I've yet to get the turbocharger installed on my car and once again I'm unsure where I should go from here. The junkyard shortblock in my car still runs great N/A, but I noticed under high load and high rpm if you jump off the throttle into decel then back into WOT it blows some blue smoke. That actually really worries me about the high mileage of the motor really showing through now. Shortly after we boosted my friends blue car thats how it started, now it blows blue smoke 100% of the time under any and all throttle.. A 4 lap autocross event costs the car 4 quarts of oil...

My plans have been to find a reputable crankshaft machine shop to add and re-machine my factory 1.8 crankshaft into a faux stroker crankshaft, use the H-Beam rods I picked up through group buy, and have some JE pistons custom forged to offset the wrist pin for stock rod length. This is a practice I've used before in SBCs, and racers have done longer than I've been around so I figure with a reputable machinist there shouldn't be any problems with this build. My crankshaft guy decided to retire a couple years ago and I've been unable to source a local reputable person.

Basically heres my question: Should I just buy off the shelf forged pistons and assemble the motor which I have all parts for and prepare to swap it in after I kill the junkyard shortblock or go for the goal with the stroker? From what I've seen the extra 200cc is pretty well worth the extra cost and work but I just don't know at this juncture.

 

I'd go for a stroker engine, but that's just me..

 

That blue smoke actually sounds like valve seals - does it do it on start up?

Are you talking about offset cut on the mains and oversized bearings? That's ok for NA, but contrary to what you want for boost since you're reducing the mains' girth.

 

You should run a compression or leak down test and find out what's wrong with your motor and if there's anything wrong. From there it depends on your budget and any time constraints you may have.

 

Nope on both accounts.

Does not smoke on startup, cylinder head is basically brand new -- < 3000 miles on it since full rebuild. Ran a leakdown on it before I put it in the car and numbers were VERY VERY low (good, little to no leakage) but the cylinders are visibly worn..

Offset cutting is what I'm talking about, but what we've done in the past is they actually tig weld on more material on the top of each rod journal to replace what they cut away from the bottom so the diameter of the journal isn't actually changed, just offset from where it was. Dunno.. I'm seriously thinking about just going for the stroker.

 

I'm definitely an advocate of displacement for turbo 4 cars, but I think it's always worthy to consider cost. I don't know that I'd spend a grand on 200cc when a turbo (2560 for example) can be sized to produce similar torque results and great hp up top with optimization to other parts for that money.

 

I agree about the displacement m2.. Every little bit counts, but I too am not sure if 200cc would really be worth what it'd cost. Don't remember what the crank work would cost, but Ben was talking about getting that China forge company to make a 2 liter stroker crankshaft for 1200$ from Billet steel... I figure around 4-500$ for the machine shop to stroke out my crankshaft, maybe 600$ total for the custom forged pistons, assemble myself and have the whole assembly balanced might cost around 200$? Either way with that China crank or my factory modified crank it'd need to be balanced again..

From what I saw on FM's dyno charts, the extra 200cc on an identical build was worth 75tq from a GT28 turbo, which in theory might be a little more with the monster turbo I've selected..

 

$1,300 for 200cc?

Look at it this way: 200cc is an 11% increase for a 1.8L motor. Since it's all stroke (making the engine even further undersquare) then all else being equal, I'd expect said motor to produce somewhere in the neighborhood of 11% more torque. If the motor was making 250 ft/lb to start with, we'll call it an additional 27.5 ft/lb.

Seems like a lot of money for not a lot of gain. That cash would probably be better spent on headwork and an awesome manifold and exhaust.