I make the harnesses @ 60$. If you’d look at the materials there is a huge difference.
Good for you for offering a more budget friendly option.
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As an engineer...how do you equate a value/dollar figure to heat cycling resistant?
I gotta say I received a quality harness from 8JVR6.
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Any benefit using AEM 5bar MAP? Currently mine is running 34PSI with just lower 4bar installed, I can see actual boost from VCDS.
Now on to the problem with the Bosch 4 bar... I think its the the pressure range rather than the resolution. The little data I've found on it, says it only reads down .5bar (-7.25psi relative vacuum at sea level). This is not enough for a gasoline engine as they tend to idle and operate at low throttle in the -9psi to -12psi range. So this sensor won't work properly when used on the manifold for load/fuel calculation. It'll work fine as a TIP sensor since it doesn't need to measure vacuum there. The AEM 5 bar, for example reads down to 0 bar (-14.7psi relative).
So this explains why some of you are having idle and low throttle drivability issues with the Bosch 4 bar in the intake manifold. There could be software tricks around this by calculating low load based on baro pressure, temperature, and throttle angle, but that's far from ideal. So until we can find a better a P&P 4 bar solution, it seems that the AEM sensor is the best bet.
So I’ve been testing out the 4 bar sensor and there is definitely an issue at very low throttle angles right at the transition to decel. The sensor can’t read the high vacuum properly and results in -34% fuel trims and unstable a/f in that area. The result is a bit of a dead spot in the throttle in that transition as well as slightly jerky on/off throttle transition. This is most noticeable around 2000rpm in the 0-10% throttle range. I could see a lot of people not noticing or being bothered by the resulting drivability issue, but its not correct regardless. I’ve been able to smooth out the transition some with some tuning tricks, but at the end of the day, it’s just masking a real deficiency. For those talking about UM cars, I’ve only had one such car on my dyno, but that car also had a hard stutter at that spot, so I don’t think there’s anything too different going on.
FWIW, we’re at sea level and this issue would likely be much less prevalent or even cured at higher elevations. Maybe the folks reporting no issues are just at high enough elevations to get back into range of this sensor.
Matt, you should also mention that you have a boost gauge and that's why you have that "T" fitting with your AEM 5bar and boost tap. For those, like myself, that don't have a boost gauge, you would connect the 5bar MAP sensor directly to the boost tap.