Length of MAP line?
 

Does the length of the MAP signal line matter very much? I ask as I will be installing my MS in my 97 soon with it mounted behind the passenger seat next to the stock computer. Obviously the 94-95 PNP will be in the same place, so I assume its ok to run a MAP line from there to the engine and still have ok results. I just wanted confirmation that a long MAP signal line shouldn't lag too much to affect anything.....

length has no affect at all

Any sane length of line, and quite a few out and out loony lengths, will work. I've heard accounts of people testing a 100 foot coil of MAP line to see what happened, and it worked.

The MAP line that came with my MSPnP kit was just the right length. I had to use every inch of it from the ECU to the vacuum nipple on the front of the intake manifold. Nothing's stretched at all, but I needed every bit of it.

If you're really worried, keep the MAP sensor underhood and run wires between the MS and MAP.

Stan-- did you use the middle nipple on the plenum or the front nipple near the TB? We're now recommending the middle nipple as there is less pressure oscillation there. And it should take less hose too.

Poor beta testers-- they don't always get a completed manual ;). Here's a draft of the MM9495 manual that's probably 99% ready...

http://megasquirtpnp.com/models/mm94...495_manual.htm

My map line is about 15 FT long, no problems at all. I ran it from the TB to the fender, around the fender inside the engine bay, against the firewall, into a rubber grommet near the AC unit, down the passenger's side foot well, under the carpet, to my MS behind the passengers seat.

I used the nipple on the front of the intake mani near the throttle body... I'll switch it to the middle if that's your recommendation. I never really witnessed any variations there...it's been the vacuum hose for my boost gauge forever. But then again, a VDO boost gauge is probably nowhere near as sensitive as a 4 bar MAP sensor :)