Increase boost!

[neapleaze]

hey i just found out how to increase boost on my saab 2004, add a T- Vaccuum 3/16 from your turbo... i just did it and my first and second gears are boosting a lot better now... if anybodyhas tried this.. any kind of negatives if so what? I cut the vaccuum hose from my turbo to... dont know the name.. just got shown from a friend...

[ctrlz]

Intriguing

Please post details and pics. If you know the theory behind this mod please share it.

[M4Gunner]

me too, me too.. i wanna know! NOW!! :wink: 8)

[neapleaze]

i'll take a picture of what i did and send post it tomorrow

in quick detail this is what i did... cut a tube i guess you could call it from the turbo... i think its coming from the asperator? but you cut it and then what you do is you buy a T-Vaccuum hose make sure its 3/16 by 1/4 shaped like a "T." well you put each of the Top of the T's connected to the tube from which you just cut, and then you have one tube open for more air access... this gave me more boost in my first and second gears... also you can hear the cool whistle sound, its louder... somewhat resembles a blow off valve. Picture will come soon!

[M4Gunner]

how long ago did you do this? im just wondering about any issues it may cause. it just seems like if it was this easy, people would have been doing that for years now. ive never heard of this, but that doesnt mean a thing, im just cautious i guess. where does your boost guage needle stop now?

[neapleaze]

i just did it today, i was hoping others would know... let me ask arond for more info

I first tried the 3/16 x 1/8 but it wasnt bringing enough air into the turbo i guess... so i put a 1/4 and i felt a major positive impact. I got better acceleration this way.. and i am really desperate for that right now... my first mod.. just owned my saab for a week now

[M4Gunner]

ok, ill talk to my speed shop guys and see what else i can find out as well.

[neapleaze]

thanks i will do the same... but for sure i will take pictures of my baby tomorrow

[M4Gunner]

thats cool.. ill PM you my email address. send em ASAP if ya can! ty

Gunner

[Cayman1]

This is exactly the trick i did with my skyline.
what it does is allow more air to the turbo's actuartor/wastegate and bypasses the cars boost control.
i also played around with different size t-fittings but be careful because i tried a large one and the boost just kept on going and going.

Not sure if this is a healthy boost solution for our cars though.

[ctrlz]

I think I found an explanation for this.

What it actually does is LIMIT the amount of pressure getting to the wastegate actuator. The wastegate opens later, and you get MORE boost.

Just using a T-fitting (as described above) bleeds off some air, thus lowering pressure.

I found this alternative solution, which works by inserting an adjustable restricting valve. Looks pretty neat, is adjustable, and won't whistle. Plus you can back it off completely when you take the vehicle to the dealer.

http://www.autospeed.com/cms/article.html?&A=0028

Very cool! Time to scour the web for appropriate parts. Somebody get the diameter of the hose in the 9-3 quick! I'm guessing neapleaze used a fitting for 3/16" hose with a 1/4" tee. If you're gonna do it this way, better use a metal fitting.

[ctrlz]

Here's a start:
http://www.boostvalve.com/moreinfo.html
http://www.boostvalve.com/pricelist.html

[ctrlz]

This setup is a bit different than the one in the autospeed article:
http://www.boostvalve.com/tech/IC_install.html

neapleaze's method and the autospeed method work by fooling the factory boost controller. One by bleeding off pressure, the other by limiting it.

The boostvalve system eliminates feedback control from the turbo outlet (note the vacuum caps), and uses actual intake pressure. Pressure builds to a specific level (based on the spring in the valve), then dumps instantly to the wastegate. So this is a pressure relief valve, rather than an adjustable needle valve. Price is reasonable, dontcha think?

Any thoughts on which approach is better? It would seem to me the system which fools the boost controller would be safer, but the boostvalve approach would make for a snappy ride! Also, we will have to take a closer look at the Saab actuator, and find a convenient line with intake manifold pressure. Boostvalve sells kits for the 9-3 (probably older generation), but I'm guessing it's doable for our cars.

[ctrlz]

Some interesting reading:
http://features.evolutionm.net/article/machvcorner/30/1

[pjku79]

Ok i read some of the stuff Ctrlz linked and according to that there should be more boost lag with using the T. Can you varify this neapleaze? Is there more or less turbo lag? Next if we use the boost control valve, this should reduce the turbo lag even more, right? Personally i dont mind the turbo lag at launch but it pisses me off when i shift gears.

[ctrlz]

Another interesting approach:
http://www.autospeed.com/cms/A_0670/...popularArticle

[ctrlz]

The best (cheap )systems to reduce turbo lag are the ones which incorporate the pressure reflief valves. One thing to watch out for is there has to be a way to bleed off pressure in between the valve and the wastegate actuator, or the wastgate will never close once it's opened.

The system with the pressure regulator downstream of the PRV uses a special kind of regulator which will bleed down. This is NOT the standard type used for air compressors. The product offered by boostvalve probably incorporates a tiny bleed hole somewhere.

The more I read, it seems there is a BIG difference in performance between the simple systems which REDUCE pressure going to the actuator compared to the systems which completely BLOCK it.

[M4Gunner]

well... good hunting ctrlz! im on my way to the store to see what i can find!

[Vector-SS]

Do you guys thing this upgrade can be done to a PPC'd Saab, or would it be too much

[pjku79]

i think i might be the boostvalve one just so i have the option to adjust it. plus its only $40.