[serge]

275-285 rwhp average on dynojets...I guesstimate 250-260 rwhp on Mustang dynos. Excellent numbers!

[Insider]

Originally Posted by shiv@vishnu

Hi guys,
Just one thing to look at. The correction factor down below. It says 1.06 which means that the actual, uncorrected numbers are 270whp and 281lbft (divide SAE corrected numbers by 1.06). Judging by the baro pressure at the bottom of the graph, the test was done well above sea level. This means that the dyno rightfully applied an altitude correction. The only problem is that altitude corrections are only reasonably accurate on naturally aspirated cars. Modern turbo cars, like the 335i, adjust boost pressure to compensate for thin air. So, in effect, the dyno results shown represent a double correction, once by the dyno and once again by the ECU. Nothing shady going on by any means. But the results are overstated in relative terms. It's just one of the things that happens when comparing dyno results taken in different conditions.

Cheers,
shiv

It sounds like he was in Vegas, which is 2,200 ft above sea level.

[WilyB]

Just one thing to look at. The correction factor down below. It says 1.06 which means that the actual, uncorrected numbers are 270whp and 281lbft (divide SAE corrected numbers by 1.06).

I am afraid SilverState will have to modify his signature!

[CoralRedPlz]

Originally Posted by WilyB

I am afraid SilverState will have to modify his signature!

yeah, those original #'s just dont make any sense. i would defer to shiv's opinion on this one.

[Terry335]

There is no point in dyno-racing.

[soma4u]

Originally Posted by grkm3

oct...

are you planing on installing the procede?I'll take a stab and say this car will break 360whp with exh.procede,and 93oct

doubtful...

[CASHBY]

Originally Posted by soma4u

doubtful...

Didnt shiv make 350-355whp on 93 octane?

[musc]

Originally Posted by CEA 3

Didnt shiv make 350-355whp on 93 octane?

355 with exhaust and 93 octane.

[CASHBY]

Originally Posted by catm3

355 with exhaust and 93 octane.

so he could do that as well maybe mroe.... but inflated #'s dont count.

[musc]

Originally Posted by CEA 3

so he could do that as well maybe mroe.... but inflated #'s dont count.

True. He at least will be able to see the gains using the baseline numbers as a reference.

Hopefully we will see 380s or so with a DP and additional tuning. Also curious to see what 100 octane would add to the current setups.

[DrM]

Originally Posted by catm3

True. He at least will be able to see the gains using the baseline numbers as a reference.

Hopefully we will see 380s or so with a DP and additional tuning. Also curious to see what 100 octane would add to the current setups.

Shiv thought that a 100 octane map would provide another 20whp or so. Given that the turbos are pretty much maxed out, I am unsure that the gain would be that large.

[CASHBY]

Originally Posted by DrM

Shiv thought that a 100 octane map would provide another 20whp or so. Given that the turbos are pretty much maxed out, I am unsure that the gain would be that large.

its not the boost that is going to give us more power...its the timing that will give us more power.

in my A4 I ran same ammount of boost on race gas as I did pump gas...only difference when i put race gas in is i would bump timing up a bit and it makes about 50AWHP more wiht race gas.

[OpenFlash]

Originally Posted by SilverState

Exactly!

Yes, the dyno did apply an altitude correction as it was designed to do. The only problem is that it doesn't apply to the 335i which essentially applies its own boost correction to compensate for the high altitude. This makes the SAE corrected numbers in your sig file overstated. It's not your fault and you did nothing wrong. It's just one of the problems associated with one-size-fits all environmental corrections. Your car is right in line with just about every other car we've tested and there is nothing wrong with that

Shiv

[musc]

Originally Posted by SilverState

So in your opinion, a boost car would run the same et and mph on an altitude track as it would on a sea level track (providing traction is the same)?

Given your logic, the 335 should apply "its own boost correction to compensate for the high altitude"?

To a degree. The density of the air is still different. You will still have some loss. A stock 335i can compensate an extra 0.2 bar for elevation changes. Not sure if the PROcede still maintains that function.

[WilyB]

Silver:

Which part of "The Dyno corrected by +6% for altitude for a non boosted car while your turboed 335's ECU did the same, thus you number are off by 6%" you did not get?

[musc]

Originally Posted by SilverState

Less air at altitude. You must adjust for that. Ask any long time racer and they will tell you the same thing.

Yes, but what Shiv is saying that at your elevation, the the overboost feature is coming into effect. So when you use SAE correction, it makes your numbers slightly skewed because the ECU itself is already compensating for altitude. A NA car on the same dyno wouldn't have that benefit, so it'd be appropriate to use the correction.

Regardless, if you use the same dyno each time, with the same correction, you will still be able to gauge the gains of your future mods (exhaust, tuning, etc). The baseline number doesn't really matter unless you are some kind of dyno shoot out. Just dyno it the same way each time you make a change and you'll get the data you need.

[WilyB]

Originally Posted by SilverState

Incorrect, a turbo car, or any other car, makes less power at altitude. That is true even for BMWs.

You skipped Turbo 101, didn't you?

[musc]

Originally Posted by SilverState

I don't think you get it. The ECU can try to do what it can to make power even at altitude, but the car will still make less power at altitude...hence the correction factor.

BTW, if you read my previous posts, you will see that I understand what a baseline is and how to use it.

Ok. The additional boost is forcing more air in. Regardless of density, the ECU will just force more air by increasing the boost to match the power levels at sea level. You are basically saying that there isnt enough buffer to match the power at sea level, but I'd disagree. 3 psi should be enough to compensate for your 2K elevation.

[musc]

Originally Posted by SilverState

The turbo or supercharger helps at elevation, but the car will make less power...hence the correction. The turbo can only do so much.

I don't think you are understanding this. Yes, both NA and FI cars will loose horsepower at elevation. I think everyone agrees with this. And turbo cars lose less than NA at elevation. Yes. But the both still lose power, yes.

However, the 335i has the ability to automatically dial in more boost at elevation, up to an additional 0.2 bar. This closes the gap and allows to make same power as it if were at sea level.

Make sense? This is why someone mentioned it would be useful if they had recorded your boost during the dyno run.

[BMWPower06]

wow impressive numbers for stock...

[musc]

Originally Posted by SilverState

I understand just fine. And I agree that there is less of a difference with a forced induction car at altitude than with a n/a car.

Nevertheless, there is a difference, and that is why a correction factor is needed. People who race a lot know and understand this. So to say that there should be no correction on the dyno because it is a turbo, even if it is at elevation, is crazy.

I have been around racing awhile myself, including competing in IHRA.

The ECU negates the need for correction. If you had a turbo car with no ECU adaptation for elevation, then yes, you'd still use a correction.

No one said there should be no correction because its a turbo....that would be crazy...8.5 psi boost at sea level vs 8.5 psi 2500 feet = big difference in power.

What did say there should be no correction because its a turbo with an ECU that overboosts up 0.2 bar to compensate for elevation. ...8.5 psi boost at sea level vs 11.75 psi at 2500 feet = equal? you do the math

[musc]

Originally Posted by SilverState

Let me ask again.

You take the same turbo car and run it at a sea level track and run it at an elevation track. If what the recent haters say is true, they should run the same on the track (et and mph) given the same traction, correct?

We all know that is not true.

Obviously. Please read what I wrote over and over. No one is a "hater" here. Just trying to help you understand.

At elevation, your car is running more boost than at sea level. The average turbo doesn't do this on its own. The 335i compensates for elevation.