bov to atmosphere

[3.0 GT]

I have an 88 7mgte with the basic supporting modifications SAFC 2 and wideband to tune, 550, lexus, fuel pump and regulator, holset turbo and so on to support this setup. But with out recirculating the bov air back into the system i cannot let it out to the atmosphere. I would really like to have a larger BOV to be able to let the larger amount of bypass air created by the holset at into the atmosphere as my recirculating bosh one from Drift Motion is making the turbo surge.

But when i Blow off to the atmosphere my car richens up and stalls. I have tried to tune the SAFC 2 with the decel air set up with no luck. I am just curious to how others have been able to accomplish this with out stalling the engine after every pull.

Any ideas or solutions would be appreciated! Im up for trying anything, well besides a mafpro, that will have to wait...

 

[hvyman]

Isc might be dirty.

Also at your stage might be better to switch to a maft pro and go map. Next best thing besides a standalone.

 

[Kai]

On the stock system, even with piggybacks, you should never use anything but a reirculating BOV.

 

[RiyadYar]

you need to run a speed density setup such as the maft translator or maft pro .this will replace your afm and you will then be able to run your bov to the atmosphere . their was also dashpot mod that could be done to the dashpot on the intake to keep the rpms high an extra second when you let off the throttle so you wouldnt stall but as far as tuning many people seem to be happy with the maft pro

 

[3.0 GT]

the idle air control is clean, i will check out my dashpot to try what another member did by restricting the flow, but id rather not have excessive high rpm drops... ill look into the maft with speed density if that fails i guess

 

[CyFi6]

You can recirculate a lot of the larger BOV's, just need to be a little creative with the routing.

 

[IwantMKIII]

A little known secret i've learned over the years is the TB is the answer. There are adjustment screws on the TB, slightly open the TB and no more stalling. Yes, it will slightly up your idle depending how much you do it, but its an easy solution to no stalling when venting to ATM

 

[bioskyline]

you learn how to drive and not stall after a while, but i just went speed density (with the older HKS VPC) and problem fixed.

 

[mk3_7m]

Yeah with the AFM it's hard to bypass stalling with a BOV.

 

[scotty]

What situations would make a BOV, going to atmosphere, be able to stall the engine? I've run ATM on my car for severeal years, owned another MK3 with ATM BOV, driven 10+ with the same. Never stalled.

 

[HitmansEVO]

+1 for recirculating. Tuning with SAFC or the adjustment screw on the TB are bandaid fixes that don't address the problem you're having.

 

[jonahs_supra]

with speed density like vpc/safc or maft you dont have to recirc bov correct?

 

[digihonk82]

with a huge turbo hes prolly runnin lots more than stock boost..maybe the cause of stalling...???

 

[Dan_Gyoba]

I bought a recirc fitting for my HKS SSQV. Bonus (to me) it gets rid of the whistle.

Some cars won't stall, but they'll probably give a black puff for running super rich.

A MAP translator (MAF-T Pro, VPC) will allow venting to atmosphere with no ill effects, since the air isn't really metered until it's in the intake manifold. It's a nice solution, and I'd like to go there eventually.

 

[Nick M]

bov to atmosphere...

I just wanted to point out that all blow off valves blow off to atmosphere.

 

[supraman72]

Ok, so my car has the same issues with stalling, Its an 88 7mgte and when not recirculating i have rough idle and stall when decel. I have cleaned the idle air valve and adjusted the tps to speck. But a friends 89 7mgte runs absolutly fine with out recirculating at idle and under hard rev then decel as if the bov was recurculated. Why is this? Its frustrating and the only thing i can think of is if they have different computers from the two year differences?

Any ideas?

 

[jdemara]

BOV = Blow Off Valve (Venting to atmosphere)
BPV = Bypass Valve (Recirculates back into intake)

Bugs me when people say "stock bov" and "bov vented to asmotphere"

I never had any stalling issues what so ever on my old stock Supra with a SSQV, but this supra came with some cheapo bov, and it stalls all the time if you dont let off the throttle properly at the right time. However the adjustment on this one is crap and I can hear a vacuum leak from it at idle... time for an upgrade.

 

[Nick M]

Ok, so my car has the same issues with stalling, Its an 88 7mgte and when not recirculating i have rough idle and stall when decel. I have cleaned the idle air valve and adjusted the tps to speck. But a friends 89 7mgte runs absolutly fine with out recirculating at idle and under hard rev then decel as if the bov was recurculated. Why is this? Its frustrating and the only thing i can think of is if they have different computers from the two year differences?

Any ideas?

Maybe you have a leak at the valve.

 

[Dan_Gyoba]

There will always be individual differences between motors, even if the electronics are the same, particularly if neither one is exactly new.

Some people's cars stall when they vent to atmosphere, some don't. Some just get black puffs from the super rich moment, others might get afterfires.

Even with the recirc, I get some black smoke and the occasional afterfire. Without it, I got a lot more, but hardly ever did I actually stall. My engine is an '87 GTE.

 

[planemos]

What is afterfire? I would guess it is excess gas going into the exhaust and then igniting. I have a sound like that sometimes in my car with stock BPV. It's like a popping sound. It sounds like a flame is coming out of the exhaust its cool haha. But It's probably not enough gas to actually come out the tip of the exhaust. Am I right?