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FYI: Ramblings...

Some Tech Stuff

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We have been receiving a lot of e-mail asking questions on many issues, which are important. We thought this would be a good place to post what we have learned from different sources and experiences.
  • We heard of an ECU recall: VIN numbers 2G500050 to 2G504423. Check yours and get it into the Subaru dealer immediately!
  • We're finding the install time for the Stage 4 is about 10+ hours of labor. This is because the uppipe takes about 5 hours by itself to install. The uppipe is the single most difficult upgrade to install.
  • If you are building up your engine, remember the stock WRX engine connecting rods can not handle torque over 400 ft/lbs. and 420 hp to the flywheel. We are told they are going to snap or blow a piston....
  • If you are running about 400hp and above, you must be prepared for parts to wear out quickly. The car is under a massive amount of torque and it takes it's toll. You could expect early replacement of your clutch, synchros, gears, u-joints, rings and more. This is the price of PERFORMANCE! Many say it's worth it!!!!
  • Don't waist your money on performance heads and cams in search of better air flow. Just turn up the boost.
  • We are told for a WRX to break into the 10s in the 1/4 mile will take more than 400 hp at the wheels, that's moving.
  • To be save, you should not run NOS. it takes a built engine to do this with some degree safety!
  • New uppipes are available with super hi-flow cats in them. This keeps your car protected from stock uppipe cats failing and keeps you visually correct for State Inspections. Many States now are charging $2500 fines for not having the proper number of cats. Our cats can be seen here.
  • If you are going to remove a Stage kit from your car remember to replace all the stock hoses back. I learned one of them (where the manual boost control goes in the engine compartment) has a restricter in the hose. If it is replaced with a non OEM hose it will not have the restricter the car needs to run, so it will run like shit, possibly over leaning the engine....
  • When adding gauges with O2 sensors, be careful, many have thrown the CE light....possibly tapped into the wrong place in the system or ??
  • CE lights are possible with any aftermarket exhaust system: uppipe or hi-flow system. The CEL code is usually for inefficient operating temperature of the cat or uppipe. There are aftermarket fixes for both, so don't worry.
  • During hot temperatures keep your car cool. One suggestion is to force a larger volume of air onto the intercooler, the temperature will be lowered, and the volume will be greater. The engine will work more efficient giving you more horsepower with more air. The scoops are 1 inch taller, a big difference! Secondly, upgrade the stock radiator to a aluminized one that will be a higher flowing, thicker radiator. Unknown to most users, a new radiator will keep your car running cooler up to 6 degrees C. This is a huge advantage when trying to beat the heat that is slowing you down. Of course this advise will only work if your car is driving in really hot weather....da!
  • During cold weather, remember to watch the boost. The Chips are programmed to increase boost based upon temperature, so if it's cold enough your boost could be higher than recommend. This is one of the reasons for a boost gauge!
  • Here's some words on turbo timers found from June 2001 Tech TIPS published by Subaru for Subaru Technicians: "2002MY WRX TURBO COOL DOWN PROCEDURE:FHI's position regarding this is that it is not necessary to perform a "cool down/idling" procedure, as was recommended with past turbo models. Our current 2.0L turbo engine has a far greater cooling capacity and, coupled with technology advances, makes this practice no longer necessary. This explains why information about cool down is not included in the 2002MY Impreza Owner's Manual. The heat contained in the turbo charger will begin to vaporize the coolant at the turbo charger after the engine is stopped. This hot vapor will then enter the coolant reservoir tank which is the highest point of the coolant system. At the same time the vapor exits the turbo charger, coolant supplied from the right bank cylinder head flows into the turbo. This action cools the turbo charger down. This process will continue until the vaporizing action in the turbo charger has stopped or cooled down." So I guess there's no real reason for spending money on a turbo timer.
  • On a stock WRX or when installing any engine management system, be careful of who is the manufacturer of the intake you are using. The word is many of the intakes lean the system out further than the chip programming recommends and then the CE light comes on. Also, when leaned too much you are running the risk of frying things (see above street stories). We have found our short ram intake falls within the programming parameters and our customers are having a great time without the CE light to watch! Avoid a nightmare on your street!! See stories above.
  • Only the Automatic WRX has been limited to 130 mph from the factory. If you add mods, you should be able to go above the factory set limit. But, as you know, speeds over the legal limit are for 'Off Road' only!!
  • If your car has no power over 5,000 rpm (no boost), the possible problem could be a bad EGT sensor. To test, disconnect the EGT sensor, which will force the car to default (CE light should come on). Then try the car. If it runs fine without the sensor, then its bad and will have to be replaced.
  • If you plan to add headers, it could increase your turbo lag, while increasing top end HP. So, there are compromises when using some headers. Others will act differently. Check which header design you are buying and what it will do, so you won't be disappointed.
  • If you change your plugs and have disconnected the battery to accomplish the task, remember to reset the ECU!
  • Some have upgraded their turbo without upgrading the associated parts: their fuel pump, injectors and engine management. This is living live on the edge. If you are running 16+ psi, then you run the risk of stressing your car's system: leaning out the car, frying a turbo, blowing injectors and more. Everything is max. out, so don't do it. It may feel good, but only for a short period of time before it breaks. Upgrade the fuel pump, injectors and your map or pay the consequences.
  • There has been much talk of the CE light coming on when you replace the Uppipe (has no cat) and have only one cat in the car. We are told by the Subi/rally guys that most likely the CE light will not show up, it hasn't for them. So, with this in mind, the odds are you probably won't see a CE light with the replacement of the Uppipe. But, as you know, there are no guarantees. If a CE Light does show up, the code usually refers to an improper CAT operation temperature. Since this is after the engine, it shouldn't create any problems. There is an electronic fix to stop the light, but you should have additional gauges to monitor your system. Also, remember to reset your ECU! Like candy left on the table (tempting), can you resist leaving the power of the Uppipe, about 7-8hp, on the table....Hmmm that's the question? The uppipe fix is as follows: All you do is get a 2.2 Ohm resister from Radio Shack. It should be rated at a 1/2 watt some have burnt theirs when using 1/4w. Next you want to find your EGT probe which is in the uppipe. Follow it up until you come to the sensor, that is the sensor that you are going to unplug. It should be the very last sensor on the rack. On the other side of the clip is where the resister gets installed .Wire it parallel between the two wires on the ECU side. It should look like an H. Wrap it up and you are ready to rock. Make sure you reset the ECU and that you leave the sensor unplugged.
  • When doing State inspections, be aware if you don't have the proper number of cats, you are not going to pass an emissions test, or a visual test of the exhaust system. If the visual test is a concern in your state, either reinstall the OEM exhaust system before any inspection or purchase Xcceleration's super hi-flow downpipe, uppipe and midpipe with cats. These pipes are designed to provide maximum performance and still have 3 cats on your car.
  • Watch your OEM uppipes after upgrading/increasing boost with Stage upgrades. The new weak link in your exhaust system after spending all your money on a turbo back exhaust is now the OEM cat in the uppipe. It will take a pounding from the higher boost levels and could blow, sending pieces up into the turbo, UKKKK! Upgrading the uppipe should be your next consideration before an intercooler. Get that OEM cat out NOW!!
  • If you are running a hi-hp application and a lightened flywheel, we have found you run a risk of a CEL for random misfiring or detonation. It seems the power pulleys are allowing the crank to turn faster, fast enough to cause issues with the crank sensor, which throws the CEL. If the CEL is for random misfire, then it's only a light, not actually happening, but if it's for detonation, you are probably having timing pulled which means less power. The solution is simple, either don't put it on or live with it. The code should stay away. It has for others. Power has it's price!
  • If you have upgraded your engine, and are making more power, a missed shift will earn you a blown gear or synchro. A major increase in torque going through the tranny is sufficient to destroy it, if you don't know how to shift. Be careful! FYI, built automatic trannys rule. They can't miss a shift and are winning at the track.
  • The three most important aftermarket gauges to have in your WRX are a boost gauge, air/fuel gauge, knock sensor and your CE Light! Don't be deceived into thinking this Light is just an idiot light, it is not. It represents over a dozen critical codes. The only problem with the CE light is it could miss important information you need to protect your engine. As you increase HP, the ECU becomes less accurate and it is critical to monitor your car's systems. When you add a boost gauge, air/fuel gauge and a knock sensor, you are adding additional margins of safety. It is a small price to pay to safeguard your car, buy them! If not, we may be writing your street story.
  • We have heard about the new STi as follows: Unlike the standard WRX, the STi in stock trim can, and does, detonate on 93 octane gas. (We’d hate to see what happens on reformulated California 91 Octane.) Like the WRX, the STi ECU runs highly variable ignition timing. Can you say ‘Dastek’ boys and girls? I think you can! The STi likes a nice, free-flowing turbo back with 2 cats installed to the tune of up to a ~48hp (28whp) gain (assuming similar ignition timing, of course!).
  • Heard that the new 2004 STi has pistons which are cast and coated, not forged, along with good rods. This means it most likely will not product the lofty HP everyone thinks they are going to get from mods. The word is the STi engine should be good for about 450-500hp, if the boost isn't over 18psi, while the WRX is good for about 420HP, if the boost is not over 18psi, before things start to break. So forget about that 500HP plus monsters at 19psi and higher, unless you build up the bottom end.
  • Blow Off Valves: the plus and minus - There are many people who will say that if your car has a MAF (Mass Air Flow) sensor (which is most modern turbo cars), you can't vent a BOV to atmosphere. This is not entirely true. In most cases you can, but it pays to be aware of the possible side effects. Quite often you may find the side effects are so minimal that they are not really a concern. Most factory turbo cars run some form of MAF sensor These sensors are used to determine the amount of air the engine is using so it can deliver the appropriate amount of fuel. In a car with a MAF sensor, when a BOV vents, air is escaping from a closed system. This air has already passed through the MAF sensor and has been measured, and the computer doesn't know that this air never made it to the engine. This will cause a brief rich mixture as the computer will still deliver the correct amount fuel dosage based on the amount of vented air. There are two stages to a BOV venting, as initially it is evacuating the pressure from the inlet pipes and intercooler, which usually takes less than a second (depending on your inlet system). Then once the pressure is released, the valve stays open to allow the turbo to freewheel, thus reducing compressor surge and the associated thrust and torsional loads. It is mainly during this freewheeling stage that causes the over-fueling, since the turbo is basically pumping air through the MAF sensor and out to the atmosphere through the BOV, which accounts for the majority of air that escapes the system. The resulting rich mixture is what can sometimes cause backfiring and a puff of smoke in some cars. The severity of these effects usually depend on the state of tune of the engine. In cars that are modified (say with full exhaust, pod filter, a little extra boost etc.) but still using the factory tuning, it is not uncommon for the ECU to compensate for the extra airflow it sees by running rich for engine protection. On a WRX for example, mildly modded engines can be running as rich as 10:1 with the factory ECU. It is this poor state of tune that can cause backfiring when an atmosphere-venting BOV is added. Stalling is another common problem, many people have had bad experiences with atmosphere-venting valves causing stalling problems. However, with the correct spring adjustment this problem is reduced. As long as the valve closes properly before the engine reaches idle, the ECU will have no problem maintaining a smooth idle. Most complaints of stalling actually come from people using certain Japanese brand valves, which often do not have the range of spring adjustment to compensate. Key is: some cars are affected by backfiring when venting to atmosphere, and some are not. Even two identical cars with slightly different mods can react differently. The bottom line is if you vent to atmosphere with a MAF sensor you MAY use fractionally more fuel (depending on the kind of driving you do) and there is a chance you may hear some popping in the exhaust. For those Subies wanting maximum noise from the valve this is usually not a worry! Also, if you can not stop the fluttering sound above 3000 rpm, then remove the spacer inside the BOV, this should allow for better adjustment. Also, you must make sure a BOV is installed and working correctly. If not, it could create a vacuum leak, which would be seen by the ECU as needing more fuel for the system, when it is not really needed. This fuel rich situation will destroy exhaust cats and more. So, put that BOV on correctly or else!
  • Boost Creep (Boost Spikes) The waste gate on the turbo is controlled by the ECU and is looking for a certain amount of pressure on both sides of the waste gate. When you change the pressure by using an exhaust system that is too free flowing, then the waste gate doesn't have the proper pressure and doesn't open at the correct time. This causes the boost to 'spike' too high, which can cause damage. Many have suggested polishing the waste gate on the turbo, but as usual this is a maybe solution for a complex problem. Polishing may work occasionally, but the risks from polishing are very high. One negative side effect is you can't built boost at all. The correct solution is to install the correct exhaust system in the first place and avoid the whole situation. A properly designed bell mouth design and catted exhaust system provides proper back pressure and maximum performance. Why look for trouble, do it right to begin with!
  • UTECs - We have found that using the UTEC in low HP applications has worked well for Subies in the past, but discovered that as HP increases many of our UTEC guys have had many gremlins, which they were unable to tune out. By upgrading to the Dastek Piggyback Chip, these issues have all disappeared. They have found the Dastek operates better with the OEM ECU, uses all of the OEM sensors, plus includes 2 preset maps making it a no-brainer for installation and use: true plug n play. In addition the Dastek is designed for use with all turbo Subarus (WRX, STi, XT, Baja Turbo and Legacy GT), making it one of the most versatile chips available. So why fool around?
  • Becareful, many engine management systems do not properly compensate for the changes in temperature, which means boost will increase in cold weather. You may want to verify your boost, using a boost gauge and make sure you're on target with the boost you need when the temperature drops. Also check your A/Fs. When cars were tuned in the cold, and the weather warms up, making the cars run richer. The opposite is true and the car could now run lean in the winter. In short... if you suspect problems, or have noticed more knock lately, check your boost and A/F, and make adjustments.
  • STi guys, if your car is not idling smoothly, we have found it's the crank sensor screwing up. When changed the car idles great again. We can not guaranty it will be this simple all the time, but so far we are batting a 1000 on each car we checked, vs the dealer. Reset your ECU after the install.
  • STi guys, if your car is not cruising smoothly, feeling like there is resistance, we have found that cleaning the MAF sensor has helped, and many times it has also been the front O2 sensor beginning to go. What makes this hard is that there isn't a check engine light to support the bad O2. We have just found through trial and error that changing the O2 sensor has helped 9 out of 10 times. Reset your ECU after the install.
  • Many do engine tuning on their own or use theoretical expert tuners. Tuning is a very complicated process if done right and easy if done wrong. To put your car on a dyno and flog it for hours, seeking the highest HP number you can find, not remembering the first Commandment of Tuning: NO DETONATION, things happen. Many times their results show up immediately, sometimes later. But bad tuning will always show up. Have a look at what happens to pistons when this commandment is not kept - broken pistons. click here
  • We have had a lot of calls from guys running Utecs, Reflashes or Ecuteks (reflashes) for engine management saying they have lost power and/or check engine lights for inefficient cat code. What we have found when looking further into the issue is the fellow's car is running too rich from the maps they are using. The maps have been set to run 'rich' as a safety precaution against detonation, but are too rich for converters. If you are going to run 'rich' maps for safety, then you should not have converters in the car, but this causes a problem because you need converters on a 'street' car to meet Federal Regulations. When our guys use the Dastek piggy back chip we have, this situation does not occur because the maps are designed to work with either OEM converters or our hi-flow cats. We have not had a single hi-flow cat failure, either because of the cat or the Dastek chip. Have a look at what not to do and what happens when the maps are set to "Fuelish". click here
  • Many guys are reflashing their Factory ECUs using several different programs on the market. Some of these reflashes are even done by Subaru Dealers. If your car is going to be a "Street Legal Car", not a race car, these ECU reflashes are not CARB Approved. This means you leave yourself open to Federal and/or State EPA/CARB fines. The ECU reflashes were originally designed for 'Race Only' applications ("Non-Street" Use), so don't be surprised if one day you receive a healthy fine ($2500) in the mail for not meeting CARB Standards. This would apply to Stand-a-Lone ECUs too. Remember, even if your state does not have emissions, the Federal CARB rules still apply. The only way for an ECU "Reflash" to be street legal or a "Stand-a-Lone ECU, is if it is approved by CARB and has a sicker and documentation to prove it. It doesn't matter who did the ECU reflash, even if it's a Subaru dealer. It's illegal!
  • More power is not as easy as turning up the boost. In turbo cars, increasing the boost produces more power as long as the fuel system can flow enough volume to maintain an optimal air/fuel ratio, using upgraded engine management. When it can't, the air/fuel goes lean, then the engine becomes a live grenade! So, don't turn up the boost unless you have proper engine management and upgraded fuel system components.
  • Not all bolt-on mods make power. Most Bolt-on mods are not designed to make power by themselves, but help the engine and related systems reach full potential. They are just tools to aid in the tuning of your engine more more power and require proper tuning/adjustment. Many bolt-ons even though they say the mod will fit the car, may not actually increase power for the car. Do your research, many bolt-ons have actually harmed the car!
  • Not all performance cams are better. Many performance cams make power in the hi-rpm powerband, producing power above 5,000 rpms to over 8,000 rpms. But do not add any power to low or midrange. For street performance cars, these cams are simply unusable and should be left to full race cars running hi-rpms for drag racing or circuit racing only. Street cars are looking for more power in the low and mid range and should select performance cams which add power in these rpms for maximum performance and drivability. Unless you plan to drive your car at 5,000-8,000 rpms all the time!
  • Larger intercoolers make more power. Intercoolers are heat exchangers. The cooler the air provided by the intercooler means more power can be realized with additional boost and tuning. However, be careful how you upgrade your intercooler. A larger front mount intercooler may be great for cooling, but reduce engine response if the routing of the intercooler pipes is too long and complicated. For street and under 500hp application, a larger top mount has it's advantages because of it's relatively short and direct path.
  • Dyno Tuning, it's an asset to the serious professional seeking to evaluate the performance benefits of their enhancements, without hitting the race track. But beware, it's a double edge sword! Remember, dyno testing is about repeatability and performance gains, not just PEAK OUTPUT!. There are differences between dyno equipment and technical ability of operators to be considered. A dyno is a 'tool' and in the hands of an expert, who has complete technical knowledge about your car and its mods, is a valuable asset for the serious power enthusiast. But it must be remembered, it is one tool available to the tuner, not the only tool. Many 'Professional' tuners actually tune the car on the road, rather than a Dyno, so they are tuning to actual road and track conditions. This method yields 'Real World' results. FYI: Proper Dyno tuning procedure should include a full diagnosis to the engine prior to final setup. The diagnosis should cover Electrical, Engine Management and Fuel System, and is a primary fundamental procedure which should be followed. You should insist on knowing what, if anything, is wrong with your car before the final setup and the runs begin. A Dyno tuner should able to make adjustments necessary for the mods you have, showing the before and after gains of each component, where possible. But in the hands of the uninformed, inexperienced and technically untrained, it could become a weapon of destruction. Running a car on a dyno, which is not in peak shape, could certainly accelerate a hidden problem and damage the car. Running the car on a dyno without the proper cool down between runs may damage important components in the car. Not knowing when your car is reaching its limits, could damage the car. Just to mention a few variables. It should be remembered, a Dyno checks power under ideal conditions, not actual road conditions with a 'real world' load on the engine. Most Dyno runs are in fourth gear, at full throttle, to redline. Basically this means only fourth gear is being tuned at full throttle, what about the other 4 gears, or partial throttle??? So, this type of single gear tuning leaves a lot to be considered, including real world conditions, load, hills, partial throttle, overall safety margins already in a manufacturer's map and more. If a car is leaned out too much, or timing retard excessively things happen. We have seen cats blow, uppipes fail, exhaust systems leak, turbos and pistons fry and a variety of other damage from trying to Dyno tune in search of 'ideal' maximum performance on a Dyno. For additional consideration, if the Dyno shop is tuning your chip and is not completely trained with the operation of the chip and the technical operation of your car, then this is a disaster waiting to happen. Any aggressive adjustment of boost, air/fuel or timing map could spell 'DISASTER' in capital letters. IMPORTANT: if the Engine Management System you are using to tune your car does not have "Live Tuning", and only has "DataLogging", you are basically tuning 'Blind'. This means you are making changes to your maps, loading them into the ECU, driving the car and datalogging, reading the Datalogging, making adjustments to the maps again, loading them back into the ECU and datalogging again, then reading the Datalogging to see if all is well. With luck everything is now fine. If not, start over again! At it's best, it's very tedious a procedure and requires baby steps or you could harm your motor. Become too aggressive and you blow your motor! "Live Tuning" is where you are able to see your maps on a lap top and make adjustments to the maps in "Real Time", in the ECU while driving. This way you are dealing with immediate data, not historical data and can avoid any problems immediately, such as running too lean while flat footing it down the road and popping your engine, while Datalogging. Tuning for real-world conditions is pretty much impossible on a Dyno. Remember dynos are 'tools', typically inside and the air flowing inside is never going to be as exact as when you're driving down the road. So if you must Dyno Tune, there has to be margins of safety built into the changes you are making. In many respects, using a G-TECH Pro would provide you with a more real world view of the benefits of your car and any mods, without racing the xxxx out of your car. On a positive note: Dyno FYI, issues to consider about Dynos. For those situations where tuning is required, we offer 'Real World Road Tuning', where we tune the car on the road!

As we hear more, it will be posted. Keep coming back!

Please remember they are only ramblings we hear. Take them for whatever value you get from them.