there is a good explanation of the 34 on http://gruppe-s.com i have a few wrx and sti friends with the 34 and they love it. basically the 34 is just a better design. it's a good starter turbo before you really upgrade the power

 

They are essentially the same turbo, but the 34 will spool faster due to the ball bearing design. It won't make any noticeable improvement over the 30 on a 2.5, it will just come on boost faster when you hit the gas.

 

I am contemplating on switching to a ported and polished VF34 when I decide to do a TBE. My biggest concern is that will it be OK to retain stock engine management when I do this?

 

<--- running Deadbolted VF34 with STOCK boost solenoid, STOCK injectors, STOCK engine management for 2000+ miles with no problems whatsoever.


No boost creep or spiking. Jeremy(username: Invisiguard) has had his ported VF34 on his STi for 15,000+ miles with ZERO problems. He is still running stock injectors and stock engine management. My boy Rudy(username: Jagcars26) also has been running a ported VF34 on his STi with stock injectors and stock engine management with ZERO problems as well. I'm currently waiting for my STi UTEC to arrrive so that I can get this thing tuned already!

Trust me, you will be fine running a ported VF34 on stock engine management and stock injectors. Aftermarket engine management will only help you produce more power. :wink:

 

Just turned 43K miles

had the 34 on since about 20K, keeping the boost stock and no probs, and yes waiting for my UTEC from god, cant wait 8)

 

Hey Jer,

Who will be tuning your UTEC??? Maybe we can have our cars tuned at the same time...

 

Did you guys see any sort of hp gains by switching from the 39 to the 34? I have heard of guys gaining like 30 hp with this mod? I have read that it has a bigger compressor or exhaust housing but not sure. I also heard that it was actually a little thicker and not necessarily larger. Any facts out there? Just curious. I am probably going with a 39 from a friend simply due to the price and the fact that it is much larger than my td04!

 

For some odd reason, I thought that many of the 2005's have a slightly larger exhaust housing, and are basically IHI VF34's.

I probably misunderstood this thread - but here is the reference...

http://forums.nasioc.com/forums/showthread.php?t=606432&highlight=exhaust+housing

 

Thanks for the input fellas. Looks like I am going to be running a 39 as I can get a really good deal from a friend but it is good to know these things.

 

Thanks for the input fellas. Looks like I am going to be running a 39 as I can get a really good deal from a friend but it is good to know these things.

IMO - the vf39 is a perfect match for the 2.0l WRX... quicker spool-up than a 30/34 and provide much better top end on the smaller motor :wink: