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2007 Forester XT 4EAT-VTD
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Discussion Starter #1
We often discuss power gains of one turbo vs. another, but how about build quality/durability? Which brand of turbos are built the best?

I know this is somewhat subjective, but I wonder how brands such as Blouch or FP compare to the IMI VFxx turbos in this regard...
 

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2004 Subaru FXT MT
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We often discuss power gains of one turbo vs. another, but how about build quality/durability? Which brand of turbos are built the best?

I know this is somewhat subjective, but I wonder how brands such as Blouch or FP compare to the IMI VFxx turbos in this regard...
Wow, there are just to many environmental impacts on reliability that its really tough to give you a good answer.

Nearly all bolt-in subaru turbos start off life as IHI or Mitsu center cartridges. Only a handful start life as Garrett cartridges. Really all of those are going to be very reliable, so long you stay in the operating parameters.

Really, heat and turbine speed are the major operating parameters you have to concern yourself with. You will destroy any turbo in short order if you try to operate on the far edges of the compressor island.

Thinking about assembly though, the turbo manufacturer has a huge impact on long term reliability. Proper rotating assembly balance, proper wheel runout and clearances, torque specs, cleanliness, etc.

So, just like engine building, an OEM turbo typically has a better shot at being reliable than an aftermarket turbo. But, there are shops out there that have higher quality standards and more rigorous quality checks than the OEM's do. How about all of that for a "I don't know" response...lol
 

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2007 Forester XT 4EAT-VTD
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Discussion Starter #3
Scott, thanks for the insight. Looking at my graph below, do you think I'm pushing boost with the VF48 too far (it tops out at 20.3 PSI)? That is what prompted me to ask this question.

Right now, I'm taking a serious look at the Aquamist HFS-3 WI system to lower IDC (currently at 98% max) and pull peak boost back to under 20 but hold hold a little more than what I have now at the higher RPM.

Thoughts?


 

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2004 Subaru FXT MT
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check out the attached compressor map with demand lines. You have to take density ratio into consideration, but you can safely run up to 25 psig on your VF turbo.

I'm speaking to 2.5L's with all of this...

If you want your turbo pushed, but safely, you can target 22 psig from 2-4k rpm, tapering to 15 psig by 5k and 6 psi by redline. You really need to taper it hard otherwise you can overspeed, and you are without a doubt just blowing really hot air.... The VF39/43/48 is still too small for the 2.5L imo.
 

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2012 VW TDI R-Wagen DSG
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If you take a look at EFI"S data base.
I went from a VF43 to FP 68 HTA.
I only gained 18hp and 8 tq.
The upgrade would cost you around $800-$900. Includind selling your turbo.
The Foz felt like it made a lot more power than that because it held that power almost to red line.
 

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2008 FSXT M/T
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of course it gave him more gains, more boost = more gains. the methanol enabled chris to turn the boost up - thats what makes the power in the end, not the parts themselves.

forget peak numbers though, its the area you gain under the curve... dyno numbers mean jack squat, you guys really should take your car to a track to see a trap speed every now and then. thats a real world test IMHO...

too many variables can come in2 play between dyno visits to truly gauge performance gained.
 

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of course it gave him more gains, more boost = more gains. the methanol enabled chris to turn the boost up - thats what makes the power in the end, not the parts themselves.

forget peak numbers though, its the area you gain under the curve... dyno numbers mean jack squat, you guys really should take your car to a track to see a trap speed every now and then. thats a real world test IMHO...

too many variables can come in2 play between dyno visits to truly gauge performance gained.
hells yea, lets get some trap speeds up in this piece!:biggrin:
 

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drag strips break cars. some of us have too much money invested and too much power to just go to the drag strip and break axels, rear diff's every time out
 

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Jim, I have indeed been studying your graphs on EFI's website! It looks like the water/meth injection gave you the bigger gains. My plan is to do the same with the VF48 and see how it goes, perhaps in combination with TGV deletes.
That is a good plan. those turbos are to close in power for all that money.
 

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The larger Perrin TMIC and WI should offset that somewhat, yes?
No, the turbo is still seeing the high temperatures. You are just making sure your motor doesn't see the same temps with WI and a large TMIC.

What really are your goals? Your current tune looks like you are fine. You are in a good spot in the mid range. Only area I would question is up top where you are still running 14 psig. You are probably just blowing hot air up there, but you would need to thermocouple it to verify. You are most likely safe though.
 

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drag strips break cars. some of us have too much money invested and too much power to just go to the drag strip and break axels, rear diff's every time out
Only your car Vinny..lol

You have to pick a weak link man. What's it going to be? The clutch? Axles? Rearend? Tranny? Tires? With your setup, most people don't start breaking stuff until the race rubber goes on. If you stay on street tires, or better yet, crappy all seasons, you won't break stuff.
 

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you dont need to launch the bejesus out of your car to see a trap speed. roll out and get on it... yea itll be down a few mph but still give a good generalization..

not for nothing why go thru doing a built motor, 6speed, 35r and the bells and whistles to DD the thing. thats just a waste of money IMHO... every1 here is guilty of doing pulls on the highway - whats the difference. just dont dump the clutch @ 7k and youll be fine...
 

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Only your car Vinny..lol

You have to pick a weak link man. What's it going to be? The clutch? Axles? Rearend? Tranny? Tires? With your setup, most people don't start breaking stuff until the race rubber goes on. If you stay on street tires, or better yet, crappy all seasons, you won't break stuff.
I break stuff on the street, I haven't even gotton a chance to break things at the track yet. I just know from previous cars @ the drag strip

not for nothing why go thru doing a built motor, 6speed, 35r and the bells and whistles to DD the thing. thats just a waste of money IMHO
well when you break something you upgrade...seems logical. with the turbo i wasn't really happy with the dom4 at the time and the six speed is way easier to daily drive than the ppg 5speed. and i don't daily drive it anymore, can't afford to.
 
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