DR

Those look nice, but arguably not "optimum".. yours have sharper bends, shorter runners (moving torque curve slightly, good or bad depending on usage) and makes it a lot tougher to change the spark plugs (which is the reason for the offset bends on 4 of the runners to start with).

I am sure it works great and I applaud the execution, but pretty hard to say those are better than the Euro S..or even the stock versions, without lots of testing.

slate blue

Well what my concept is based off is wave tuning, I did use a calculator however none are perfect as many things can influence the final result, such as cam timing and correct measurement of the internal diameter. My S runners give a plenum to valve length of approx 44 cm. That number does play out well with max power being developed at 6,000 rpm.

The S2 runners are 5 cm longer and I suspect that the reason they have that crimped down area near the injector is.for increased velocity due to those injectors having such a poor spray atomization.
If anybody has seen them on the test bench they will know these injectors spray like a syringe. The CIS injectors spray much better.

As for testing, I never tested back to back on the dyne the two intakes. I can say if this is of any help? Another 928 with a brand new engine, 4.8L vs 5.0L mine being 5.0L, his having Haltech controlling the management and having a sports exhaust but no headers which mine does.

Other than different assembly tweaks no major differences except what is already outlined. There was a 60 rwhp difference and the difference in drivability is very different also.

BC

Almost any new aftermarket ECU will make this happen. With proper tuning that is.

slate blue

Brendan, his car was 60 rwhp down on my car, same day, same dyno and operator. My car has much better torque also. Mine ran factory management with the timing gear altered to advance the timing.

U-928

Wow. You'd expect the Haltech car to have had a little better output then that. Was that car not tuned?

slate blue

By U-928 The day these runs were done was a 928 dyno day, my engine and the other fellows were both new, his had been tuned but later was optimized a little more like mine, on the actual day mine beat his by 77 rwhp. I reduced this to 60 as next week he went and had it retuned by the Haltech dealer and gained about 12 to 13 hp. I didn't mention this so as to cut a long story short. Mine late a gained another 5 hp or so and does 311 at the wheels.

That equates on the dyno we use in "shootout mode" to around 390 (to be conservative) HP as other late model cars, do about the same that have slightly in excess of 400 crank HP such as the LS2 chevies and 5.4 Litre overhead cammed Fords (Prodrive)

His car with around 240 rwhp (manual gearbox) was about right when compared another S with CIS and an auto which did 213 rwhp. A late model (hi comp) S4 did 250 rwhp on the same day. Unfortunately some cars didn't turn up to give us better bench marks.