Alfa Romeo 4c Max Speed
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Discussion Starter · #1 ·
Is the top speed of the 4C limited by drag/hp or by a ECU limiter. While the quoted stock top speed is 160, it would be interesting to see if the tuned cars are capable of more. By my rough calculations a tuned car should be able to get around 180 unless it has a electronic limiter. Drag may be the limiting factor here but HP should overcome that to some extent. HP probably also drops off before the red line is reached so that could also limit top speed.
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The issue is actually gearing. 6th will run out at 159mph.
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Pogea made claims that his first tune, stage 1, got beyond the 160 mark.
If you watch the test video of The Ring with a professional driver, he is hitting the mark (kph) in fifth gear.
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I've had 262 km/h on the Autobahn, GPS. Claimed top speed here is 258 km/h.
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The issue is actually gearing. 6th will run out at 159mph.
Put bigger diameter tires on. Speedo will be wrong, but GPS would show faster.
Of course, driving it off a cliff will increase the speed of a stock 4C (depending on the height of the cliff, naturally).
I've had 262 km/h on the Autobahn, GPS. Claimed top speed here is 258 km/h.
262 km/h = about 162.8 in American.
258 = 160.3
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Of course, driving it off a cliff will increase the speed of a stock 4C (depending on the height of the cliff, naturally).
And before kpg says it, this will void your warranty.
:x
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...driving it off a cliff will increase the speed of a stock 4C
I don't think maximum terminal velocity was the number he was thinking of really. LOL!
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265 on my little test strip
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Put bigger diameter tires on. Speedo will be wrong, but GPS would show faster.
Of course, driving it off a cliff will increase the speed of a stock 4C (depending on the height of the cliff, naturally).262 km/h = about 162.8 in American.
258 = 160.3
I've noticed at 70, the car is 3 mph off from gps.
At 80, it's 4mph.
At 130, it's still 4mph off.
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Discussion Starter · #10 ·
speedometer error
I've noticed at 70, the car is 3 mph off from gps.
At 80, it's 4mph.
At 130, it's still 4mph off.
Others have reported errors in line with what you stated although I tested mine with my GPS and it was either 1 or 2 mph optimistic at all speeds which is pretty accurate. Manufacturers tend to do that...my Chevy van is about 3 -4 mph optimistic. Both it and my ALFA have the stock diameter tires.
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I admit I may have small balls (and has nothing to do with my Asian heritage), but anything over 90 MPH the 4C's steering is so light that I don't feel comfortable pushing past that.
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Discussion Starter · #12 ·
The issue is actually gearing. 6th will run out at 159mph.
Not sure if that is correct....the final drive of the 4C is .62/1 which means that the speed is 28.7 mph per 1000 rpm. So if you were to run it up to the fuel cutoff red line which is 6500 rpm it would reach 186 mph. Even if you only went to 6000 rpm it is still 172 mph.
So my thought is that the limit is not running out of gear but drag limits it due to hp running out. So theoretically if you are putting out more hp like in a tune it should be able to get a higher top speed at least until drag overcomes the higher hp.
This is not taking into account if there is a speed governor in the ECU that is limiting the top speed even if more was available. Does anyone know if this is the case or is it drag limited....the Car and Driver test mentioned it was drag limited but no mention of a governor.
Not sure if this makes sense but my engineering background surfaced. In any case there is no way I am going to be the person testing this out ;-)
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Not sure if that is correct....the final drive of the 4C is .62/1 which means that the speed is 28.7 mph per 1000 rpm. So if you were to run it up to the fuel cutoff red line which is 6500 rpm it would reach 186 mph. Even if you only went to 6000 rpm it is still 172 mph.
So my thought is that the limit is not running out of gear but drag limits it due to hp running out. So theoretically if you are putting out more hp like in a tune it should be able to get a higher top speed at least until drag overcomes the higher hp.
This is not taking into account if there is a speed governor in the ECU that is limiting the top speed even if more was available. Does anyone know if this is the case or is it drag limited....the Car and Driver test mentioned it was drag limited but no mention of a governor.
Not sure if this makes sense but my engineering background surfaced. In any case there is no way I am going to be the person testing this out ;-)
You're right. I read what the max in each gear was somewhere and it listed 159 - probably due to the listed max speed. I didn't do the math.
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Not sure if that is correct....the final drive of the 4C is .62/1 which means that the speed is 28.7 mph per 1000 rpm. So if you were to run it up to the fuel cutoff red line which is 6500 rpm it would reach 186 mph. Even if you only went to 6000 rpm it is still 172 mph.
So my thought is that the limit is not running out of gear but drag limits it due to hp running out. So theoretically if you are putting out more hp like in a tune it should be able to get a higher top speed at least until drag overcomes the higher hp.
This is not taking into account if there is a speed governor in the ECU that is limiting the top speed even if more was available. Does anyone know if this is the case or is it drag limited....the Car and Driver test mentioned it was drag limited but no mention of a governor.
Not sure if this makes sense but my engineering background surfaced. In any case there is no way I am going to be the person testing this out ;-)
That was my experience. Steering becomes super light and you can feel the engine fighting the drag. Seems drag becomes an issue at about 220km/h. It's actually made me reconsider putting spacers on the wheels. Thinking it's going to negatively affect total drag at top end.
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The issue is actually gearing. 6th will run out at 159mph.
Not sure if that is correct....the final drive of the 4C is .62/1 which means that the speed is 28.7 mph per 1000 rpm. So if you were to run it up to the fuel cutoff red line which is 6500 rpm it would reach 186 mph. Even if you only went to 6000 rpm it is still 172 mph.
So my thought is that the limit is not running out of gear but drag limits it due to hp running out. So theoretically if you are putting out more hp like in a tune it should be able to get a higher top speed at least until drag overcomes the higher hp.
This is not taking into account if there is a speed governor in the ECU that is limiting the top speed even if more was available. Does anyone know if this is the case or is it drag limited....the Car and Driver test mentioned it was drag limited but no mention of a governor.
Not sure if this makes sense but my engineering background surfaced. In any case there is no way I am going to be the person testing this out ;-)
Pogea once said something about his tune being able to overcome a speed barrier. He wasn't clear on that, probably a language difference, and I can't remember verbatim what he wrote. But my impression was that he ment there is a speed governor and he disabled it.
Possibly AR knows something about the aerodynamics and lift of the 4C and a speed governor is the 'cover their ass' policy.
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I admit I may have small balls (and has nothing to do with my Asian heritage), but anything over 90 MPH the 4C's steering is so light that I don't feel comfortable pushing past that.
The steering does get light but it's really mostly a matter of getting used to it. It's still communicative and efficient. Me and others drive routinely way over 200 km/h (120 mp/h) and after a while it's a non issue.
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The steering does get light but it's really mostly a matter of getting used to it. It's still communicative and efficient. Me and others drive routinely way over 200 km/h (120 mp/h) and after a while it's a non issue.
I have driven up to 230-240 Km/h and I must admit that above 200 is not much fun..... True say you really get used to it though; I guess it is important to avoid becoming too tensed and holding the wheel too tightly as this doesn't help.....
Nevertheless, I do not like cornering stability over 200Km/h especially if I have to lift off or brake the car feels very wobbly! I have been desperately trying to work on this by changing wheel alignment settings. I MUST be able to improve that! Although the car is not made for high speed (see short wheel base and light weight) I cannot believe that in fast corners the car is supposed to be so unstable (or at least feel so unstable). Anybody want to comment on this?
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Nevertheless, I do not like cornering stability over 200Km/h especially if I have to lift off or brake the car feels very wobbly! I have been desperately trying to work on this by changing wheel alignment settings. I MUST be able to improve that! Although the car is not made for high speed (see short wheel base and light weight) I cannot believe that in fast corners the car is supposed to be so unstable (or at least feel so unstable). Anybody want to comment on this?
This has been my experience as well--very unstable when moderate braking from 230kph. My impression is that it's not the front that is the problem, but the rear. I think it gets too light under braking. Maybe downforce in the rear by way of a redesigned wing, or reducing dive overall through spring rates? This is not territory I've had to delve into before so I'm definitely no expert here!
I don't really feel that the front is uncommunicative at this speed. I haven't gone faster though.
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This has been my experience as well--very unstable when moderate braking from 230kph. My impression is that it's not the front that is the problem, but the rear. I think it gets too light under braking. Maybe downforce in the rear by way of a redesigned wing, or reducing dive overall through spring rates? This is not territory I've had to delve into before so I'm definitely no expert here!
I don't really feel that the front is uncommunicative at this speed. I haven't gone faster though.
From talking to different people and expert tuners it seems as if the 4C doesn't have the best suspension setup irrespective of front/rear. Further, the actual concept in enough of itself does not favor high speed stability (short wheel base and stiffness) but then again I do not want to accept that this is it! SO.... before considering changing suspensions, I want to try and keep working with small adjustments as I have done so far. This way, so far I managed to deal with tramlining and understeer and I am happy. If with the standard suspensions I will not reach an acceptable compromise with the high speed cornering stability, I may even come to the conclusion that this car is not the right one for me :frown2: I say this very modestly and aware of not being a professional racing driver. But then again, a car capable of 260 Km/h in my opinion should be able (by working on it) to be more stable at high speeds...
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I've had my LE up to 130 mph on the track. I could feel it swaying, almost twitching back and forth, side to side. It wasn't scary, but I was concerned. It never did anything alarming, but I didn't like it.
And yes, I had it up to 130 every time I went down that section of track for two days. I suppose that I did eventually get used to it, but it would need to be addressed if I were to drive that fast regularly.
To me, it seemed to feel like it was generating from the rear of the car. Jamie sells a solid bushed rear control arm that might address this.
Braking hard in a straight line was perfect. At these speeds, you don't do anything sudden. Smooth and controlled.
Source: https://www.4c-forums.com/threads/top-speed-of-4c.30490/
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