jorgea3281
Member
I went to the dyno on Saturday. My 1 run was about 273, 2 run 276, and 3 run 292. To me they sound way to high for the mods that I have. And yes this is to the wheels. What do you guys think? My mods are listed in my sig.
Sounds to good to be true?
- Thread starter jorgea3281
- Start date
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- 2006 VRM Mazdaspeed6 GT, 1983 RX-7 GSL
If you didn't have the AP, I'd agree with you. Sounds about right to me, though.
-Jay
-Jay
Well, the numbers spit out by a chassis dyno aren't actually "hard" numbers anyway. Chassis dynos vary wildly between manufacturer to manufacturer and sometimes even dyno to dyno from the same manufacturer. They are best when you are trying to get comparisons utilizing the same machine over and over again (either different cars to each other or your car over and over again).
It is possible that your HP varied about 6% throughout the day as the numbers showed. That is a value that is pretty accurate. You could have put your car on a Mustang Dyno -- which usually reads low -- in between and it could have showed you 240-ish. The "real" number is probably somewhere in the middle of the two extremes.
Just call it 292 and be happy. That number is just as accurate as the horsepower numbers anybody else is throwing around here. Just don't be surprised when somebody puts down 300+ on the same dyno. It's all relative anyway.
It is possible that your HP varied about 6% throughout the day as the numbers showed. That is a value that is pretty accurate. You could have put your car on a Mustang Dyno -- which usually reads low -- in between and it could have showed you 240-ish. The "real" number is probably somewhere in the middle of the two extremes.
Just call it 292 and be happy. That number is just as accurate as the horsepower numbers anybody else is throwing around here. Just don't be surprised when somebody puts down 300+ on the same dyno. It's all relative anyway.
jorgea3281
Member
Well the it was a dynojet. And the three runs were done in less than 30 mins. I do agree that you use the dyno a reference point for future mods. Just seemed high for such little mods and a basic map. My friend with 03 cobra put down 426 with just a k&n filter. Everything else stock. I also thought that was high. Hopefully it's just me that is seeing it like this.
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- 2006 VRM Mazdaspeed6 GT, 1983 RX-7 GSL
I think the real question here, though, is if it's realistic to expect an MS6 with bolt-on upgrades, a test pipe, and a Stage 1 93 octane tune to average 280 WHP over three runs. I think it is.
At the very least, you can brag to your WRX friends about a 292 WHP run and have the proof to back it up. (thumb)
-Jay
At the very least, you can brag to your WRX friends about a 292 WHP run and have the proof to back it up. (thumb)
-Jay
Sounds like your dyno operator is "playing" with the dyno settings. A Speed6 with your mods and OTS map should put down about 250. The power will drop on subsequent runs, not increase, as well. Ask them for the drf run file and send it to me.
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- 2006 VRM Mazdaspeed6 GT, 1983 RX-7 GSL
Nevermind. Forzda knows more than I do about this stuff...
-Jay
-Jay
What was the correction factor formula used, if any? If ANY corrections are calculated into the results, then the numbers are invalid for any comparisons. The correction factors are based on normally aspirated engines due to temp, baro, and altitude. When NA correction factors are applied to FI engines the results are generally skewed WAY high. This fact is why I post the uncorrected raw numbers for my dyno results....
jorgea3281
Member
I will be going back this saturday to get my new tires installed. I'll talk to them to see what corrections they made. The car has half the mods your car has(forzda 1), but the same power. For me that make it questionable.
You know, honestly, I'm not sure. All I know is that Tim Bailey did an awesome job with my car's issue
.My car was overboosting like crazy (spike to 22psi, drop to 17psi, then creeping back up to 21psi). My stock wastegate wasn't dumping enough so he said to remedy that I either need an external wastegate or a high-flow cat. So, until I get either one of those...he set my boost level to where it's at. No boost cuts or anything of the like and it definitely pulls harder and runs better than it did before the tune!
I'm guessing that I'd have to get in touch with Surgeline to get the formula?
Really all you need is the dyno sheet if they printed a full version of it for you. The correction factor (it will be "1.00" +/- the correction amount. 1.10 says the dyno added to the result and 0.90 says the dyno subtracted from the result) and method (STD, SAE, "Uncorrected", etc.) should be listed right on it.
Oh, and the amount of "Smoothing" applied to the graph will affect the max power number as well. The graph trace is always a little bumpy/erratic and the dyno software can "smooth" it out. Generally speaking, the higher the Smoothing" factor, the lower the peak number.
Some dynos are calibrated to produce "higher" numbers and some "lower" numbers. The local conditions, temp, baro, and humidity all affect the power, but less so on turbocharged cars. The dyno I use is calibrated to "reality" numbers based on the airflow and the OEM rated crankshaft power minus drivetrain losses. The Speed6 will lose ~25% of the crankshaft power in getting it to all the wheels. Here is a ballpark conversion formula table:
http://www.mk5cortinaestate.co.uk/calculator4.php
According to this table, 292 awhp would require 360 at the crank. So does anyone really believe that an intake pipe and a "tune" will raise the OEM power from ~270 to ~360 = +90hp? I don't think so Tim....
I (re)posted my last two dyno sheets so you can see and compare. You can see the high-speed oscillations in the first pull as the VVT was trying to maintain cam timing and in the second pull the VVT actuator failed internally and "lost" control of the cam position. The sudden spike in cylinder pressure as the cam advanced at high rpms blew the #3 injector seal. Also note that I was revving the motor all the way out to 7k rpms to see how the power held up. Note that this was my first experimental dyno runs right after the turbo install, so they are not the "final" numbers by any means. You gotta break a few eggs to make an omelet....
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I would add that drivetrain losses can't be expressed as a percentage of the total. Drivetrain losses are almost fixed. If you are losing 50hp at stock power levels you won't lose a lot more in the drivetrain as you add more power. Bearing and gear loading won't suck up power in a linear fashion as power goes up. The percentage drivetrain loss has to be one of the most overused and believed old wives tales in car tuning.
A common sense example is say you had an AWD car making 200hp at the engine. You measure 150 at the wheels and assume a 50hp drivetrain loss. If you then doubled that cars power to 400hp would you now be losing 100hp and only making 300hp measured at the wheels? Not at all likely. That is a massive amount of energy being dissipated in heat(which is what drivetrain loss turns into). To give it some scale an additional 50hp drivetrain loss is the equivalent to 620 60 watt light bulbs. Imagine the amount of heat they would put off and all that heat being under the car. Better yet all that heat being concentrated in the transmission, drive axles etc. These things would be ungodly hot after a dyno run if that were the case. But they are not. In reality you might see an additional 10hp lost as the power went up.
A common sense example is say you had an AWD car making 200hp at the engine. You measure 150 at the wheels and assume a 50hp drivetrain loss. If you then doubled that cars power to 400hp would you now be losing 100hp and only making 300hp measured at the wheels? Not at all likely. That is a massive amount of energy being dissipated in heat(which is what drivetrain loss turns into). To give it some scale an additional 50hp drivetrain loss is the equivalent to 620 60 watt light bulbs. Imagine the amount of heat they would put off and all that heat being under the car. Better yet all that heat being concentrated in the transmission, drive axles etc. These things would be ungodly hot after a dyno run if that were the case. But they are not. In reality you might see an additional 10hp lost as the power went up.
