Blm's

[87gnblackdemon]

Should BLM's ever drop into the 90's, even for just a second??

The only time I've ever checked my BLM's was at idle, and they've always been and still are. After a BOV install and the car bogging down on me when coming to and leaving a stop, I checked my numbers and my blm's were dropping into the 90's during that period. Disconnected the BOV and it's history pretty soon. The bogging down has stopped and car feels fine but driving around while watching my blm's they still drop into the 110's as you give it gas, get on it harder and they rise back to where they should be. They are also dropping to around 93 for not even a split second when I first apply the gas, say leaving a stop or so. But car feels fine.

Extender Chip, 43 fuel pressure. Are other numbers are good except the IAC, which has been high forever.

 

[87gnblackdemon]

What do I look for that would cause this condition? Hello? Anybody know anything on this board?

 

[VadersV6]

BOV's are crap for street cars. They shoot off air thats already been metered. The computer adds the right amount of fuel for the given air, and the the BOV blows it off. Now you have a rich condition. A bypass system is the way to go. I made a dual bypass sytem on my cobra. One bypass before the IC and one after. Under vacuum (cruising), the valves are open, and the engine is running off air that is being bypassed around the compresser. When you hit WOT, vacuum drops to zero and the valves close. Now its running straight off the air coming from the compressor. When you let off, the valves open and dump the compresser surge back into the intake tube before the compressor inlet. This way, the air that gets blown off, is air that was metered for, and is being recirculated back in, after the MAF. You get no rich condition, bucking or surging. It worked beautifully on my cobra after trying a few different setups. One of these days Ill set one of these systems up on the GN. I told wicked87gn about it, so he had a single bypass put on his car, but for some reason it didnt work out well. You need the right bypass valves (plural), and need a way to prevent MAF wash when the air dumps back in the intake tube. The vacuum sources need to be right. This setup also saves the turbo bearings like a BOV, but without the drivability issues. I have a couple bypasses leftover from the cobra days, so it shouldnt take too long to get it together. If people are interested in something like this, I can hurry up with it, get it right, and maybe put some kits together if people are interested. It can be done successfully. You just need the right system. Only problem is, a dual bypass setup usually isnt the prettiest thing around.