Supercharged engine

[rv6ejguy]

At the same 80hp level none of this matters, no need for oil squirters. A 1600-1700cc engine will easily put out the same hp at a few hundred rpm less than a 2180, just using 4-5 psi boost. I don't see any show stoppers there, just match the turbo properly

 

[BobbyZ]

At the same 80hp level none of this matters, no need for oil squirters. A 1600-1700cc engine will easily put out the same hp at a few hundred rpm less than a 2180, just using 4-5 psi boost. I don't see any show stoppers there, just match the turbo properly

True but I'm hoping to have a little extra on tap if need be

 

[rv6ejguy]

True but I'm hoping to have a little extra on tap if need be

2 more psi would take you close to 100hp but you'd have to watch timing and detonation margins on mogas. On 100LL, no issue.

 

[syclone]

It seems to me that the limitation on a VW is the exhaust valve; you need to take good care of the exhaust valve. It only cools when it is closed, and the heat flows through the valve face into the seat then into the head. Keep your expectations modest and there are some performance gains to be had - but only at high altitude. If you like to fly cross country above 8,000 feet, or it your airport is above 5,000 feet, then the supercharger (and fuel injection) makes sense. For most of us, a set of 94 mm cylinders and perhaps an 82 mm crank will be sufficient. The normally aspirated engine will lose power at the rate of about 3% per thousand feet, so there's a crossover up there somewhere.

 

[rv6ejguy]

You do have to be aware that cooling mass flow drops off with altitude on turbocharged engines and this can be a big deal on air cooled engines which already have marginal fin area.

 

[Vigilant1]

You do have to be aware that cooling mass flow drops off with altitude on turbocharged engines and this can be a big deal on air cooled engines which already have marginal fin area.

+1. Though the cooling air's temperature does drop with altitude, the drop in density of the cooling air is a more significant factor.

 

[Pops]

My company proved the reliability of stock block based turbo engines long ago in racing. Our turbo engines were able to slay atmo engines with over twice our displacement race after race going on to win 7 championships. The engines were way cheaper, way more reliable and way more powerful than our competitors high revving big displacement non-turbo engines. The bottom ends were completely stock except for forged pistons and SPS rod bolts. I actually used OTS Mahle VW pistons in our 1700 and 2400cc Toyota engines. The mechanical stresses are indeed lower at lower rpms, with a bit of boost, at the same hp level.

The typical kit VW components like cranks, rods and pistons are easily capable of taking the loads imposed at the 100hp level and and 3500 rpm pretty much forever. You'd need a bigger oil cooler almost for sure. The only big question is- could you reject the heat from the heads?

Revmaster makes their own VW type heads and have the best cooling heads on the market with the fin and other mods they use. I would use their heads right from the start on a tubo VW engine. Also Bob Hoover's oil (HVX) mods for better oil flow to the heads that helps on the cooling.
Dan