Tuning; where to start?

[CFreed11]

I was going to take my car to a shop to have it tuned, but have since decided that I want to tune it myself. I want to be able to do literally all of the work on my car myself, and tuning is the last for me to learn. I've read through some of the stickies here and read TurboV6Camaro's website, and understand most of the things to go through, but I have no idea where to start.

Currently I've gone with a larger cam and bumped up the compression to around 10.5:1, but am still on the "custom tune" that came with the car. Next spring I will be dropping in a new engine that has been completely gone through and rebuilt as a street/strip motor and want to be ready to tune it when it's ready.

I'm assuming I start with getting the injectors calibrated properly, but then what? Timing or fuel? I know how to do almost any mechanical work, but electronics (specifically pcm's/tuning) is my weak area.

Thanks

[Docta]

Re: Tuning; where to start?

I'm right in the same boat with ya... I'm mostly flying by the seat of my pants, trying things out. Little changes here and there. I've had the most luck with timing, and small additions to air flow rates, since the cam needs more air. More air means more fuel. Seems like a cyclical thing to me, add one, if the car likes it, add the other 2.

[ssms5411]

Re: Tuning; where to start?

Aslong as you tune with a wideband O2 you should be good.

[Hib Halverson]

Re: Tuning; where to start?

First...I trust you have tuning software such as HPTuners?

Next...you mentioned tuning for injectors. Do the injectors you're using have a higher flow rate than stock? If so, the first tuning operation you need to do is recalibrate for those "larger" injectors.

After that, you need to recalibrate the main VE table for your aftermarket cam and the higher compression.

Once you've got that done, then you can do the WOT fuel and spark.

You can order a great DVD from Summit Racing which trains viewers on the basics of calibration using HPT. The DVD is produced by Greg Banish's "Calibrated Success".

[CFreed11]

Re: Tuning; where to start?

Yep, HPTuners is what I'm using. I don't have bigger injectors installed yet, that will come along with the new motor in the spring time. The setup in the car right now is basically going to be my test bed to learn on.

When getting into the VE/PE tables, TurboV6Camaro's guide says VE is only a fail safe in-case of MAF failure and that when adjusting the PE tables, ~12.5:1 is an acceptable number for heads/cam...is this correct then? His guide doesn't mention anything about an increase in compression though, so should I aim more rich than that?

I'll see about that DVD or a tuning book, we sell all that stuff where I work.

[ssms5411]

Re: Tuning; where to start?

12.5 is pretty safe for heads and cam, thats what I've been running for years.

[Gutless]

Re: Tuning; where to start?

Dont waste your time on VE table. Doesnt do anything.

Calibrate the MAF, and do what the turbov6camaro site says and add fuel with the adder if lean.

[LETZRIDE]

Re: Tuning; where to start?

VE tables are still referenced even when using the MAF. Just they are not used as much as the MAF tables and are used I believe more so in tip in throttle circumstances if memory serves me correctly.

Irrc, you also need to tune them seperate from each other. i.e, you must unplug your and fail your maf in order to accuratly tune ve as the numbers you get with the MAF plugged inare different from those numbers you get with it unplugged.

[Hib Halverson]

Re: Tuning; where to start?

Dont waste your time on VE table. Doesnt do anything.
(snip)

If the goal is proper calibration for good performance and drivability.
The above is poor advice.

(snip)

When getting into the VE/PE tables, TurboV6Camaro's guide says VE is only a fail safe in-case of MAF failure and that when adjusting the PE tables, ~12.5:1 is an acceptable number for heads/cam...is this correct then? His guide doesn't mention anything about an increase in compression though, so should I aim more rich than that?

(snip)

If "TurboV6Camaro's guide" says that VE is only a fail tafe, whomever wrote that misunderstands how the engine controls work.

The engine controls "decide" whether to use the MAF for airflow measurement or to derive the airflow from the VE table depending on what's going on with the engine at the time.

In the case of heads/cam/higher compression, because those mods fundamentally change the engine's volumetric efficiency, especially at high rpm, you have to get the VE table right, first, then move on to other issues. Most calibrators agree that to get the VE table "perfect" you need a load-bearing chassis dyno. That said, if you understand the tuning process and you're good at "test driving", you can do a reasonably good job of setting the VE table on the track.

Calibrated Success' beginner DVD recommends the chassis dyno and states it can't be done on the track.

The Tuning School's home-study course explains a way to do the VE table on the track.

I used a mix of both methods and got my VE table very close. from 1600 rpm to 6400 rpm, my lambda error was seldom more than .03. My engine has cam, headwork with larger valves and Extrude Honed intake but stock compression.

As for PE, 12.5:1 is a good starting point for air:fuel when the engine is in PE regardless of whether the engine is stock or modified, but I think it's better to tune for lambda rather than AFR. One benefit of that is you don't have to screw with different AFRs for different fuels (ie: gasoline vs E10). My engine is tuned for .85-.86 lambda when in PE with straight gasoline that's about 12.5, on E10 that's about 12.1.

Lastly, just a reminder...you need wideband to do the tuning you're talking about.

[CFreed11]

Re: Tuning; where to start?

I have a wideband o2 hooked up. I also have fuel and oil pressure gauges mounted but not connected yet. And the reason for using TurboV6Camaro's guide was because it was the closest thing to a walkthrough specific to the 3800.

[Gutless]

Re: Tuning; where to start?

I drive my fireturd year round in MN/ND winters and beat on it more than enough and its fine. Stock VE table with a MAF table I took from somebody elses tune of the HPT database. Changed a little bit on the cruise to lean it up from what he had. And really, if your boost (your not, but I am) the VE table stops at 140KPA. There is no 2 BAR upgrade to upgrade your ECM to be able to 'read' the boost. I run a 2 BAR map just so I can track the boost. My map reads 50KPA at ATM and 80 some under boost since I cant scale it. So really my VE table is WAAAAYYY off, yet my AFR is pretty good.

I spent hours modifying the VE table trying to get close and it didnt do anything. If the AFR is good, who cares about the VE. If your running speed density, sure mess with the VE. The ECM has built in auto tuning capabilites. Cars ran with carbs for decades at wrong AFR's. The ecm will find where it wants to be.

Look at the 600-800HP LS stuff with nothing more than head studs (maybe), valvesprings, LS9 cam, some cheapo ebay/Borg s400 turbo and running 9's. Think every one of those is spot on tune? No.

Yeah, theres a 100% right way to do it, but if it runs, doesnt blow up, and runs strong, its good.

My methods may not be the accepted way, but my AFR stays from 11.4-11.8 under boost all across the 3000-6200RPM range with about 10 minutes of work.

Not saying dont touch VE, but mess with other stuff first, and if you want to spend the time, calibrate the VE.

[Hib Halverson]

Re: Tuning; where to start?

If your engine is supercharged, you're working with a stock controller and OS., you're only concerned with wide-open throttle air:fuel ratio and you want to get the car onto the drag strip as soon as possible. then, some of the suggestions "Gutless" makes, might be useful.

[Hib Halverson]

Re: Tuning; where to start?

I was going back and reading previous posts in this thread...

Dont waste your time on VE table. Doesnt do anything.

Calibrate the MAF, and do what the turbov6camaro site says and add fuel with the adder if lean.

Ok.
For the sake of discussion, let's say optimizing the VE table is a waste of time.

Also, for the sake of discussion, let's say that you do not have a flow bench and you have to calibrate the MAF on the engine.

Even though we assume the VE table is a waste of time, since the engine controls do use the VE table to derive fuel delivery in some situations, the question becomes: how do you force the system to ignore the VE table and use the MAF all the time, because, lacking a flow bench, to properly calibrate the MAF table, you, first, have to temporarily force MAF only operation so you can get data as to the extent of the MAF error

I'm curious about how you do that using HPTuners and the stock operating system?

[bigbrian442]

Re: Tuning; where to start?

I was going back and reading previous posts in this thread...



Ok.
For the sake of discussion, let's say optimizing the VE table is a waste of time.

Also, for the sake of discussion, let's say that you do not have a flow bench and you have to calibrate the MAF on the engine.

Even though we assume the VE table is a waste of time, since the engine controls do use the VE table to derive fuel delivery in some situations, the question becomes: how do you force the system to ignore the VE table and use the MAF all the time, because, lacking a flow bench, to properly calibrate the MAF table, you, first, have to temporarily force MAF only operation so you can get data as to the extent of the MAF error

I'm curious about how you do that using HPTuners and the stock operating system?

Look at Russ K's V6 MAF tuning thread over on the HPT board. Lots of answers there on this.

[Hib Halverson]

Re: Tuning; where to start?

Look at Russ K's V6 MAF tuning thread over on the HPT board. Lots of answers there on this.

Actually, I've read that and feel it's not the right way to get the data.

It's easier just to set the open loop threshold to 284°, zero the entire Open Loop Adder table and zero the PE adder. That keeps it from going closed loop and, once the ECT normalizes, holds AFR at 13:1 until PE then holds the base PE AFR.

Then all you do is set up VCM Scanner to read Commanded Lambda and Lambda Error then set-up a histogram for MAF vs Lambda error.

All that disconnecting oxygen sensors and so forth is not necessary.

My engine is not boosted and uses a stock TB and MAF. Interestingly, with the exception of the very low end of the MAF table where the engine is idling and fast idling, I had 0.98-1.01 (ie: no significant) MAF error from 2500-Hz to 9625-Hz.

Apparently, even with a Whisper Lid, Green filter and intake Extrude Honing, flow characteristics of the MAF, itself, are not disturbed much.

So at this point, I've got my MAF table and my main VE table as good as they can be without a lot of expensive time on a load-bearing dyno. As a result, my fuel at WOT is lambda .85-87 from 1600 rpm to 6300 rpm. That's using an RC Engineering 23-lb injector and a Racetronix fuel pump.