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Old 03-09-2009, 06:24 PM   #1
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Default BOV signal source

OK. I'm a bit confused. I'm looking for where to get the BOV signal from. I was reading the Flying Miata install manual and it states that the BOV should get its signal from the intake manifold (past the butterfly). But I've been reading some forum entries where some of the more knowledgeable members were saying that it should come from a location between the IC and the throttle body (it seems to me that this is the same source as one of the sides of the BOV).

I was under the impression that when the butterfly on the throttle body closes, it creates a vacuum that pulls open the BOV. Otherwise, it sees a boost on that line and keeps the BOV closed.

Is that not the way it works, or am I crazy?

Tony
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Old 03-09-2009, 06:32 PM   #2
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Yes, you are right in how a BOV works. Get the signal from after the throttle body.

Maybe, you are getting confused with where the wastegate gets its signal from?

--Ferdi
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Old 03-09-2009, 06:49 PM   #3
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I pulled my vaccum from the plugged off extra port in the top front of the intake manifold.
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Old 03-09-2009, 09:20 PM   #4
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The BOV signal must come from the intake manifold, after the throttle body.

The BOV intake must come from the intake tract prior to the throttle body, preferably after the intercooler.

The Wastegate (or MBC) signal can come from any one of three places:
1- After the compressor but before the intercooler. Easiest to route, but leads to boost dropoff.
2- After the intercooler but before the throttle. Best for a street car- regulates boost very evenly.
3- After the throttle plate. This is for race cars only- the turbo will be spooling like mad all the time.
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Old 06-24-2010, 06:29 PM   #5
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Quote:
Originally Posted by Joe Perez View Post
The BOV signal must come from the intake manifold, after the throttle body.

The BOV intake must come from the intake tract prior to the throttle body, preferably after the intercooler.

The Wastegate (or MBC) signal can come from any one of three places:
1- After the compressor but before the intercooler. Easiest to route, but leads to boost dropoff.
2- After the intercooler but before the throttle. Best for a street car- regulates boost very evenly.
3- After the throttle plate. This is for race cars only- the turbo will be spooling like mad all the time.
This is my 1st time adding a Turbo and I had a question regarding the above?

In the photo below you see a DIY hot side intake/BOV intake adaptor (came in the used kit I bought) I also notice that there is a plug in it currently. Would I be best to take the WG signal from that plug as in example #2 above? I can just stick an adaptor with a nipple in there.

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Can you also tell me if this is the proper signal for my boost guage (blue line with the white T-fitting) and which one of these other lines can I use for the BOV signal?

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Old 06-24-2010, 06:42 PM   #6
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that port was not for a BOV but an AIT.
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Old 06-24-2010, 06:46 PM   #7
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I have the FM intake tube and that is where I stuck my stock IAT sensor. Is that correct or does it fuel better on the hot side. I guess I just answered my own question as I thought about that sentace - the actual air getting combusted is the hot side air so the fueling amount/timing should be relative to that correct? If so why does FM have that location for the IAT is it for cars withou IC's ?
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Old 06-24-2010, 06:48 PM   #8
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you guesseded it.
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Old 06-24-2010, 06:54 PM   #9
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If so why does FM have that location for the IAT is it for cars withou IC's ?

Where do FM and BEGI place the factory IAT then? I mean am I safe doing it this way, I guess I would have richer A/F's having the IAT in the cold side than in the hot side so at least Im safer for now until I figure out my next move.

What gains will I see by placing it in that hot location, 1 or 5 or more % more hp? I'd rather be safe right now as it's all new to me.

Can I still run the WG signal there - is that preferred ?

I do remember way back reading about a GM IAT is that one threaded - I'll do some searching?
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Old 06-24-2010, 07:46 PM   #10
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So BEGI puts the stocker in their cold air box i see.

Looks like you all prefer locating it in the IC piping after the IC. I think I'll get the car running then decide on a GM IAT later.

Thanks for identifying that bung/plug I had no idea.
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Old 06-25-2010, 12:16 PM   #11
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I did this for now, put the WG line in there going to the MBC.

later I will put a GM IAT in there. Not sure when.

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Old 06-25-2010, 02:34 PM   #12
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If you put the IAT in that bung, it will be sitting behind the radiator and will get heatsoaked like a ****. You'd be better off leaving the WG reference on that bung like you have it and drilling a new hole for the IAT that's in the end tank of the IC itself, or in the piping after the IC, somewhere not directly behind the radiator so it's not getting blasted with hot air all the time.
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Old 06-25-2010, 07:03 PM   #13
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Thanks,

I'll wait until a GM IAT comes available for cheap and then look at the end on the IC to install it to.
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Old 06-26-2010, 07:28 PM   #14
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Quote:
Originally Posted by Landrew View Post
I'll wait until a GM IAT comes available for cheap
WTF are you talking about? They're $22 brand new with a connector and pigtail. How much are you gonna save by holding out for a spectacular deal, five bucks? LOL
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Old 06-28-2010, 11:49 AM   #15
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Are you kidding me, have you not been to Canada. How do you think we pay for all that A/C to keep it so cool up here, that money has got to come from somewhere! It comes in the form of everthing you buy down there add 50% - 100% up here.

If I buy the IAT then I have to but a tap for the IC which means I have to drive to the store so now that $22 part is $136.54CDN dollars.

Allright I had no idea they were that inexpensive. I still need to get rid of my stock exhaust first and believe me up here a 3" exhaust is not cheap.
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