Serious Garrett GT30/GT35 series builders need a turbine housing that matches the correct bolt pattern for their downpipe, and this T31 narrow 4 bolt housing does exactly that. Engineered as the alternate T3 housing with the narrower 2.5″ bolt spacing, it’s built for enthusiasts running ball bearing GT30 and GT35 series turbos who need direct, correct fitment rather than the standard GT 4 bolt configuration. This is the housing of choice when your turbo’s turbine wheel and downpipe flange call for the narrow pattern, not the wider 3″ spaced standard housing.
Specifications
- Housing Type: T31 (T3) turbine housing
- Outlet Configuration: 4 bolt outlet
- Bolt Spacing: 2.5″ (narrow pattern)
- Turbine Wheel Fitment: 60mm turbine wheel (GT/GTX3071R, GT/GTX3076R, GT/GTX3082R)
- Turbine Wheel Fitment: 68mm turbine wheel (GT/GTX35R / GT3582R)
- Available A/R Ratios: .63 A/R
- Available A/R Ratios: .82 A/R
- Turbo Selection Options: GT28/GTX28
- Turbo Selection Options: GT/GTX3071R with 60mm turbine wheel
- Turbo Selection Options: GT/GTX3076R with 60mm turbine wheel
- Turbo Selection Options: GT/GTX3082R with 60mm turbine wheel
- Turbo Selection Options: GT/GTX35R (GT3582R) with 68mm turbine wheel
- Turbo Selection Options: GT3071R-WG Dual BB, 84 Trim Turbine (additional cost)
- Turbo Selection Options: GT3071R-WG Dual BB, 90 Trim Turbine (additional cost)
- Garrett P/N: ATP-HSG-038
- Alternate P/N: ATP-HSG-041 (2.5″ V-Band machined outlet version)
Performance & Application
This housing is designed to fit the turbine wheel found on all GT30 and GT35 series ball bearing turbos, making it a direct-fit solution for builders running GT3071R, GT3076R, GT3082R, GT35R (GT3582R), GTX30, or GTX35 turbochargers. It is specifically the alternate T3 housing with the narrower 4 bolt pattern, distinct from the standard “GT 4 bolt” housing which uses a wider bolt spacing and a longer tapered discharge on the downpipe side. Enthusiasts should select this housing when their downpipe or exhaust flange is built to the narrow 2.5″ bolt spacing rather than the standard configuration. Choose between the available A/R ratios to dial in spool characteristics and top-end flow for your specific build.
Compatibility & Fitment
- GT3071R
- GT3076R
- GT3082R
- GT35R (GT3582R)
- GTX30
- GTX35
- GT28/GTX28
- GT/GTX3071R with 60mm turbine wheel
- GT/GTX3076R with 60mm turbine wheel
- GT/GTX3082R with 60mm turbine wheel
- GT/GTX35R (GT3582R) with 68mm turbine wheel
- GT3071R-WG Dual BB, 84 Trim Turbine
- GT3071R-WG Dual BB, 90 Trim Turbine
- GT/GTX28R series (fitment noted with Product Code ATP-HSG-038)
Frequently Asked Questions
- What is the bolt spacing on this turbine housing?
- This housing features a 4 bolt outlet with 2.5″ bolt spacing, which is the narrow pattern rather than the standard 3″ spacing.
- Is this the same as the standard “GT 4 bolt” housing?
- No. This is the alternate T3 housing with the narrower 4 bolt pattern and is NOT the standard “GT 4 bolt” housing, which has 3″ bolt spacing and a longer tapered discharge on the downpipe side.
- What turbos does this turbine housing fit?
- It fits the turbine wheel found on all GT30 and GT35 series ball bearing turbos, including GT3071R, GT3076R, GT3082R, GT35R (GT3582R), GTX30, and GTX35.
- What A/R ratio options are available?
- This housing is available in .63 A/R or .82 A/R.
- Is there an alternate outlet style available?
- Yes, an alternate 2.5″ V-Band machined outlet turbine housing is available as part number ATP-HSG-041.
For builders running GT30 or GT35 series ball bearing turbos with a narrow 2.5″ bolt pattern downpipe, this T31 turbine housing delivers the correct, direct fitment your build demands.
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