Does high altittude affect engine performance?

[Sinergy]

Originally Posted by gmag21

Im 41 ft above sea level, is this good?

You should be, as long as there's not a 42 ft tsunami.

[Phase V]

I just moved from Germany(1.5kft) to Arizona(4.6k) and noticed less ummph. Was hoping I could mod the ECU to compensate until I read this :(

[VADER SS L99]

I wouldn't be surprised if there was a 100HP difference between 10,000 ft and sea level.

[EDFHOBBIES]

Watch pikes peak fast n Loud!

[blackoutVIII]

You know what sucks even more 91 piss water and elevation!!! I felt the difference coming from Tx to AZ. I also felt the difference in my EVO VIII. Going from Killeen, TX to AZ altitude and 91 piss gas, there was a 20% drop in WHP in my EVO. I could only imagine what the loss is on a NA engine as our LS3/99s.

Anyone have a dyno difference of at sea level and 4k plus?

[JDP Sales]

Here in SLC, we're at 4500 ft actual with the D/A being 7500+ most days. Generally our 1/4 mile times in a 100% stock car are almost a full second slower than at sea level.

Best regards,

Tyler
888-308-6007

[ChocoTaco369]

Originally Posted by blackoutVIII

You know what sucks even more 91 piss water and elevation!!! I felt the difference coming from Tx to AZ. I also felt the difference in my EVO VIII. Going from Killeen, TX to AZ altitude and 91 piss gas, there was a 20% drop in WHP in my EVO. I could only imagine what the loss is on a NA engine as our LS3/99s.

Anyone have a dyno difference of at sea level and 4k plus?

Why would that suck? The less air density, the less octane you need. Octane is a detonation retarder, so running very high octane in very high altitude just will slow combustion. You wouldn't run 100 octane in a Civic, right? Octane is something that you want as little of as you need. High octane fuels are only used when people greatly advance timing to limit detonation. Not advancing timing and just adding octane, if anything, will slow you down. It certainly won't make you faster.

[1sick_eg]

Originally Posted by ChocoTaco369

Why would that suck? The less air density, the less octane you need. Octane is a detonation retarder, so running very high octane in very high altitude just will slow combustion. You wouldn't run 100 octane in a Civic, right? Octane is something that you want as little of as you need. High octane fuels are only used when people greatly advance timing to limit detonation. Not advancing timing and just adding octane, if anything, will slow you down. It certainly won't make you faster.

100 octane? Nah. Q or FTW fuel

[blackoutVIII]

Originally Posted by ChocoTaco369

Why would that suck? The less air density, the less octane you need. Octane is a detonation retarder, so running very high octane in very high altitude just will slow combustion. You wouldn't run 100 octane in a Civic, right? Octane is something that you want as little of as you need. High octane fuels are only used when people greatly advance timing to limit detonation. Not advancing timing and just adding octane, if anything, will slow you down. It certainly won't make you faster.

I would disagree. We have a fuel station here where I live which has 100+ octane. I bought a gallon of it, took it to my tuner, we ran the 91 piss water and then the 100+, I was able to up my boost, and my AWDHP increased at the same boost levels as with the 91 water. This was on the EVO.

I do agree with the purpose of octane being a detonation retarder, because when you have detonation, the knock is likely to be present. But, if a tuner is advancaing timing and increasing fuel for more power, while keeping the knock in check, then higher octane is needed. But, that is a different subject.

I was just letting the OP know what sucks even more about elevation is, when you are used to sea level WHP versus higher altitude WHP.

Going from 354 AWDHP, and 375 TQ with 93 Octane at sea level and then going to 4k+ elevation with 91 Octane, really made a difference to dyno at 300/300 AWDHP on a 2.0l with a turbo.

[blackoutVIII]

Originally Posted by Phase V

I just moved from Germany(1.5kft) to Arizona(4.6k) and noticed less ummph. Was hoping I could mod the ECU to compensate until I read this :(

I feel you man!! Even on Forced Induction the difference is there. To make things worse, 91 Octane fuel, which also kinda sucks.

[ChocoTaco369]

Originally Posted by blackoutVIII

I would disagree. We have a fuel station here where I live which has 100+ octane. I bought a gallon of it, took it to my tuner, we ran the 91 piss water and then the 100+, I was able to up my boost, and my AWDHP increased at the same boost levels as with the 91 water. This was on the EVO.

I do agree with the purpose of octane being a detonation retarder, because when you have detonation, the knock is likely to be present. But, if a tuner is advancaing timing and increasing fuel for more power, while keeping the knock in check, then higher octane is needed. But, that is a different subject.

I was just letting the OP know what sucks even more about elevation is, when you are used to sea level WHP versus higher altitude WHP.

Going from 354 AWDHP, and 375 TQ with 93 Octane at sea level and then going to 4k+ elevation with 91 Octane, really made a difference to dyno at 300/300 AWDHP on a 2.0l with a turbo.

I'm really confused. Or rather, I think you're really confused.

You went to your tuner and then advanced timing based on running a higher octane and performance increased?

No kidding. That is the point of running higher octane fuels. This is what racers do at the track. They have handheld programmers to flash back and forth with tunes. They have their normal 91/93 octane tune, then they go to the track, fill up with race gas, load the high octane tune and up the boost to retard detonation.

What happens when you take a stock Camaro SS made to run on 91 octane and put in 100 octane fuel without changing your tune?

It'll run better, and maybe worse. Octane is something you want the minimum of.

[blackoutVIII]

Originally Posted by ChocoTaco369

I'm really confused. Or rather, I think you're really confused.

You went to your tuner and then advanced timing based on running a higher octane and performance increased?

No kidding. That is the point of running higher octane fuels. This is what racers do at the track. They have handheld programmers to flash back and forth with tunes. They have their normal 91/93 octane tune, then they go to the track, fill up with race gas, load the high octane tune and up the boost to retard detonation.

What happens when you take a stock Camaro SS made to run on 91 octane and put in 100 octane fuel without changing your tune?

It'll run better, and maybe worse. Octane is something you want the minimum of.

The V8 beast is completely stock and untouched, never put anything higher than 93 octane in. My point of the whole thing is, I understand OPs concern about elevation and power loss. And that what sucks even more is lower octance gas and elevation together. I have driven up to 10k ft with the V8 beast and you can feel the difference as you go up with power loss.

[ChocoTaco369]

Originally Posted by blackoutVIII

The V8 beast is completely stock and untouched, never put anything higher than 93 octane in. My point of the whole thing is, I understand OPs concern about elevation and power loss. And that what sucks even more is lower octance gas and elevation together. I have driven up to 10k ft with the V8 beast and you can feel the difference as you go up with power loss.

But that doesn't matter. Lower air density requires LESS octane, not more. Running 100 octane at a higher elevation means even less. Octane is a detonation retarder. Low air density = less air into the engine = less detonation potential, which requires less octane to retard said detonation. You need more octane in negative DA's. This is why Atco is such a legendary raceway. Constant negative DA. I grew up 25 mins from Atco.

High octane + elevation is BAD. At 10,000 feet, 93 octane is practically race gas. You don't need it, and that's why it isn't available in high elevation areas. It is a waste of money for refiners to pump cars full of octane that doesn't do anything but potentially impair proper engine function.

[digdeep0169]

welcome to my nightmare! Alb, NM - elev: 5500

my car ran 13.2 @ 111mph

sea level corrections would be 12.2 @ 112mph

:shakingmyhead: