metaphysical

iTrader: (3)

As most of you know, I blew my engine road racing. Unfortunately, I learned after the fact that my tune wasn't safe enough for road racing, and this mistake cost me thousands of dollars. Fortunately, David Buschur has bent over backwards to help get my motor back together. The most important thing is understanding that your factory engine can withstand huge amounts of stress, and tuning is the most important aspect of reliability.

No matter what system you use to tune your car, whether it be a simple piggyback, reflash, complete piggyback system or a stand-alone engine management system, these suggestions apply to you.

I talked to about a dozen of the best tuners in the entire country to develop this list of suggestions (and franky, things you must do unless you plan on buying a new engine)

These are general ideas/concepts/suggestions, not specifics - let your tuner handle the specifics. But, the more you know, the better your car will run.

1) Finding a tuner
There are a lot of great tuners out there, you don't have to drive 2000 miles to find a competent person to tune your car. Find someone who is familiar with the system your using. Explain to them what your going to do with the car in detail. Let them sell you, they should be experts, they should be able to answer all your questions - so if they can't, don't have them tune your car.

2) Autocross and Roadracing require different tuning approaches
**And your tuner may not know the difference**
Your car is under great stess whenever you are on boost and at WOT throttle, there is a huge difference between 12 seconds of WOT and 45 minutes. The main difference is simple physics. Your turbo is spooled by exhaust gases, these gases happen to be very hot. So, the air is compressed by your turbo, but subsequently it is compressed and very hot. Your intercooler is designed to cool this air down before it enters your combustion chambers. If you roadrace or autocross, you will be under WOT for a long time, thus making your turbo extremly hot (hot enough to glow red), and eventually your intercooler will surpass it's efficiency and become very hot. This is an extremely bad thing - you then begin pumping extremely hot compressed air into your combustion chambers. If you have a tune designed for drag racing or daily driving (and apply tip #1, if your tuner has never autocrossed or roadraced think twice about going with him) your engine may be destroyed.

3) Take every safeguard to combat the heat problems with tuning
Tune your car with a large safety margin, the harder you plan on driving, the more safety margin you need. Use a very safe air/fuel ratio and timing - ie. a 10.5 air/fuel; it may not make as much power, but it is safer than anything above 11:1. Don't use too much boost - boost creates heat. This will also make less power, but if you want to make big power use race gas. Most tuners I talked to didn't advise anything above 20psi on 93 octane. Pump gas varies from store to store, so don't expect 93 octane to always be 93 octane. So, in short, you want your tune to be conservative.

4) Use knock control and have a full set of gauges/warning lights
**Your tuner might not have it enabled - turn it on**
Use knock control, period. It works, it may save you a motor. The only reason not to use it is if you run straight racefuel and have tuned your car extremely rigorously (less than 5% of us). You can cheaply and easily wire knock warning lights to alert you. The more gauges you have the better, in the event of a problem you can get answers fast. Gauges may cost money and give you zero hp, but they can save your motor and help you get answers to your problems fast. Don't assume that knock control is turned on, so if you have already been tuned, check and see if it's on. If your EMS system has a datalogger, learn how to use it. This can help you spot a problem well before it happens, and your factory sensors can tell you quite a bit, much more than a set of three gauges can. If you don't want to take a computer with you at the track, consider other alternatives (AEM EMS Specific). Gauge-tech.com makes a stand-alone monitoring system for the AEM EMS and it has a built in warning light which you can have triggered with EGT, knock of a/f warnings.

5) Fuel and spark run your engine - use the right gas and right spark plugs
$30 dollars of racegas may save you thousands on a engine rebuild. Racegas is added assurance. It works. If your tuned for 93 octane, add 3-4 gallons of leaded gas for extra safety. You can't stop heat unless you stop racing, so the extra octane and lead will stop or help to combat detonation. Water or Alcohol injection can work wonders, but keep in mind that you can have fuel slosh, pump failures or run out of water/alcohol with these systems also. Alcohol injection, in most cases, will not pass a road course tech inspection (think twice before putting something highly flammable in your windshield washertank). If you want to make more power, tune your car for straight race gas. A pump gas tune won't make as much power as a race gas tune, for a simple reason besides octane - 93 octane isn't always 93 on the other hand Sunoco GT100 is always 100 Octane. Leaded gas can ruin your 02 sensors, but it's much less expensive than a $3000 dollar motor. Change your spark plugs often, NGKs are inexpensive. And more importantly, inspect your spark plugs, they will show detonation spots and other signs. Run the correct heat range plugs. You may want to run a different (colder) heat range for road racing (BPR7ES for daily driving/BPR8ES for road racing). Ask your tuner for recommendations for spark plugs, if he/she doesn't seem to know, go somewhere else.

6) Overbuild your cooling and fueling
Read AEM EFI basics (available on the aem forums at www.aempower.com). Make sure your fuel pump, injectors and lines are up to the task of fueling. I wouldn't recommend doing any roadracing without a Walbro 255 pump. Make sure your injectors can supply enough fuel for your power levels. Most of the other parts of the fuel system can support very high horsepower, but it's always better to be safe than sorry. Roadrace on a full tank of gas, if your gas gets low, don't go out. If your serious and competitive, buy a fuel cell and or full fuel system with a surgetank. A larger intercooler is an excellent safety mod, if designed properly it will cool more efficently and help prevent heat induced detonation. If you do extremely long road racing events in extremely hot weather, consider an upgraded radiator. Heat in your engine can cause detonation.

7) Dynos lie (and so do knock sensors)
Refer back to the heat induced detonation failures. A dyno pull in 3rd gear with ample cooldown time does not stress your engine, your intercooler may still be operating at full efficiency and you may get zero knock with too much boost, too low of an air/fuel ration and/or too much timing. If your dyno operator uses a huge fan/sprays water on your engine/intercooler and gives you a 20 minute cooldown between runs, you may not be safe even if you get zero knock (I wasn't). Don't add racegas and get a reflash unless you plan on running racegas all the time. Keep in mind, you can strap your car on the dyno and run it through all the gears at WOT, it may not make huge numbers but it will make you feel better when your on the road course for 45 minutes. Road tuning can also be used, but be safe. A load bearing dyno is also a nice thing, but any type of dyno, if properly used, can do an adequate job. When you get tuned: Get a print out of your dyno sheet, but more importantly, find out how much boost your running, timing and your a/f. And it's not a bad thing to tune your car in extremely hot weather, nor is it bad to skip cooldown runs, nor is it bad to have low dyno numbers - after all, do you want to beat someone on the racetrack or the dyno?


Thanks,
JD

And many thanks to all those who helped and advised me.

metaphysical

iTrader: (3)

Fueling equations taken from aempower.com

"If the engine is enhanced via forced induction or nitrous oxide, the stock fuel pump is inadequate. If the engine’s power is increased more than 15-20% fuel delivery must increase as a factor of the power gain.

The way to determine the proper-size fuel pump is based on the desired brake specific fuel consumption (BSFC) of the engine. This term refers to how much fuel in pounds per hour (pph) the engine consumes per horsepower and is a measure of the efficiency of the engine. It is a useful term in determining the total fuel requirement of the engine.

On vehicles equipped with forced induction or nitrous oxide, higher BSFC’s are required as an added measure of safety to prevent detonation or high combustion chamber temperatures. Below is a guide of BSFC’s with standard CR that AEM uses for various engines that run on gasoline:

· Naturally Aspirated engines have a BSFC of .48 to .50
· Forced Induction engines have a BSFC of .65 to .68

Methanol (alcohol) powered engines require twice the amount of fuel so the BSFC’s are doubled.

Calculating the total fuel requirement of an engine requires simple equations that we outline in the following section. You must know how much power the engine is anticipated to make and we recommend that you guess on the high end. The fuel requirement will be determined in pounds per hour of fuel flow. Since most pumps are rated in gallons/hour you must know the weight of your fuel/gallon. (The vast majority of gasoline based fuels run at 7.25 lbs./gallon.)

The equations to determine your fuel requirement is as follows:

· (Power x BSFC) x (1 + Safety Margin) = pounds/hour
· Pounds/hour / 7.25 = gallons/hour.

An example of this equation is:

· 500 hp gasoline engine using moderate boost with a 30% safety margin
· (500 x .625) x 1.30 = 406.25 lbs./hr.
· 406lbs/7.25 = 56 gallons/hour.
· If the pump that is being considered is rated in liters per hour, use the conversion factor of 3.785l/gallon. The pump described above would be rated at 56 gallons x 3.785 liters = 211.96 liters/hour.

In the fuel pump sizing, always use a safety margin greater than 20%.
Fuel Pump Location
The fuel pump should be located at a level that corresponds the lowest part of the fuel tank. This does NOT mean that the pump should be in a vulnerable position such as hanging below the tank. The pump should also be positioned so that it is protected from the road hazards (speed bumps, curbs, road debris etc.). In the event of an accident, the vehicle structure around the fuel pump should not deform to a point where the pump and its electrical connections are compromised.

The wiring for the fuel pump MUST be rated for the amperage of the pump. As with all high current wiring, a fuse rated for the amperage of the pump should be used. It is always better to err on the large side for the wire size. The ground for the pump must be the same size as the power lead and be mounted to a location that is clean and clear of any undercoating or paint.
Fuel Injectors
The AEM EMS requires the use of “saturated” or high-impedance fuel injectors. If “Peak and Hold” or low impedance injectors are to be used, an injector resistor must be used or you will damage the ECU. Resistors can be purchased from AEM. The PNP version of the AEM EMS is configured for the stock injectors and no additional parts are required.

To determine the size of the injectors, the total engine power must be estimated or known. The fuel pump calculations and BSFC information mentioned in the previous section provides a good understanding of the fuel requirements for an engine. The following equation will allow you to determine the requirements of your injectors:

Using the same engine as above:

· ((Power x BSFC) x (1 + Safety Margin))/Number of Injectors = pounds/hour
·
An example of this equation is:

· 6 CYL. engine rated at 500 hp on gasoline using moderate boost with a 15% safety margin on the injector
· 500 x .625 = 313 lbs/6 = 52 lbs/hr/ injector. 52 x 1.15=60lbs/hr/ injector

If we take the flow of the injector (60 lbs/hr) and multiply it by the number of cylinders (6), we arrive at a total of 360 lbs/hr of flow. As you can see, the fuel pump described above has enough capacity to feed the engine with a little room to spare.

It is a good idea to know the maximum operating pressure of the fuel injectors. In some cases the fuel injector will not open if the fuel pressure exceeds the design limit of the injector. Also, at the higher pressures the injector fuel flow may become non-linear and cause inconsistent fuel delivery, usually creating a lean condition. Most injectors can withstand up to 70 psi. Many of the pintle style injectors can withstand higher pressure.

In the fuel injector sizing, always use a safety margin between 15-20%. "

metaphysical

iTrader: (3)

Moderators: you may want to sticky this

MrBonus

iTrader: (4)

Fantastic posts, Metaphysical. Good luck in getting your engine reassembled and back on the road and/or track!

4G63>OOOO

iTrader: (1)

My rules:

Tune for pump gas.
Run race gas.
Lower boost.
Add water injection.

Keep your speed up in the corners and you won't have to worry about beating on your motor in the straights.

Happy motoring.

propellerhead

iTrader: (3)

Thanks man. You've gained hero status.

ColinL

WHOA

huge problem with that "add leaded gas" bit.

um.... NO

lead destroys oxygen sensors. no car using them should use leaded race gas, or any additives containing lead. use UNLEADED race gas, even if it is more expensive. there is no *can*, there is WILL.

metaphysical

iTrader: (3)

That point is well taken. But 3-4 gallons leaded in a full tank of 93 will due no harm. I know many people who have run straight leaded several times a month and had their 02 sensors last 30K miles. The more miles on the sensor (before using leaded)the longer they tend to last. You can repair a fouled 02 with a butane torch and/or simply keep an extra in your car glovebox (they take 5 minutes to replace). Worse case scenario is it will put your car into 'safe mode' (if you run a factory ecu) and you'll run extremely rich. Keep in mind you can take out your UEGO wideband sensor if you don't want to foul it, and you can run a EMS without an 02 after it's been tuned. Shiv ran C16 during the one lap (take a look at the trailor ). Out of everyone I talked to, this tip was specifically recommended by Jason Siebels, the engineer of the AEM EMS. And as pointed out by ColinL, don't use leaded if you have a catalytic convertor. So, I recommend running one and getting a Buschur (or copied design) to easily remove your catayltic convertor at the track.

And yes, unleaded 100+ works great, but it can be extremely hard to find. None of my local tracks carry it, and Beaverrun was completely out when I attended (although they had 112 leaded instock, which would have saved my engine had I known all this beforehand).

Two other options are Torco octane booster, it works, other brands may not. It comes in leaded and unleaded, you can keep a bottle or two in your car for added assurance. Toulene and Xylene also work, but they may be harder to get a hold of, and anytime you use chemicals be careful.

And Alcohol and/or Water injection work, but make sure your system is up to task for the events you run. Both the SMC and Derekdevises kits have failsafes/warning features. If you run out of water and your tuned to use it, you could do damage to your engine.

ColinL

you aren't looking hard enough. hallett is nothing compared to socal's tracks and the northeast, and down there I can easily source several brands of unleaded 100+ octane during any race. phillips and VP are always there-- if you can get C-16, you can get VP unleaded 103. I can buy phillips 100 at a PUMP here in Wichita!

but what you say is somewhat true. you probably will not restore function to an o2 sensor with a torch, but it will take some time to kill it. what will die very quickly though is any catalytic converters-- I know a lot of people run test pipes (I would as there is no emissions testing in KS) but if you have a stock or high flow cat, just one tank is enough to trash it.

anyway this is a nearly insignificant sidenote on your two VERY good posts. the information is there, but don't expect all your fellow Evo enthusiasts to bother to read it, remember it, or even be able to interpret it all. motorsport isn't cheap.

kevo

iTrader: (7)

Very good write up. It's just a good insurance to run race gas whenever you know you are going to beat on your car, track day, autox or even drag. Out of these three, I think autox put the least stress to the motor considering the speed and gear and you are not always on full boost. Track days and time trial put the most stress to the motor, I found that gauges with playback and peak hold is very useful to monitor my engine condition. I usually record the gauges in the middle of the section so I get an idea what's going on with the motor on those laps. Everything get 10x hotter compare to autox, engine, turbo, all the pipes, tires, brakes...etc.

JD, what size of injectors are you running /or are you planning to run with your power level?

robi

iTrader: (24)

And people look at me funny when I tell them my 91 street tune is at 18 PSI! (and I only run 116+ at the track) too many years of high stress two stroke 18,000 rpm motors to get me to run anything else! Great posts if they wont sticky it we'll keep bumping it!

MyCre8n=Evlshn

Thanks metaphysical! Great posts!

propellerhead

iTrader: (3)

To add to tip #4, if you're running any sort of system that allows datalogging, whether it be an AEM EMS, UTEC or LM-1 WBO2, do it! Log all the data you practically get your hands on.

The AEM EMS, for example, can sample critical parameters such as knock voltage, WBO2, fuel pressure, EGT, etc. at extremely high sample rates, up to 250Hz. Stuff will show up in logs that you'll probably never even see as a "blip" on a gauge. Plus with the EMS you can have logging activated by a hardswitch or it can capture when certain load conditions are met. This way you can record your hard runs and analyze them back in the paddock giving you the chance to call it a day or make adjustments before you grenade your motor. I'm sure other engine management systems, standalone and piggyback offer similar functionality.

Just my two baht... but I love datalogging.

KK

iTrader: (4)

I agree. Datalogging is like having eyes in the motor. Gauges are great for warnings, but they rarely show you much else if anything. The EMS offers so many nifty features if only we take advantage of them.

Mark

metaphysical

iTrader: (3)

Thanks for the suggestions, I added/modified a bit.