[serper3]

Originally Posted by Idaho2018GTPremium

Here's more examples, info. from the test published today by C&D on the M3 Comp vs Alfa Giulia:

'21 M3 Comp:
60-130 mph: 9.3 sec (3% slower than ZL1)
100-130 mph: 5.2 sec (4% slower than ZL1)
130-150 mph: 5.5 sec (9% quicker than ZL1)

'21 Alfa Giulia Quadrifoglio:
60-130 mph: 10.3 sec (14.4% slower than ZL1)
100-130 mph: 5.7 sec (14% slower than ZL1)
130-150 mph: 6.5 sec (8% slower than ZL1)

The ZL1 should be getting quicker and quicker compared to these lower powered cars as speeds climb, not as in this case noticeably slower than an M3 Comp 130-150 mph. And the Giulia should not be closing the gap vs the ZL1. Obviously, with the M3 Comp running 1/4 mile in 11.6 @ 124 mph it is a lot more than 503 crank hp, but the ZL1 is quicker below 130 mph, yet slower above 130 mph.

I might chalk this up to the one test by C&D having a ZL1 that was a bit slow, but MT ran the exact same time and trap speed (11.5 @ 125 mph as C&D, however w/ 91 octane), and I noticed the same large drop off above 130 mph in the ZLE A10 test by C&D (vs. the GT500 and Redeye in 2019). Again, aero can't explain it because the GT500 CFTP has a large wing and aero bits as well, and was MUCH quicker above 130 mph than the ZLE. More so than the 110 hp Delta suggests.

Anyway, I'm still sticking to my theories #1 and #3 above. I think it's a combination of undersized HEXs that can't keep up for long WOT applications + hotter ambient air testing conditions (can't make up loss of timing with DA corrections) + subsequent timing loss = slower at the end of a long WOT pull.

I wonder how much of an improvement over stock just an e50 flex fuel sensor and tune would be.

I am in CA so have been considering this but do not want to do LTs or anything else difficult to go back to stock.

[Stephen12ZL1]

Originally Posted by serper3

I wonder how much of an improvement over stock just an e50 flex fuel sensor and tune would be.

I am in CA so have been considering this but do not want to do LTs or anything else difficult to go back to stock.

it helped a bit with E50 on my '17 so I tuned my '21 immediately. I will confirm/post the performance difference after VIR in October.