daftphunk

I was under the impression that ambient temperatures would also affect the tune/how your car would run with a MAFS as well, no?

Melonburst

As far as the load sensors (MAF vs. MAP) debate goes. Yes, MAF's are preferred for low horsepower applications because they are easy to tune with higher accuracy success rates and enable tighter control of emissions. They measure actual air flow and take into account barometric pressure, altitude changes, humidity, and ambient temperatures and adjusts fuel accordingly but also has a higher chance of failure due to its design, break the hotwire with a slight wall tap (combined with old crappy S-Chassis harnesses) and you run rich and risk engine failure. Another downside to MAF sensors is that at idle or low RPM situations there can be vacuum pressure which tampers with its accuracy, they also don't respond well to the cold since condensation can occur on the hotwire again leading to inaccuracy.

Now MAP sensors are praised for their simple and minimalistic design measuring actual manifold pressure (Pressure! which is Baro Pressure + Altitude changes) but does NOT take into account humidity. Then the IAT sensor measures the temperature and is read earlier by your EMS to calculate A/F ratios and improving throttle response over MAF sensors. MAP sensors rarely if ever fail/break, again due to its design. MAP sensors aren't as accurate and require a lot of knowledge to become so and in addition are much harder to tune. A properly tuned MAP based system is far more beneficial compared to a MAF based system on a forced induction car. Especially when you're running a car with over 450hp.

In conclusion they both have their pros and cons and ultimately it comes down to the users preference and platform/supporting mods and the tuners skill level. Hope this clears things up a bit.

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S14DB

MAP does not take Barometric Pressure into account unless the ECU is designed to take a Baro reading before the engine starts. It goes on the Vacuum Pressure at idle compared to the expected value. If the VE of the engine changes it can't compensate.

Some modern ECUs will quickly grab a Baro Value on ignition on before engine start to correct the base map. Earlier models had a idle trim pot on the ECU to dial it in depending on the altitude and VE.

I have not seen a aftermarket ECU that grabs the Baro Value before engine start.

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Comments should be taken as Opinions not as Statements of Fact

Gription

I'm surprised no one has suggested doing a blow through maf setup.

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smelly240

AEM has an internal baro - Haltech has a internal baro -

just about every standalone has some sort of baro (some do it before u start the engine like lots of stock computers - like megasquirt)...

Blow through lowers the max hp capable of the maf. I maxed out a z maf at 456 - put it draw through and i got 51 more hp before it maxed... Also nissan mafs dont seal well... you gotta fill them up with epoxy.

If you're running 360hp on your 2871 and dont plan on going much past 400 - maf is great. After 400 - I recommend a standalone. Yes you can make 500 something on a std ecu - but you'll find out that it is far less stable.

readings get less stable - and the runs arent going to be as repeatable. A lot of it has to do with the stock crank/cam angle sensor with its remarkable resolution... it just isnt good for a hard revving engine. It is excellent until you get up in HP.

AEM ships now with a CAS disc with 24/1 configuration with their EMS because of stability issues at high HP/RPM. Mazworx also makes a sweet trigger setup similar to what t1 does for hondas.

Mazworx SR Hall Sensor Kit - Electronics - Mazworx

Either way - SD/maf - both have positives and negatives - but it depends what setup you're running. Street cars dont need to go MAP. Racecars and high HP cars definately benefit from it.

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HREs on a S13 - check, 6262 - check, Girlfriend.... - nope

Corbic

LS-series run MAP, and I believe the JZ-motors are all MAP as well.

A GM MAP sensor is around $60. MAF sensors are stupid expensive.

smelly240

LS1 has a maf as do all LSX

2jz has a maf (except Aristo)

a nice map (stainless steel 3.5 or 5 bar) is like 155 bucks GM 3bar is ok - but i recommend a restrictor pill or a tiny vac line or you'll see all sorts of fluctuation comapred to a nice map sensor.

A z32 maf at the auto parts store is like 120

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HREs on a S13 - check, 6262 - check, Girlfriend.... - nope

Corbic

I guess I haven't been around a stock LS1 in to long a time. My 5.3 setup uses a MAP.

SomeoneWhoIsntMe

megasquirt does, and you can add a second MAP sensor to take constant baro readings