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Chip burning

Discussion in 'The Garage' started by mtn. burb, Mar 30, 2005.

  1. mtn. burb

    mtn. burb 1/2 ton status

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    For an 87' 350, I notice the aftermarket chip's provide high rpm hp/torque increases. Is it possible to have a chip burned for more low end torque 1000rpm to 2500rpm for example??

    Just wondering. Only mod to my engine is an RV cam.

    :dunno:
     
  2. dirtwarrior17

    dirtwarrior17 Banned

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    that is the whole concept of chip burning....

    you can change ANY part of the fuel map.

    In a perfect world it would be 14.7 A/F ratio all the way across the map which would give you optimum power everywhere but it almost never ends up like that...doesn't mean you can't try tho. If you know what your doing and have a lot of extra time you can get it to run within .5 of the 14.7 optimum ratio but each accelaration will cause a different ratio depending on how the throttle is applied.

    so the answer to your question is yes.
     
  3. mtn. burb

    mtn. burb 1/2 ton status

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    Thankyou, dirtwarrior 17. :thumb:
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Even on stock applications you can make some major improvements to what GM programmed. Wringing out better performance and economy with NO engine mods is quite possible.

    Just as a clarification, 14.7:1 is not the ideal air fuel mix. To make a stock system happy in most situations yes, but not ideal all the time.

    Probably common knowledge to the automakers now, but most tuners are finding around 13:1 makes best power in fuel injected apps, and GM ran the early injection setups even richer than that, I won't speculate on why, they just did. So people end up leaning out acceleration, which saves gas without hurting performance.

    For economy, 15:1+ was run by GM (check out "highway mode") but you've got to be careful with that. Believe that was a TPI only thing, at least when GM first started "cheating" with it.

    These different ratios are why tuners are so big on wideband O2 sensors, the narrowbands don't allow you to "see" these ranges, and force you to guess at anything other than where 14.7:1 is ideal.

    Aftermarket chips (like Hypertech) are absolute worthless garbage (I have one to sell that I found BTW lol) and not worth anything. Almost nothing is changed over stock except timing, and even that was a generic poorly executed idea. Each vehicle is different, GM has a different PROM (calibration) for every single vehicle variation you can think of. Chassis, engine size, transmission, head material, induction, rear axle ratio, and so on and so on. Way too many variables for one chip to improve for every single vehicle.
     
  5. dirtwarrior17

    dirtwarrior17 Banned

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    Never heard that before... 14.7:1 has always been the goal of tuners... and on almost every add for anything that has to do with AFR they all say "get the ideal AFR of 14.7:1 or something like that... How can the ideal AFR change from a stock engine to a modded one? a stock motor is still FI.

    not trying to argue but if you ask almost any mechanic or tuner they'll tell you its 14.7:1. that is also the goal of many hot rod shows which have nothing to gain by lying about ideal AFR.

    wasn't there studies done showing the most efficient way air and fuel to burn is if its at 14.7:1?

    once again... I just want to know the answers of these questions... im not saying your wrong.
     
    Last edited: Mar 31, 2005
  6. Fierospeeder

    Fierospeeder Banned

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    a lot of misinformation about air fuel ratios. Havn't seen anything 100% correct in this thread. Except the part of burning a new chip.
     
  7. CyberSniper

    CyberSniper 1/2 ton status Premium Member

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    Most people aim for 11.5:1 to 12.5:1 at WOT for accelerating. Carburetor people sometimes push it as far as 11:1. Rarely do you see a manufacturer go past 13:1 due to EPA regulations on "high load" emissions.

    Cruising and slowing down, most manufacturers aim for 16:1 while advancing the timing as far as they can get away with. If there is any change in throttle position or anything it is usually immediately returned to 14.7:1 anticipating further change. At 14.7:1 you still have decent economy but you have a lot better throttle response than at 17:1. I think it's Subaru or someone that runs as high as 17.5:1. GM and most other manufacturers are doing "displacement on demand" instead of running really lean. Chrysler runs goofy lifters that collapse for "displacement on demand" whereas GM and Ford just shut stuff off last I knew.

    14.7:1 gets you stoich but neither gets you maximum acceleration nor fuel economy.



    PS:
    By tuning at all you're going to improve anywhere. Most aftermarket chips don't touch the middle at all due to drivability concerns. The only way to improve cruise-area power is to burn your own chip.
     
  8. dirtwarrior17

    dirtwarrior17 Banned

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    what do you mean 14.7 gets you stoich?
     
  9. Fierospeeder

    Fierospeeder Banned

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    ask your chemistry teacher.
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    Here's a decent article for you to read, they get into richer mixes and what not. No reason to reinvent the wheel.

    Car Craft

    I'm sure it's not 100% correct dirtwarrior, if you see any errors perhaps you could point them out and explain your view.
     
  11. dirtwarrior17

    dirtwarrior17 Banned

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    I don't know if that was an insult or if you were serious... want to clarify?

    If it was an insult I don't know where it came from... i said i wasn't saying you were wrong... i wanted to know the truth.
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    No, it was not intended as an insult.

    I figure if you see something you don't agree with, you'll post up with information showing otherwise. I'm just posting information and links that I believe will assist you in answering your question. Always the possibility of misinformation.

    BTW, on that vein of goodwill, here is a tuning thread I ran across that I thought might help you when you get your tuning equipment. Not sure if you've seen it or not. Here you go.
     
  13. Fierospeeder

    Fierospeeder Banned

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    that article barely gets into the concepts of fuel mixtures. DW should talk to a chemistry teacher at his HS.
     
  14. dirtwarrior17

    dirtwarrior17 Banned

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    ah......

    didn't think so but i didn't see anything "wrong" other than the fact it is too short.

    I've heard of stoichiometric but never really got into what it means... I don't have a chemistry teacher anymore. :grin:
     
  15. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    It's an 'impress your friends ' way of saying the perfect fuel/air mix! The most efficiant burn mixture!
     
  16. dirtwarrior17

    dirtwarrior17 Banned

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    :thumb: I C

    thought it had something to do with that...

    so if stoich doesn't translate into most powerful or best gas mileage what does it translate into?
     
    Last edited: Mar 31, 2005
  17. Wingnutt

    Wingnutt 1/2 ton status

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    Well since I've been playing around with my chip for almost a year now, I guess I'll throw my two cents worth into the frey. First off, the 14.7:1 ratio is the optimal ratio for general driving. Now I'll throw a monkey wrench into the works. As has already been stated, richer for WOT and power enrichment modes (right now, I'm set at 12.1:1 for these) and as high as 17.2:1 (I'm at 16.6:1) for highway cruse mode. Of course the timing curve, fuel quality, humidity, gear ratio vs tire size, ambiant and engine termeratures will all affect where your individual ratios can be set at.

    Don't waste your $$ buying a "one size fits all (insert your vehicle here)". There are to many variables to do anything else but add a few tenths to the WOT fuel mixture, and bump the timing a touch.

    IMHO, the best thing you can do would be to get in touch with a decient chip burner and have them burn you a chip (from your data logs) to get you close; then learn to tweak it for your particular vehicle. You will be surprised how much you can wake up a stock vehicle with just tiny tweaks. In the long run you will be much happier with the results and spend less in to long run. Unless you become addicted to tuning of course. :D
     
  18. dirtwarrior17

    dirtwarrior17 Banned

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    a custom chip burned at a shop using a dyno is roughly $400, then another $400 for the stuff to burn your own. A labtop off ebay for $100 and a speedtronics prominator for $275 is the route im goin... plug and play and ill never have to remove or install a chip. Just change the map save and go. you can save multiple maps at a time(not sure if its on the labtop or prominator) for example if i had to pass smog i could burn a smog map and a non smog map and switch to the non smog after i pass.
     
  19. Wingnutt

    Wingnutt 1/2 ton status

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    I used to have Brian at TBI chips burn my changes into the chip ($75 for the initial tune, then $10 per burn for my changes), until I found about the Prominator. Now I've just about saved up enough to order mine so I can finish the last couple of tweaks (until I install the next goodie). Plus whenever I manage to get my HT383, I'll aready have everything I'll need to tune it. It sure will be nice not to have to pull the glove box and the computer just to get to the chip! I've done it so many times now that it only takes me about 8 minutes to change the chip out. :grin:

    One last thing; the Prominator is not plug and play! You have to have a .bin to load into it along with the software to edit the .bin with. They ship it without a .bin unless you supply it, then Bill will load it for you. Oh yea, I almost forgot, you will need to send him your computer so he can solder the Prominator in place. The last time I talked to him, the turn time around was averaging a couple to three weeks.
     
  20. dirtwarrior17

    dirtwarrior17 Banned

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    who is bill? on the website it says you use a plug instead of soldering it. even if you have to solder it soldering is real easy if you get alot of practice.

    Can't you get .bin yourself? I dont' really know what a .bin is but from what i've learned about this prominator there was no need to send it off to get all this done.

    http://www.speedtronics.net/aboutprominator.asp
     

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