Boost Bypass Valve Mod

I may have missed it on our forum, but I was reading on another forum about the Boost Bypass Valve Mod...Is that for both Series I and II engines? Worth doing?

http://www3.sympatico.ca/aepa/bypassvalve.html

Some people do it, but most think it is not worth it. Unless you have a tuner it may be harmful. Something about not having enough fuel to match the air coming in I think.

Personally, I wouldn't do it. Doesn't make sense to me why you would want more boost down low. We already have a gob of torque even at 2k RPM. I'm still spinning at 35 mph after a launch.

The Series I makes its peak torque even lower than the Series II, so I'm guessing if you did it, you'd be breaking tires loose much easier, chirping tires at shifts... sounds cool, but bad on transmission, imo.

Having said that, I've never tried it... it's only my opinion.

hmmmmmm i read this but i have a series !! and i just dont understand thsi i kno where the bypass valve is but nvr took it off wouldnt it be cool to have a blow off valve LOL jk but what am i doing taking off the bypass valve and putting it back on>>>??? well how much HP is that or how much more boost
???

I did mine last night. Sometimes it acts like the timing is being retarded when I floor it (sort of like a hesitation, but not really)...sometimes it launches very well. I dunno what the dealio is... I may change it back and see if it fixes it.

jax95riv wrote:

I did mine last night. Sometimes it acts like the timing is being retarded when I floor it (sort of like a hesitation, but not really)...sometimes it launches very well. I dunno what the dealio is... I may change it back and see if it fixes it.

so did it feel as though u gained any sort of power??

you cant gain any power wiht the BBV mod, only change when you get into + boost #'s. at WOT you still make the same power and boost.
this is not a mod i recomend doing, kinda like the MAF screen removal...some ppl have problems.

OK question...I notice a bog since I moved the valve. But, I've also noticed more low to mid range torque for lack of a better word...Is the bog because I'm not pulling enough air into the engine to keep up? Will the FWI I'm getting ready to do tomorrow help this? Or am I just WAY off base? Or do you recommend I just change it back?

One of the problems with not having a scanner is that you are modding "blind". The hesitation you feel could very well be retarding of timing, and that can be a result of KR. The BBV mod has been known to cause "flash KR", which could create the symptoms you are seeing.

Another thing you may want to consider is what this is going to do to your fuel economy. With boost kicking in sooner, your car will be burning a lot more gas with a lot less pedal.

I still haven't tried this, so not saying it's all bad, but I'd be scanning very carefully if I did. If it was something for nothing I'd think they'd have set it differently from the factory.

mr. riv wrote: MAF screen removal...some ppl have problems. maf screen? is that the throttle body debris screen?

robotennis61 wrote:

mr. riv wrote: MAF screen removal...some ppl have problems. maf screen? is that the throttle body debris screen?

That is not a debris screen, it monitors/measures the amount of air passing into the throttle body.

The screen doesn't measure anything, but it straightens out airflow so the MAF can function properly. Take it away and you'll get some wild MAF readings which can make you rich or lean or anywhere in between...

And to anyone who rereads this and considers it, do NOT do the "BBV Mod", it's useless and gives you a mid throttle KR spike.

Thanks for the correction regarding the function of the screen.
Not enough coffee at time of post.
That's my story and I'm sticking to it.!!!!!!

http://www.fastfieros.com/tech/boost_solenoid_bypass_mod.htm
I have been reading all about what the boost control actuator really does. Has anyone ever seen or experienced themselves negative effects from doing this?

Quote :

Boost Solenoid ByPass mod
Why even do it? Two reasons in my opinion. First and most important, does it hurt the engine, or help the engine? Its really there to relieve the NOISE of the supercharger... Striaght from Eaton's website > > Are superchargers noisy? The Eaton supercharger system incorporates a specially designed bypass valve, which is actuated by a vacuum motor near the throttle body and recalculates the supercharger air flow when boost is not required. During typical driving conditions, the engine is under boost around 5% of the time, which means the remaining 95% of the time the engine is under vacuum, allowing for better fuel economy and a quieter ride. In addition, the helix angled rotors, along with specially designed inlet and outlet port geometry, also reduce pressure variations resulting in a smooth discharge flow and a lower level of noise during operation. Careful attention to the techniques used in installing the supercharger also plays a major role in reducing the noise emitted by the supercharger.

Never read that before but....

I tried the BBV adjustment mod eons ago and although the car felt torquey at low throttle around town, it took a nasty hit or KR which ultimately killed performance at higher rpms and with quick stabs of the go pedal. This was in my Regal. I thought about doing it in the Riv just because it almost never sees boost but realized it could be fatal to the motor. My belief is putting the valve all the way down does not allow for as much if any boost to be bled off so the PCM has a heck of a time adjusting fueling and keeping up with it when you drop the hammer.

I ended up adjusting it all the way up. No more odd KR spikes. MUCH better.

I have tuned cars with the BBV "mod" and you need to readjust the timing table a lot bit to avoid some medium throttle KR spikes. If you do that, then it works - you get "quicker" boost. But in all reality the valve opens so quick anyway there is really no gain to this. It's a stupid "mod", don't waste your time, leave it where it belongs. Your performance will be better in the long run for having the valve open later. It still opens just as much when you step on it.

Agree 100% with previous two posts. I'm repeating myself, but it's not like we need any more low-end torque than we already have. Our throttle response is near the very best - it's one of those things the 3800 SC does very well, even stock. No, I haven't actually done the mod, but this is one of those things, when you think about what it really does, it just doesn't make sense. No reason to try it.

PS - I disagree with the quoted link on the previous page that says the BBV valve is mostly for noise control. Changing its operation could impact fuel economy, and driveability. And as mentioned, it could produce dangerous KR. Besides, if we assumed it was just for suppressing blower whine, then adjusting it obviously cannot improve performance!

Was just searching around and I found this.

http://www.zzperformance.com/blog/boost-bypass-mod-free-mod/

Anybody? I'll be a guinea pig on this one.

Already stated my opinion above and on page 1. There's no good reason to do it.

ZZP: "It also helps some cars achieve full boost that were having problems with the bypass not closing all the way during WOT."

Or... replace your bad BBV with one that works!

Basically, re-biasing the boost bypass valve isn't doing anything for throttle response that you couldn't replicate by pressing the gas a little more, but based off what Derek is saying, it can hurt so I would just say don't.

I think using a smaller pulley maybe a better solution. You won't change the nature of the valve operation. However, when the boost is needed you'll have a little more of it.