Upgrading twin turbos - only secondary, or both?

[Cervantes]

I have 2 TD04's on the way, and I was thinking about swapping both turbos. I talked to someone who said it was probably better to leave the primary as is, as change out the secondary. I don't want to go single turbo, only as a last resort if this doesn't workout the way I'm hoping it does. Would it be worth swapping both turbos to TD04s, or just swapping out the secondary?

Thanks

[chuckthefuk]

What exactly is the goal for your turbo setup?

Different configuration will yield different response times, VoD, and spool times.

[Huffer]

Your primary turbo needs to spin up quickly, it's not a power generator - the 2ndary is what brings your top speed.
If you are looking to increase response in the lower gears/rev range, you would need to replace the primary for a higher efficiency one that spools up quicker, and doesn't puff out too quickly.

Whatever you do, you'll need to make sure your tuner is right on the money because any significant delay in switching to the 2ndary turbo, having the correct fueling for your air ratio, is going to create issues that could cause your engine to lunch itself. Just so you're aware, the GT-B engine is prone to munching the main bearings when too much power is sought.

[anothernord]

Well, 2 TD-04s wont work anyway because one of them will face the wrong way.

[StatGSR]

^?

guess i've never seen the TT set up that clearly

[Cervantes]

I'm going to use the housing from a VF14 and one from the VF25. From what I've been told, it should work with a tune.

[Cervantes]

this is a HUGE pain in the ass....might not finish this

[Huffer]

Just go single turbo. You'll enjoy it more.

[Cervantes]

Seems to be the less complicated route also.