MAP sensor location

[thedugan]

Where are you guys putting your MAP sensor. I want to hide it as best I can. Does it have to be above the plenum? Is distance a problem>

Thanks

Doug

[GetMore]

I don't think it's location is critical. You do want to use a line large enough to not cause restriction. Height shouldn't make any difference.

[camcojb]

you want it as close to the vacuum source as possible. A few inches is fine, and it can be hidden wherever, doesn't have to be above the manifold at all. I would avoid putting it inside the vehicle just due to the distance of the line, affects the signal to the map.

Jody

[amx2334]

Probably not a problem on PT cars but you don't want a low spot in the hose.Condensation can build up in the line. I used to work on alot of K-cars.

[viper11]

I
have mine under the throttle body at the back of the manifold
don't quote me on this but I read on a very reputable site that vaccum hose length(a few feet) has a negligable effect on the signal
anybody know for sure???
jason

[red67camaro]

The MAP vacuum needs to be sourced from the plenum to keep pressure pulsations to a minimum.

I've seen quite a few vehicles that come from the factory with 2-3 feet or more of vacuum hose to the MAP with no ill effects. I've even seen some with a small inline reservoir to, I assume, dampen pulsations and/or keep fuel vapor from reaching the sensor. In later years, I've seen more and more MAP sensors mounted directly to the manifold with no hose at all.

Adding length to the hose will slow the MAP sensor's response to actual manifold pressure changes so keeping it as short as possible would be a good thing. That being said, I wouldn't worry too much about having a foot or two of hose as long as it was of suitable diameter and had no kinks or other restrictions.

[Fuelie Fan]

Pressure waves travel at the speed of sound, which is about 1100 ft/sec or 1.1 ft/ms. I'm a few years out now, but the company I used to work at sampled the MAP every 15 ms. even at a 5x factor, this still allows for 3ft of vacuum hose. Some of the OEs are actually using the MAP fluctuations to glean more information from the engine, in which case the damping provided by the flexible hose is a problem. Plus, it's just plain cheaper to integrate it. But a few feet should not be a problem.

[greatwhitess]

Run a vacuum line off of the back of the intake somewhere and hook it to the MAP with a hose clamp nice and neat out of the way.

[thedugan]

Great this is what I want to hear.

I got a spot out of the way, low behind the engine.

Thanks Guys