Off-the-shelf calibrations are offered, as well as bespoke software tuned to your specific combination of engine, injector size and modifications. That said, larger MAF sensors are now in production that can handle higher engine speeds on big engines. Speed density systems can handle much higher rev counts than ordinary MAF sensors, which tend to go on holiday when you get up to the realms of 8000-9000rpm – although other variables apply here. That said, many MAF sensor-equipped cars still use O2 sensors to be safe. With one sensor and the live ‘revs, operating phase, idle etc’ information coming through the ECU the air density being sucked into the cylinders is calculated and fuelled for. ![]() ![]() The extra voltage that the car has to send to the wire to keep it a constant temperature is directly proportional to the air flow. By controlling the intake valve timing and lift to suit the engine load and speed conditions, AVCS optimises the engines volumetric efficiency and combustion. Most use an electrically-heated wire that is cooled by the passing air. It sits smack-bang in the middle of the intake air flow, away from bends in the plumbing and centrally in the pipe so that it the core air flow has to pass it – ensuring the most accurate measurement. Following the tuning schools printed course on gen 5. However, because of the concept of volumetric efficiency, the calculated and measured values will be quite different, related by the equation below. The following table presents the fuel efficiency, in miles per gallon, for a sample of convertibles and a sample of sports cars. 2002-2005 Subaru Impreza WRX (Manual Transmission) Glossary of Acronyms ECT Engine Coolant Temperature ECU Engine Control Unit IAT Intake Air Temperature. By knowing the engine displacement and RPM, I can estimate the volume of air that the engine should be pushing through. Uploaded a no maf tune which is shown below. C:Program FilesOpenECUEcuFlashrommetadata). Delete the Subaru folder (backing up if necessary) in the Metadata directory specified in File->Options menu of EcuFlash (ex. Choose the file with the units you wish to use (metric or standard). Estimates of gas mileage, greenhouse gas emissions. Download the latest EcuFlash definitions file available HERE. A speed density kit (Image via SP Engineering) The 'SD Volumetric Efficiency' table is the primary means by which the SD tune is accomplished. 1984 to present Buyers Guide to Fuel Efficient Cars and Trucks. Probably not a bunch of help but a free bump if nothing else. The easiest way would be to capture data directly from the stock MAF and use the calcs in that link above. Would like to just get a conservative map set then start tweaking it since im still really new to all this. I calculated up a bunch of other stuff but been interrupted too much this morning and not sure how accurate it is. Tuning a ej251 on a wrx ecu with the carberry rom which has a volumetric efficiency map, that im going to be tuning for and NA ej251, looking to see if anyone else has any Volumetric efficiency maps or tips I can reference for the ej251. Below is a list of three cars, we look at the RPM of the peak VE and see how much tuning potential these engines have (without increasing engine stress) Honda S2000, 2004 Normally Aspirated (Non Turbo) Nissan Micra 1.2, 2009 Normally Aspirated (Non Turbo) Ford Focus ST, 2014 Turbo. TAF = 285.87 Ft³ (theoretica air flow from displacement) Some things that might help kickstart your calculations if you don't have them already. I'm sure a dozen other variables that I haven't even come across. You'd have to take into account pressure drops from IC, turbo efficiency (from a compressor map, incidently I don't know of one for Suby turbos), engine's naturally aspirated VE (probably ~80%), boost pressure, atmospheric pressure, temperatures, IC efficiency etc. To actually calculate it from scratch without the data would require a lot of calculating I believe. 06:36: Now the numbers in this table represent the engines volumetric efficiency. 06:30: In the middle of the page you can see here, weve got our VE table which is filled with a whole lot of numbers. I don't yet have scanning software to help determine the actual volumetric flow rate on the Suby yet (use datamaster for my T/A). And here were on the VE or volumetric efficiency tuning page which is where were going to be making changes to our fuel delivery. Click to expand.Hmm, let me just offer this up.
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