the region of 4.5-5ltr/hr which is way too much...also be careful not to place too much faith in your AFR meter etc wideband reading at idle with a cam installed due to the excess air produced by the cam, it will always read leaner (I reckon) than the system actually is....Use your scanner to monitor engine vacuum at idle and then identify the part of the 'MAIN VE PRIMARY' table the engine is idling in and start to reduce the numbers by 10% or so at a time, be careful not to go to MAD on the % you take out and test after every 10% reduction but you will see idle fuel use drop to the 2.4-2.6ltr/hr soon enough and the idle will improve by a lot. ps std ls1 tend to use approx. of 1.9ltrs/hr..just mine little bit of input...

[blownbluez06]

I haven't seen anyone mention that when you are working on the VE and have the MAF disabled, don't be working from the primary. You adjust the secondary only, get it nailed down, copy it over to the primary, interpolate and smooth in between.

[THE CHAD]

primary ve or multiplier on mine , I work straight from the original tune and go from there, I personally don't use another tunes info cause every cam/set up is different... With cam mods maf in the bin and smooth after every change I do but every tuner is different and the way they work could be different than mine or anyone else, what works for me not necessary works for you....The only time I will use a MAF is when I tune the later 6ltr engines etc, IM SURE THERE IS A DIFFERENT VE SET UP ON US CARS THAN AUST CARS CORRECT ME IF IM WRONG GUYS OR DEPENDS ON OS

[Monaro 383]

The secondary VE was only used in VT II LS1's in Australia after that you only had the Primary VE unless you convert to 1 bar map SD, but in either case they should be almost identical because when using a Maf there both a way for the PCM to detect Maf failure and calculate fueling, tailpipe widebands are useless on bigcam's but a O2 bung just before the cat at least 150mm past the collector so you don't pick up individual pulses is the most accurate unitl you go an old school CO2 gauge,
I always disable LTFT's on big cams even just stock engines with a Mafless tune as they slowly richen up over time unless your VE is set rich as for STFT's not good for idle but for light throttle they work well as once the engine goes back into C/L they control fueling so there handy if you have you rich/lean voltages set correct.

[THE CHAD]

monaro 383 , I don't rely at all on the tail pipe sniffer only when running on dyno and by then I have logged enough info before hand ie using my own portable wideband (near cats)... Exactly that's the way when I tune big cam's etc I disable LTFT'S also cause if the VE map aint quite spot on those LTFT'S fuel trims can carry over into the PE (W.O.T) fueling strategy.....Also guys the fuel trims in the PCM are there also to compensate for minor differences in the factory calibrations and also engine wear, they are not designed to be a BAND-AID TUNING TOOL that allows the tuner to forget about getting your VE tables/map right....I personally get good fuel economy and drivability spot on with my FUEL TRIMS TO BE LESS THAN 2% EVERYWHERE I think that is crucial in tuning these....if the engine has to compensate too much for INACCURATE TUNING it will all the time overcompensate and use excess fuel to keep the engine SAFE......also a little known fact these fuel trims are carried over into WOT as the designers of the system decided that if the engine thought it had not the correct fueling via THE TRIMS it should carry these over and into the WOT fueling strategy to safeguard the engine.....this has been one of the things that has sparked the myth that the engine needs to learn and adapt to the mods that have been done , basically the PCM sees a error has happened and tries to correct it , and remember IN A MODIFIED LSX ENGINE TUNED PROPERELY AND CORRECTLY THIS DOES NOT HAPPEN.....JUST MY OPINION FELLAS