someone explain speed density

**TurboRacerGSX** · January 21st, 2007, 03:26 PM

and also tell me why im gonna regret buyin a maf-t set up.

**TurboRacerGSX** · January 26th, 2007, 10:41 AM

noone knows huh

**Jon** · January 27th, 2007, 08:16 PM

Other than tuning, I see no regret in putting a MAF with translater in place of a MAS. There's a writeup on speed density and such on vfaq I think. Otherwise google will provide you with answer that I cannot.

**TurboRacerGSX** · April 8th, 2007, 08:27 AM

Speed Density
Speed Density systems accept input from sensors that measure engine speed (in rpm) and load (manifold vacuum in kPa), then the computer calculates airflow requirements by referring to a much larger (in comparison to an N Alpha system) preprogrammed lookup table, a map of thousands of values that equates to the engine?s volumetric efficiency (VE) under varying conditions of throttle position and engine speed. Engine rpm is provided via a tach signal, while vacuum is transmitted via an intake manifold-mounted Manifold Air Pressure (MAP) sensor. Since air density changes with air temperature, an intake manifold-mounted sensor is also used.

Production-based Speed Density computers also utilize an oxygen (O2) sensor mounted in the exhaust tract. The computer looks at the air/fuel ratio from the O2 sensor and corrects the fuel delivery for any errors. This helps compensate for wear and tear and production variables. Other sensors on a typical Speed Density system usually include an idle-air control motor to help regulate idle speed, a throttle-position sensor that transmits the percentage of throttle opening, a coolant-temperature sensor, and a knock sensor as a final fail-safe that hears detonation so the computer can retard timing as needed.

**99 VR4** · April 8th, 2007, 11:19 AM

Jason...
speed density= best of both worlds. no restriction in your intake piping, and if you get a boost leak it wont screw up your a/f ratio. Aside from that it's more accurate and stable method of measurement, and will idle way better than a MAF-T setup. But it's also more expensive :) and requires a standalone or piggyback EMS.

**98spydert** · April 8th, 2007, 03:12 PM

You won't regret the MAFT set up. It's better than anything EXPECT a speed density set up. It's better for tuning the SAFC and more accurate than the stock MAS. The position right before the throttle body is also way better than the stock set up. Personally, I'm not going to be running 9s... ever. I just won't put the money into it. So DSMLink and the MAFT is as good as I'll ever need. It's perfect and comfterable for a DD and capable of 60 lbs/min. If I thought I'd ever get serious enough for some 600+whp numbers, I'd probably go all out on a standalone and speed density set up.

**TurboRacerGSX** · April 8th, 2007, 08:06 PM

sweet thanx guys. our plans are to take my ported built head and mate it to scotts built block and keep mine for back up. his i sbuilt to handle 1000hp. my dumbass put eagle rods in mine lol. the we wanna hook a turbonetics GTK-900 to it and run DSMLINK.:)

**98spydert** · April 8th, 2007, 08:32 PM

DSMlink V3 will support the hotwire MAF directly. No need for a MAFT. But it might take another year for V3 to be released so I woudln't bother waiting for it. V2 with the MAFT works perfectly.

my2AWDgst · May 5th, 2007, 08:23 PM

How much for a V3 upgrade?

**98spydert** · May 6th, 2007, 10:11 AM

The V2 upgrade was only like $65. V3 is a complete rewrite so it might be more like $100. But DSMLink will go up in price when it comes up anyways because it'll rivel AEM and other high dollar systems.

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