Supercharged 3.1 in a Sonoma

[Superdave]

Nice, watching as well!

[pocket-rocket]

Watching.

Ditto.

[Purple pit]

Watching.

[Mars]

We went with a frame notch rather than an S10 2.8 oil pan because a) it was cheaper and b) it should leave enough room to to pretty much drop in a 3400 in the future.

^ cool.

[caffeine]

Flex pipe welded into Y-pipe. Fits mint now


Engine fitment pics



Mounts



In the next two pictures, you can see where the crossmember was notched. Notch is slightly bigger than was necessary, but it worked well. Next it will be boxed in.



Rough position supercharger will inhabit


With flex pipe welded in, Y-pipe fitment is excellent. Appears to be no ground clearance issues as a bonus.


Mounts still need to be fully welded and reinforced, but pretty much all the major stuff is taken care of. As long as the ECM and fuel lines are sorted out in time, we're gonna try to fire this up on Wednesday. So far I think we're only on week 3 so that's pretty good for time! Been doing most of the work on Wednesdays from 10 PM to Thursday 5 AM lol.

We went with a frame notch rather than an S10 2.8 oil pan because a) it was cheaper and b) it should leave enough room to to pretty much drop in a 3400 in the future.

[caffeine]

2.8 Fiero oil pan (because that's where the timing cover came from), pretty much same size as 3.1 oil pan. Motor mounts were done today. Pics to follow.

[Mars]

This is a cool little swap. 3.1 is an ideal truck motor.

Are u using the FWD oil pan ? Will it clear ?

[unchained01]

I have commend you on your tenacity. Hope it all works out !!!

[caffeine]

So recently a friend of mine blew up the 2.5 in his 93 Sonoma. Since this is more-or-less his DD, he needed to get a new engine in as quickly as possible. A week later his brother gave him a 94 Sunbird with a rebuilt 3.1. So that's how this project came to be. Goal is to make as much reliable power as possible, maybe with a 3400 upgrade in the future. So far only around $500 has been spent.

Old duke coming out




Engine bay before and after


Just a quick tremclad roller paint job

Fiero engine to be used for a few parts, like the RWD timing cover

2.8 was pretty sludged up. Like it had never had an oil change. This engine had only 100,000 miles on a rebuild

Sunbird engine coming out



Next he picked up a Supercoupe M90 for $100


Block torn down



RWD timing cover mocked up with intakes. No drilling out of holes or plugging extra coolant passage necessary for mounting on a gen II, and only minor grinding to the upper tab on the cover were necessary



Heads off and ready for some mild porting



Heads and LIM reinstalled (LIM flipped 180*), new timing chain installed also



T5 mounted up with clearanced 2.5 bellhousing, 3.1 FWD flywheel, the old duke's clutch (still plenty of life left), and a new Sachs pressure plate



OBX S10 2.8 headers!

Lower holes slotted


OBX Y-pipe mocked up




Timing cover and water pump re-installed (I know the water pump has the wrong pulley on it right now)


Rough drawing of planned belt routing. Going to be mounting the alternator and power steering pump in the same place as on my 3500


So for the rest of the build here are the plans:
Modify the crossmember for oil pan clearance (would be helpful for future 3400 swap)
Solid motor mounts similar to the ones on my 3500
Remote mount supercharger on the passenger's side
Use TGP intercooler to aid in keeping IATs down
Old Greddy BOV from his Audi A4 1.8T
Weld a flex-pipe into the OBX Y-pipe (fitment isn't ideal anyway)
Run $12P on a 7165 with a mostly stock wiring harness or use the stock 6647 if it's compatible (pinouts are identical to the 7165). Use a 3800sc 2-bar MAP sensor for boost.
Stock VR6 injectors leftover from his VR6 A4 project
Play with pulley sizes to get the right amount of boost (anyone have experience with this?)

Obviously the gen II motor isn't ideal, but it was free and this should make boatloads of power more than the 2.5. The T5 could be a weak link but could be upgraded with a V8 WC T5 eventually. The OBX headers are actually quite nice; only snag is that the y-pipe wasn't designed very well and needs an O2 bung added. Injectors and clutch may need to be upgraded as well.