3.0L 11.1 Compression 1000+ awhp 3/S on stock cams at Altitude

[donniekak]

Correction factors work well in a moderate range of circumstances. Like anything else, when the equations are pushed the results start to become less accurate.

[HellBringer]

That dyno might as well be a picture of dogs playing poker. Without any of the pertinent contextual details it means nothing. Not to mention the 30º difference in AOT... Regardless, don't bother because it's irrelevant...

The fact of the matter is a fixed multiplier simply cannot accurately derive even close to a real number due to the litany of variables. On to more facts, there isn't a 76mm that can support the airflow at "27psi" on a 3.0L to produce the stated numbers, and definitely not with that type of delivery. And before you say nitrous, the comp ratio and whatever combination of fairy dust contributed, remember that the turbine still has to evacuate that flow (and through a 3" downpipe..). So again, what are the details on this turbo?

The 1033 number is simply not real, not at any altitude, and you know this; otherwise you're not as smart as you let on to be. Go trap mid 150's + and prove me wrong. Until then, with the correction applied it's all bullshit.

[J. Fast]

It's a shame there is such a huge difference in outside air temp. I know it won't skew numbers that much, but it is still something to consider.

Temp doesn't have an effect on turbo power output like some believe. The hp difference in 50 degrees is like 10hp. Its the density.. Take the track conditions at Bandimere Raceway Colorado at 2pm . They are pretty close to the conditions on the dyno pull. 24in/hg, within 10 degrees of dyno weather and very similar humidity. The air density is 77%. That means the dynojet SAE correction factor will be 1.23.
Density Altitude Forecast for Bandimere Speedway

Now look at the track conditions in Kent Washington Pacific Raceway. They are nearly identical to the pull #2 which was at English Racing in WA. 50 degrees, 85% humidity with 29in/hg. The air density is 98%. That means the dynojet SAE correction factor is 1.02.

Density Altitude Forecast for Pacific Raceway

You stand to gain 21% more horsepower from the air density increase alone. Temp plays a very small part but it's primarily the density. That's what Turbochargers and engines compress..

[Chris@Rvengeperformance]

I can't come up with a bunch of engineering to prove why it is, but if you think of it like this you can see how corrected numbers may be a lot higher than it really makes a low altitude.

Let's say you are flowing 800 HP worth of CFM at high altitude. Now you go down to a lower altitude or DA. You can't instantly flow 1000 HP worth of CFM because you have reached the choke flow of the compressor and/or turbine and/or the housings.

This is even simplifying things because as you know the compressor map can have a huge impact on how the turbos perform at different altitudes because the PR and flow is going to be different at different turbo inlet pressures.

[J. Fast]

On to more facts, there isn't a 76mm that can support the airflow at "27psi" on a 3.0L to produce the stated numbers, and definitely not with that type of delivery. And before you say nitrous, the comp ratio and whatever combination of fairy dust contributed, remember that the turbine still has to evacuate that flow (and through a 3" downpipe..). So again, what are the details on this turbo?
....

I believe built 3.0 2JZ Supras are putting down 900-950whp on low 30's psi on 76mm turbo's and C-16 racegas so what's there not to believe? His compression ratio is 3+ points higher, he's using meth which has atleast 20points higher octane than racegas which means he can run max timing plus he's spraying it. Seems pretty legit.

I suppose if it were a Supra on the rollers your bias would go the other way...

I can't come up with a bunch of engineering to prove why it is, but if you think of it like this you can see how corrected numbers may be a lot higher than it really makes a low altitude.

Let's say you are flowing 800 HP worth of CFM at high altitude. Now you go down to a lower altitude or DA. You can't instantly flow 1000 HP worth of CFM because you have reached the choke flow of the compressor and/or turbine and/or the housings.

This is even simplifying things because as you know the compressor map can have a huge impact on how the turbos perform at different altitudes because the PR and flow is going to be different at different turbo inlet pressures.

I'd have to agree with you. If you don't have turbo's that can hit the numbers and run out of flow than it's not realistic. I think a 76mm is capable of flowing about 1000hp worth of air with simply boost only. I think where everything is getting jumbled up is the chemistry. The boost, I get that and it makes sense. When I drive down to sea level at 30psi I make 750whp and when I come back home at 30psi I make 600whp. I can understand that and have proven the CF is actually valid. What I have never seen before is increasing the charge density chemically with 3 different fuels. What appears to be taking place is he's basically recreating the relative air density of sea level in the combustion chamber by mixing all those fuels. When he drives down to sea level he will be able to combound the added 20% of air density BUT, he will have to have the fuel to support the extra air.


That was the kicker on the high altitude dyno vs sea level experiment posted. The SAE numbers, were almost an exact trace of eachother. The uncorrected power output was infact increased almost excactly to the SAE CF numbers seen at elevation. At the same boost at elevation vs sea level it was necessary to add 20% more fuel in (give or take) to offest the air increase.

So yes, there are some added variables like having a fuel system that can pump 20% more fuel in, and a turbo that can flow the air, and an engine that can stay together given 20% higher output, but if you've got that covered than it's certainly possible.

[HellBringer]

My only "bias" is for truth. Only the new billet/CEA 7675's are making those numbers. They're certainly not hitting 1k at 5400RPM. The older cast PTE 76GTS is good for an honest all-boost mid/low 900's all-in with all of the supporting mods; the Turbonetics 76's had a hard time touching 900 period.


The nitrous is also going to greatly skew things, further invalidating the correction factor. If you remove the 20% correction then the numbers are realistic.


For comparison's sake, here is a 7675 on a 3.4L, 10:1, E85. Boost was 38-39psi:

[donniekak]

A t76 flows 93lbs/min according to Garrett. That's good for mid 900's on an all out, fully optimized setup, squeezing every pound of boost its good for into a built engine, through excellent heads, and huge cams.

You can do what you want with fuel, it's air that makes the power. Different fuels let you take advantage of the air to a higher degree than others. It's a general rule that at best, 10lbs/min is good for 100whp on a very good setup.

Personally I don't let a dyno graph weigh in to much on how much real power a car makes. Post a weight, and trap speed. That's where the proof is.

[wingnut]

Personally I don't let a dyno graph weigh in to much on how much real power a car makes. Post a weight, and trap speed. That's where the proof is.

.....[/thread]

[UPPCOS]

Wholly crap, I step out for a minute and it goes nuts in here, I don't even know where to start.....

First off, the turbo. T76 is good for 9xx? Even the nay-sayer's in here agree with that right? Well cool, it only made 894 off the bottle so we all agree then that's possible. If you can't grasp that concept, go read a book.

Next, the nitrous. Yes, it adds power, it is a oxidizer, so there's my oxygen, it cools the charge which is denser so there's more oxygen, compound all this with the methanol which is aprox 50% oxygen by mass.....I have oxygen! . Now as I'm pretty sure I stated before there is a slight cheat here because technically the CF should NOT apply to the nitrous, as NO2 is really the only thing that's not truly effected by altitude. However there is no true way for the Dyno to separate this out and determine which is which, so we're left with a slightly skewed number. But if you really want the math ((1033-894)/1.2)+894= 1009hp K, good talk.

Next, ForestGump, you're wrong bud. I understand what you're saying, but you're infact saying it wrong. You are correct in a sense, the CFM never changes. That is a cubic foot is a max limited flow. This is like saying the moving man can move "x" boxes per minute. However you forget what's in the boxes. The density of the box at lower altitude simply has more air. You're still moving the same box of air, the same "cubic foot", just the density of that cubic foot is more to begin with. A few things to look at here. 1. Compressor maps generally aren't stated in CFM anymore, they're rated in LB/Min, as it tends to be more accurate and take into consideration density. 2. Compressor maps aren't rated in PSI or BAR on the Y axis, they're rated in P1 vs P2, that is the RATIO of pressure going in vs whats coming out. Because the pressure of what's going in plays a BIG roll in what's coming out. 3. This is the WHOLE principal behind a compound setup, I know because I made "Triple Charged", which was inherently a compound setup. The power of the system as a whole is determined by the first pump in the system. That is, the first turbo in a compound setup, the second turbo is always smaller. So how can the CFM of the first turbo flow through the second smaller turbo? Because it's more dense when it does.

If you still don't get it, look at it like this. The turbo is a pump, our engines are pumps. That being said they're the same. Now a 3.0L engine simply does not flow enough CFM to make 5XXhp right? No, it really doesn't. But if you boost it, the engine is still consuming the same CFM of air (measured at the TB) as it was before, it's still the same displacement. However the air is denser to begin with when it consumes it, so it does...

The dyno: This shit just gets old, you can't accomplish something so my equipment must be faulty right? This isn't rocket science kids. Hellbringer, let's look at your dyno. So using a 76mm turbo they cracked off 1135hp (yea, I rounded up the .6) at 38psi huh? Ok so why it it hard to believe that with 11psi less I was missing 241 hp? Would you expect it to be that I should be missing more? Because if you factor in that I'm 1 full comp raito higher, MUCH colder IAT's, AND have the added oxygen of methanol, AND have the ability to max out my timing..... 241hp for 11psi doesn't sound too bad, in fact it sounds like if I took a bit more time I could do better! Now you mention the "By 5400" I'm sure you're looking at the "with nitrous" map, which is SIGNIFICANTLY different than the off nitrous map. Turbos multiply what you feed them, hence the fact there is a non-linear exponential graph that follows the boost curve....I fed it ALOT of extra at the beging which prespools the turbo and compounds into alot more power (sooner), but notice not as much of a peak to peak gain.



I got so sick of hearing "This dyno reads high", "that dyno reads low" crap that I put them to the test. I PUT UP THE MONEY, I had the testing done! And guess what, they all pretty much read the same (except one, but they just don't know how to operate a dyno). There was an article written on this:

[UPPCOS]

Dyno Comparison Challenge Results

What We Did

We went around to all the local dyno facilities to gather data and see what and how big the differences are between them. Do all the dynos really tell a different story? Though lengthy, this is just a summary of the results found. We'll expand on this with a full-length version in the near future.

I'm sure we've all been there. Someone asks how much power you make, and when you tell them the results of your hard work, the response is "Yea, but on what dyno?" It's as if all your accomplishments are reduced to nothing more than a faulty piece of equipment spewing lies. Well, now there's concrete evidence to back up or deflate your response.

How We Did It

We chose one car, a turbocharged Honda Civic with an H22 making ~600WHP. We chose it because with such high horsepower, variances in readings show up more easily and with more detail. The car's owner built and tuned it himself, which means he had no ties to any one shop. The theory is since he has no ties, we'll get honest readings that any general customer off the street should expect to get. (We didn't want anyone purposely messing with numbers!) We tried to dyno the car at as many places as possible, on the same day when possible, to eliminate as many variables as possible. Because we were the ones hosting the testing, we decided to go first, to eliminate our messing with our numbers to match/raise/lower the results.

Results Summary

Generally, this is a subject that's very controversial, with loads of speculation coming from both sides of the aisle. But really, should there be speculation? After all, a dyno is nothing more than a tool for measuring. You never seem to hear Stanley and Craftsman arguing over who has the most accurate tape measure, so why does the automotive world argue? Well, this should end the debate. A dyno is a tool that uses a series of mathematical calculations to produce an end number. That is, measure how fast a given known mass is accelerated (inertia) or by measuring the strain (torque) during acceleration with a resistance applied (or both). They really should all read the same. And for the most part, they do!

We measured five different dynos and came up with numbers varying from 487 to 617HP. In order to throw out the odd-ball highs and lows, we decided to use the median average from all the tests as our documented standard and came up with 598HP. This gives us an even measuring point as to how far each dyno is from what would be the "average" power measured.

Improper Correction Factor?

As this chart shows, if we assume the car has the median measured 598HP, all of the dynos are within +/-2 percent, or a maximum variance of 3.9 percent. Pretty close, even considering the one with the biggest difference (-2.07 percent) was documented to have tire slippage, slightly skewing the results. And all of these are right in par with the dyno this car did in Virginia (at sea level) with a measurement of 603HP. That is, of course, except for dyno number 5, but as the notes column states, a "different" correction factor was used (for whatever reason), so let's take a look at that.

Correction Factors

A correction factor (CF) is probably one of the most misunderstood properties of dyno testing on cars. It's commonly seen as "Correcting for sea level" or "The power it would make if it were at sea level." Well, it's not!

In order to understand the CF, you must first understand why you're using a dyno in the first place. The dyno prints a number on a piece of paper, which is a measurement. But what good is a measurement if you have nothing to compare it to? The whole premise behind a dyno is to compare numbers of one car to another (or to itself after changes). Therefore, you must compare on an equal playing field. If you measure a distance in yards and another in centimeters, the two measurements are useless without some sort of conversion factor (for the dyno the correction factor) to make them comparable.

Simply stated, that's all a CF is: a calculation taking into account known variables to equalize the comparables. If you dyno your car on a hot day, then take it home, add a header, and re-dyno it on a cold day, the power numbers measured will change. But are they changing because you added a header or because the temperature was colder on the second dyno day? A proper CF takes this into account.

A CF simply calculates the changes for known variables: temperature, pressure, and humidity and calculates the measured horsepower into corrected power. The SAE (Society of Automotive Engineers) has come up with predefined constants for these (77degF, 29.234inHg, 0% humidity). Now that we have constants, we can adjust accordingly. These adjustments are made all over the U.S. on every dyno (usually automatically by the dyno software). This now makes a level playing field where you can compare your numbers from a dyno at 6000 feet in Colorado on a 32-degree day, to someone at 0 feet in Florida on a 102-degree day.

This, however, does not mean that if you take your car to sea level, these are the numbers you will produce. If, for example, you max out your injectors at 6000 feet, when you travel to sea level, the air density changes, and you have to use more fuel, fuel that's not available. Therefore, your car will not produce the corrected power numbers. (In fact, it will probably run lean and explode!) It's simply a way for people to fairly compare different setups during different conditions.

Changing the CF (half CF)

The claim is that on boosted (super/turbocharged) cars, the CF should be only half of what it is for naturally aspirated cars. This is about the most ridiculous thing you can do! Not only is it incorrect, but it creates numbers that are absurd that cannot be compared with any other dyno (oftentimes not even with itself!), and back to the basics, isn't that why you're using the dyno in the first place – to compare? Think about it, if we're correcting for humidity because the water molecules in the air are displacing the oxygen molecules, does that mean that on boosted applications half the water is simply going to "leave the air" before being sucked into the intake? No! So why are we only correcting for half of it? There are some applications where SAE J1349 states not to use a CF. (We will address this issue in the full review but even then, it's not some made up number of half!)

Uncorrected Numbers

Again, these numbers are not correct(ed)! Many people like to brag using "uncorrected" numbers. Well, were those numbers measured on a hot day or a cold day? One car on a hot day may show less power than another on a cold day, even though the actual results are different. The only thing an uncorrected number is good for is to show what that specific car would run at that specific time, temperature, altitude, humidity, and pressure if you were trying to calculate what it should run in the ¼ mile right then. Tomorrow, if the conditions change, the results will also change.

So Why the Differences?

As you can see from the chart, all of the dynos read within +/- 2 percent of each other except one, but why? If four out of five agree, you really have to start questioning the 5th one. Is it possible that it's just a poor dyno? No, not likely. If some company produced a dyno that consistently created numbers out in left field, the general public would eventually catch on, and the company probably wouldn't sell very many dynos.

Chances are it's probably the dyno operator. Whether he mis-calibrated the dyno, is untrained in exactly how to use it, or is just downright shady, one can only speculate. But if you take a moment to look at the numbers, and listen to what the dyno operator is saying, you can often pick up some clues! Dyno #5's operator used a trap speed calculator with this car since it has been known to trap 130mph in the ¼. Based on that and the weight, he comes up with a number of 488HP, pretty close to the numbers he already has from the dyno. Convenient? No, not really, it's pretty simple math here. What the dyno operator does not realize is that the trap speeds are based on the uncorrected numbers, not the corrected numbers! Why? Because that's what your car is actually outputting to the ground, at that exact given moment, and that's exactly how it will perform. But mind you, we're still at 6000 feet, so those numbers would do no good to compare with anyone else's. What this seems to equate to is though the dyno operator claims a correction factor of 1.15, it appears there really is no correction factor being used! Either he mis-calibrated the dyno itself, or he's an untrained user of the software. Either way, clearly the numbers are wrong!