It will decrease the reliability of the vehicle; think about it, you're asking the car to output more than it was designed for. What do your compression/leakdown results look like? Take-off VF turbos don't really flow enough to spell instant/imminent death, but it does increase the likelihood.

That said, a good tune, proper maintenance, and sensible driving will go a long way, but ultimately, YMMV.

 

Compression and leak down tests both look pretty good - indicating only slight wear. The car has about 90xxx miles, so I was happy to find that out.

Take-off VF turbos don't really flow enough to spell instant/imminent death, but it does increase the likelihood.

What do mean by not flowing enough? Are there better/safer upgrade turbos to use? From what I've read I like the plug and play aspect of the vf series.

 

Compression and leak down tests both look pretty good - indicating only slight wear. The car has about 90xxx miles, so I was happy to find that out.



What do mean by not flowing enough? Are there better/safer upgrade turbos to use? From what I've read I like the plug and play aspect of the vf series.

He means they are not really big enough to add too much added stress to the engine. He also means that anything that adds more power than what it came with stock will add some stress to the engine and tranny...

 

What do mean by not flowing enough? Are there better/safer upgrade turbos to use? From what I've read I like the plug and play aspect of the vf series.

If it were me, I'd go with a 16G-variant

 

I had an 07 WRX that I put the vf39 upgrade on. Install was easy, and felt fine for the 8K I had on it before selling it for my STI.

In general - if you muck with a car, you are inevitably doing something the manufacturer hasn't tested out and therefor you are only increasing risk - even if you are reducing power. That said, I did the upgrades and loved it.

I have read many times before that the 02-05 WRX transmissions are problematic if you increase power too much. I think your engine will be fine as long as you are VERY careful not to create boost spikes and surges. If I were you, I would be more concerned about whether the transmission can handle the power you are about to put into it.

I don't know much about the 04s.. but I didn't need new injectors or a new fuel pump for my vf39 upgrade. Just an STI intercooler (already was stage 2 with COBB DP before I put the turbo on) and I was ready to go.

 

If it were me, I'd go with a 16G-variant

Without looking it up (and I will) - those require the same basic supporting mods correct? And if I recall - they're simular in gains?

Thanks for the input - I'll check into it!

 

as long as you are VERY careful not to create boost spikes and surges.

OK - now I'm getting lots of stuff to look up! as to being carful in regaurds to boost spikes - does that fall into the category of having a good tune - or are the further precations that can be made/taken/purchased?

Does anyone else have opinions on the vf series vs. others?

 

I highly recommend a boost gauge before doing the mods you talk about - otherwise you will never know if your boost is where it should be. The terms you should "google" or search on this site is "boost surge" and "boost creep." These 2 are very different, and can both destroy your engine.

 

I went with the VF39 because I could start with a COBB OTS map and tune myself from there. If I could do it again knowing what I know now - I still would have done the VF39. The lag on the VF39 is just a little worse than my TD04, while the 18G would have created much more. The 18G would have given much more "high end power" - but I would have had to get the injectors/fuel pump to realize it.

You may not hit full boost as soon with the 18G, but you'll be flowing more air pretty much everywhere, which means more power.

 

I highly recommend a boost gauge before doing the mods you talk about - otherwise you will never know if your boost is where it should be. The terms you should "google" or search on this site is "boost surge" and "boost creep." These 2 are very different, and can both destroy your engine.

Do have a boost gauge - that and an EGT gauge are the only mods installed to date. And an AP, I guess.

I went with the VF39 because I could start with a COBB OTS map and tune myself from there. If I could do it again knowing what I know now - I still would have done the VF39. The lag on the VF39 is just a little worse than my TD04, while the 18G would have created much more. The 18G would have given much more "high end power" - but I would have had to get the injectors/fuel pump to realize it.

I was thinking the same about the COBB map. Though I was under the impression that you would have to do the injectors/fuel pump with the VF39 - is that not true?

You may not hit full boost as soon with the 18G, but you'll be flowing more air pretty much everywhere, which means more power.

I'm thinking the 18G may be a bit much as far as keeping the reliability up! I've been doing some research on the 16G's though. Thanks for all the imput!

 

I was thinking the same about the COBB map. Though I was under the impression that you would have to do the injectors/fuel pump with the VF39 - is that not true?

2.5L vs 2.0L

I'm thinking the 18G may be a bit much as far as keeping the reliability up! I've been doing some research on the 16G's though. Thanks for all the imput!

If you can swing the extra $$ for a 16G over a used takeoff, I'd do it. Either one will require fuel upgrades.

 

2.5L vs 2.0L



If you can swing the extra $$ for a 16G over a used takeoff, I'd do it. Either one will require fuel upgrades.

After doing some reading I'm leaning towards the 26G series - but it's hard to go away from the used VF39 price tag! Thanks for the clarification on the fuel upgrades - pretty sure I knew that......but the old noggin neads to be jarred sometimes

 

http://www.clubwrx.net/forums/faq.php?faq=rules#faq_nohijacking

 

"16G series" - stupid fat fingures!

 

After doing some reading I'm leaning towards the 26G series - but it's hard to go away from the used VF39 price tag! Thanks for the clarification on the fuel upgrades - pretty sure I knew that......but the old noggin neads to be jarred sometimes

If you go with the 16G, you'll want 650+cc injectors. If I were in your shoes, pick up the DW 750cc; they're only $30 more than the 650s, and will be easier to sell if/when you part the car out or upgrade further.

 

I would agree.