A couple of questions..

[glt-4-6]

What is the highest boost pressure I could reliably get out of a stock turbo on a 97 Talon TSi?

Is it possible to bolt up an external wastegate with the stock turbo?

And, if I can bolt on a wg what size (mm) and spring rate would I need to get to build the boost from the first question?

 

[xreaction122]

IMO i wouldnt run more then 16psi just to be on the safe side. and your stock smic loves to get heatsoaked.

as for the ext. wastegate setup,yes. but it really isint necessary to do so on a stock turbo.
your gonna have to do some welding and get a new o2 housing or a exhaust manifold thats made for a ext. gate.

bottom line:not worth dropping money on the t2small

 

[cano86]

^^^ Great advise couldn't have explained it better myself.Enjoy your ride

 

[VergeTSi]

possible... yes, worth it..... no, like he said not worth it

 

[kahl23]

What is the highest boost pressure I could reliably get out of a stock turbo on a 97 Talon TSi?

Is it possible to bolt up an external wastegate with the stock turbo?

And, if I can bolt on a wg what size (mm) and spring rate would I need to get to build the boost from the first question?

With stock injectors, the most you can safely run would be about 14-16psi. The amount of boost you are able to run is entirely dependent on your supporting mods. Do some searching on this site and look through the upgrade paths here and I think you'll find most of your questions have already been answered around here. As stated above, external gates are entirely overkill on a T-25, which is the turbo you have now. If you're looking to make more power, I would do a few things:

1. Make sure all your maintenance work is up to date, very important, it will save headaches later.

2. Do all the "free mods" found in the upgrade path here

3. Invest in some sort of datalogger so that you can actually know what's going on inside your engine

4. Basic upgrades: Hard IC pipes, new BOV (or a used 1g BOV), exhaust, MBC

5. Upgrade your fuel management, most common setups would be a larger pump, larger injectors, and AFPR to control fuel pressure, and some sort of fuel control. The most common fuel control systems are Apexi AFCs, DSMlink, ECU+, DSMap, I could go on. Do a search you'll find a lot.

Once you get to that stage you should have learned enough to know exactly what you would need to run a larger turbo, but if you don't search here, and if that doesn't work ask a question, most people here can help you out.