Vf46 vs vf52

Okay so I have a 2007 Legacy Gt 5eat. It’s stage 2 right now. Basically I’m looking to have a fun DD car and don’t really car too much about top end. I was looking into a vf52 upgrade but I’ve seen some people posting that even though they are making 280+ awhp with the vf52 the 0-60 is slower and the 1/4 times are the same. Does anyone have any experience with this? I’ve seen another post where the vf 46 only spooled 200rpm faster than the vf 52 and the vf 52 made more power after that everywhere. So personally I don’t see how the 1/4 would be the same or 0-60 would be slower since 200rpm is basically nothing. Please let me know what you guys know/think and if you owned both vf 46 and vf 52 and have proof of the 0-60 and 1/4 then great I’d like to know!

I have a VF52 and came from a VF46. I don't time this car, so I can't give 1/4 mile differences. In my tune, I picked up a few hp, but I retuned for the different turbo. The difference was so small that it could be attributed to the difference in tunes. I changed it out for diagnostic purposes as I thought the VF46 was having problems. Turned out not to be the case, and the car runs pretty much the same on both turbos. Now keep in mind that my other car is a Bugeye with a Dom 3 and a JDM ej207, so I'm used to big lag and huge top end. This car is the opposite - quick spool, and runs out of breath up top while not making much power. So coming from the Dom 3, both of them (VF46/52) spool quick, and both don't make much up top.

 

If people are saying their 1/4 mi times are slower or the same, it would probably be related to the transient response. I'll say that the VF52 does have pretty slow transient response relative to it's quick spooling characteristics. Again referencing my Dom 3, it's a dual ball bearing turbo, and it's transient response is VERY fast relative to the spool. Comparing the two, the two of them seem to get back up to boost between shifts in about the same down time, assuming shifting at redline. Of course there are other factors, but the one thing that I wasn't expecting with the VF52 was the amount of time it took to get back up to full boost between shifts. The VF46 might be better in that category, but I don't remember at this point. I'll say that since the Dom 3 and the VF52 feel pretty much equal in their transient boost time, then that's either good for the Dom 3 or bad for the VF52, with the Dom 3 being much bigger and boosting to 25psi vs the VF52 only going to 20.

 

If you're looking for an upgrade from the VF46 for DD purposes, I'd look at the Blouch 20G XTR 10cm.

I have a vf52 on my 05 GT wagon 5mt and the stock vf46 on my 09 Spec B. Both have a Invidia catted down pipe, Invidai catless up pipe on the 05 and stock up pipe on the 09.

 

Both cars are tuned by the same Tuner, the wagon was done on a dyno back in 2011. The 09 just street tuned. Both are on stock fueling. Tuner said both are putting out 19psi on the street tunes since the wagon was on the dyno.

 

The wagon is much faster. Tuner is tuningalliance@gmail.com

Comparing the application of two different turbos by 1/4 mile times is inaccurate. So many factors outside of the turbo itself determine a mile time or 0-60.

 

The general consensus is that the stock VF52 is better in almost every way to the stock VF46 for a more fun daily driver. This varies based on driving style and goals.

If you have a VF52, I can make it spool just about at the same rate as a VF46, OR, I can make the VF46 spool even quicker than stock and pull all the way to redline.

If you have a VF52, I can make it spool just about at the same rate as a VF46, OR, I can make the VF46 spool even quicker than stock and pull all the way to redline.

 

I have one of his VF52s, it's awesome. ^

+1 for JMP’s VF52 builds, have one on my Outback daily driver and love it

Thanks guys. I don’t have the vf52 yet it was more of a future reference question. Didn’t know if I should stick with the vf46 or go with a vf52 whenever that time comes but looks like the best of both worlds is jmp’s vf52

I just remembered Tuner replaced the boost pill also in that short hose off the compressor housing. He used a wire splice which had a smaller hole.

 

He did that back in, I think it was 2008. That hose was transferred to the vf52 in 2011.

I have a JmP custom VF40 on my specB and it's not fully tuned yet, but I can't wait to get a downpipe and tune...

I have to add another +1 for JMP's VF52.....I have been sitting on one of his custom turbos for nearly the last 2yrs.

Build quality is A++++.

Will be installing it in the next week or two and should be able to give you a better comparison coming from a VF46 in my spec. B going to a VF52.

 

Cool let me know how it is whenever you’re done.

If you have a VF52, I can make it spool just about at the same rate as a VF46, OR, I can make the VF46 spool even quicker than stock and pull all the way to redline.

 

 

So, are you saying that VF46 > VF52 in terms of response and performance?

So, are you saying that VF46 > VF52 in terms of response and performance?

 

Curious about this as well. I'm on the fence for which direction I'll go when turbo upgrade time comes.

I can increase the spool on VF46 with a Custom wheel to make it quicker and it will also pull to redline without going flat. I can also increase the spool on the VF52 with a Custom wheel that will help it off the bottom some, and because it's larger than the VF46, it will pull harder through the mid-range and harder on top all the way to redline.

So it sounds like vf46 > vf52 (given these are both customized) at a lower rpm range until a certain rpm threshold, and then the vf52 wins.

 

 

 

Do you have a plot of vf40 vs vf46 vs vf52 all customized? That would be sweet!

Dyno results from a JMP VF52 and a VF46 on the same dyno

 

http://i672.photobucket.com/albums/vv87/JoshEAllen/BB54CF76-9A38-41F9-966A-7907738E6A98.jpg

 

This JMP VF52 was previously modded by Grimmspeed and tune by GST. I would expect slightly better low end on a pure JMP VF52.

Interesting.. I like the idea of full torque 1k rpms earlier, but past ~4k rpms that VF52 looks like a winner.

 

I'm pretty sure the VF40 & VF46 are nearly identical turbos otherwise. A stock VF40/46 vs. JMP custom VF40/46 would be interesting to see on a dyno compairison though.

 

Gonna be a minute until I'm ready, but pretty excited to fully tune my JMP VF40.

Yeah, according to that plot above, that vf46 stock has quite a lot of torque compared to the jmp vf52 before ~3500 rpm. And I have to say I prefer a 'quick' car vs a 'fast' car. So yeah, would love to see a plot of vf46 vs vf40 vs vf52 all 'jmped'.

 

Thanks for that plot though wrx usa.

Custom VF40/46 are about the same, but they are extremely quick and solid in the middle while the Custom VF52 is pretty quick (much better than OE VF52 due to much lighter 11 full blade billet wheel and lighter inconel turbine/shaft assembly) but faster on top end and stronger in the middle.

 

#1 is VF40/46 OE wheel. #2 is Custom wheel for both.

#3 is OE VF39/43/48/52 wheel. #4 is Custom wheel for those.

#5 is Custom 16G and #6 is Custom 18G.

Remember this all relies on the tune and making sure your fuel and exhaust are correct for that particular turbo.

What exactly is different then between a stock VF40 and a stock VF46?

Compressor housing shape but it gives virtually no difference in performance. Subaru needed a new turbo number for the new model, so IHI built them a new turbo. I personally prefer the VF40 because it's easier to install due to the compressor housing being a bit smaller OD than the VF46. VF40 on the left and VF46 on the right.

I was gonna say I have a stock VF40 on my wagon and a JmP custom VF40 on my specB, but there are a handful of differences btw them that wouldn't make it apples to apples even on the same dyno.

Whatever route you go, consider having one built by JmP. I was in a tough spot and came across a bent impeller fin while I was finishing up my engine rebuild and he rebuilt and upgraded my VF46. Was plenty cheaper than a new oem and a lot higher quality.