Hey, go explain that to everyone else who doesn't know about this...

Why are you trying to convince me?


-Ted

 

Havn't seen you do any testing for it. Im actually getting some where with MY testing.

They can't see there is no clamp on the BACV?

 

I doubt anyones trying to convince you Ted. You're far too stubborn for that.

 

Because you're trying to convince us that removing the BAC valve is better/easier than replacing a hose and gasket and/or adding a couple of clamps. I did all that just with stuff lying around the garage... (3/4" heater hose off-cut, gasket paper, spare clamps)

 

As far as I can tell, BAC/IAC removal seems to be a uniquely RX-7 phenomenon. Not really sure why. Maybe it's the fact that so few people actually understand how the whole EFI system works and rotary people are simply much more prone to tearing stuff out the other car owners.

I quite enjoyed my BAC when it was on the car, but alas for some dumbass reason I did not but the BAC option when I purchased my Microtech so currently I'm idling off of the throttle body. Frankly it's a pain. The idle has to be tuned far richer then it should be to prevent the idle from dropping ~500 RPM when a big electrical load is switched on (e-fan...). Additionally it's far harder to get a good clean cold start by tuning fuel alone as the engine really needs a higher idle for about 10 - 20 seconds (every modern car I've driven/owned does this as well, including my Insight) while the engine stabilizes and fuel stops sticking to the side of the manifold/port runners. It's also a lot harder to stall the engine after making a mistake engine braking (we've all dragged the engine down too far...) if the BAC can go wide open and catch the idle.

I guess the advantage in removal is that the engine bay is slightly cleaner and it eliminates a possible failure. In all the RX-7s I've owned I've never had a BAC related failure though, and I can't recall ever seeing one that was not cured by just cleaning out the valve.

The primary reason for removal seems to be lack of knowledge about it's function. This thread is perfect evidence of that.

This winter my Microtech goes back to the dealer to have the BAC option fitted. I'll be happy next spring when I can electronically regulate my idle.

 

I don't understand all the talk about the cold start issue!!!
My cold start idle is fine the thermo wax take's care of it, idle's up to 1500 cold start like it did before the MS and my warm idle is around 800 rpm it is a tad rich at 12.7, like i said before only issue is the a/c for me. Don't get me wrong I am not saying to take it off i just didn't set up my ms for it, i was trying to make the ms as simple as possible until i got the any bug's worked out, in my opinion there would be no reason to take it off with a stock ecm.

 

If you really want to clean the engine bay up, loose the EFI and emmissions related crap and go with carbs. If you want the driveability, economy and features designed into our second gens., fix the problems, don't bypass them.

Read the FSM, especially chapter 4 (see my sig. for link). Once you know how everything works (or at least have a good idea), all those gizmo's bolted on won't bother you as much.

Removing something like the BAC won't clean up your engine bay, or significantly increse reliability.

I'm going on a tangent here now, but it's very popular to remove this or that for the sake of weight or power. If you use the car mainly for driving around and not competition, there's no need for any of this. If you really need to remove stuff for a better power to weight ratio, you probably don't have a lot of power to begin with. This, coming from an NA owner.

 

Removing the bacv for a weight issue.... BACV must weigh around 30lbs?

 

I recently capped my BAC inlet off and unplugged it because my air line got old and started to leak.

My problem is finding hoses to mate from the Apexi feed pipe to the BAC inlet.

I have been driving withou BAC for about a week now and my idle is rock solid and I've yet to stall about because I was using my power steering. :P

I'll eventually make it work again. Probably next month when I have to pass emissions

 

How do i checked my BAC? The car idles poorly with the a/c on and tends to shut off by itself when it's on. Also the idle is quite low (even without the a/c) and i have trouble even rolling the car when i have it in 1st while slowly letting the clutch out. It's a stock 87 n/a.

 

Sorry, I keep thinking in terms of my setup. I have a Mustang 75MM throttle body which has no thermowax. In my case I'd use the BAC to raise my idle a bit on cold starts. Stock systems have the thermowax, which of course works very well.

 

I don't have BAC on my car, so the lowest my idle can go is 1000rpm.

Car runs real rich on idle, so that's probably the cause of it.

 

^ You could adjust the variable resistor if you have a S4 for the idle AFR

 

Your can can idle fine w/o a BAC. Personally, my idles set a bit high. My car's rarely at idle anyways so it's not that big of a deal for me.

 

Nope, idle speed has little do do with mixture.