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Discussion Starter #1
Hi All,

I've mined through and read all the salient posts and am wondering if anyone who has more experience then I do at the tracks and in 1/8 and 1/4 miles and general launches with the 4C could chime in. (I've only been running my 4C for a few months, but am an old hand at SCCA and 1/4 miles with my other cars in my life.

My 4C is factory track exhaust and the brilliant Eurocompulsion Phase 2 (complete). I'm running daily driver Nexen Nfera SU1s

I'm one of those knobs that will do outlaw 1/4s and 1/8s on weekends etc.

So this is my quandary:

1. In Race Mode and doing a full launch (6k) I get tire spin for about 20+ feet with the rev limiter chiming in prior to full rear tire link up. Then I just keep it matted and let the pre programmed shiftings occur. It seems to me that the non link up has put me at a disadvantage when going heads up off the line (albeit a crowd pleaser).
Throttle control comes to mind however; I do not want to throttle back and find out that I have gone out of those pre programmed shift points.

2. Im thinking that running in Dynamic manual and just matting it at "go" will provide a quicker lap as there is immediate link up.

I've even looked at the video on the Eurocompulsion a number of times that is the 4C vs.the Ferrari F430. The 1st run I am pretty sure is in Dynamic as there is not wheel spin and it seems to over take the Fer easier. The 2ns run for sure is in full Race-Launch and the tire spin sets the 4c back.

I would really appreciate anyone's qualified thoughts on this if you happen to have the time.

Thanks in advance,

Blisken
 

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Have a look at Spidermans’ posts. He’s got the runs on the board and as far as this forum goes appears to be a drag start Ace. A decent set of semi-slicks and drop the rear pressures seems the best bet if you want better hook-up. As for me I think 6,000rpm race launches are cruelty to clutches and are to be avoided. It’ll reap vengeance on you eventually.
 

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You should use the first step LC from the lower rpm (around 4000) - this is done still in race mode but without pulling the paddle.
The optimum might above that point at around 4200-4500 rpm depending on grip.
To do that you initiate the LC and after you pull the paddle you also release the brake when the rpm goes around 4200-4500
 

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Out of curiosity, being in Race Mode means: Peak throttle and trans response and zero nannies as you modulate traction off the line, so do your best launches in Race Mode, reduce RPM and modulate throttle as you can (if you can) but have throttle pinned on upshift and you'll get the fasted/hardest upshift possible -- ??
 

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To be honest you really need to look at what rpm the hp falls off, where the auto set shift points, where the rpm drops to when shifting are etc etc....or you not analyze the whole situation and send it. I personally would try the 1st step LC then the 2nd step and see which keeps the best time. And let it shift on its own unless you can pick the rpm points better then the computer. I think it runs you up to either 6k or 6.5k which in reality is past its peek hp point but when it shifts to next gear that is where the determination is on whether it is optimum or not...... I just let the computer do its stuff. Here is the shift points someone posted once for you tech geeks :)

If someone has a stock dyne run to show where the hp starts to taper off or drop you can add it
101012
 

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Discussion Starter #7
Hi Cipsony,

I've practised with all the variants-like the one you just described. The issue with that in a race setting is that you have to be ready to launch at the reaction of the light. So you either have to stage in LC1 or LC2. When you 2nd paddle for LC2, you have no control of the throttle at that point. If you activated LC2 at the GO light, you would lose time. Hope my description makes sense.
 

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Discussion Starter #8
Out of curiosity, being in Race Mode means: Peak throttle and trans response and zero nannies as you modulate traction off the line, so do your best launches in Race Mode, reduce RPM and modulate throttle as you can (if you can) but have throttle pinned on upshift and you'll get the fasted/hardest upshift possible -- ??
To clarify: In RM and in using full LC- You pin the throttle and never let up until the race is over. When in RM using full LC-the computer shifts automatically for you-even though you are in M (these points are pre programmed from the factory by some genius) at all the optimal places.

My issue is I am afraid to let off the throttle and find that cues the computer to stop shifting automatically and then you have a protracted red line and find out by surprise that you now have to do the shifting the rest of the way.
 

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Discussion Starter #9
To be honest you really need to look at what rpm the hp falls off, where the auto set shift points, where the rpm drops to when shifting are etc etc....or you not analyze the whole situation and send it. I personally would try the 1st step LC then the 2nd step and see which keeps the best time. And let it shift on its own unless you can pick the rpm points better then the computer. I think it runs you up to either 6k or 6.5k which in reality is past its peek hp point but when it shifts to next gear that is where the determination is on whether it is optimum or not...... I just let the computer do its stuff. Here is the shift points someone posted once for you tech geeks :)

If someone has a stock dyne run to show where the hp starts to taper off or drop you can add it View attachment 101012
That is a fantastic chart! I agree with you also. Best to keep it pinned and keep the human brain out of the way.

My only issue honestly is the tire spin off the line so I am now thinking a set of dedicated street legal rears just for race days (every Saturday here). I think I will get this set up and do some testing and repost here for the curious.
 

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To clarify: In RM and in using full LC- You pin the throttle and never let up until the race is over. When in RM using full LC-the computer shifts automatically for you-even though you are in M (these points are pre programmed from the factory by some genius) at all the optimal places.

My issue is I am afraid to let off the throttle and find that cues the computer to stop shifting automatically and then you have a protracted red line and find out by surprise that you now have to do the shifting the rest of the way.
I was working from the opening post premise that blindly giving it full beans and spinning tires would cost time, thus an attempt to stay in race mode, extract all the benefits, but not simply be on the hook to blindly mash the throttle. In race
Race mode plus stomp it and go vs race mode but modulate throttle and go vs dynamic mode blindly stomp the throttle and go.

I wasn't seeing it as binary.
 

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If you need to start when the light goes green then you should definitely use LC1 (from the lower rpm) --> I believe with any tire you will be faster.
LC from a higher rpm (like 4500) is for when you just want to set a time and you don't have to start immediately when the light goes green. If you spin the tires you loose time.

In terms of tires: you can use pirelli trofeo R -- These are quite light and grippy.
Use narrow tires on both ends (even on the rear) --> You can go with the OEM size on the rear (if available) or even narrower. It's also important the surface from where you lunch: semislicks and slicks are good for treated surfaces while street tires are good for basic asphalt.

And wait for the gearbox to cool down - if you can drive a bit after LC.
 

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I don't have wheel spin with the launch control at 6000rpm. Ofcourse you need to warm up the tyres a bit, but nothing special. I do drive AD08R tyres, and that makes a lot of difference over P Zero's or Michelin PS4.
Sometimes the programmed shift moments are giving a little disadvantage, but sometimes they are perfect as they should be. But, launching at 6000rpm is for me by far the fastest way to get off.

If your launch is perfect, the shifts will be also:

 

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Pretty cool that there is very little drop of boost during shifts. I've never watched the boost gauge while accelerating.

BTW, there is no such thing as LC1 or LC2.

There is only one launch control. That is in Race mode with left paddle pulled and 6k rpm. Anything else is launching without controls. RTFM.
 

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Discussion Starter #14
You can launch if you'd like after the you mat it with the break on. That is kind of what we are referring to LC1 as for a common reference. The 1st stage of LC. Dig it?
 

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While it may be fun to drag the car and blow off a lot of muscle cars, the 4C is NOT a drag car and as some have found out.....multiple WOT with Launch Control is going to do some major $$$ damage to the trans and differential after a while. So be warned ????

As far as optimum RPM for a launch....that depends on a lot of things....surface traction, tires, ambient temperature, mods, etc. You don't have to launch at full 6000 rpm.....just back off the gas to any other rpm and launch there. You will loose the automatic shifts in R mode though....but you may find it better to shift yourself.

You can also use Dynamic which will limit you to 3600 rpm launch but allows use of the autoshift at that lower rpm. I think you will find R mode will be faster though due to the ECU set shift points and bit more performance in R mode if you have swapped a performance ECU in.

Some hints for best performance....lower rear air pressure from stock a bit for improved traction and raise fronts higher for less resistance. If you run multiple times and every time do a "perfect" launch....your times will get slower each time. That is because you have to let the engine, turbo and inter-cooler cool down a lot between runs. A boosted engine will loose hp significantly as the incoming air charge heats up. That is one reason some are installing larger IC on their cars used for tracking. They don't give more HP....but maintain it longer as the engine and turbo heats up.

Removing the engine cover may help in cooling and open the rear engine hatch to let it cool also. Some have placed ice in the opening for the IC or sprayed water on the IC between runs.
 

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To clarify: In RM and in using full LC- You pin the throttle and never let up until the race is over. When in RM using full LC-the computer shifts automatically for you-even though you are in M (these points are pre programmed from the factory by some genius) at all the optimal places.

My issue is I am afraid to let off the throttle and find that cues the computer to stop shifting automatically and then you have a protracted red line and find out by surprise that you now have to do the shifting the rest of the way.
Your fears are correct - to "cancel" proper LC, you need only lift on the throttle. That returns control of the transmission to the driver.

 

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Discussion Starter #20
I think we are running pretty close to the same with my mods and tune so I am guessing tires.
What size AD08R tires are you running F & R? I may get those skins. Are you on factory wheels?

I'm on Nefera SU1's F 215/40Z R18 89Y and R 245/35Z R19 93Y.
 
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