What Do These Things Do!?? [Archive] - SaabCentral Forums

: What Do These Things Do!??

24-02-05, 02:34 PM
Hey guys, I'm new here.
I have a '90 aero and I've decided to drop a lot of money into it but first i need to know what these things do and what I'm going to want them for-
what will a performance bypass valve do for me?
blow off valve do for me? Fuel Pressure Regulator do for me? 3in down pipe do for me? is it worth it to upgrade my Ignition System? Who makes the best APC upgrade?

Where should i start on this thing? the body looks great, now I just want to get it boosting higher, moving faster and being an all around better car.
Thank You.

24-02-05, 02:55 PM
A blow off valve would replace the stock bypass valve. The stock one is a recirculating valve which is made of plastic and liable to leak. You can replace it with a performance recirculating one made of metal, or block the location off and install a blow off valve instead, which is an atmospheric dump valve. The Forge FMDV004 is popular, as is the Bailey 0026. Either way it must be a dual piston valve. The performance gain is not much - smoother gearchanges on boost, and a nice whooshing sound when shifting, but that's about it.

The FPR all depends on the other mods you have, but the stock one should be fine for a while. If you are in the US you have an SPG, not an Aero (same car more or less, different name), and it will be the 2.8 bar FPR I believe. You can change it for a higher rated one if you are running lean but not much point before.

3" downpipe is held to be a very worthwhile mod that frees up quite a bit of power. Minor drawback is that you'll have to relocate the battery, usually to the boot/trunk.

Lots of people sell upgraded APCs. It is apparently very easy to do the mod yourself, by turning up the P and F pots and maybe replacing resistors. Many on here have done the work themselves, or got the specs and had it done by a local sparky. The place to find out about APC tuning is on www.900aero.com .

The best way to find out about these mods and others is to do a search (http://www.saabcentral.com/forums/search.php?) of this forum, as that will give you many more replies than you will ever get in one thread.

Welcome to Saab Central :cool: