Can an M3/4 hit 200MPH?

[paliknight]

I have to also agree with the wobbly feel at speeds over 150 MPH. seems dangerous to drive over 150 due to the flimsiness of the car.

[ZZZZMD1991]

Originally Posted by Don Molina

Math time:

the force that the engine has to exert to beat wind resistance at ~320kph (200mph, ~89m/sec) is:

0.5 x 0.34 (M4 cd) x 1.825 (car width) x 1.377 (car height) x 1.225 (typical air density) x 89 x 89 (m/sec equivalent of 200mph)

The above times 89m/sec gives you the power (power = force x speed, because energy = force x distance) and the power is something like 370Kw.

Which is about 490hp or 496 BHP or somewhere around the ballpark.


So if a car can push 500BHP at the wheels it could hit that mark.


IMHO the 0.34 cd is way too high, especially with no mention of any downforce at any speed, but at least it's good looking.
The E60 M5 had something like 0.26 which is like 25% better, so it could easily hit 200mph with 500 at the crank.

Very nice analysis.....I suppose you are assuming laminar flow which might be unlikely without other aero aids on the car.....But a close approximation, nonetheless!!
The real question is whether you can hit that speed on the FDR Drive!

[metomwhou]

Originally Posted by paliknight

I have to also agree with the wobbly feel at speeds over 150 MPH. seems dangerous to drive over 150 due to the flimsiness of the car.

I'd offer that the flimsiness you're feeling is due to the lift our cars make. Stock, these cars don't make much down force and actually make lift so the faster you go the lighter it starts feeling....

[hellokitty]

Originally Posted by metomwhou

I'd offer that the flimsiness you're feeling is due to the lift our cars make. Stock, these cars don't make much down force and actually make lift so the faster you go the lighter it starts feeling....

What aero actually works for this car?

[paliknight]

Originally Posted by metomwhou

I'd offer that the flimsiness you're feeling is due to the lift our cars make. Stock, these cars don't make much down force and actually make lift so the faster you go the lighter it starts feeling....

Yes for sure. It's not the car itself but the lift that occurs that makes the car wobbly which is unnerving.

[NoMoreAudi]

Limited aero for BMW. Market share isn't there for big power builds. 1/2 mile events... I think the record F8x trapped 170 something mph? BMW can't put down the power like other platforms for some reason. Maybe when someone goes syvecs it will be able to... which will probably be never since there's no market for it. Would need tuners too...

My F8x on E85 had about 550whp and got up to 190mph pretty easily but it did not feel good.

[CanAutM3]

Originally Posted by hellokitty

What aero actually works for this car?

The CS hood, front lip and rear gurney flap

[dallastide]

Originally Posted by hellokitty

What aero actually works for this car?

[blockdoc]

Originally Posted by dallastide

🤮

[bagekko]

To hit 200 the car would need some gearing changes, above 180 I would say in DCT or 6spd your gonna be above redline. I have been meaning to check the 6spd ratio differences between my M5 and the M4, M5 can absolutely exceed 200, I figure in stock the M4 limit is 175-185.

[jona9876]

https://www.bimmerpost.com/forums/sh...php?p=30648682

[stuart255]

People trying this are much braver than I am.

I remember 25 years ago doing 130mph in an E36 M3 and it was scary as hell because the steering got so light. IF you intend to push past factory design limits in a modern M3/M4 I would do quite a bit of homework first.


A few people talking about the gearing...

I'm pretty sure a rolling road would be able to replicate the road speed and torque that is theoretically required at 200mph, without having to worry about the actual aerodynamics, and do so safely.

Stage I, do some aero sums and figure out how much drag you expect at both 150mph and also at 200mph, make three estimates; high, medium, low for drag for both 150mph and also 200mph.

Stage II, go to rolling road, have them do a program that replicates the torque due to your drag calcs and check how your engine and transmission performs under all 6 conditions. Do you have the power at the necessary rpm?

Stage III, test drive at 150mph and see if your engine numbers correspond to your high, medium or low drag calculations. Benchmark approx where your aero performance is on the curve. You can then extrapolate your 150mph test numbers to some 200mph estimated numbers.

Stage IV, you now have some idea of actual aero performance and also engine / transmission performance for the actual vehicle in question so you can sit down and do the math to see if you can hit 200mph IN THEORY. If you think you can... go test it, if you think not, you should be able to figure out if power mods or power mods + aero mods are required to get you there. Likewise you will also unveil any inherent limiting that the car has.

Beware of aero mods...
more control = more downforce = more drag = slower aero.
Faster aero = less drag = less downforce = less control.

Suspect power + downforce are the only way to proceed. Do NOT attempt drag reduction outside a pro racing team. Do not add crank melting power without adding extra downforce.

Pretty sure it's possible if you take a systematic approach and follow the data.

[DeTh]

Originally Posted by stuart255

People trying this are much braver than I am.

I remember 25 years ago doing 130mph in an E36 M3 and it was scary as hell because the steering got so light. IF you intend to push past factory design limits in a modern M3/M4 I would do quite a bit of homework first.


A few people talking about the gearing...

I'm pretty sure a rolling road would be able to replicate the road speed and torque that is theoretically required at 200mph, without having to worry about the actual aerodynamics, and do so safely.

Stage I, do some aero sums and figure out how much drag you expect at both 150mph and also at 200mph, make three estimates; high, medium, low for drag for both 150mph and also 200mph.

Stage II, go to rolling road, have them do a program that replicates the torque due to your drag calcs and check how your engine and transmission performs under all 6 conditions. Do you have the power at the necessary rpm?

Stage III, test drive at 150mph and see if your engine numbers correspond to your high, medium or low drag calculations. Benchmark approx where your aero performance is on the curve. You can then extrapolate your 150mph test numbers to some 200mph estimated numbers.

Stage IV, you now have some idea of actual aero performance and also engine / transmission performance for the actual vehicle in question so you can sit down and do the math to see if you can hit 200mph IN THEORY. If you think you can... go test it, if you think not, you should be able to figure out if power mods or power mods + aero mods are required to get you there. Likewise you will also unveil any inherent limiting that the car has.

Beware of aero mods...
more control = more downforce = more drag = slower aero.
Faster aero = less drag = less downforce = less control.

Suspect power + downforce are the only way to proceed. Do NOT attempt drag reduction outside a pro racing team. Do not add crank melting power without adding extra downforce.

Pretty sure it's possible if you take a systematic approach and follow the data.

It's definitely possible. I've hit 196mph with BM3 OTS E30. Most custom tunes will probably hit 200, and any big turbo(s) cars should do it with ease.

[DeTh]

Originally Posted by bagekko

To hit 200 the car would need some gearing changes, above 180 I would say in DCT or 6spd your gonna be above redline. I have been meaning to check the 6spd ratio differences between my M5 and the M4, M5 can absolutely exceed 200, I figure in stock the M4 limit is 175-185.

Are you familiar with the gearing ratios for F8x? The 6 speed redlines in 6th at 201 I believe. In 7th the DCT will do way over 200.

[BitchinManWheels]

This car has been on the road for a long time now.
Do we have any confirmed speeds over 200mph? Any TOP speeds?

[domacuratl]

Originally Posted by BitchinManWheels

This car has been on the road for a long time now.
Do we have any confirmed speeds over 200mph? Any TOP speeds?

Yes and here's proof:

[jaylazy2020]

Originally Posted by BitchinManWheels

This car has been on the road for a long time now.
Do we have any confirmed speeds over 200mph? Any TOP speeds?

I hit 293km/h at my first piece of straight autobahn I found when driving to Stuttgart last June

Car felt stable and I stupidly pulled 7th too early and killed the revs plus it was slightly uphill.

I keep meaning to get out early on a Sunday morning as no trucks are allowed on the road and see if I can at least crack 300km/h

305km/h would be cool so I could crack 190mph

I can’t see if going past that. I’ll try to film it.

[j2dad5389]

Originally Posted by dallastide

"How much downforce do you want?"
"Yes"

[Master Apex]

E60 M5 with 500HP hit over 200mph because of the gearing and rising torque after 6k rpm.
So if F80 M3 engine does not cut back power due to heat soak of sustained high speed/boost, it may reach 200mph.
Stating it because most stock F90 M5 is actually slower than E60 M5 from 180mph and up.