s57_s2k

hi

My MAP reading at WOT is ~97 kpa below 6000 rpm and 95~96 above 6000 rpm , considering ATM pressure is 101 kpa , I think my car is choking above 6000 rpm and I need CAI .

what is your reading ? and do you think an exhaust system will help the car to breath in addition to CAI ?

DFWs2k

what's your reading at idle?

D1sclaimer

I wouldn't worry about it. If anything, I think its probably your tune.

deibit

Hi.

I just took some measurements.. there was traffic on the highway so I was not able to pass 6000rpm at WOT (my VTEC entry point is lowered thought)

At WOT I got the following (those are averages, not peak values)

4000rpm: 99.0 kPa
5000rpm: 98.4 kPa
6000rpm: 97.7 kPa

I will try to get tomorrow a longer measurement (WOT from 3000rpm to the cut).

By the way, I have OEM intake, but ASM 07 Header, Berk HFC (those two things really help with breathing), a Tanabe dual exhaust, and a Giles tuned EMU.

I have a F20C-DBW (EUDM MY08)

Today is rainy (so low barometic pressure).. but I did not log the exact pressure sorry.

s57_s2k

~27 kpa when ECT is 90 C .

s57_s2k

I do not think my car has any problem , I just want my MAP reading to be a little bit higher . my car now has 212 rwhp (dynojet , mod test pipe only) .

Dan1987

If all atmospheric conditions are deemed as constant for the sake of this point, then the only way to raise your MAP reading is to reduce any choking that may be occuring INFRONT of the sensor, i.e. Throttle body and intake.
This is why s2000's often run slightly lean if mods are done to the header and exhaust prior to a tune, because the MAP reading drops as the exhaust side has been free'd up and the intake is still standard (or not as great an improvement in flow compared to the exhaust side). And as fueling is dependant on MAP readings (especially in the DBW cars) this can result in that leaner condition. If intake mods are done without a tune and without exhaust mods then the fueling should still be running at the same AFR as before..as the MAP should have also increased accordingly.

Dan

wadzii

from my experience an intake or throttle body wont solve this.. IMHO its intake manifold related, but I havent been able to do any good testing to prove it..

thats one of my goals once i get my car back together.

deibit

I think that would be right if the sensor would have been placed in the intake manifold.. but for some reason the sensor is placed in the TB.

So, it seems like the S2000 MAP doesn't measure the pressure diference between the intake manifold and the atmosphere (which would be the academic definition of "vacuum") but the pressure difference between the TB and the atmosphere..

(But I might be probably wrong in that)

wadzii

honda did a good job with placement of the map sensor.. but it really doesn't matter where the map sensor is the readings will be the same. The passage on the tb that "feeds" the map sensor is behind the throttle plate.. .anything behind the throttle plate is the plenum.

I run a custom 4inch CAI on my car along with a 70mm throttle body.. on the dyno there was no real difference between WOT map readings with any combo I tested.. 3inch short ram or stock throttle body. Mine would dip to around 91ish kpa at high rpms

Gernby did an experiment and moved the map sensor to the middle of the plenum, the readings were about the same.