they said "it can't be done" 2G bov mod.

[DSMmonster123]

Well I was going to go with a 1G bov but I ran out of money for this month sadly , Ahh the life of a college student, anyway I had the day off and decided to attempt to mod my 2G bov so I could dial in my MBC and actually have the w/s gate open. Until today I had no idea what the MBC was set to b/c the bov leaked so badly. I had 14 psi wheather it was fully open or screwed shut.
so heres how to do it...

tools need
wire snips
needle nose pliers
a few screw drivers
an old flashlight
and most of all PATIENCE!

With the bov out of the car and looking into the low pressure/ intake side you see the small metal rod that connects to the plunger, the basic idea of the mod is simple, wind a spring around the plunger rod and increase the spring rate. The spring will come from that old flashlight thats been sitting around in the garage for years. You'll need a spring that is about an inch or so in height. As far as I know they all have about the same spring force but the heights will vary. I tore apart 2 before I found a good spring. Now cut off the larger coils that are close together on the bottom and trim the spring so it will fit through the opening on the bov. Be sure its still got plenty of force and is slightly larger than the distance between the plunger and the plastic nub that the rod goes through on top.
Now heres the tricky part try to wind the spring around the plunger shaft by rotating the spring, this will take time and patience, I used a few screwdrivers to hold and push the spring and the needle nose pliers to rotate it as well as my thumb. NOTE: if the spring is cone shaped place the smaller part upwards toward the vaccum chamber. I spent almost 2 hours trying to get the damn thing on but if you cut it correctly it may go on much easier. ABOVE ALL REMEMBER PATIENCE!! ITS ONLY PLASTIC!!, and if you're broke like me you can afford to replace it.
When done it should look like the picture keep the spring below the round plastic nub where the rod goes into the top. This will give you the proper amount of compression. On my first run I had a boost spike to 17 psi and imediatly backed off the throttle (It's basicaly a stock engine) so idk how much the mod will hold however Its a huge improvment over the stock setup. With the stock spring alone just putting the bov to your mouth and blowing you can hear it leak. With the mod that leak is almost gone and I now see around 10psi at about 1/4 - 1/3 throttle compared to the 1/2 or more throttle to acheive the same 10psi on a stock setup.
It's only worth the effort if you have time to kill, in hindsight buying a 1G bov is much less work and probably more reliable.

 

[WizardTSi]

I love little tweaks and projects like this. The ones that take more time than they are worth. Cool for the 2g guys.

 

[guseclipse]

Looks like it gets the job done.

 

[spawn87]

looks pretty legit great work on putting this together.

how ever for those thinking of running this little mod as well remember its just a band aid for the moment dont rely on this to work miracles.

 

[NvDiS]

looks good so now with this mod you hold the boost alot better? boost leak test?

 

[bsbllfit7]

ya lets hear some numbers, ill do this to my old 2g and sell it if it produces good numbers

 

[DSMmonster123]

Yea didn't think of a leak test. I'll try to do one on my next day off. If your staying stock for awhile this is definetly worth it. My car runs so much better and gets into boost much quicker. Glad I thought of it, .

 

[Detail]

I'm impressed. In my need to argue, I'd like to point out how terrible it would be if that spring popped out, went back into the intake, and got sucked through the turbo. That a possibility?

 

[bsbllfit7]

my guess is you could use a thicker spring as well or slightly larger and this would work even better, and as for the spring going down the intake, highly doubtful, it takes alot of effort to wind it around the plunger(i think thats what its called) and would not come out easily. Ingenious idea that will help alot of stock people out

 

[DSMmonster123]

yea no way thats springs going to come out, it took so much effort to get it in plus it would have to spin to come off. I was hesitant to do it at first b/c I didn't know what the stregnth of the spring I needed had to be. The thing is once its on if its wrong you have to cut it off, if you can that is, in order to try a stronger spring. Does the bov need to be open at idle? that was one of my big concerns with a super strong spring. Might be able to do a pressure test tomorrow I spent all day digging it out of the snow today, we got hammered here in CT.

 

[DSMmonster123]

well I did the pressure test today, it will hold 5 psi no problem but after that it develops a slow leak. I only took it up to 12 psi or so, all I have is a bike pump, and it takes about 8-10 sec to leak from 12 to 5 psi. its only plastic on plastic after all maybe a gasket glued in there would help or a stronger spring idk. but for $0 and 2 hours it makes a hell of a diffrence over stock.

 

[gofer]

+1 on innovative thinking! If you ran a stiffer spring it would be possible to hold 20psi I suppose, a great 2g bov mod if you don't want to modify your IC piping to fit an aftermarket or 1g bov.

 

[empie1]

Cool idea...not worth the time imo though. 1g ftw.

 

[JusMX141]

Lots of time invested on a dud.

Took me 15 minutes to make a flange for a $20 used 1G BOV that fit my buddy's 2G. Initially the stock 2G valve was not allowing the car to make above 14psi; after the 1G install the car made 21psi and dropped to 16psi by redline.

For the money versus the time you spent to achieve a similar result, it's much more cost-effective to just buy a 1G valve and build a flange to fit into your stock piping....or just pick one of the flanges up on eBay for $15 or so.


Seriously- go without Ramens for a month or sell one of the college books you don't use on eBay or Amazon and do the job right the first time. I'd hate to think what your turbo would look like after that spring you fabbed gets sucked into the intake.

 

[gofer]

I'd hate to think what your turbo would look like after that spring you fabbed gets sucked into the intake.

How would it get sucked into the turbo, its on the cold side of the intercooler?

 

[RadDsm]

How would it get sucked into the turbo, its on the cold side of the intercooler?

Maybe if it pops off while the BOV is closed and goes through the recirc hose and back to the intake. That's all I can think of.

 

[gofer]

Maybe if it pops off while the BOV is closed and goes through the recirc hose and back to the intake. That's all I can think of.

haha. I haven't been recirc'd in so long I was thinking Justin was going crazy, good call!

 

[spyder420]

Its an ok write up I took the how to make your 2g bov not suck. I went 13psi to 16psi super easy 10 min for free mod thanks turbo BMW!

 

[polarmoment]

Or, for almost free, just turn the valve around.

Plug the hole in the bottom of the shaft (that's where the pressure reference for the lower port comes from) and drill a small hole to the outlet side of the valve in the shaft near the bottom so that the pressure reference comes from the other side of the valve seat.

Connect the outlet of the valve to where the inlet used to go, the inlet to where the outlet used to go and the valve will hold all the boost you can possibly throw at it, since boost now holds it shut, it opens via pressure differential between the charge pipes/manifold, so it still reacts quickly. This is how HKS designed their valves, which was based off a yamaha/denso patent.

 

[gorf]

Lots of time invested on a dud.

For the money versus the time you spent to achieve a similar result, it's much more cost-effective to just buy a 1G valve and build a flange to fit into your stock piping....or just pick one of the flanges up on eBay for $15 or so.

When I first started modding my dsm the best bang for the buck was a hard upper intercooler pipe and a 1g BOV. Look on ebay for the whole UICP with 1g bov or as Justin said just get a 2g flange and used 1g bov. You will not be disappointed.

 

[tveljano]

It's definitely interesting, but not worth it if you ask me. I was a poor college student too, so I got a job. Pretty quick fix for when you are lacking in money...

I give you props for being innovative definitely, but I would have just done what others have said and gotten a 1g BOV for $20 and not have to mess with it twice.