Rebuild or swap?

[mr.kyle.henderson]

My fox has around 140,000 miles on it. Engine needs work but it still has a lot of power.
I want more horsepower and acceleration either way, but IDK if I should rebuild my current motor and upgrade it or if I should find a clean ABA or Bubble block.

What would you do?

Either way a turbo is gonna happen.

[voxwagen88]

I'd take the money that was going to rebuild the 1.8 and build a plus size 2L and keep in NA.

But as you are determined to force air into the thing....
I'd follow Jonathon's old recipe for a strong low compression 1.85L engine.

1.85L 8V using 1.7L crank, Audi turbo rods, JE 82.5mm pistons, ported head with stainless valves,

Engine is 1.7L crankshaft, MC1 pistons, 1.8L block, ported head with the aforementioned stainless 41/34 valves, three-angle grind. Stock 1.8L cam, but we might switch to the shorter duration ABA cam for better midrange and torque. DBG admits that he seldom revs past 5K, so we will try to make the most of that part of the power band.

If I'm right, 1.7L crank is same stroke as Fox (86.4mm) however it use a 46mm rod journal instead of the 48mm like most VW. MC engine (2.2L 5-cyl Turbo) also use 46mm rod journal and also have a 86.4mm stroke and 81mm bore but use 136mm rod instead of the Fox's 144mm. More importantly, MC engine had forged pistons and stronger rods so the 1.7L crank let use the MC pistons and rods into a 1.8L block. This is a perfect low price setup for a turbo engine because it give you a 7.8:1 compression ratio and a stronger block.

[ziddey]

yikes, that is low compression.

How much hp are you looking to make, Kyle? Our trannies really can't take all that much. Not too easy keeping traction either


Jonathan's setup may be a bit over-engineered . It shouldn't be too tough working with a 10:1 ABA 8v counter-flow turbo setup, if you're looking for around 160-200hp (tough on the motor that is, assuming proper fueling / ignition timing).

Or, if you're able to get creative, a 16v setup would always be splendid if you wanted to stay NA. Those things flow so well compared to the 8v's.


I'd say start off with an ABA swap. Upgrade to the dual outlet manifold / downpipe, get a better cam, and go from there. That should keep you satisfied for a little while. When the time comes, figure out a turbo setup (assuming you're willing to give up AC / don't have AC)

[mr.kyle.henderson]

Do I absolutely have too take the A/C out?
200HP was my original goal lol I'm still at the drawing board tho.

[ziddey]

No, I'd rather not either when (getting to be more and more "if") I go FI.

Alaincopter might have something to say about this.

It's all in how you mount your turbo, although a lot of readily available turbo manifolds end up putting the turbo where the compressor is.

[alaincopter]

Yes - the short version would be that it's possible to turbocharge while keeping the AC, as long as you're not going to run CIS-E.

That would require using a specific exhaust manifold from brazilian SPA Turbo, available in North America through Design Engineering, Inc. This would be the manifold to get. To make it work, you'd also need this AC compressor relocation kit.

All this would place the turbo around where the fuel distributor would be on a CIS-E - there's ways around that of course, like relocating the battery and placing the FD in its place, or going EFI

[QuantumSyncro]

If you go with ABA get an OBD1 engine, IIRC the cranks are forged and they have piston oilers.

steve