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Old 07-12-2012, 11:33 PM   #1 (permalink)
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Question performance change at higher elevations?

Hello, i have been driveing my 2000 Impala LS at 4500-9000 feet in montana. i have put a K&N cold air intake, Overkill PCM, airaid Helix TBI spacer, mallory coils, JRP 10.4mm wires, poly mounts, Iridium Plugs, 180 thermostat, Intence raceing shift kit and filter change, 2.5" downpipe with high flow cat and u-bend deleate, and 2.5" cat back, new radiator, new fans and so on. i really enjoyed the power gains. then i drove to washington. i noticed when i got down closer to sea level my engine turned into a whole new monster. dispite the 100 degree heat and high humidity, the engine just had some extra snort when i stomped on the throttle.

Now, i read atricles that say "EFI outo adjusts to any condition so the engine will run perfect all the time no matter the elevation, weather, heat, ect."

this is either not true or something is wrong with my car. any explenations? im kind of confused and dont really want to take it back to the mountains because it will feel slow again. unless there is a way to fix the problem. can the engine be tuned for higher elevations?

Thanks!

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Old 07-13-2012, 12:28 AM   #2 (permalink)
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yea actually you can have your car tuned that way... but as far as knowing where between montana and washington i have kno clue at all..

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Old 07-13-2012, 07:15 AM   #3 (permalink)
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The way your car runs will definitely change with elevation changes. You've got changes in Oxygen, pressures, temps, humidity, etc. You can have your car tuned to run differently in each situation, but ideally, you'd want to have something so that you can adjust the tuning depending on which situation you're driving in at any particular moment. I don't know a whole lot about the tuners for these Impalas and if there even is a tuner that will allow you to do that. Was your Overkill PCM done before or after you made all the other changes to your motor? If it was done before, I'd recommend you have it redone to optimize all the other changes you made. That may make it run better for you in your home use, but you'll probably still feel a change when you drive to other elevations. Who knows - it might make an even MORE noticeable improvement at the lower elevations then!!

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Old 07-13-2012, 07:20 AM   #4 (permalink)
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Yes EFI compensates for the changing altitude, but at higher altitude the air is thinner with less oxygen to burn fuel so the car makes less power. The EFI keeps the air fuel ratio correct and such but can't do anything about the lower oxygen content of the air.

TBI spacer is a waste.
Mallory coils were a waste, the 10.4mm wires are just harder to route making them more prone to damage.
Iridium plugs are to reduce gap errosion so they last longer, heck the car might have come with iridium I am not sure when they switched from platinum to iridium. But basically the stock ignitions are VERY good on modern vehicles to meet the LONG tuneup intervals and emissions standards. All you have done to the ignition didn't gain you power and probably didn't hurt but in all likelyhood it is going to need parts replaced sooner than if it had been OEM stuff.

I am NOT a "stock parts only" guy but there are some stock parts that are very good.

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Old 07-13-2012, 07:39 AM   #5 (permalink)
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Quote:
Originally Posted by mtimpala View Post
airaid Helix TBI spacer, mallory coils, JRP 10.4mm wires,
I'd go back to stock on these items.

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Old 07-13-2012, 11:09 AM   #6 (permalink)
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the reason i changed to the big wires is because all smaller wires inclueding the stock ones fell apart every time i took the boot off the spark plug. so i got rather angry and bought some that so far i havent had problems with, coils were next to first mod i did. i still have stock coils, so i can put those back on if needed.

so basicly im SOL unless i have 600 bucks to spend on a HP tuner? from w-body store or who ever has the best deal?

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Old 07-13-2012, 11:35 AM   #7 (permalink)
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Quote:
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Yes EFI compensates for the changing altitude, but at higher altitude the air is thinner with less oxygen to burn fuel so the car makes less power. The EFI keeps the air fuel ratio correct and such but can't do anything about the lower oxygen content of the air.

TBI spacer is a waste.
Mallory coils were a waste, the 10.4mm wires are just harder to route making them more prone to damage.
Iridium plugs are to reduce gap errosion so they last longer, heck the car might have come with iridium I am not sure when they switched from platinum to iridium. But basically the stock ignitions are VERY good on modern vehicles to meet the LONG tuneup intervals and emissions standards. All you have done to the ignition didn't gain you power and probably didn't hurt but in all likelyhood it is going to need parts replaced sooner than if it had been OEM stuff.

I am NOT a "stock parts only" guy but there are some stock parts that are very good.
when i bought the car it held melted down outolite's in it. and the wires were toast, im pretty sure it was a granny car before i got ahold of it.
What amazed me is that the car lot didnt even check the plugs or anything

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Old 07-13-2012, 11:42 AM   #8 (permalink)
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The computer is already tuned to be able to cope with varying conditions, that is what the MAP and IAT sensors are for.

At lower altitude there is more pressure and therefore more oxygen available to the engine to burn fuel so it will make more power there, no amount of tuning will cause it to make equal power at high altitude.

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Old 07-13-2012, 11:44 AM   #9 (permalink)
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Iridium was stock on all w-body cars. A tuner isn't going to help here, it's like Dwayne said, less oxygen is less available power, more oxygen is more available power, oxygen content in the air is directly proportional to altitude. The only thing that will make any difference at higher elevations would be if you rigged up some sort of oxygen injection system. Silicone in the spark plug boots will help keep them from sticking to the plugs.

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Old 07-13-2012, 12:13 PM   #10 (permalink)
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Iridium was stock on all w-body cars. A tuner isn't going to help here, it's like Dwayne said, less oxygen is less available power, more oxygen is more available power, oxygen content in the air is directly proportional to altitude. The only thing that will make any difference at higher elevations would be if you rigged up some sort of oxygen injection system. Silicone in the spark plug boots will help keep them from sticking to the plugs.
you and i think alike on that oxygen injection, and i think its a good idea. i have a feeling if i personaly tried to rig that id blow the car and myself to smitherines. but if you find someone who can let me know

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Old 07-13-2012, 01:18 PM   #11 (permalink)
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traditional "oxygen injection" system combine the oxygen with nitrogen think about it you will figure it out.

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Old 07-13-2012, 02:36 PM   #12 (permalink)
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traditional "oxygen injection" system combine the oxygen with nitrogen think about it you will figure it out.
haha i could think about it all i want. but i know nothing about injection of anything other then fuel.

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Old 07-13-2012, 03:46 PM   #13 (permalink)
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Nitrous oxide hits sold by Zex, NOS(Nitrous Oxide Systems), Harris Speed works and a LOT of others

NOS is a brand name but it has become popular slang much the way "Coke" is used to refer to cola

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Old 07-13-2012, 04:13 PM   #14 (permalink)
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Hey, you could justify the use of that TB spacer if you did it!

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Old 07-13-2012, 05:19 PM   #15 (permalink)
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Hey, you could justify the use of that TB spacer if you did it!
it has grooves in it. its suppost to give the incomeing air a vortec. idk if it is true or not. but to be honest i dont even think that it can seat nitrus. i might have to take it out and put a blank spacer in there. im not sure AirAid's spacer will hold up.

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