MAP input for ITB

[Trump]

I am up rating my NA 4Cyl from multi point, fully sequential, single TB and plenum, to 4 independent TBs. It is not complete yet and I have a question regarding the acquisition of suitable MAP readings.
MAP readings for my engine at idle is around 60-65kpa and requires a fair amount of smoothing and a fuel filter in the MAP line.

The TB set up I will be using has no balance tube connecting all four inlet runners. If the MAP was taken from one runner it would have a very lumpy reading based on one cylinder.

Would this be suitable for the fuel PRV and the MAP sensor? How do other set ups get the MAP reading.

[wes kiser]

Most tie all 4 together with a small plenum and reference that.

Even still you will find the best results mapping using a blended SD/Aplha N appreach. ITB mode is an "easy" way to do this if not boosted.

[Trump]

My intention is to use the ITB mode but need to know if I really do need to build in a small balance tube to get a MAP that will be suitable for both fuel PRV and the MAP sensor.

[GDP]

I have done a few ITB setups but not familiar with a triump, but if its a piston engine with valves just remember that using one cylinder wont work cause as the intake and exhuast valve close for compression stroke there in no vacuum in the intake runner to reference, but the other cylinders will be needing fuel, this why you need to have all four tied together, for the map of couse, plus the added noise of the intake valve closing and air reversing direction, blend has always worked well for me with alpha-n.

[kaeman]

I would make a small plenum to tie all the cylinders together for your vacuum signal, mine also required the small fuel filter in the line, I also idle at 65 to 68kpa, but I am running speed density only, I have been doing this for several years, car runs great.

[Trump]

Thanks for the input. It would appear that my concern was justified. I will make up a small plenum to feed both PRV and MAP sensor.