SkullV

iTrader: (11)

Hey everyone. I had my CTS-V tuned a while ago and the tuner did a great job as far as I can tell. Picked up a bunch of power over the previous tune and made the car feel a lot better and pull much harder too.

The weird part is that I just got HPtuners and I was looking over the VE table on my tune and the VE table of a stock 2005 CTS-V and they are exactly the same, but the MAF calibration is different on mine.

I don't know much about tuning yet, but the first thing I have read everywhere is that you need to do the MAF calibration and VE table before you touch anything else.

What's the deal here?

TheBlurLS1

iTrader: (8)

99% of hired gun tuners don't touch the VE when doing a "dyno tune", and most of the time they don't even need to. The only thing they will change is the bottom couple columns with big cams and such, then let MAF/LTFT take over.

Most guys on here only have 1 car to tune, so they do tons of loggings/tuning to get their cars perfect, so their idea of and good tune and "a person who just brings it somewhere for a tune" is very different. In order for a shop tuner to dial in the VE, it would take a lot more time than they are willing to spend. You've got to remember they make the same amount if they spend 30 minutes or 8 hours.

WeathermanShawn

iTrader: (1)

Some tuners just work the WOT areas in order to give you the HP/TQ gains that you will readily appreciate.

If you are running a properly calibrated MAF with the stock VE table..well it can be done, but your car may not perform at its maximum capabilities. This will really become more apparent with the addition of a cam and/or heads.

You can really open up a hotly debated discussion with VE/MAF issues. All I can say is that it really does help to have a VE Table that is consistent with the what the MAF airflow is reporting. It is all about getting the correct fueling.

With a wideband and an hour or two, you can easily do it.

Good luck.

..WeathermanShawn..

koolaid_kid

iTrader: (21)

The first time I went to a tuner, all he did was tune the MAF. I no longer use his services.
I guess I am just slow, but it takes me more than an hour or two to tune the VE table. But it is my personal vehicle, so I am more meticulous than if it were not.

SkullV

iTrader: (11)

Yeah, well I'm going back to him to get some tweaks done and I'll ask him about the VE thing, if he doesn't think it needs it, or wont do it I'll still be happy with what I paid for the tune becasue it really does feel MUCH better then the last professional tune, but I'll just learn to do the VE table myself now that I have a wideband and HPtuners. Thanks for the replies!

Matt@SNLPerformance

iTrader: (1)

There should not be too much work needed on your VE table by looking at your mods. You can probably dial it in yourself if you have a wideband.

SkullV

iTrader: (11)

I will probably end up doing that, but now that I know a little more about tuning when I go back to the tuner on July 11 I will make sure he does a FULL tune. His website even says same price whether it takes an hour or the entire day!!

Doc99SS

iTrader: (2)

Learn as much as you can about tuning so that you can talk "tuning" with your tuner. In the end, you will tune your car yourself, and most likely get alot of satisfaction out of it because you are tuning your own car.

SkullV

iTrader: (11)

That is the best advice anyone can give....I do have HPtuners pro and a wideband and I WILL be tuning my car myself even after the professional tune is done whether it be constantly tweaking his tune or creating my own!

Haans249

iTrader: (24)

Matt is right, there won't need to be any changes made to your VE table. If you cammed it then definitely, but since its still on stock cam/heads, just some exhaust work, there would be NO need. Don't **** off your tuner haha, he knows what he is doing so far.

Slowhawk

iTrader: (12)

I wouldn't expect your VE being touched with the mods you have. The fine VE tuning is widely debated. I'm a full time tuner and my personal H/C A4 car runs the stock VE.Has 5k miles and gets raced almost every weekend.Runs perfect.

SS Enforcer

But don't you find with a properly dialed in VE table you get a nice crisp throttle response. ?

Mine is a cammed ls1 running full OL SD tuned with efilive cos5.

If the VE table is the measure of airflow isn't it important to get this tabled nailed ?

cheers

Doc99SS

iTrader: (2)

If the VE table is the measure of airflow isn't it important to get this tabled nailed ?

Yes, for sure if you are SD. However, if you are running a MAF, the MAF table is the table you have to nail. As discussed above, a MAF car can use the stock VE table because the VE table is not the primary fueling table. And again, it all depends on your mods. If you have built a stroker and have a wild cam, tuning the MAF table first, followed by the VE table is a must (plus numerous other un-named tables).

LinearX

iTrader: (4)

If you make airflow mods to the engine, it's important to get both tables nailed. The ONLY way you can skip MAF is if you're running pure SD.

Making airflow mods and then tuning the MAF but leaving VE stock is the wrong thing to do. The GM ECM, being hybrid in nature, references both tables. If left in stock configuration, MAF is only referenced above 4000 rpm so it's imperative that VE below 4000 rpm be dialed in as well. If you only tune MAF and leave VE alone, what happens when the MAF fails? I bet the engine runs like hell.

Slowhawk

iTrader: (12)

On a setup like mine- not at all. I can unplug the MAF and it still runs very good.
Now,as said if you have a stroker motor or huge Cam the results will be different. Pretty much points out that not all cars need a perfectly dialed VE to run right.

foff667

iTrader: (2)

Yup, most of the coding on LS1's is maf based, over 4000 rpms its ONLY maf based so your talking about a minimal amount of area the VE tables even have a slight hand in.

For the most part GM just uses the ve table(s) as a sanity check so that if the maf does fail your car won't stall and leave you stranded but for most tuners to tune both for maf and then ve is like doing two tunes. I'm sure if they were charging you $900 instead of $450 they would tune both if you asked them but doing both takes a large amount of time and many tuners don't have access to a steady state dyno to be able to do so and few want to take your car out onto the road & risk all kinds of liability dialing it in that way.

For years before HP Tuners & the like were even available tuners didn't even have access to the VE tables via their software now it seems everything thinks their tuner should spend several hours dialing in a secondary system that in most cases is not necessary. If you have tuning software, unlimited access to the vehicle & alot of free time on your hand yes its great to toy around with ve tuning but for a shop making a minimal amount for tuning its hard for them to justify an extra 2, 3 or 5 hours tuning a secondary table, ultimately pointless for many.

-Bill

edcmat-l1

iTrader: (10)

I agree. I never VE tune a bolt on car. Only cammed cars and up.

Ryan L

I spent countless hours trying to tune my VE after my cam swap since all of the 'real' tuners said it was 100% necessary. The car kept running worse and worse as I tweaked the VE table, so I opted to disable VE and run 'MAF only' and now it runs as smooth as eggs. Every car is different, but this worked for me.

macca_779

I personally don't bother tuning VE when in the rare instance I tune a MAF car (Everyone goes SD here). But I sure as hell don't leave it stock. To compare a stock VE table to a full SD tuned cars VE table is like day and night in differential. Sure a MAF tuned car doesn't use VE all the time, but it uses it enough to warrant more correct data than the joke of a VE table that is in a stock tune. The benefit of that is improved throttle response almost as good as going 100% SD.

Now like I said, I don't bother tuning VE on MAF cars but hell I'm sure most professional tuners would have done enough SD cars in all combos to get a good idea of what VE should be like in a car. So instead of leaving it stock.. Use one from a previously tuned SD car. It wont be perfectly suited to the car they're currently working on. But it will be a hell of a lot better than using a stock table.

macca_779

You must of been doing it wrong.
Did you filter out large delta throttle inputs?
Did you get over 50 hits in the main cells you wanted to tune?
Did you use a Wideband? And did you disable fuel trims when doing it?
Did you disable the MAF?

Each one of those is mandatory when VE tuning. Miss one and your wasting your time.

VE tuning is not hard. It amazes me most tuners outside of AUS still haven't seen the light of SD tuning. Hell we even had our high end performance models come out from factory MAFLESS SD tuned here.