Total Performance Solutions

As a tuner, one of the most integral parts of what I do is reviewing and interpreting datalogs. One thing that I find sorely lacking in most DIY tuners’ toolboxes are the tools with which to properly view and quantify the data they have collected. Being able to visually see data helps identify problems such as faulty O2s, slipping supercharger belts and proper fueling and spark advance curves.

Let me walk you through a simple example with my personal car – a supercharged 1995 GT running CBAZA strategy U4P0 base calibration. The combo consists of the stock 150,000 mile longblock, Trickflow heads, S-trim at 15psi and a water methanol kit through a 4R70W automatic transmission. This example finds me dialing in the water/methanol kit with both pre and post blower nozzles. Datalogging software and hardware in this example is Clint Garrity’s BinaryEditor through a Moates Quarterhorse chip.

Before we start go ahead and download a few things to follow along… Dyno Chart, Datalog, SCT’s LiveLink. The calibration used in this example is available on request if you drop me an email – wes@tpsperformance.com.

The first thing to do is get LiveLink installed. Even if you do not have any SCT hardware, you can still use LiveLink to visualize and zoom in on your datalogs as long as they are in a standard CSV format with the column headers in the first row. BinaryEditor saves logs in this format “out of the box”. twEECer’s CalCon datalog files can be saved out as CSV and they will be viewable as well.

I will not give you a step by step instruction on using LiveLink – it is quite intuitive (and also useful if you have a SCT handheld to log ODBII data in realtime). Check the help file under “Toolbar Options” for a quick runthrough of the options.

Once you have LiveLink loaded, go to the “File” menu and select “Open”. Locate the datalog file you downloaded. If you datalog a lot of parameters they may not all fit in the list on the left – you can either trim out some of the columns in Excel or right click the listing and change the font size to something smaller to allow additional room.

With the datalog open, I normally first click on “RPM” to give me a feel for where my pull is. You can clearly see the RPM jump up towards the end of the log – this is the pull on the dyno. A nifty trick to zoom in on a particular portion of a log is to RIGHT CLICK AND HOLD on the start of the section of interest and while holding drag to the end of the section of interest. LiveLink will automatically zoom in on this portion for you.

Go ahead and do the right click and drag zoom on the pull on the dyno. You will get a screen similar to this:

Dyno Run

You can check the checkbox next to each parameter you wish to view. A few interesting ones to watch are LOAD, PW1, SPARK, MAFV and ACT.

Running through each of the params mentioned, you see as RPM increases LOAD goes up – this is typical of centrifugal blower cars… the more you spin ‘em the most boost they make. This is verified with the dyno chart. A N/A car will show a LOAD that closely follows the torque curve on the dyno chart as the volumetric efficiency of the vehicle peaks and then decreases. A load in the 180s is roughly correct for the observed boost so that is an excellent indicator this vehicle is calibrated correctly.

PW1 is the pulsewidth of the 60lb injectors – you see that it steadily increases as airflow increases, this is good.

SPARK follows what I am commanding in my calibration, again, this is good.

MAFV shows that I still have some headroom with my peak at about 4.5v on the SCT BA2400 meter.

ACT is an interesting one. Because of my ACT sensor placement, I am not seeing as rapid of a temperature change when the methanol fires (there is very little room for the mixture to evaporate) but you can clearly see that the temperature peaks and then falls. The somewhat erratic AFR (and large difference between AFR on the dyno chart and LAMBSE in the datalog) shows that the meth is indeed spraying and further tuning is needed to dial it in to what I am looking for.

HEGO cycling

If you click the “Fully Expand Chart” button in the toolbar, you can then turn on HEGO1 and HEGO2 – you’ll see that HEGO1 is cycling as we would expect but HEGO2 is dead. On most cars this would be a problem, in this case I have disabled HEGO2 in the calibration to accommodate a wideband O2 sensor in its spot.

In a nutshell, that is it. Visualizing data is a very important part of what I do as a tuner. By incorporating it into your tuning regimen I have no doubt your tuning and troubleshooting will improve. LiveLink proves to be quite useful in viewing data allowing much quicker access to “pan n’ scan” around than if you were using Excel.

More updates coming soon, here are some sights n’ sounds from the last week or so…

Ezell’s “Terminated” ‘01 Cobra

TJ’s Turbo’d Auto ‘04 GT

Tommye’s Cam’d S197

Wes’s Stock Block at 15.5 PSI

We’ve covered in the past how race gas affects not only your spark advance but also the readings on a wideband and ultimately the calibration in your vehicle. In this article I want to show you an example of this on the dyno and then show you how to calculate the change in fueling if you know the stoich of the fuel you are using.

I get quite a few questions about what each race fuel will do to your calibration and how it will affect things. Before I give you the stoich for various race gas mixtures, I can tell you that generally speaking leaded fuel is going to be closer to pump gas than unleaded race fuel will be. When you start mixing unleaded race gas in your car tuned for pump gas you want to be extremely careful. The amount that you get leaned out might make the difference in a burned piston or not.

The green line at the bottom of the graph is a car run on the dyno with 93 and then run with a mix of 104 and some spark changes (street tune vs race tune). Notice how given no fueling changes the AFR shifted leaner.

Here’s how to figure out what a fuel will do for you. You first must know which fuel you were tuned on. We’ll work these ratios in AFR instead of lambda since that is what most DIY guys are familiar with. For the following examples we’ll assume you were tuned on non-Ethanol fuel at a 14.64:1 stoich.

If you empty your tank of this pump gas and load up some Sunoco 104 (GT Plus Unleaded – I run into this one a lot), what happens to the 11.8:1 AFR you were seeing going down the track? It jumps well into the mid 12s! Our two fuels in question have a 14.64:1 stoich and a 13.7:1 stoich – you can see the 13.7:1 stoich needs much more fuel per air than 14.64. About 7% more (original fuel divided by new fuel OR in this example 14.64 divided by 13.7). You could raise your wide open fueling up about 7% and compensate.

Now what if you’re mixing fuel – this is what happens for most of my customers that make a track visit in their track vehicle. Say you drive in with a quarter tank of 14.64:1 and want to mix in another quarter tank of 13.7:1 fuel. How much fuel should you add to compensate?

This is simple math – you’ve got half of each fuel, so (13.7/2) + (14.64/2) = 14.17. We can then use the formula above of old divided by new to get 14.64/14.17 or a little over 3%.

This isn’t all to the story – different fuels will make optimum power at different mixes, but this should give you a good overall understanding of what is going on.

I generally recommend my customers mix C16 at the track for their race tunes – it raises octane and the brief time you run it at the track will not hose your O2 sensors. C16 is easy to get and because of its close stoich to pump gas you do not have to worry about mixing ratios.

Without further adu, here is the list of stoichometric ratios I have compiled from talking to vendors, various literature on the fuels and other resources.

Pump Gas Non-ethanol: ~14.64:1
Pump Gas E10: ~14.08:1
Turbo Blue Unleaded (100 octane): 13.9:1
Turbo Blue Unleaded Plus (104 octane): 13.7:1
Turbo Blue 110: 14.7:1
Turbo Blue Advantage: 14.9:1
Turbo Blue Extreme: 15.0:1
Sunoco MO2X UL: 14.5:1
Sunoco 260 GTX: 14.4:1
Sunoco 260 GT: 13.9:1
Sunoco 260 GT Plus: 13.7:1
Sunoco Standard: 14.8:1
Sunoco MO2X: 14.5:1
Sunoco HCR Plus: 14.8:1
Sunoco MaxNOS: 14.9:1
Sunoco Supreme Leaded: 14.95:1
Sunoco Maximal Leaded: 15.01:1
VP Street Blaze 100: 14.16:1
VP C10: 14.53:1
VP 110: 15.09:1
VP C16: 14.77:1
VP C12: 15.00:1
VP C23: 14.93:1
VP C44: 12.87:1
VP MS103: 14.26:1
VP MS109: 13.41:1
VP Import: 14.15:1

When we left off in Part 1 we were discussing where our best torque would be made. We determined there was a spark advance that could be found for a particular engine combination that would make the best torque. We’ll delve a bit further now into the factors affecting how closely we can run with this optimum advance. I could not possibly go into the full extent of this discussion (see my earlier posts on some great textbooks to read for more detail) but I will give you some things to think on and by the end you should have a great understanding of our results and be able to begin thinking creatively how this could apply in other situations and on your own vehicle.

Let’s take a look at what can increase our power production. We have all heard that an engine is a glorified air pump, you improve how well it can get air in and out and you make more torque. The proper setups can even use the inhale and exhale of the engine to cause a ram and sucking effect to move air in and out of the cylinder. In our datalogging we can measure the inflow of air and measure the “volumetric efficiency” of the motor to see how well (or not) we are doing at pumping (how close to 100% of a cylinder full of air are you?). This also comes in handy when you are modding a car, you can judge very quickly if the CAI you just added actually got more air into the engine or if your butt dyno just needs a recalibration. I do this with every airflow mod I dyno test, it is a great way to judge what you have done alongside dyno numbers.

If you decide you are tired of trying to improve the pump and want to instead ram air into the motor you can step up to a compressor (pick your poison, blower, turbo, centri) or nitrous which really is just cold, dense burnable oxygen. This now gets us well past 100% volumetric efficiency. Our 281 cubic inch motor in this example is now taking in the air that a 400 cubic inch motor would normally ingest.

This newfound airflow comes at a cost, we have to expend some energy to spin the compressor. Some compressors are more efficient than others but they all waste some sort of energy and as it relates to our discussion, they all create heat.

So you hear supercharged guys rattling on and on about how high their air temps are, especially down here in Louisiana during the summer. But what is it about heat that makes it so bad? To understand how big of a part this plays, let’s look at some factory Ford programming. We’ll consider the 03/04 Cobra platform at wide open throttle since it is what we are getting to in this discussion (in a round about way I know, but you need to understand the principles in play to interpret the data and the reason why we get the results we do).

On these vehicles from the factory once you cross over the 100 *F mark on your air temps, timing is pulled. For example at 150 *F you are down about 4* of spark. Now on the dyno we can say that every degree of spark is somewhere around 8-10rwhp just to give it a round number. So this is big news. You can understand why those boosted guys now whine about hot air temps and heatsoak, it matters.

On a side note, this is also where those little eBay mileage saver deals come from – they fake out the ACT sensor and report lower air temps and the PCM commands more timing/less fuel or some combination thereof. Some actually “work”, I’ve tested it on the dyno. You can begin to appreciate how this hack could lead you to a situation where the motor will knock. We are much better off actually calibrating the vehicle than just lying to it. Like the old adage goes, “garbage in, garbage out”.

Stay with me, so we understand now that spark advance plays into power. We understand that there is a spark limit of each engine combination, at some point additional advance will not help you. At this unknown point we are firing too early to reach optimum mechanical advantage (torque).

We now know that heat plays into not allowing us to run at this optimal spark advance, but how? As heat is added into our combustion event, our fuel becomes increasingly likely to pre-ignite.  This is where your intercoolers can make more power than non-intercooled car. As the temperature of the incoming air rises, we have to pull spark to keep us out of knocking territory. Water-methanol injection (I’ll do an in-depth article on this if there is interest) has a two fold benefit of both taking the heat out of the air and also increasing the octane of the fuel. There are also downsides but that is another subject for another time.

Now the results.

93 Octane Dyno – 24* advance

Here’s the first pull – normally you will tune a combo like this to lower 20* spark on a safe street tune. 24* is as far as I got before I lost power on 93 octane.

116 Octane Dyno – 24* advance (overlaid on previous chart)

Drained the tank, loaded in C16, corrected for change in stoich and pulled again with similar engine/air temps. Roughly the same – slight gain at the tail end – possibly seeing the beginnings of detonation up top over the 93 but otherwise identical.

116 Octane Dyno – 26* (overlaid on previous chart)

Power drops off here. As you now know, we found that MBT at WOT at higher RPMs was roughly at 24* on this particular combo.

93 Octane Dyno 24* vs 116 Octane Dyno 26*

Here’s the “money shot” on 93 vs C16 in this instance at 24 degrees and 26 degrees respectively. We also left the car on the dyno and ran the engine cold the next morning with minimal warmup time and observed no gain over 93 at 24*.

Conclusion, in this case we are not limited in power by the fuel we use. This is the exception to the rule and also why I thought it a good subject of this article. On almost all engines we are limited by the octane of the fuel that we have available. On this Cobra we were able to reach the point in which we can make no more power even with fancy fuel, in fact adding spark advance even in the absence of knock lost us power.

Now is this all to say C16 is pointless? Absolutely not. In fact even without the gain here, we pick up a good deal of safety running 24* timing and C16 should we be hot lapping the car, having a heatsoaked intercooler etc.

So where do you go from here to take advantage of the C16? Given proper internals we increase cylinder pressure while keeping IATs down (MORE BOOST!!!) and attempt to maintain our peak pressure at the optimum degree of crankshaft rotation, thus keeping torque high, tires spinning and the competition in our taillights.

Thanks for reading – if you have any questions or comments I would love to hear them. Feel free to drop me a line – wes@tpsperformance.com.

I had the opportunity to do some playing around with one of our shop vehicles running on both 93 octane and then race gas, tuning as close to the edge as I wanted. It is your basic no-frills 04 Cobra setup, ported Eaton motor making about 400rwhp at 12psi on the MustangDyne. Runs a mid 11 second quartermile.

So with the stage set I first pushed the 93 octane tune as far as it would go. I drained the tank and filled up with race gas and pushed some more. Now when you hear “race gas” thrown around you immediately think huge power but is this always the case? What is it about race gas that makes power? Like pretty much everything in tuning there is more than meets the eye. Let me show you some of the high points and give you some tech and things to ponder that you might not find elsewhere.

There is a concept we deal with in Ford calibrations called MBT. This value represents the maximum spark advance that Ford engineers have determined through rigorous testing that will produce the best torque on the engine combination. There are then other spark tables that are derived at a certain temperature and octane. The spark advance is further modeled with adder and subtractor tables based off of engine temps, air temps and a good many more things. As the vehicle runs, the PCM constantly analyzes all these tables and does quite a lengthy math equation to arrive at which spark advance to run given the conditions. To further complicate things, the maximum spark that the engine can support changes as you modify the characteristics of the engine, fuels etc. It is a somewhat common tuning practice to make use of the data Ford acquired at set conditions to produce best torque and run the car at this spark advance rate. You can imagine that this might get you close to always making the best power all the time, but unless you are dealing in the controlled conditions Ford calibrators were, you are selling yourself short and taking a risky move.

So what are we doing when we add spark advance? In essence we are timing the moment we fire the spark plug to achieve a peak cylinder pressure at the optimum time that will give us the optimum mechanical advantage on the crank. This is physics 101, certain levers give you more “push”. We are doing just that. This mechanical advantage shows up as “torque” on our dyno graph. What we have working against us is a phenomenon called spark knock. The fuels we use have a tendency to ignite before the spark plug fires as the cylinder pressures and temperatures increase. When this happens the pressures in the cylinder double, triple or more – it is these rapid pressure waves that you can hear as pinging and this is how things break, shatter or otherwise not happen as we intended.

On the dyno we can steadily increase spark advance and maintain a consistent fueling and watch our torque increase. There comes a point where we continue to add spark but no more power can be found. This type of tuning at the bleeding edge is where our loaded MustangDyne dyno really shines, with accurate aerodynamic loading it makes this type of research and pushing (or simply finding) the limits a breeze.

So with these concepts in mind (and hopefully a LOT of unanswered questions if you are reading between the lines), what happens when we push the edge of 93 octane fuel and then load in race gas and push even harder? Did I blow it up? Did it live? Is it running 9’s? Read part 2 to find out!

Spot the funny in the background. You'll have to look behind that big hood to see it though.

We had a great time at the track today ran into quite a few customers out enjoying their cars and got some new bests from our shop ‘07 GT and Matt’s S-trimmed ‘02 GT despite a lil’ midday heat. Look for even better ETs from them, more plans are in the works for both cars.

We’re working hard lately, things are going great over at TPS. Look for some new blog articles and a pile of customer car profiles (I am waaaay behind!).

Of particular interest is a followup to my AFR article earlier – I touched on the fact that race gas can potentially carry with it a different stoichiometric value. I’ve got a dyno chart of a car tuned on 93 and then we put in a half talk of 104 (about 13.8:1 stoich) and did the same pull under the same engine conditions.

Stay tuned for more…

In the last article I left you with some questions – with the changing stoich values for fuel, how do you know what your wideband should read? I also alluded to how fuel with different stoich values can lean out your vehicle. In this article we are going to nail down how to know that you can trust your wideband (or can you) and how to protect your vehicle when mixing in race fuels at the dragstrip. Just because it is a race fuel doesn’t mean it will give you additional safety!

So let’s setup a real world example.  Say your vehicle is tuned for unleaded gasoline. It has a stoich point of 14.64:1. When you are cruising (termed “Closed Loop”) your vehicle is taking readings from the O2 sensors. The PCM will run a calculation to shoot fuel based upon its built in programming. The PCM then polls the O2 sensors after a short period (some longtubes need tuning for this delay because of how the O2 is moved) and measures the results of this calculation to see how its calculation worked out.  These errors are collected and learned over time and a correction is applied to the calculation to keep things in check for fuel variations, changing conditions, aging sensors etc. If you are far enough out on your tune or a sensor the car will throw a check engine light along with a rich or lean code. Typically a vehicle can learn a 15% correction either way before throwing a light. When I tune a vehicle I shoot for no more than 3-5% correction in cruising conditions.

So say that your vehicle is perfectly tuned and the trims are within a few percent of each other. Now you get a tank of E10 which requires more fueling to make that same lambda of 1.00. Essentially when you fill up with E10 you have now leaned your car out. The closed loop correction will take care of you and enrichen the mixture back to a lambda of 1. The trims will be adding roughly 4% more fuel with the E10.

So with this learning things should always be kosher. Not quite… when you nail the skinny pedal you leave the happy world of closed loop. The vehicle now requires a mixture richer than stoich and the stock narrowbands cannot accurately read outside of a small range around a lambda of 1. Because of this you get no correction to the fueling, what is programmed in is what gets squirted out of the injectors. You can see why this might be bad if your car is run with a different fuel than it was programmed for. Some new cars can learn this and apply a correction. Most cannot.

This brings us to a discussion of wideband air to fuel meters. They are capable of reading outside a lambda of 1. Not all widebands are created equal. Not even close. Most consumer widebands use the Bosch LSU-4 sensor. It is a very cost effective sensor but over time as the sensor ages the readings can drift. When I dyno tune I use a sensor/controller combo that is proven accurate and does not exhibit this drifting phenomenon. While it works fine in a daily driver type scenario to get a sense of if things are going horribly wrong, on the dyno I have to trust what I am seeing – the Bosch sensor in my experience does not give me that warm fuzzy feeling.

Ok so we have a wideband controller and display, it says we are running 12.8:1 at wide open throttle. Is this correct? Is 12.8:1 really 12.8:1? What is stoich? To understand this you must first realize that the wideband reads in lambda and then multiplies the data by a hardcoded (or programmable on some) stoich value. This is important to know when you are using a wideband. Some widebands use a stoich of 14.7, some use 14.54, some 14.64. This will skew your numbers so keep it in mind. The error is not a huge deal but it is something you need to realize when tuning or watching your gauges. On your higher end widebands you are able to program the stoich point or forgo reading in AFR alltogether and instead just see the lambda values.

The short answer is to know the stoich of your fuel, educate the tune appropriately and then interpret the readings of your wideband with these things in mind.

So now let’s setup another scenario… you go to the race track and decide you want to mix in some race fuel for added safety. Going down the track you notice your tune that was dialed in at 12.8:1 is now running 13.8:1 on your wideband! What happened??? You’ll notice that the unleaded race fuels typically have a much different stoich value than the leaded fuels. Leaded fuels are normally quite close to the stoich of unleaded gas. Unleaded race fuels aren’t uncommon to have a stoich in the 13s, effectively leaning out your vehicle. If you have a particular fuel you are curious on the stoich of let me know and I will look it up for you.

Let’s take a final example. You have your vehicle tuned for unleaded gasoline with a stoich of 14.64:1. There are 3 gallons of this in the tank. You add in 5 gallons of Sunoco GT plus unleaded (112 octane) with a stoich of 13.8:1. Doing the math you now have a stoich value of roughly 14.11:1. Your car will be running just over half a point lean. It is not the octane that makes the difference but rather the changed stoich value. Keep this in mind.

There are still even more considerations when tuning in the fueling on your vehicle, these items just brush the surface of the larger picture but they are things I want every one of my customers to understand.

Thanks again to Michael Rauscher at L&M Engines for proof reading and offering suggestion to  keep me on the straight and narrow.

What is this you ask? This is the learned fuel trims values being viewed in realtime from my '95 Mustang off the O2 sensor data.

Someone sent me an entertaining article that compared the code in luxury cars to that of a fighter jet. The car had MUCH more code to make all of its subsystems work. Crazy eh!?

Read it here.

A quick shout out to Alex – his latest best is 13.00 flat @ 107.95! I also heard a certain N/A black Cobra is now well in the 11s! Great driving guys!