IW STi Forum banner
Cancel
Create thread New Garage Forums

VF48 vs 18G vs 20G vs VF52 vs DOM3

3 reading
Jump to Latest
21 - 40 of 49 Posts
Discussion starter · #21 ·
Re: VF48 vs 18G vs 20G

burnstacp said:
Excellent! Thanks for the info. Is your buddy going to do anything to try to make it spool up faster (EL headers...)?
Click to expand...
Once we've got the boost stabilized at 22psi I will start by adding more % to the ramp up before boost hits. This may net a 100-300rpm spool increase but I'm really not hopeful that it will get much better than this here. Keep in mind this is also in 3rd gear so 4th will drop a few hundred as well.

I think the only things that may help beyond that would be an Up-Pipe, MBC Hybrid or EWG, all of which we probably won't be doing on his car. I will be doing an up-pipe when my 18G goes on so we'll see if that helps out.
 
Discussion starter · #22 ·
Re: VF48 vs 18G vs 20G

Another update to the original post. We are now up to 22psi and you can see the VF48 and 20G both hit 22psi at roughly the same point. The only difference is that the VF48 gives you a little bit more flow under 3500 and then starts losing it quickly. The 20G takes over and continues to hold boost towards redline. We believe on the IWG and stock boost solenoid it'll hold 19.5-20psi at redline.
 
#24 ·
Re: VF48 vs 18G vs 20G

Peleg said:
Did IHI resolved the issue with the VF wastegate housing cracking? SOME VF-39 and 43's had this issue, which would make me shy away from anything IHI makes.

Just for my curiousity, I was looking up alternatives to the VF-39 for someone who just has a simple stage 2 and isn't looking for more power.

I came up with the following: APS SS45 (45 lbs/min) and Blouche Dominator 1.

Any opinions? Again, my VF39 is doing fine, I'm just curious about this stuff.
Click to expand...
the two turbos you mention are way bigger than the stock vf39 ;) the dominator1 is about the size of an FPgreen ;)

if you are happy with stage2 power, and your vf39 dies; get a vf34 ... or for slightly more power, a 16G.


J.
 
#28 ·
Re: VF48 vs 18G vs 20G

Very nice info! I can't wait to see the VF48 vs 18G info, as I've been very curious about how the 18G stacks up to the OEM IHI turbos on these cars. Thanks for posting, can't wait to see results for the 18G!
 
#29 ·
Re: VF48 vs 18G vs 20G

XPT Tuning said:
Forgot the last 2 pics, added up top. Gabe I have a 5gal Meth jug left if you want $40.
Click to expand...
Have not checked this thread in awhile. I got one from RallyDave for 20 bucks. ;)
 
Save
Reply Quote Like Like
#30 ·
Re: VF48 vs 18G vs 20G

XPT Tuning said:
Another update to the original post. We are now up to 22psi and you can see the VF48 and 20G both hit 22psi at roughly the same point. The only difference is that the VF48 gives you a little bit more flow under 3500 and then starts losing it quickly. The 20G takes over and continues to hold boost towards redline. We believe on the IWG and stock boost solenoid it'll hold 19.5-20psi at redline.
Click to expand...
I am at 19 at redline on my 20G but using a 3 port. I could push it further, but at 20 PSI airflow started to dropoff. 19 PSI seemed to be the sweet spot on my car. The VF43 would do 17 at redline. I peak the 20G at 22 PSI.

Why is it that our boost curves usually look the same? ;)
 
  • Like
Reactions: Kjef
Save
Reply Quote Like Like
#31 ·
Re: VF48 vs 18G vs 20G

How was the install of the 18g? I just heard back from a friend who did the install last night on an '08 and apparently it was a nightmare getting it to fit properly; coolant line, ic hose, etc. I had pictured this install as a simple swap, but maybe not?
 
Discussion starter · #32 ·
Re: VF48 vs 18G vs 20G

We haven't put my 18G in yet, still waiting on parts from Perrin before I toss it in. The only time I've had trouble with a Blouch was with the Dom3 and an APS TMIC, there is VERY little clearance between the turbo to TMIC elbow on that thing. I've also purchased an aftermarket 90 degree elbow for the turbo to TMIC as they don't fit the factory hose 85% of the time.

On the 20G we were able to re-use the factory hose but it was a tight fit.
 
Discussion starter · #34 ·
Re: VF48 vs 18G vs 20G

sutter2k said:
What happened to the images on the first page?
Click to expand...
Sorry about that, fixing them now. I had moved my web server and the links are a little different now. I'm going to also be adding pics of the VF52 (09 WRX) next to my 18G and soon next to the VF48 coming out this weekend!
 
#35 ·
Re: VF48 vs 18G vs 20G

ev8siv3 said:
Sorry about that, fixing them now. I had moved my web server and the links are a little different now. I'm going to also be adding pics of the VF52 (09 WRX) next to my 18G and soon next to the VF48 coming out this weekend!
Click to expand...
I'm anxious to hear a review of the install of the 18g. I like the idea of a stock location turbo using the stock IC, but I have heard that some modification (read: grinding metal off somewhere?) is required. :rolleyes:
 
Discussion starter · #38 ·
Re: VF48 vs 18G vs 20G

AP1 said:
would a TD06 20G 8cm have less boost taper than the TD05? can a 20G hold max boost to redline?
Click to expand...
The TD06 would have slower spool but slightly better boost retention. What's your definition of max boost? We are holding 20-21psi at redline without the EWG right now.
 
#39 ·
Re: VF48 vs 18G vs 20G

ev8siv3 said:
The TD06 would have slower spool but slightly better boost retention. What's your definition of max boost? We are holding 20-21psi at redline without the EWG right now.
Click to expand...
Would a TD06-20g w/7cm housing have any better top end?

Or pretty much the same, with more chance for creep?
Is creep with a 7cm really a concern with a catted turbo back?
 
Discussion starter · #40 ·
Re: VF48 vs 18G vs 20G

7cm will be more prone to creep, but loses your top end airflow. If you don't care about early spool and want mid-top power a TD06-20G-8cm2 would be the best. If you want good spool and pretty good mid-top the TD05H-20G-8cm2 is the best combo. You get the best of both worlds.
 
21 - 40 of 49 Posts
About this Discussion
48 Replies
21 Participants
Last post:
Karlot
IW STi Forum
posts
4.1M
members
124K
Since
2001
A forum community dedicated to Subaru Impreza and STI owners and enthusiasts. Come join the discussion about performance, engine builds, exhaust, modifications, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
GD-General 2.5 Liter/Litre Factory Motor GD-Members' Journals General Subaru Discussions 2015+ STI Discussion