MAF value = Horsepower potential
03-06-2019, 12:50 AM
#77
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03-06-2019, 12:57 AM
#78
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Well there's a bit of that aspect to it, but it's also practical. Let's say you baseline your car. Now you make a change. You want to know how much of that change (different MAF values) was due to the change vs. the fact that yesterday it was 40F and 10% humidty and today it was 60F and 40% humidity.
This is about putting some science down that we can all do without renting dyno time. Poor man's dyno.
This is about putting some science down that we can all do without renting dyno time. Poor man's dyno.
Also look at my IAT temps, cool air, you wont get that on the Dyno !!! I think that is one reason our cars do poorly on the Dyno..
03-06-2019, 01:21 AM
#79
I'm using Bluedriver. I don't think I can monitor altitude and humidity. Using a weather app, it's 58F and 85% humidity. Basically sea level since I was on Pacific Coast Hwy.
03-06-2019, 01:32 AM
#80
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BTW, how many miles on your 3.4? Any mods?
EDIT : I see your Mod list above, but mileage?
Last edited by Porschetech3; 03-06-2019 at 01:52 AM.
03-06-2019, 09:44 PM
#81
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But our numbers are airflow with fuel delivered, so won’t our calculated/measured numbers going to be higher than what a dyno would measure? I’m not talking about transmission and diff/driveline losses, just other engine losses like crankshaft, piston ring friction, crankcase pressures, camshaft chains, valves and valve springs, etc.??
03-06-2019, 10:19 PM
#82
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I’m guessing everyone’s figures won’t take into account all sorts of losses, such as oil pump, accessories, etc.? I mean the actual HP an engine produces is probably higher than what can be measured at the crankshaft unless these accessories are included in the crank-based dynamometer.
But our numbers are airflow with fuel delivered, so won’t our calculated/measured numbers going to be higher than what a dyno would measure? I’m not talking about transmission and diff/driveline losses, just other engine losses like crankshaft, piston ring friction, crankcase pressures, camshaft chains, valves and valve springs, etc.??
03-07-2019, 02:56 PM
#83
I'm not sure of exact mileage. The Porsche dealer put in a re manufactured motor in late 08/ early 09. Roughly 70k miles
03-09-2019, 01:46 AM
#84
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03-09-2019, 03:34 AM
#85
My sample rate for my setup is 5 times per second for the ELM327 and Torque Pro, but I'm monitoring MAF.IAT, fuel trim long and short, 02 sensors, coolant temp, throttle position, timing, all on different flip through screens. 5 times per second seems to be enough to be consistent if doing a 3rd gear pull, may not be fast enough for a 1st or 2nd gear pull.
BTW, I think the way Torque Pro works is it only queries for the PIDs that are relevant to the current screen you're on so the fact that you have other PIDs on other screens should not slow it down.
If you turn on logging for the run, you will see the log spits out about 10 rows per second. Each row will have the readings of all the PIDs you selected but then their values change at most once a second even though you know they change constantly in reality (e.g. rpm during a pull).
03-10-2019, 03:37 PM
#86
Logged a quick run with my foxwell today. Outside temp is 62, local elevation is just under 600 ft. Quick 2nd gear run had .46lb/s at an IAT of 75. In grams that's about 208. Car is a 2000 C2 6 speed with IPD competition plenum and tb, AWE headers, speedtech mufflers, catless X-pipe. I'm going to try a 3rd gear pull and see what that nets.
03-10-2019, 03:51 PM
#87
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Thread Starter
Logged a quick run with my foxwell today. Outside temp is 62, local elevation is just under 600 ft. Quick 2nd gear run had .46lb/s at an IAT of 75. In grams that's about 208. Car is a 2000 C2 6 speed with IPD competition plenum and tb, AWE headers, speedtech mufflers, catless X-pipe. I'm going to try a 3rd gear pull and see what that nets.
03-10-2019, 04:42 PM
#88
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You are absolutely correct, our measured numbers are for absolute power with no losses. No losses from alternator, power steering, water pump, friction, drivetrain ect. We should probably come up with a new name for it since it is a new way of measuring power/potential out of the many ways that already exist. Here is a link to an article on some of the ways horsepower is calculated/corrected. https://www.dynomitedynamometer.com/...horsepower.htm
03-11-2019, 07:15 PM
#89
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The expected change in air flow from bolt-ons would be 7.5 g/s per 10Mhp.
With over 5k views there seems to be enough interest, just need to put out a little effort to help the community. Don't be concerned to take the engine to redline, if it can't go to redline it isn't healthy anyway.
Last edited by Porschetech3; 03-11-2019 at 07:30 PM.
