BCD, Dashhawk & you!

Does the BCD mess up the ECU's boost reading?
The Dashhawk is reading spike 14.6 holding 8-9psi. But, my Greddy EBC is reading spike 19.5 holding 18. I cannot figure out why...

boosted3 said:

Does the BCD mess up the ECU's boost reading?
The Dashhawk is reading spike 14.6 holding 8-9psi. But, my Greddy EBC is reading spike 19.5 holding 18. I cannot figure out why...

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The dashhawk displays what your MAP sees. If you are tricking your MAP with a BCD, Clamp, Whatever, the Dashhawk will not read accurate boost.

Yea at least tune your greddy unit with a real boost gauge first, than disconnect it unless you dont care about a accurate boost reading.

Sierra117 said:

The dashhawk displays what your MAP sees. If you are tricking your MAP with a BCD, Clamp, Whatever, the Dashhawk will not read accurate boost.

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your ECU is also only tuning for whatever the MAP sensor sees. so if your MAP sensor is seeing 15 psi and you are at 19 psi, your ECU is only tuning as if you were running 15 psi.

it is my understanding that the car doesnt tune off of the MAP sensor ....
it is there for referance only. it tunes off of the MAF and o2's.
i know cp-e claims that you can clamp the MAP down as low as you want (several are down to 10psi) and it has no effect on the tune or fuel addition.
i know i am clamped at 10.5psi and running 20 !! i think if my car was only adding fuel for 10.5psi when there is really twice as much i would have blown up by now. especially in the freezing temps we have been having.

it definetely has a tuning effect. we opened up alot more usable horsepower and smoother fuel curves once we ditched the BCD on the dyno at P&L. totally different car once we clamped it with the XEDE rather than use the BCD. thats not to say its the only reference point, but it is a major one.

clamping it, especially with the CP-e and XEDE, works differently than bleeding off boost with the BCD.

i agree you will make more power and be more efficient with a map clamp or xede, just for the simple fact that the boost is not bled out with those like it is with the BCD from ATP. the point i was trying to make is that the car does not make "tuning" related adjustments based on the info it recieves from the MAP sensor. just because the MAP says there is 10psi in the manifold does not meant the ECU is only adding fuel for 10psi. from what i have seen the map is used for nothing but to trigger overboost cut. the BCD and electronic clamps do the same thing.....lie to the ECU. one does it electronically and the other manually. i knew the BCD was not the best way to trick the ECU, thats why i was the first to do the map clamp !! but to answer the original question. the dashhawk will never show the actual manifold pressure if you have ANY of these MAP signal modifiers.