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Old 06-25-2008, 10:48 PM   #26
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Quote:
Originally Posted by Defiant Autospeed View Post
Well, in all fairness, the 43s probably had lower milage on them. We know that at least, the differences in the pics are true. Getting the housing off the VF43 will tell the story on the hot side wheel comparison. I will get comparison pics there as well.


Not yet, Im sure I will get my hands on one at some point. I have been doing a decent bit of porting turbos lately, so the chances of me having a 48 and either a 39 or a 43 at the same time are decent. I will get pics when I have one.
If im going to be buying a VF43 from the subaru... should i just buy the VF48?

i heard their the same price...
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Old 06-25-2008, 11:42 PM   #27
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YES.

48>43


I just bought a 48 from P&L Motorspots.
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Old 06-26-2008, 12:55 AM   #28
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YES.

48>43


I just bought a 48 from P&L Motorspots.
What makes you say that the 48>the 43?

What data are you basing this off of, we cant go by the numbers that the 08 STI is making, there are too many factors there that can radically change the output regardless of the turbo used.
Im not saying you dont have data or its not true, I would just like to hear where this is coming from, because nothing I have seen points to any real benefit between any IHI from the VF30 to the VF43. The VF24/29 and VF22 are the only real standouts that I have seen, and even then, the difference is small.
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Old 06-26-2008, 12:56 AM   #29
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If im going to be buying a VF43 from the subaru... should i just buy the VF48?

i heard their the same price...
You should skip both and do either a 16G or an 18G. The 39 and 43 are every bit equal to a 16G, and an 18G is definately larger than a 48. IHI turbos are decidedly inferior to the mitsu based turbos, so if you are buying one, just get something worthy to begin with. Never chose an IHI turbo if you have other options. Not that they are garbage, but comparatively, they kind of are. They are nowhere near as efficient, they spool quite slowly for their size, they are sluggish to respond for their size, and they taper off more than the should up top.
The 16G is, as the VF39/43/48, too small for the 2.5L motor, at the smallest, an EVOIII 16G, if not at least an 18G should be the smallest turbo you would consider. A TD05-18G 8cm (with a proper compressor housing, not the tiny one some builders are using to push cheap turbos out the door, they just dont perform the same) is an excellent match for someone who wants a turbo upgrade but doesnt want huge power.

Last edited by Defiant Autospeed; 06-26-2008 at 01:02 AM.
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Old 06-26-2008, 01:13 AM   #30
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dang, great info for me!!
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Old 06-26-2008, 04:12 AM   #31
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Originally Posted by Defiant Autospeed View Post


People also need to understand that porting the turbo doesnt only benefit you by reducing creep. It wildly changes the spool and response characteristics of the turbo. This isnt as much of an issue on the 2.5L as it is on the 2.0L, which needs all the help it can get in that dept, but its still a big difference between how fast a ported turbo is than a non ported turbo. Moral of the story there is that ANY stock location turbo benefits from porting. Even a TD06-20G 8cm, will perform a good bit better if properly ported.
where do you feel the most gains can be had from porting? exhaust outlet and inlet?

is porting the compressor inlet and outlet worthwhile?
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Old 06-26-2008, 04:39 AM   #32
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I have seen a lot of IHI turbo's and the VF number doesn't seem to have any relation to anything apart from the fact that it apperars to be a numerical number to when it is put into production

If IHI produce a new VF number then there will be a change from previous model however so slight
it could be as simple as a change in housing A/R...

example is the VF30 and VF35 which are identical except the VF30 has a P18 exhaust housing and the VF35 has a P15 housing

The PXX number on the IHI exhaust housing is IHI's number for A/R (metric based)
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Old 06-26-2008, 07:25 AM   #33
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Originally Posted by Defiant Autospeed View Post
What makes you say that the 48>the 43?

What data are you basing this off of, we cant go by the numbers that the 08 STI is making, there are too many factors there that can radically change the output regardless of the turbo used.
Im not saying you dont have data or its not true, I would just like to hear where this is coming from, because nothing I have seen points to any real benefit between any IHI from the VF30 to the VF43. The VF24/29 and VF22 are the only real standouts that I have seen, and even then, the difference is small.
My tuner claims I will be able to flatten my torque curve significantly compare to my (now cracked) 39.
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Old 06-26-2008, 09:11 AM   #34
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It's okay, these are small fry turbos. I like BIG
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Old 06-26-2008, 09:32 AM   #35
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It's okay, these are small fry turbos. I like BIG
Would you like a cookie?

I like lemonade on hot days, but that has nothing to do with comparing IHI turbos.
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Old 06-26-2008, 02:34 PM   #36
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Originally Posted by fastwrx25 View Post
where do you feel the most gains can be had from porting? exhaust outlet and inlet?

is porting the compressor inlet and outlet worthwhile?
Honestly, 95% of the gains come from porting the hot side inlet. I usually do work the hot side outlet as well, but with a lot of VF43s, the hot side is seized onto the center section, and porting the outlet is too dangerous because of how close to the surface the blades of the turbine are.

If you look at how poorly matched the size of the hot side inlet is to the up pipe (especially in the case of aftermarket up pipes), then look at the fact that the outlet essentially just dumps in to a big pipe (downpipe), you will understand. I mean, you can benefit from smoothing the edge that the flow "drops off" of as it exits, which helps, but as far as measurable gains, 95% or more come from the hot side inlet. There are also the boost control benefits to cleaning up the entrance into the wastegate passage.

Porting the compressor side is really a complete waste of time. I used to do it (long before I was a vendor) then one day while talking to Jerry (deadbolt) I asked about it, he said it wasnt worth doing, and was maybe a 1-2whp thing. SO I stopped doing it, and I saw zero difference.
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Old 06-26-2008, 02:35 PM   #37
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It's okay, these are small fry turbos. I like BIG
"2006 STi Black&Gold
XPT Stage2+Enginuity Tune"


Then shouldnt you get a big turbo?
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Old 06-26-2008, 03:46 PM   #38
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good info here

btw how much do u charge for PnP v-39
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Old 06-26-2008, 07:18 PM   #39
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thanks for the heads up Defiant Autospeed
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Old 06-26-2008, 07:38 PM   #40
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good info here

btw how much do u charge for PnP v-39

PMing you
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Old 06-26-2008, 09:49 PM   #41
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Shoot me a PM on porting the hot side on a VF43 please? What the average turn around time right now for you guys on that? Thanks!
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Old 07-01-2008, 06:20 PM   #42
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Quote:
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My tuner claims I will be able to flatten my torque curve significantly compare to my (now cracked) 39.
I dont possibly see how. They are the same turbo with a different actuator as far as we now see. Unless your crack is messing things up, which there is little chance it is. Only very severe cracks cause issues. Honestly, your tuner is almost certainly going off internet rumors if they are telling you that you can make big changes to your TQ band. Just looking at dyno plots with earlier model cars with VF39s and 43s alone proves that there is no difference. Some make more or less on either turbo, they average to be the same.

Check out my new findings..

So I just took a couple pics and measurements.
The WG hole is identical in size and shape. The entry into it is identical.
The outer diameter of the exh housing is identical, as is the hot outlet and inlet.
The hot side on the 43 came right off, I have been fighting with the 39 for about an hour now, as soon as its off I will know the story on the hot side wheels.
But as it stands, the common thought that the 43 has a bigger hot side, is wrong. The idea that the WG is bigger to prevent creep, is definately wrong, that we do know now. The difference is the WG actuator. It seems to be stronger. Its definately different you can see that just looking at it.

I have taken a couple measurements on the compressor side, and its also the same. Slight differences on the outside shape, but the same size.
My earlier statements about the 39 compressor being slightly larger were incorrect, its just how they look. They measure out to be the same.
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Old 07-01-2008, 06:29 PM   #43
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OK more info.

Housing is off the 39.

The hot wheels are identical.
The hot housings are identical in every way, every shape and size of every passage, is the same.
WHich means the hot side is, from a performance standpiont, you guessed it, identical.

Which points at every internet rumor about the 43 being different in the hot side to prevent creep, or larger making more power, as being completely false.

There IS one difference. The casting numbers.


The VF43 says
R5-E4-17 5F7

The 39 says
R5-E3-17 6FM


I also took a VERY close look at the compressor wheels, they are the same, as is the diameter of the entry to the compressor wheel. Which ultimately limits power capabilities. SO the compressor side, I feel VERY confident in saying that it is identical from a performance standpoint. The only differences seem to be the outside shape of the compressor housing, but I also measured those, and those are the same diameter.
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Old 07-01-2008, 06:37 PM   #44
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More news, the WG actuators have different part numbers. We already knew they were different by the slight color and shape changes. The part number further backs this theory up.

Maybe some intense googling with the part number will turn up some info...


I am leaving, but I will post the part numbers in a while.
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Old 07-01-2008, 07:08 PM   #45
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This has to be one of the best threads I have seen in a little while. I've wondered about the differences between these two before, and almost paid extra for a VF43 a while back only because I thought that it was supposed to flow a little more. I ended up with a 39, and can finally feel good that I didn't shell out the extra change for another, similar mileage 43.

I vote that this should be stickied in both the 2.0 and 2.5 liter forums.

The above being said, I have read that Cobb doesn't recommend using VF39 maps with the VF43s. I wonder if this is just to cover themselves because they have not done testing yet, or because of the slight wastegate differences? Then again, maybe now they advise differently.
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Old 07-01-2008, 07:23 PM   #46
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I would bet my life that its a CYA move. Cobb is very carefull about covering themselves. Its like them saying that only THEIR intake works with the AP base maps. Others do work, they just cant SAY that because that would mean they would need to do extensive testing with a bunch of other intakes. Its just easier for them to make an intake that they KNOW works safely.


There is no wastegate difference. The WG itself is 100% identical, no slight differences. HOWEVER, the Actuator is different, How so, we cant say yet. But if there is a WG pressure difference, or if something about the WG actuator reacts differently, it could throw things off.

You have to understand, There is a reason Cobb stuff takes longer to come out, but when it comes out its dead on. They are way anal about how they develop their stuff. They go so far as to have deatschwerks set up injectors special just for their maps. Because the DW tolerances arent tight enough for their liking (and DW tolerances are very tight to begin with)
So its no suprise and makes perfect sense (to me anyway) that they would not recommend it.
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Old 07-02-2008, 10:03 AM   #47
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When are we going to see a VF48 vs VF39/43 comparison?
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Old 07-02-2008, 10:09 AM   #48
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When are we going to see a VF48 vs VF39/43 comparison?

In a week or three I can do it.
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Old 07-03-2008, 09:44 PM   #49
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Figures. I just bought a 43. Defiant, you have a PnP job coming up! I will PM early nexxt week after fedex has a look at it (the damage i PMd you about).

I vote sticky +1
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Old 07-03-2008, 10:58 PM   #50
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Thats fine I figured out what I am going to do to fit it on that other one, which will be the same on yours. I am just trying to determine if I can get a 90deg fitting for it...
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