Things that I know - Answers to FAQs

Discussion in 'General Chevy & GM Tech Questions' started by mjalstad, Mar 23, 2009.

  1. mjalstad

    mjalstad Rockstar 100 Posts

    Here are some answers to questions that I see asked almost every week. Maybe this will help some people out with the answers.

    Q: What is the best intake?

    A: 95% of people are going to tell you the same thing on this one. They will say the K&N FIPK. This is a nice intake but the only reason everybody is going to tell you this is because of the name. K&N has been around for a long time and is the most heavily advertised of any intake, therefore almost everybody that has an intake has the K&N and is going to tell you that it is the best even though they have no experience with any other intake. Pretty much all intakes are going to be the same as far as performance goes. What you want to make sure you get it one with a plastic intake tube, the metal ones will transfer heat from the engine bay into your incoming air. Personally, I think the Volant is the best intake out there for our trucks. They are 100% completely enclosed from the engine bay to not let heat in and they sell an optional ram air intake tube that goes from the air box to the opening for your tow hook. I have had the K&N on my '97 Suburban 350 and the Volant on my '99 Silverado 4.8. Performance gains are pretty similar, but I highly prefer the sound of the Volant. It has a nice deep tone when you get on it, when I had the Suburban it sounded like I had a vacuum leak when I was idling with the K&N.

    Q: What is the best programmer?

    A: I have been selling Hypertechs on eBay for the fast few years so I know a lot about this subject for gas vehicles. I don't know too much about the diesel applications, but here goes. As far as performance goes, you are not going to notice any difference between different handheld programmers. Every company spends time tweaking and tuning a vehicle and then they put that tweaked tuning file on the programmer. Every company is trying to get the most power out of a vehicle and has basically the same knowledge and skill. Hypertech is probably the most popular programmer for the same reason as the K&N is the most popular intake, it is a name that has been around for a long time and it is one of the most heavily advertised programmers.
    Now, if you want to stay with the Hypertech you have two options, the Power Programmer or the Max Energy. The Max energy is going to cost you a lot more than the PP3 (Power programmer III) and it is going to be a lot easier to find a used PPIII. The Max Energy has the additional feature of being internet updateable. This makes people think that Hypertech engineers are constantly working on increasing power results and as they do more work, they will release updates which can make your car have a more powerful tuning program. This is wrong. The updates only allow the programmer to work with a newer computer calibration. What does this mean? If you buy a PP3 and a month later GM comes out with a new computer calibration for your vehicle and your truck goes to the dealer to have some work where they reflash the computer the PP3 will no longer be able to read your PCM and will not work, but with the Max Energy you can go online and update it and it will work again. So if you have a 2003 Silverado, just save your money and buy a used PP3 on ebay for under $200 instead of buying a new Max Energy for $400. If you just bought a 2009 Silverado which is going to be getting work done at the dealer for the next few years, you may want to spring for the Max Energy.
    Now, if you really want more options and tuning power, you are going to want a Diablosport Predator. They have the same generic tune that Hypertech has so you can just pop that in and go or you can modify custom parameters. This is especially helpful if you have other modifications that are going to change your fueling or allow you to increase spark timing. What are some examples of this? When I got my Jet MAF, my truck would set a check engine light for a lean condition because more air was coming in than the computer thought (This is a common problem with aftermarket MAFs). By changing my fuel injector curve with the Predator, I was able to get my fueling right on preventing the check engine light from appearing and more importantly keeping my truck from running lean. If you remove your catalytic converters you can disable the post-cat O2 code so you don't get a check engine light, you can also increase spark timing more if you'd like to get more power and MPG that way, or turn off torque management. Also, the newer Predators are internet updateable so you can update for newer configurations for free online.

    Q: Can I remove my catalytic converters? Will it hurt performance? What do I need to do with the post-cat O2 Sensors?

    A: Yes, although it is illegal. It will not hurt performance since you will be reducing backpressure (kind of like putting on a cat-back exhaust), but it's not going to give you another 2mpg and 20 horspower either. You are probably never going to see a noticable increase from removing cats. A lot of people will tell you that you need cats or an O2 simulator because your cars computer takes readings from the post-cat O2 sensor and without it your truck will run like crap, THAT IS WRONG. The post-cat O2 sensor is there to monitor catalyst efficiency and that is it, your truck will run the exact same way with or without the post-cat O2 sensor functioning correctly. You will however see a check engine light, so how do you get rid of that? Either with O2 simulators or with the use of a custom tune where they have deactivated the post-cat O2 sensor codes or you can use a Diablosport Predator to disable the codes from appearing.

    Q: What is a leveling kit?

    A: On trucks with front suspension incorporating torsion bars (Most 4WD trucks, not including the '08-current NBS trucks) this is going to be a new torsion bar key which has a different indexing which is going to allow you to crank the torsion bar up higher giving you about 2 inches of lift. With the stock key, you will probably only be able to get another 1-1.5 inches of lift and the key will be bottomed out, not allowing as much wheel travel resulting in a slightly stiffer ride. Now, if you just want to level your truck out an inch, you might be better off just cranking up your stock torsion bars as long as there is some more room left for the key to move. It is a free inch so you will save yourself the cost of keys, a puller, and the hassle of getting the old keys out. It only takes about 15 minutes to crank your torsion bars up but can take a couple of hours to put in new keys. And anytime you change the front geometry by changing the position of the torsion bar, you are going to want to get an alignment to prevent your front end parts from premature wear and failure.
    The other kind you can get is for trucks with a front spring suspension which is going to be pretty much any 2WD truck. That is going to com in the form of a spacer. I don't know too much about those, so I'm not going to try to talk about them.
    Now, maybe you want to lift the rear of your truck as well to match your new leveling kit. No problem, you can get an add-a-leaf for under $100 which is an extra leaf that you install in the rear leaf pack. This not only gives you another 2 inches of lift, but increases your payload capacity as well. Maybe you want to keep a softer ride and don't care about increasing payload, well the other option is a block. This is simply a block that goes between your leaf pack and your rear axle which will lift up the rear 2 inches but not affect ride quality.
    Are you going to need new shocks? check with the manufacturer of your kit. Or just go ahead and install your kit and if it needs new shocks you will find out when they overextend and you have no more shock absorption. Then go ahead and buy some new shocks. You might save yourself $200 from shocks you won't need, if you do need them, you just will have to deal with a very bouncy ride for a little bit until you get your new shocks in.

    I hope this may help some people out and maybe I will try to add on this in time to come.
  2. mjalstad

    mjalstad Rockstar 100 Posts

    Q: What are fuel trims? How are they used for tuning?

    Your computer calculates how much fuel to put in according to how much air is coming through the MAF. This is done by a set of values in the PCM and that calculation is considered 0.0%. The O2 sensor then reads the air/fuel ratio of the burned fuel and changes how much fuel is going in by a percentage. If the engine is running 5% too rich, the computer will remove 5% of fuel making the LTFT -5%. If the engine is running lean by 2%, the computer will add 2% more fuel and the LTFT will be +2%. There is a maximum percentage which the computer will alter your fueling which I believe on my Silverado is 25%, on my Grand Prix it was 16%. After it reaches this value, it will throw a check engine light and it will no longer be using a corrected amount of fuel which is very bad because the engine is not running stoichiometrically correct.
    Theoretically you want your LTFT's to run right at 0.0% because your computer will not have to compensate as much for things, but that's nearly impossible which is why they say to stay between 0 and -2%. When you go WOT it enters open loop, where it does not rely on your O2 sensor readings because they are inaccurate at different A/F ratios than 14.7. It will rely on the set calculation I talked about earlier. Now if you are running 10% lean at cruise and your fuel trims were at +10%, your computer will automatically command an extra 10% fuel at WOT so you will be running rich which will kill your power. If you are running rich at cruise, say your LTFT is -10%, it will not remove fuel when you go WOT because then there is a chance it could be running lean which could cause engine damage. Theoretically, you want to keep your trims at 0.0% so your computer will not have to be compensating for things as much, but the general rule is to stay between 0 and -2% so that when you go WOT, it will not add fuel causing you to go rich and lose power.
    There are 2 types of fuel trims, Short term and Long term. Long terms, LTFTs, are averages of the short terms which is what you want to look at. Since the short term trims change many many times, a scanner can not read the data fast enough and if you average your short term trims, you will be missing a lot of the readings and incorrectly averaging them. This is why you want to look at the long term trims instead of the short term trims.
  3. adampaul1964

    adampaul1964 Epic Member 5+ Years ROTM Winner 1000 Posts

    Excellent post, I'm sure this will help a lot of members and I'm sure there will be a lot added to it! :great:
  4. TRPLXL2

    TRPLXL2 Epic Member 5+ Years 1000 Posts

    Hey if you sell Hypertech products how come you didn't mention the Hyperpac, I absolutely love mine for it's versatility. I was just wondering, other than that I have been a happy Hypertech customer for the past 8 years and counting.............:great:

    Forgot to mention the K&N 77 series I have with the metal tube, you are right about what you said about heat. I have finally made up my mind to take mine off and put the stock air assembly back on, It just makes the motor run hotter and that's about it besides looking cool. And no it's not for sale, I keep all of my spare parts for possible experimentation.
    Last edited: Mar 23, 2009
  5. mjalstad

    mjalstad Rockstar 100 Posts

    Yeah, I guess I could have mentioned those as well. I've actually never had a Hyperpac in stock before, they are not as plentiful as the PP3's or the Max Energies.
  6. toolskizm

    toolskizm New Member

    Do you guys know if the 08 Hypertech Max Energy works with the 09 Silverado? And the same for the K&N intake or Volant?

    I have a 09 1500 LS 4.8 gas...

    Looks like the DiabloSport does, like you said in the post Hypertech is all I've really heard of (though, I've never really shopped around for a programmer). I'm assuming DiabloSport is a respectable company too?
    Last edited: Mar 24, 2009
  7. pavee

    pavee New Member

    Great thread, thank you.
  8. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    Thanks for the info. Good stuff!
  9. jeff652

    jeff652 New Member

    Good Stuff. Thanks!
  10. bzboardco

    bzboardco Rockstar 100 Posts

    Thank God for this post! :great:

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