hsg wrote: ↑20 Sep 2024, 20:57
jjn9128 wrote: ↑26 Jul 2020, 18:17
Lag is an ever-present issue with turbo race cars, F1 just has a big electric motor to spool it up and fill in the lower RPM power gap. There are inherent advantages and disadvantages to both, turbos come with intercoolers which increase weight and cooling drag, that weight is also higher up which is a detriment to laptime. If you go back to the 80s when turbo cars ran alongside NA cars the pattern would generally be - NA faster in corners (less weight, better COG, easier packaging, easier on tyres) with the turbos blasting past on the straights (more power overcoming the losses).
I'm not sure I agree with your assertion that turbo engines are cheaper/lighter/more durable. It'd be cheaper for F1 to go with a NA 2.5-3li V8 revving to 12-15k made by Cowsorth/AER/Gibson/Judd or someone.
If both cars have same mass and engines same
peak power, which car will do better lap time?
Why is peak power important?
Surely only cumulate power (work) is important?
[Which some people say as "torque wins races", but that shouldn't interpreted as peak torque but rather average torque for a given engine class -- i.e.,
average power.]
No use having (for example) 225hp @ 9000rpm if that tuning means you lose 10 hp from 6000-8500rpm, the engine with 215hp peak but (average) 10hp more from 6000-8500rpm will almost certainly perform better -- assuming say a 1500cc aspirated engine class.
[Or say it's a 1000cc aspirated class, then 215hp peak @ 13800rpm may outperform 230hp peak @14000rpm, if the first engine is less peaky and makes more power than the second from 8000-12800rpm (assuming rev limiter of say 14200rpm). I.e., what you gain in the last 1400rpm before redline may not be enough to offset what you lose compared to the first car below 12800rpm, having tuned the engine to be super peaky for peak power. AFAIK, such bike engines don't tend to have varioram or VVT.]
Though in some class (those with fixed gear ratios
but free inlet runner length), the teams have different inlet runner lengths to move the torque band to suit the characteristics of different circuits -- since obviously the rpm when exiting a corner will be different for different circuits, as gear ratios are not free to choose.
F1 does allow varioram systems (now on turbo engines when it's not as relevant, which is weird!) but not VVT. I guess VVT, VVL and varioram systems can help with having a broader spread of torque when they are permitted.
Sequential turbos were a fad in road cars at one point (e.g., FD RX7 or Subaru Legacy B4) to have two different sized turbos each with a different torque peak, but I take it they are not popular in race cars? How about twincharging (supercharger and turbosupercharger) in race cars, e.g., the VW 1.4 TSI twincharge have a supercahrger to provide boost at low rpm which disengages with a clutch and then the turbocharger provides the boost at medium rpm.
I take it twin scroll turbos with different sized scrolls are popular now, and provide much of the benefit of sequential turbos with far lower complexity?