For A 3.2 Boxster S, Nothing Should Beat Displacement: Why Not Going To 3.8 ?
For a 3.2 Boxster S, nothing should beat displacement: Why not going to 3.8 ? For a 3.2 Boxster S, nothing should beat displacement: Why not going to 3.8 ? Now that my 2001 Boxster S is having great suspension and brakes (i.e.: PSS9, adjustable low arms, large Brembo rotors with 6 piston calipers). All looks good, ..but, I would love to have some more juice ! Engine runs fine, ..after currently more then 1300 miles in Laguna Seca, ..and some other hundreds of miles in Sears Point. My big question is : Why Jake seems to not willing to use the 101mm bore option, available at LN to build 3.8 engines ? OK, the truth with 101mm bore, you are at 3749 cc (3.749 liter), ..not exactly 3.8 ! I would love to understand that. For my point of view, 鈥渘othing beats displacement ! Being Swiss, I could add (joke), the Nickies should be like the cheese: if the holes inside are larger, you have less cheese, ..and it is cheeper, because cheese is sold by weight !
All the above taking in account that the crank stay as original, i.e.: in the case of the Boxster S 3.2, the stroke is 7.8 cm. We may add that an S 3.2 has a bore of 9.3, or, the exact displacement is 3.179 liter ! Who can explain to me why moving up from a 3.2 into 3.6 would be better than 3.8 ? Then why aren't all of us driving 10 liters? I would much rather have a better built, more efficient medium displacement engine with a broad power band as most anything I can think of. Based on port flow and shape studies that we have carried out the M96 cylinder head cannot adequately feed an N/A 4 liter engine. The M97 cylinder head has dramatic changes that can sustain this on the 3.8 liter factory engines and these even outflow the new DFI port in a back to back comparison that we carried out a few weeks ago.
I included the port characteristics in my most recent Flat 6 newsletter. There is no better way to create a worthless engine than to make it so large that it's displacement exceeds the capability of the cylinder heads. I own both a 996 and 986S. Its utterly amazing to me how the Boxster engine dies at 5,000 rpm compared to the 996 engine. The exhaust and intake are awful in this application. I used to think that theres no replacement for displacement, which is true to a point. So I installed a 400 cubic inch engine instead of a 383 cubic inch because I wanted those extra cubes. It was a bad decision, as the 383 would have actually produced more power, more reliably. Everything is a tradeoff at some point. Id rather have slightly lower displacement and be able to rev the engine a bit higher. In my opinion, an IMPORTANT REASON why the displacement is limited in ALL racing categories, is simply because higher displacement makes an easy difference ! Or, easy rules to equalize power is to limit displacement.
In my opinion, an IMPORTANT REASON why the displacement is limited in ALL racing categories, is simply because higher displacement makes an easy difference ! Or, easy rules to equalize power is to limit displacement. Right, if all things are equal, then displacement should win. But in my 400 vs. 383, the block design was slightly different where cooling in between the cylinders caused ovaling of the cylinders over time for the larger engine. With these Porsche engines, I suspect there are trade offs that cannot easily be overcome, which is why keeping displacement a bit lower reduces those trade offs. The responses from Jake may be 7 years old but the engines have not changed since he made his response. The 3.2l engine from the Boxster S or the 3.6l engine from the 996 hasn't magically developed better intake, heads, ports, etc, to accommodate the air and exhaust flow a larger displacement engine would require.