4AGE Blacktop 9K RPM

Описание: Very High lift & duration cams. Too low compression ratio, did not make sufficient power. Dynamic compression way too low.

Still, sounds nice.

Engine made 180HP @ crank, with valve spring float (Supertech) and potential clutch slipping (clutch was absolutely shit from the get-go after dyno @ Alastaro TimeAttack race, eventually slipping on soaking wet from accelerator alone). Could have squeezed out a few more hp with cam timing etc, but we decided not worth the effort and the project failed.

All cylinders had slightly higher blow-by than stock, but #1 cylinder had a score in there so high blow-by. We didn't have time to bore and fit larger pistons.

Considering with all the same ancillaries we made 174hp from internally completely stock engine with ~90k KM on the clock, and almost 2 seasons of racing this was a very weak result.

The main benefit was that all the power gains were above 5500rpm, and we gained a very lively extra 1100-1200rpm for strong 9k RPM red line. Big difference above 8k RPM, where with these gear ratios power was most desperately needed for.

Engine spec:
20V BT Stock Pistons
Way way too thick Cometic HG (we didn't have sufficient time to machine valve reliefs and we wanted to retain a healthy safety margin). This ruined squish band gap as well, despite being only slightly thicker than stock.
Cams something like 304/296 degrees (actual, not 0-lash), huge overlap, 10.8/10.3mm valve lift (lost the spec sheet)
Forged rods
Adjustable intake + exhaust cam pulleys
Cylinder Cleaned up ports, multi-angle valve seat job
Supertech valve springs w/ titanium retainers
ARP hardware all around
Strengthening blocks on crankshaft mains


Don't build an engine like this, stock cams + well tuned VVT-i would have yielded much more power.

This engine would have made wild power with around 13-13.5:1 compression ratio (not piston mfg number, but calculated) and longer rods with lower compression height pistons. Also better valve springs are required, the supertechs were simply too close to their limit. Squish area gap needs to be around 0.8mm or less as well.

We were in a hurry, and we paid for it.