Well... the game doesn't have to be a simulator, but I agree that I think it should, at the very least be believable. Now, just how fast can one of these cars accelerate realistically? That is a great question. In reality we have nothing of the sort to compare this too (at all) but that's not going to stop me from trying
The closest thing that I can come up with for comparison to real life is an M1 Abrams tank... purely because it's a tank, powered by a turbine, and shaped like a brick. Sounds like an "OK" start.
Weight = 65 short tons (for the heavy one), 130,000lbs, or 59,000kg
Power = 1500HP
and literally nothing else really matters... but let's get rid of those tracks and use wheels for efficiency sake.
65 tons sounds about right for one of these cars so that's a pretty good comparison. However, this thing has a top speed of only 45mph... that's not a lot (yes I know it's governed, but still) so lets see what it would take to really get this thing humming at 400KPH shall we?
Negating rolling resistance and wind resistance and just traction in general, we would like to see 400KPH in about 3 seconds am I right?
To do that madness (according to a silly little calculator I found on the internet) we would need:
Damn... thats a lot of power... a LOT of power. 163,000 lot-o-power... Well... how do we get ourselves out of this pickle... I am still gonna try anyways, but after seeing that number by the end of this post I might just be like "make go fast happen" and just leave it at that...
Alright, well, modern drag cars have the ability to make 10,000HP out of just an 8.2L V8. Thats pretty darn good going.
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That means that (according to my engine calculator) if we were to run it on normal pump gas... we would have to be running over 110psi of boost. Of course they don't run these things on normal pump gas for those reasons, but since I don't feel like doing the math right now, we shall move on... these are our stats... now let's make the engine bigger.
Upping the displacement and number of cylinders to the V12 out of a P51 Mustang takes us to a 27L V12 at 21,600HP
Well these things are all engine and armor anyways right? Let's go bigger!
Upping it to a GE 7FDL engine out of a train (I know its a diesel and I am doing gas calculations... go away) we can get a hefty 80,000HP and 188,000lb/ft of torque... Now that's an engine... and it also fits in our weight limit only weighing in at 40,000lbs! (I know... that's like... more than half the car... but it's a race car right? So who cares. Also, hilariously, the blower would be sucking as much as 5,500HP away just to run at this state!)
Now, as I proposed in one of the other threads, I think these cars are like IC engine and Jet engine hybrids. This would mean that the engine would help turn a fan that would then have even MORE fuel dumped into the combustion chamber of the jet producing tons of thrust on top of what the engine is already doing! So let's go find a fast heavy jet.
The internet tells me that the F18-E has a dry weight of 13,400kg and a thrust of 197.4kN of combined thrust from two G.E. F414-GE-400 jet engines. Cool. What's that tell us.
Well... If we use 4 of these jets... we can propel a very decent portion of the vehicle up to 400 in that time.
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We are now making near our acceleration requirements. I don't feel like doing the math right now, but with some slightly bigger jets, we could get the acceleration to within our requirements. Also weirdly enough. With the wheels only able to provide up to 2.2G's of Acceleration (in earth's gravity on pavement... good old friction) the faster we go, and more downforce we generate, the more traction we have and the faster we can accelerate! So this could definitely be possible, especially if I would have been using afterburners (which I wasn't)