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PDX-944 PDX-944 is offline
Join Date: Oct 2012
Location: Wilsonville OR
Posts: 923
Building a stroker/wet sleeved 951S - Borg Warner EFR 6258

I had started another thread inquiring about doing a rebuild, and some of the options. I might as well start this as a build thread now that I'm going to get started - I still need help making some decisions.

First off, heres what I have

951S Silver Rose
Wolf3D V400 EMS using MAP sensor
J&S Knocksafe (tuned for 16psi on premium fuel, tunable via laptop)
B&B Header
EFR 6258 Turbo with internal recirc valve
3" Stainless downpipe (ceramic coated)
4" Lindsey Racing stainless cat-back
Custom oil cooler
Custom aluminum intake piping (larger diameter)
Aluminum flywheel
Spec Stage II clutch
Tial Wastegate
72# injectors
Aluminum fuel rail
Adjustable Lindsey "stock location" FPR

So Im looking at 3.1-3.2L wet sleeved and stroked.

I have access to a machine shop that from what Im told through my connection, makes anything. They can pull apart a motor or trans, figure out what they need, and just make it.
I can have this done at material cost.

Im going in there tomorrow to meet them for the first time with the person who I have the connection through, and I'm looking to figure out what all to ask about:

- If they can machine and wet sleeve the motor/deck
- Offset grind or simply make me an offset lighter crank (they can)
- They can make a cam from scratch, but I have no idea what they would make me or what to ask for
- Whatever else they recommend that they can do for me during the build.

What I'm trying to figure out and piece together right now:

Possible 3.31L
Deck Height = 9.05”
Bore = 106mm = 4.17”
Stroke = 94mm = 3.7”
Rod Length = 145.288mm = 5.72”
Chamber Volume = 56cc
Gasket Thickness = .039 or .055"
Piston Dome Volume= -31
Pin Height (Compression Height) = 1.425?

Or, same as above, with 104mm bore, I end up with a 3.2L

This is my first build of this depth, but I'm determined to make this work, and it will be done before next race season.

This is my hillclimb and autocross car. I compete in a series of hillclimbs locally and the car is already doing very well, but compression is getting poor, and I need to rebuild between seasons.

Do the above numbers look reasonable? Im a bit unsure about the ones with question marks, and could use advice and guidance during this!

Ive been reading every thread out there that I can find about other builds, theyre all over the board and most end at 2.85L

2x 1984 944 N/A; 1988 951S Silver Rose; 81 VW Rabbit Diesel; MK4 VW R32
President - Bridge City Autosports

Last edited by PDX-944; 09-14-2017 at 12:39 PM..
Old 09-14-2017, 10:44 AM
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