New performance Slant article in Hot Rod
Is it complicated to turbocharge a Slant 6? It looks pretty cool and I bet it's a quick little thing! :D
Good questions! My experience (limited to approximately six years with slants and turbos) is this:
There are a couple of stumbling blocks along the way, in turbocharging a slant six; the main one is evident in any kind of turbocharged, blow-thru carbureted car, and that is, "tuning." It is not easy. But, the problems of tuning a carb on a blow-thru slant six would be about the same problems you'd face, tuning ANY carbureted motor, V-8 or six, or, 4, for that matter, in a boosted environment.
The best thing about slant sixes is their super-strong infrastructure. They can withstand abuse (excessive boost) that would turn most other engines into a pile of scrap.
I have a frriend who has run THIRTY-SEVEN pounds of boost as an experiment on his turbo slant, with no apparent damage. Don't try that with your thinwall cast 360 Magnum.:D
The
worst thing about a slant six is the strangulated, asthmatic. choked-off cylinder head, which makes turbo or supercharging almost, a lead-pipe cinch neccessity, for most serious high-performance output.
Ten pounds of boost can take a lethargic, 18-second A Body down into the high 14's, which is 383 Road Runner territory.
You can build a ten-pound (boost) motor using stock slant six pistons, rods, crank. cam and valvetrain and a stock, unported head and have a fun, pump-gas car that will surprise a lot of V-8s. Just add a 2bbl carb and manifold, a turbo and a "PISHTA" J-Pipe...
But, even with this mild-application, the tune is ultra-important, with special attention needing to be paid to the Air/Fuel ratio and, total spark advance.
You will,
absolutely, need a high-quality, wideband, data-logging, 0-2 sensor ... and they are not cheap, regardless of the carbureted system you choose. Maybe one is needsed for the F.I. systems as well; I don't know about them.
Forget about trying to tune a blow-thru, forced-induction induction system (carbureted) without one... Those sensors have very recently come down from $300.00+ to about $200.00, and one of the new ones are not affected (damaged) by leaded fuel. I wish they'd had them available when I bought mine.... ask me why I wish that...:banghead:
The next build-level would be the 15-pound and up, system that utilizes the stronger, more boost-friendly, forged internals (pistons and rods) , which will make possible horsepower-levels of 300, 400, or even 500+...
It costs about $1,100.00 for forged pistons (including rings,) and forged rods. These forged pieces have a lot more resitance to the damaging forces of detonation and usually last a lot longer than the cast, OEM (original-equipment manufactured) parts. A higher horsepower engine, you would probably want to O-Ring the block (Iskenderian rents a pretty fool-proof (I made it work!) tool, for cutting the O-Ring grooves, and supplies the needed wire.) Stronger ARP head sstuds help seal the cylinder-presssure, and a new cam and lifters is usually usedd, but is in no way, a typical high-performance grind. Turbo motors like this one seem to work best with canshafts thaat have near-stock duration, wide lobe separation (115-degrees?) and somewhat increased lift. Even the 500-horsepower motors have a slow, smooth, dle, much like a stock motor. No drama, here... A relatively mild, 5,500rpm refline is the max; they just don't perform well, after that...
The intake system seems to work well with a holley 2350 (350 or 500CFM) Super Six 2bbl manifold for the 10-pound motor, while any of the 4bbl manifolds (with a Holley 600-650 DP) with blow-thru mods, will feed the highter-output motors, effectively, with a heavy-duty mechanical (but boost-referenced with a tube from the intake manifold to the backside of the pump-diaphragm,) while the higher boost motors will need a full-blown, electric pump (a Walbro gsr392 is the one I use,) and a boost-oriented, presssure regulator to reduce the line pressure to 6 pounds (plus boost,) , from 50. That system also requires a return-line -to-the fuel cell.
It's not easy, nor cheap, but having an A-body that will runs as fast as high tens (and, maybe faster,) is possible and, is a breath of fresh air (no pun intended, ) in a sea of engine-swapped A-Body 360s (and, their stroker-variants. )
Hope this helps... Here are some pics of mine; 3,000-pounds, 225 on 15 pounds of boost; 12-seconds flat at 112mph... More to come.later this year with 20 pounds of boost....:prayer::prayer::prayer:
