2007 2.5i rear diff ratio?

The G.O.A.T. · 01-09-2011, 03:52 AM

just a quick question.
What is the rear diff ratio on a 2007 2.5i, and what years of diffs would work from WRX's/STI's?

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RaceFaceXC · 01-09-2011, 04:16 PM

trans/driveline forum, n00b

williaty · 01-10-2011, 02:11 AM

3.900.

No STi rear diff will work.
No WRX (complete) rear diff will work.

You could transplant the VC LSD unit from inside the rear diff of a WRX into the rear diff of a RS, but why would you want to? The VC LSD units are crap.

SubIELove · 01-15-2011, 08:11 PM

I have a 3.9 Sti r180 that's going in my 2.5i in the spring. Why would this not work if my stock diff is a 3.9?

williaty · 01-15-2011, 08:15 PM

Quote:

Originally Posted by SubIELove

I have a 3.9 Sti r180 that's going in my 2.5i in the spring. Why would this not work if my stock diff is a 3.9?

With a sufficient swap, yes, you could change the entire rear end and put in an R180. However, you'd need to determine how much of the mounting hardware, rear subframe, etc, you'd have to change to get the R180 in there.

Most people, when they ask what you did, want to know if it's a direct bolt on or if they can swap internals, etc.

SubIELove · 01-15-2011, 08:22 PM

My full setup will be the v8 Spec C STi 3.9 2 way plated diff and axles, and 04 Sti full hub assemblies. I also have the 5x100 rotors from the spec c. Pretty straight forward bolt in affair.

williaty · 01-15-2011, 08:25 PM

Well, for most people, diff, axles, knuckles, brake assemblies, etc all at once doesn't count as straight forwards. To me, that's "Tuesday afternoon", but for most people that's "hire a mechanic".

Have you confirmed the R180 has the same bolt pattern on the snout as the R160?

SubIELove · 01-15-2011, 08:29 PM

It doesn't, the snout ring needs to be replaced in favor of the r160 ring to keep the stock driveshaft. The splines are identical on both snouts and the rings are interchangeable. This is a fairly involved job, will most likely take me a weekend. Pretty straight forward bolt in job. I'm converting the car to RWD using an old school Chip Torque Australia center diff spool as well.

williaty · 01-15-2011, 11:28 PM

No, I mean the bolt holes for securing the snout of the main casting to the carrier.

SubIELove · 01-16-2011, 12:42 AM

Yeah it's all the same, all gd's use the same rear subframe.

01-09-2011, 03:52 AM	#1
The G.O.A.T. Scooby Newbie Member#: 149724 Join Date: May 2007 Chapter/Region: W. Canada Location: Calgary Alberta, Canada Vehicle: 1999 leggy gt 5speed Blood red	2007 2.5i rear diff ratio? just a quick question. What is the rear diff ratio on a 2007 2.5i, and what years of diffs would work from WRX's/STI's? * Registered users of the site do not see these ads.

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01-09-2011, 04:16 PM	#2
RaceFaceXC Scooby Specialist Member#: 165749 Join Date: Dec 2007 Chapter/Region: South East Location: stupid Florida Vehicle: 2007 No YELLING on the bus!	trans/driveline forum, n00b

01-10-2011, 02:11 AM	#3
williaty Scooby Guru Member#: 71092 Join Date: Sep 2004 Chapter/Region: MWSOC Location: Delaware County, Ohio Vehicle: 2005 2.5RS Wagon Regal Blue Pearl	3.900. No STi rear diff will work. No WRX (complete) rear diff will work. You could transplant the VC LSD unit from inside the rear diff of a WRX into the rear diff of a RS, but why would you want to? The VC LSD units are crap.

01-15-2011, 08:11 PM	#4
SubIELove Scooby Specialist Member#: 107571 Join Date: Feb 2006 Chapter/Region: NESIC Location: Rocky Hill CT Vehicle: 2004 OBS JDM V8 Sti UsVERSUSThem WFC #197	I have a 3.9 Sti r180 that's going in my 2.5i in the spring. Why would this not work if my stock diff is a 3.9?

01-15-2011, 08:22 PM	#6
SubIELove Scooby Specialist Member#: 107571 Join Date: Feb 2006 Chapter/Region: NESIC Location: Rocky Hill CT Vehicle: 2004 OBS JDM V8 Sti UsVERSUSThem WFC #197	My full setup will be the v8 Spec C STi 3.9 2 way plated diff and axles, and 04 Sti full hub assemblies. I also have the 5x100 rotors from the spec c. Pretty straight forward bolt in affair.

01-15-2011, 08:25 PM	#7
williaty Scooby Guru Member#: 71092 Join Date: Sep 2004 Chapter/Region: MWSOC Location: Delaware County, Ohio Vehicle: 2005 2.5RS Wagon Regal Blue Pearl	Well, for most people, diff, axles, knuckles, brake assemblies, etc all at once doesn't count as straight forwards. To me, that's "Tuesday afternoon", but for most people that's "hire a mechanic". Have you confirmed the R180 has the same bolt pattern on the snout as the R160?

01-15-2011, 08:29 PM	#8
SubIELove Scooby Specialist Member#: 107571 Join Date: Feb 2006 Chapter/Region: NESIC Location: Rocky Hill CT Vehicle: 2004 OBS JDM V8 Sti UsVERSUSThem WFC #197	It doesn't, the snout ring needs to be replaced in favor of the r160 ring to keep the stock driveshaft. The splines are identical on both snouts and the rings are interchangeable. This is a fairly involved job, will most likely take me a weekend. Pretty straight forward bolt in job. I'm converting the car to RWD using an old school Chip Torque Australia center diff spool as well.

01-15-2011, 11:28 PM	#9
williaty Scooby Guru Member#: 71092 Join Date: Sep 2004 Chapter/Region: MWSOC Location: Delaware County, Ohio Vehicle: 2005 2.5RS Wagon Regal Blue Pearl	No, I mean the bolt holes for securing the snout of the main casting to the carrier.

01-16-2011, 12:42 AM	#10
SubIELove Scooby Specialist Member#: 107571 Join Date: Feb 2006 Chapter/Region: NESIC Location: Rocky Hill CT Vehicle: 2004 OBS JDM V8 Sti UsVERSUSThem WFC #197	Yeah it's all the same, all gd's use the same rear subframe.