Vec Pulls and Log Questions

[DAMN YANKEE]

I'm about to start my Spring logs and I thought I would ask if any of you out there have any strong recommendations.

I was planning on 3rd gear pulls from about 1,500 to 5,400 RPM. Flat roads with a warm engine. i figure I'll set the vehicle weight to 3,900 (2000 GTS, plus me, plus S/C) and run it against 250 RPM increases. Targeting 11.8:1 A/F.

I've got a nice Xcel spreadsheet to load the data in, if I could find a resource to allow others to download it, I would.

Any recommendations? Tricks or Traps? Special set-ups or Log configurations?

 

[Knight Viper]

I want to learn all I can also, I was amazed today when on my second pull I saw almost 10 psi of boost with a 6.5 pulley. I e-mailed Sean because I thought I did something wrong but he said everything look fine, the extra boost is from the water **** injection...COOL... (pun intended).

 

[DAMN YANKEE]

KV, Are you running a Wideband as well?

 

[Knight Viper]

Not yet, I would like to, but I also need to learn what I've got already (new to the whole computer tunning thing). To start I want to run a wire from the stock 02, after reading your install on the wideband and benefits of having one it will be on the priority list to install now that I've got tunning capabilities and what to upgrade further in the future.

 

[Dave T(BADVENM)]

I'm also just figuring out how to datalog with my VEC3. I've got an AEM a/f and would like to be able to datalog it as well. I'm new to this also. Until I know what I'm doing I'm coordinating my results with Joe Donovan at PBJ. He's new to the tuning at a mile high (sometimes two miles given the density alt during the summer) so maybe we can both learn something.

 

[KenH]

If you are going to do your own tuning on the road with a VEC2/3 a WBO is an absolute must. Wire it into the VEC as a logging input. Conversion files are available that convert the voltage output of the WBO into an A/F reading. I wouldn't mess with wiring in the stock O2 sensors as they are only useful for closed loop operation and you aren't programming the VEC for those conditions.

3rd gear for pulls is good as it keeps the speeds reasonable during tuning. 4th is nice if you have the open space for it. 1st & 2nd are too quick and violent to get good data. It is also useful to do some logging runs while running through the gears.

I personally shoot for about 11.8 A/F as well to give myself a little safety margin. With water/**** 12.2 is considered optimal for power, but I prefer a safety margin. I am currently boosting my octane level with Torco for additional safety margin on my cast pistons.

A useful tool is the torque measurement graph. A dip in it can indicate a spot where you can benefit from adding a little more timing. Keep in mind that a too rich condition can be a sign of not enough ignition advance as well as too much fuel.

Pay particular attention to the air temperature that you do your tuning at. You will find a strong corrolation between air temperature and your A/F settings. The VEC3 may be better in this regard than the VEC2, but not sure. With my VEC2, I need to have about 3 different tunes for cool, warm and hot days.

If you are running water/methanol, that adds significant complexity to the whole tuning process and you have the basic decision to make whether you are going to use more water/methanol to boost your octane or rely upon less and use mainly for cylinder cooling. I tend to use mine just for the cylinder cooling which helps to extend how far I can go on a tank and minimizes the risk if I should run out of water/****. BTW, I also see up to 10psi on my 6.5lb setup with water/****.

 

[DAMN YANKEE]

I would concur, there is no need to wire int your narrow band O2 sensors.

For those that really do want to begin the process of learning how to propery attend to your VEC, I would recommend that you get a copy of the "terminology" document I created. Just Private Mail me with your email address and I'll send it to you.

I am looking forward to mastering this to some degree and getting out some structured guides. Its a big piece of work as it has t be 100% right. I'm on it.

KenH, good data points. There are a couple of us experimenting with IAT right now as we live in the East and the temps change alot. What is most interesting tro me is the idea of watching the torque graph and its potential resolution utilizing adjustments in the timing. The vast majority of those that I talk to are willing and engaged with the Fuel Tables, few have ever adjusted the timing tables. Anything more you have to say on that subject is very much appreciated.

I will finish my spring pulls and begin to post them on VCA as a primer.

I am going to put my specs under my signon now and recommend that all who want to start digging in on this do the same as it will allow us to quickly see what the configuration of our Vipers are.

 

[Mr Hemi Head]

Everything Ken said
+
Newbies can get comfortable with tuning by E mailing the log files to Sean Roe.

Sean can analyze the results and reply with new tuning parameters for you to load.

 

[Mr Hemi Head]

DY Quote:

The vast majority of those that I talk to are willing and engaged with the Fuel Tables, few have ever adjusted the timing tables. Anything more you have to say on that subject is very much appreciated.

DY tweaking timing should be reserved for a dyno visit. IMO

A Viper, with a modified exhaust, can be too loud to hear detonation at WOT while street tuning. Just one event can damage cast pistons.

For example during my last dyno visit the dyno operator, sitting in the drivers seat, could not hear the slight ping in the mid rpm range.

Add road noise and other distractions, like watching out for track officials lol, detonation can easily go undetected.

 

[DAMN YANKEE]

Good advice....many thanks!

 

[Steve 00RT/10]

Ken hit the nail on the head and Mr. hemi head with some good points as well. I too found I needed 3 cards for different temps. BIG difference in AFR between 45F and 90+F. A card tuned at 45 degrees to 11.5 will be in the mid 9s (AFR) on a real hot day.

I am one who has never monkeyed with spark, but do have my AFR tuned in quite well to 11.5.........I guess that's my question. My marching orders last year were to shoot for 11.5 with my non h2O/**** 5 pound cast car. Is it actually OK to shoot for 11.8? I'll likely not change anything, but it would give me added safety margin to know 11.8 is all right.

I upgraded my VEC to 3 capabilities and am now playing with the IAT function some....which leads me to another question. My understanding of the IAT function is that , when dialed in properly, it will compensate for the IAT and add/subtract fuel accordingly to hit your target. My initial testing is showing that even with 5% in each direction--my 2nd log run is running a little richer. Will heat soak affect the AFR regardless of the setting as the car gets hotter from multiple runs?

Has anybody dialed in this IAT function yet? I will say this....The difference in my cold card to hot card across the meat (2500-5500) of the 3rd gear pull is over 30% different.

Even with my 5 pound cream puff, I have seen boost creep to over 8 pounds on occasion.

Steve

 

[DAMN YANKEE]

Watching us all throw up this good information has me thnking that VCA needs a`full-blown "Tuning" section where we can begin to store this info away properly.

Confirmed with Sean just last night that a 5lb, cast piston car has 11.8:1 as the goal. Everybody I know, including me has been tuning to 11.5.

I am planning on testin the IAT throughout the summer, I can't beleieve that simple heat soak hasn't been taken into account, but you never know.

 

[Knight Viper]

DY Quote:

DY tweaking timing should be reserved for a dyno visit. IMO

A Viper, with a modified exhaust, can be too loud to hear detonation at WOT while street tuning. Just one event can damage cast pistons.

For example during my last dyno visit the dyno operator, sitting in the drivers seat, could not hear the slight ping in the mid rpm range.

Add road noise and other distractions, like watching out for track officials lol, detonation can easily go undetected.

How do you detect detonation or a slight ping if you can not hear it on the street on on the dyno?? I to have a cast motor and do not want to hurt it. I want to upgrade it on my own terms

 

[DAMN YANKEE]

KV, using just the fuel tables most guys get the car running to a superb tune. The comment being made by MHH is that it is best to only touch the spark curve (another remarkable feature of VEC) only in the most controlled environment..dyno. I see some pretty clean log, well tuned with great performance figures by guys who only touch their fuel tables. Fear not!

 

[Mr Hemi Head]

How do you detect detonation or a slight ping if you can not hear it on the street on on the dyno?? I to have a cast motor and do not want to hurt it. I want to upgrade it on my own terms

On a dyno it requires someone near the engine to listen for detonation while the operator is in the car.

 

[Dave T(BADVENM)]

I've gotta try and tune for elevations/density altitudes ranging from 3000-4000 feet here in western Kansas to 5500 feet (up to 8500 feet dens alt) in the foothills of Denver (Bandimere Speedway). On the plains we can get density alt in the 7000+ range during the summer, close to those experienced in the foothills without having to travel there and tune seperately.

I'm thinking of trying to go with several programs that will be tuned to these various ranges. I'm not sure how sensitive I need to be with the various programs (a card that can go from say 3500-5500 feet dens alt, 5500-7500 feet dens alt, 7500+ density alt), thats something I'll have to talk with Joe Donovan about when those times come.

I think I'm the first guy that he's done a project on where the racing takes place a mile high...I may be wrong.

 

[Jim Wilson]

Wow, this is a great thread, and you guys have ALL provided some great info regarding tuning. Damn Yankee is right on regarding a need for a forum for tuning. It would provide a wealth of information that will help everyone who is tuning their car.

DY you have a PM.

 

[ViperBing]

It would also be nice to have a place where we could trade VEC2/3 programs.

 

[DAMN YANKEE]

I made a formal request by going to the last section of the general directory.

Please add your support for a whole new section here:

http://forums.viperclub.org/showthread.php?t=601816

Lets see if we can get this going..

 

[98vip]

I would like to see some datalog thanks

 

[DAMN YANKEE]

As you might imagine, the problem with logs is that there is no place to put files so they can be collected and distributed within the VCA a web site.
That is the reason you don't see too much traffic in the actual logs themselves, photos..yes...file content...no

We need to correct that so that we can all learn from analyzing pulls.

 

[Knight Viper]

DD, I will data log when I'm at the dyno that should give me the best info to share..before, during and after. He said it would probably take about 12 pull to get everything dialed in.

 

[ViperBing]

DD, I will data log when I'm at the dyno that should give me the best info to share..before, during and after. He said it would probably take about 12 pull to get everything dialed in.

Where are you getting this done? Keep us posted on how it goes.

Thanks!

 

[DAMN YANKEE]

KV, remember, with your Vec and your laptop, you can log anytime you want. You will want to learn how to do this so you dont have to wait for a dyno all the time. If you dont run a wideband you wont be able to accrately tune your rig, but you can log all day long and capture the current performance of your Viper. With widebands and practice..you rule.