Has anyone observed max boost before and after making an adjustment to a bypass valve butterfly that was slightly held open? I'm curious if the average needed adjustment to fully closed is indeed registered at all on boost gauge. How is the alignment of the butterfly on a new valve as a part purchase? Are they typically slightly off as well? Sorry if this was covered somewhere - I read all the threads I could find on the subject but didn't see these answers yet.

 

I just did this recently and my peak boost went up 1psi. I'm not sure, but I think the mid range boost went up more. I was thinking about testing it with different adjustments, but haven't had time. Your gain will be dependent on how it was to start.

 

same here....my boost went up 1psi
ive done this to a few cars now and everyone ive done was wrongly set from factory the majority of those have 1psi diff also

 

Well I guess I have a weekend project then.

Can it be adjusted on the car? Can the set screw just be turned out until the arm loses contact or something?


Thanks

 

After doing mine, I don't see any way you could get to the screw with unles you at least take off all teh air intake hoses. Also, you can adjust the butterfly plate as well. with it off to make sure it is centered up good.

 

This is an interesting comment -- if every bypass valve coming out of the factory is adjusted this way, maybe there's a reason? Not that I know what it is but I have a hard time believing that these parts are all set up incorrectly. Maybe it has to do with drivability or smoothness in the transition from off-boost to on-boost or something.

 

Could someone post a little "how-to" (with pics if possible) for removing the bypass valve, and adjust it properly? (might help many other members too)

I'd really like to check mine but i really don't know how to do it

thanks!

 

That has occured to me as well...

 

Hello!

If you look Here, you will see a how to to take things apart. Detroit Tuned also sells new ByPass Valves that are already reworked with a new spring that makes it close faster to make boost faster. Everyone that has bought one from us has been very happy with them. Let us know if we can help you.:smile:

 

Thanks agokart!

I did order a Ryephix bypass valve from Detroit tuned but it was out of stock, so I got an Alta cai instead...

I've done business with Detroit Tuned twice before and really liked the service.

I've look at this website for the how-to on the bypass valve, but still find it unclear...

 

We have lots in stock right now! And would be happy to help you out with getting one. i also have some directions if needed that i can e-mail you, or give me a call.

 

thanks again agokart

you've got a PM

 

Mine was adjusted correctly from the factory, moving the stop screw didn't allow it close any more than it already did. BTW, I would caution against tying the bypass shut or using a stiffer spring. Not only will fuel economy suffer, but it's possible to have parameters out of range causing a fault code and check engine light. IMHO, this is a much better idea:

https://www.northamericanmotoring.co...ad.php?t=38268

 

yeah i did this mod also andy so this may also help

You would have to take the valve off guys , so you can see if its closing properly or not....helps if you hold it up to some light and adjust from there

 

1. Get the IC off.
2. Get all that intake crap out of the way.
3. Get some long skinny screwdrivers or needle nose pliers and a lot of patience.
4. However you can, undo the stock clamp bands on the bypass valve hose. This is a fight, and how hard it is depends on where the head of the clamps are. I just trashed mine completely and threw them out.
5. Undo the bolts that hold the Al runner in place (this is the on that the bypass valve is attached to!
6. get that sucker off with brute force, but watch out! some have cracked thier TB-SC intake runner (it's plastic) here. This is a real pain (makes getting the clips off seem easy) but once you've done it once or twice, it's not so bad.
7. Use some of the nuts to acutally remove two of the studs from the intake manifold. This makes installation MUCH EASIER! But I can't remember which studs. Read throught the post on the yo-yo (I think) as there are some comments on it there. I didn't do this the first time, and it was a pain. I did it the second, and felt like an idiot, because I knew about it the first go round and just didn't think it was worth the effort. Leave the third stud in, so you have a place to hang the gasket.
8. Yank the bypass valve! Be carefull about the plastic though.
9. Fix the valve. If you want this to be easy as possible, just by a new one from Detriot Tuned. Getting the diaphram apart is an excursize in patience, and a test to see how many little screwdrivers you can get your hands on!

Also, you have several options here. You can do the Ryephix II (stiffer, shorter spring), the VGS (routing the vacuum source to the SC output side) or a hybrid (I did the VGS, but stretched the stock spring so that a higher vacuum level is needed to initiate opening). Also, you can rotate the diaphram on the bypass valve, if you want to do one of those set ups where you can change wich vacuum source you want to use. I think the Ryephix II does make more power earlier, but very light throttle operation is more difficult (it tends to act pretty abruptly, at least mine did). Day to day, I like the VGS, but if I were a track ****, I'd go RPII all the way....

10. Start putting it all back together. Make sure that you have hose clamps available to replace the stock BMW ones that you trashed ealier (I didnt' know I'd trash mine, and had quite a late night hunt through the parts bins in the garage so I could drive to work the next day.

Putting it together is much easier than taking it apart. The hardest part for me was making sure the BP valve seated into the connecting hose to the plastic intake part. Some patience here works wonders. IF you're doing the VGS system, do it at the same time, and you'll still need little hands, or some swearing when you get at the vacuum line where it attaches to the manifold.

When it's all done, drive and be amazed!

Sorry for no photos, but with all the other information out there, this should get you over the hump!

Good luck,

Matt