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#3: 10-30-2011, 08:00 AM
fahr_side's Avatar
Title: Royal Pain in the Ass
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Appendix I

Rebuild options. There are parts kits available from Ebay or what appear to be more reputable vendors like this one. There are now other vendors on eBay selling new CHRAs for about $250 but not much information is out there on how well those work in practice. Try searching the forum for recent experiences. Remember that a turbo failure puts your whole motor at risk from bearing metal shrapnel and then ask yourself if you can afford to cheap out on this. The chances are that if your VF-40/46 wore to the point that either wheel rubbed on it's housing, that part is scrap. Note also you cannot rebuild a turbo in your garage as the wheels absolutely need to be balanced with specialized equipment. You will not luck out on this one. An unbalanced turbo will quickly shake itself to death at high rpm and the shrapnel may destroy your engine, just like the original. Six Star Speed now offers a VF-40 rebuild service for $500. You could search and see what other members have to say about their experiences with this product.

Replacement turbo options. Note that upgrade turbos or those originally fitted to other models will need tuning to run safely. The larger turbos will need fuel system upgrades to reach their full potential.
This list is limited to direct bolt-up replacements which can be used directly with the stock TMIC or aftermarket equivalent. There are other stock-location turbos with different style outlets which need another intercooler solution to be used, but that is beyond the scope of this article. Vendors are listed in no particular order but OEM replacements come first. If you know of some unlisted turbos please post.

Section 1: Turbos which can sensibly be run on OE fuel system. While these do not NEED a fuel system upgrade they MIGHT benefit from one.

  • OEM replacement turbo from dealer or Subaru parts vendors. Plenty of used ones around but check condition carefully. Only the stock turbo can be run safely on the stock tune. It seems that the VF-46 can be used on an earlier car to replace a VF-40 without re-tuning on the condition that the original VF-40 pill is used. The VF-40 wastegate actuator does not bolt up to the VF-46 so you will either need to use the VF-46 item or modify your VF-40 actuator to fit. Note that some tuners require different sized pills for stage 2 tunes. Please note that only these turbos really qualify for use as a stage 1 or 2 build. All others are different enough that they fall into the stage 3 category.
  • Rebuilt VF-40 turbo from BNR Supercars. Bryan will have reconditioned units available for exchange at $650.
  • WRX OEM ('08) TD04 turbo from dealer or Subaru parts vendors. Also lots of take-offs around. This is a direct plug and play but needs to be re-tuned. The TD04 is a very solid little turbo which takes a lot of abuse. Although the turbine and compressor wheels are slightly larger than those in the stock IHI turbos, the housings are smaller and power potential is slightly lower. It does however spool instantly. You would want to start with the pills that came with the TD04. Note that '08 WRX models have one pill either side of the tee in the hoses. This works very well and you could just use that whole tube set-up.
  • WRX OEM ('09~) VF-52 turbo from dealer or Subaru parts vendors. Not quite so common used as they are in high demand. The CHRA in this one is much beefier than the VF-40/46 models but some WRX owners have had them fail in much the same way as seen on LGT models, and like the VF-40/46 they cannot easily be rebuilt. Please note that if you install this turbo on any other car than an '09~ WRX, Subaru will not warranty it if it fails. This turbo is roughly equivalent to an STi VF-48 or MHI TD05H-Evo16G and can do around 300whp on pump gas. Tune required.
  • BNR Supercars TD05H-Evo16G . MHI guts in VF-40-style housings. TD05H turbine mounted into a 7cm2 exhaust housing with the EvoX 16G compressors in a vertical-delivery compressor housing. BNR super-thread here. MHI has the advantage of replacement parts being readily available, and many vendors can rebuild them. The Evo16G model is so far perhaps the most popular non-stock replacement for a dead VF-40/46. $750
  • Kinugawa new bolt-up turbos based on MHI TD05H-EvoIII16G in either 7 or 8cm2 exhaust housing. Some more info in this thread. These turbos are made by Kamak, which is a major manufacturer of replacement turbos based in Taiwan, but are said to be of lower quality than the Kamak brand. Chinese parts are now creeping into these turbos.
  • ZAGE new bolt-up turbos based on MHI TD05H-Evo16G in a 7cm2 exhaust housing and with a 1bar actuator. These turbos are made by ZAGE which is a major manufacturer of replacement turbos based in Taiwan.
  • Kamak STS 16TX bolt-up turbos with new 9-blade turbine and billet compressor. I've tested these in both 7cm2 and 8cm2 housings and liked them. TD05H and TD06SL2-sized turbines available and compressors from 16GTX to 20GTX.
Section 2. Turbos which really want an upgraded fuel system to let them shine. Note that ANY turbo can be run on the stock fuel system but will have to be tuned to fall short of it's power potential.
  • Complete new TD05H-18G or 20G 8cm2 turbo from BNR Supercars, no need for a core, straight bolt-up replacement. MHI compressors from 18G to 20G available, along with billet wheel options or TD06SL2 turbines. BNR super-thread here. MHI has the advantage of replacement parts being readily available, and many vendors can rebuild them.
  • Blouch XT series bolt-up turbos based on MHI TD05 frames and billet wheels. Several options available. Well-known vendor but not immune to quality issues.
  • FP 68HTA bolt-up turbo based on MHI frame. FP brought this compressor to market themselves and it's very popular, especially with E85 users.
  • Kinugawa new bolt-up turbos based on MHI cartridges. TD05H-18G, TD05H-20G and TD06SL2-20G available. Some more info in this thread. This is a second-tier brand from Kamak, which is a major manufacturer of replacement turbos based in Taiwan.
  • ZAGE new bolt-up turbos based on MHI TD05H-18G, TD05H-20G, TD06SL2-20G or TD06H-20G in either 7 or 8cm2 exhaust housings and 1bar actuators. These turbos are made by ZAGE which is a major manufacturer of replacement turbos based in Taiwan.
  • Kamak STS bolt-up turbos with new 9-blade turbines and billet compressors. TD05H, TD06SL2 and TD06H-sized turbines available and compressors 18GTX and 20GTX.
  • AVO380 bolt-up turbo based on Garrett GT28R frame. These are hard to define as needing or not needing upgraded fuel as the results are all over the place.
  • AVO450 and 500 bolt-up turbos based on Garrett frames.
Please note that any replacement turbo is going to need a tune to run safely. Turbos larger than roughly a TD05-18G will probably destroy a stock 5-speed clutch in short order. How to upgrade the fuel system or transmission is outside the scope of this thread.

EDIT: I've compiled a list of supporting upgrades that turbo buyers should be aware of before choosing a snail, here. This will help you set realistic goals based on the budget you need to run a given turbo successfully.

Last edited by fahr_side; 12-15-2016 at 09:53 PM.. Reason: Moar info
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