2g->1g BOV: adds 4 psi?

[Semprini]

Does the 2g bov leak that bad? The only boost mod I have is the BCS freebie. Even with the stock bov it would boost and hold between 14 psi, which sounds about normal. I just installed the 1g bov I bought from a member and itll boost up to 18.. Im confused.

ps I searched and didnt find much on this hence the post

thanks

 

[DSM_Roller]

yes, you need to get a boost controller to turn the boost down. I was overboosting 5+ psi after installing 1G bov.

 

[Semprini]

damn.. so were the stock bov's designed to leak to keep boost down?

 

[Ja17Bmx]

I do believe that a boost controller can not turn boost down, just up. I looked in your mods and saw you have a 3" exhaust, it sounds like you might have a boost creep issue on your hands now. The stock blow off valves are not designed to leak, the 2g ones just suck and do.

 

[whiteflash]

When I got my UICP and 1g bov my boost would spike to 21. But after i got my boost controller i could set it as low as 10-11psi.

P.S. Voodoo boost controller on ebay is 20 shipped, Ive had mine for awhile and have had no problems.

 

[Semprini]

I do believe that a boost controller can not turn boost down, just up. I looked in your mods and saw you have a 3" exhaust, it sounds like you might have a boost creep issue on your hands now. The stock blow off valves are not designed to leak, the 2g ones just suck and do.

Ive read up on boost creep before but I didnt think it would be a prob since I still have the stock dp and cat... Its a possibility that Im putting my 14b on this weekend so Ill have to do some porting

 

[Semprini]

I just took it out for a quick ride. Itll boost up to about 20 and then drop to around 15. It seems to move around a bit on the gauge. I might have a leak considering the adapter I got off of ebay didnt seem to be high quality. But holy #### its a lot faster.. now its time to get some injectors. My butt dyno is working tonight

 

[DSM_Roller]

I do believe that a boost controller can not turn boost down, just up. I looked in your mods and saw you have a 3" exhaust, it sounds like you might have a boost creep issue on your hands now. The stock blow off valves are not designed to leak, the 2g ones just suck and do.

That is incorrect. I have a 95 2G. The only mods are 1G bov, and manual boost controller. I turned the boost down to 10psi since my wife drives it for work.

When I put in my 1G bov, i was spiking 20psi. I did some research, and there was hardly any info on this subject. I did find 1 or 2 posts either here or dsmtalk showing that a boost controller is the solution.

 

[Semprini]

So what am I dealing with, spike or creep.. or both. Sometimes itll hit 20 and stay there, other times itll go to 15, stay for a sec, then go up then down... my boost gauge turned into the a/f gauge without the LEDs. How did the stock bov keep it stable and this son of a bi*** makes it change psi like my ex changes her mind about what she wants out of life??

Either way Im getting a MBC asap and hoping itll solve this.

Thanks for the help peeps...

Semprini ..OUT!

 

[Splitpi]

2G BOV leaks bad at anything higher than stock, and I am guessing that that leaking causes it to not function under higher boost levels hence the higher spikes. Get a MBC and let us know how that works out.

 

[Talesin]

An MBC cannot turn boost down, only up. It does this by reducing the amount of pressure going to the wastegate, allowing it to stay closed longer.
It's physically impossible due to the way the wastegate works for an MBC to turn boost down past stock level, without hooking that MBC up to a positive pressure source higher than the boost source.

That said, lowering boost past what a direct line from the compressor outlet elbow to the wastegate would provide IS possible, but requires modification to the wastegate; specifically either by shimming the wastegate actuator (potentially leading to slower spool and a leaky WG), or replacing the stock actuator with a 'softer' one.

Yes, the 2G 'BOV' (actually a CBV, compressor bypass valve, both in the case of the 1G or 2G OEM part) is known to leak like crazy... it's a little plastic piece of junk. The 1G CBV will also leak at higher boost levels, but it can be crushed slightly to keep it sealed under higher boost applications.

If your WG actuator line is 'teed' off the CBV vacuum line, that could be contributing to your spiking. Normally you don't see too much creep/spike without going to an aftermarket exhaust, or having a leak in your vacuum lines. Only way to really fix the creep/spike with the aftermarket exhaust is to get a bit of porting work done on the internal wastegate passageway, and associated O2 housing path.

 

[HondaStylez]

So what am I dealing with, spike or creep.. or both. Sometimes itll hit 20 and stay there, other times itll go to 15, stay for a sec, then go up then down... my boost gauge turned into the a/f gauge without the LEDs. How did the stock bov keep it stable and this son of a bi*** makes it change psi like my ex changes her mind about what she wants out of life??

Either way Im getting a MBC asap and hoping itll solve this.

Thanks for the help peeps...

Semprini ..OUT!

Sounds like you have a little bit of everything. With inadequte (it's late and I can't spell) boost control (wastegate not keeping up) the weather can have a huge effect on boost levels, this could explain the very inconsistant behavior from day to day.

Also check for boost leaks, they can lead to erratic boost control as well.

 

[T is for TURBO]

An MBC cannot turn boost down, only up. It does this by reducing the amount of pressure going to the wastegate, allowing it to stay closed longer.
It's physically impossible due to the way the wastegate works for an MBC to turn boost down past stock level, without hooking that MBC up to a positive pressure source higher than the boost source.

This is true. But a stock 2G wastegate doesn't control the stock boost level. The BCS controls the stock boost level. If you bypass the BCS via a straight vacuum line from the compressor housing to the wastegate, you will see lower than stock boost levels. Some maybe lower than others as with time the wastegate may not be as strong as it used to be. By installing a manual boost controller and bypassing the BCS, you can actually "lower" your boost level (that is, lower than stock) This is why many people can lower it as low as 10 PSI. I don't think in can go any lower than that unless your wastegate is broken. I have mine set at 11 PSI on the stock wastgate.
But other than that, you are 100% correct as to how the wastegate works. Boost levels can only be as low as the maximum resistance of the wastegate actuator, and that a boost controller just fools the wastegate into staying open longer.
-Shawn

 

[Semprini]

Ok I was poking around again and realized that the upper vac line on the BCS was off. This is the line that connects to the intake pipe. It must have pulled off when I was moving stuff around to remove the stock bov. I havent had a chance to take it out bc it snowed like F'in crazy last night and I couldnt even make it to work.. do you think this has anything to do with the prob?

 

[Talesin]

Not really. You'd run a tiny bit rich from losing the shunted air due to normal BCS operation, and a tiny bit lean from having the vacuum nipple on the intake sucking in a little unmetered air.

Actually, it would more result in lower than average boost... when connected, under boost (and normal operation) that 'upper line' sees vacuum, meaning the BCS doesn't need to actuate as much to shunt the required air to keep the wastegate closed, thanks to the pressure differential thereby generated.

And you're right, T... if you totally bypass the built-in BCS (as with a direct line from the compressor outlet to the WG actuator), you can drop the boost level. I keep forgetting that 2Gs run 'stock' at 14-16psi. Still, can't go lower than what the wastegate will allow without physically modifying the WG, which seems to be right around 10psi on OEM parts.

 

[c4uldr0n]

I'll guess that it won't spike as much not, doing what you did would cause the wastegate to never open! !

 

[Semprini]

Yeah I took it out quick and itll spike to 19-20 and drop to 14-15 and hold til about 5000

 

[Gregory]

what were you boosting before you took out the boost solenoid restrictor? Did it spike then?

 

[Semprini]

what were you boosting before you took out the boost solenoid restrictor? Did it spike then?

I took that out when I got the car. It only raised it about 1 psi when I did it. This mess didnt start until I put the 1 bov on. After I saw that vac line off and reattached it, its not as bad. Still spikes to about 19 then will drop off. I think the bov is leaking somewhere. The adapter I got off of ebay is a POS. It didnt fit too snug into the UPIC pipe and even with the hose clamp real tight I think itll still leak a little.

 

[10fold]

My bad if this is kind of off topic, but it removing the boost solenoid restrictor safe? I'm not sure if mine is there or not, but if it is I'm just wondering if taking it off will mess up anything.

 

[Semprini]

Well I just ordered a Hallman ES so hopefully thatll do the trick. Should be here within a few days

 

[Splitpi]

Good luck.

 

[nad1]

Just did the same thing, had 3" exhaust put on, and the next day had a 1G bov put on, and boost spiked to nearly 20PSI. Read up on it, and ordered my MBC from DejonTool. The sooner it gets here the better, but it's still spiking everyday when I drive it.

 

[Semprini]

Ok I finally got the hallman on and it solved most of the problem. It doesnt spike nearly as much. In 3rd and up itll jump to 17-18 then settle back to 16 where it is set. I know I also have a boost leak, the adapter I bought for the 1g bov is crap and does not fit tight in the stock upic. I used the stock vac lines and the stock locations.

 

[Pat D]

Well I just ordered a Hallman ES so hopefully thatll do the trick. Should be here within a few days

I just put my new hallman on a few days ago and it works great..