just playing with ideas here but check this out.

 

 

Im thinking of a way of fooling the waste gate into think the vaccum signal is highr at lower rpms,possibly with a dash mounted valve(restriction)to kill off a little lag.I would also put in a boost gauge or blow off to manage things and a pyro.Iam currently building a 3" exhaust from the turbo back,with a cat(damn emmisions testing)and a cherrybomb.Ithink this may give a little more snap on demand.Think this idea would work,or any other possibilities(low$$).Allthe parts to do this are readily(free)available to me.

BTW,is it wrong for me to have smoked a civic si off a stop light?At first I was joking,but the he was pissed when i caught him and passed(honest)!

any (bump) thoughts?Im trying to make th kick of the turbo a little less abrupt and give a little more inital torque.

Messing with the wastegate won't make it spool faster. However, your 3" exaust will make it spool faster, if you open up your intake as well. Gave my 87 a lot more power.

 

What year Si? I've toasted many a Civic and even a 94 Accord V6 in my 87 :-)

how much boost are you running to pull so hard as to beat a civic si? i have an intake and im running stock exhaust, and stock boost. i am currently installing a boost gauge and MBC. it feels prety strong, but im not sure if itll take out an si.

si = squirls inside:D

 

any thing you do to make it breath better will reduce the mythical LAG. lag is just what your car would feel like with out a turbo. at low RPM/flow it cannot spool up no matter what you do to the wastegate signal. the wastegate is already closed then anyway.

Careful on foolin with the waste gate. I had one fail on it's own, when climing a summit with the pedal floored it would build enough pressure to blow the air intake housing off the throtle plate assembly.

I know exactly what you're talking about. Yes, delaying the pressure signal to the wastegate will increase your boost pressure. More boost--->lots more power (You describe a manual boost controler. I recommend an electronic one). Before you do that, tho', get yourself a freer flowing exaust. 2.5" is good, 3" is excellent. Install a boost gauge. Is your Subaru intercooled? If it's not, don't add over 4-5 psi of boost, or you'll only be introducing heat to your intake. If your car is intercooled, it'll probably take more boost (I don't know what's safe for your car). Make sure your cooling and oiling systems are up to par, new spark plugs, decent octane gas, etc. You might want to check the torque on your head bolts. If the head gaskets are old, you might want to replace them, and install new head bolts, at higher than normal torque. Check the turbo bypass valve. Replace if it's defective. Fuel injector size is a limiting factor. Check out rcengineering.com for that. A pyrometer is a great thing to have. install on at the manifold collector tubo, and don't turn up the boost untill you're sure what the normal value is. Turbo lag is a function of turbo size and exhaust resistance. Less resistance=less lag. Your turbo outlet elbow is too restrictive, I'm sure, judging by what I've seen on other stock turbo cars.

supradan you have some good points but a manuel bost controler will not reduce lag at low rpms. like you stated yourself making it flow better is the best bet for less lag.

I wrote: "Turbo lag is a function of turbo size and exhaust resistance. Less resistance=less lag. Your turbo outlet elbow is too restrictive, I'm sure, judging by what I've seen on other stock turbo cars."

That's what I meant. I don't think I implied that increasing boost (by use of a manual or electronic boost controller) will reduce lag. :-)