i have a 98 t5 and was wondering if this is even possible. even tho the turbo has an internal wastgate, is it possible to put on a external wastegate and how would that be done?

has anyone done a 18t swap? im looking to upgrade my turbo

 

You may be able to search the threads to get more info on turbo swaps. Never heard of anyone doing an external waste gate.

 

You probably can find more info on that on volvospeed.com

 

Why do you want to do this? The only reason I can think of doing this is to increase boost pressure and that starts to get on the dangerous side if you are running pure stock engine management, I'm not sure how much boost the stock system can compensate for. It's possible to put an external wastegate on any internally wastegated turbo system. You will need to stop the stock turbo's internal wastegate from moving (usually by welding the gate shut or by attaching the rod to a fixed area). Then you will need to install a external wastegate and use a boost controller so you can tweak your boost pressure. I would be careful, however, the only other two things you really need to worry about is finding a way to bring in more fuel (piggyback fuel injector controller) and a way to retard ignition timing under boost to prevent pre-det. A AFR meter with wideband o2 is your best friend.