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Discussion Starter #1
I just thought I'd write my quarter mile time in my Alfa 156 2.5 v6. I managed to get a 15.3 @91 which I think is a pretty good time for this model all I have done to it is custom intake and a decat. My mate raced is gtv cup with stainless exhaust,decat and Cda filter and got a 14.3 @97. If possible can other owners of the same cars give there times to see If our times were good for the mods cheers Dan.
 

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See this thread link non-believer :

http://www.alfaowner.com/Forum/motoring-images/283537-gtv-cup-82-at-santa-pod.html

Note the Number 1 on the rear window and matching number 1 on time slip.

All my 6 runs were at a terminal speeds between 96.31mph worst and 97.69mph best
1/4 mile e.ts were between 14.6866 to 14.377 secs

I must admit i was quite surprised i ran a 14.3 as i expected it to run between 14.8-14.6.
 

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very interesting...my times are considerably worse than yours and a bit better than the v6's....but my terminal speed is a few miles over the gtv's....strange...
not really strange, surely this just means that although your terminal velocity is greater, the GTV must have greater acceleration earlier in the velocity range?
 

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very interesting...my times are considerably worse than yours and a bit better than the v6's....but my terminal speed is a few miles over the gtv's....strange...
A higher terminal speed but slower time would be down to the launch.

Either you are bogging down off the start or struggling with traction and lighting the wheels up, and losing time in the 1st part of the run.
Check your 60ft, 330ft and 1/8 mile time to mine and my guess is this is where you are losing time although you have faster speed across line.

Mine was

60ft = 2.2558 sec
330ft = 6.1135 sec
1/8 mile = 9.3363 @ 77.07mph
1000ft = 12.0659 @ 89.98mph
1/4 mile = 14.3771 @ 97.35mph
 

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Yeah must be the wheel spin thats causing you problems then.

Mine only spins up like that in 1st and 2nd if the road is wet.
 

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A higher terminal speed but slower time would be down to the launch.

Either you are bogging down off the start or struggling with traction and lighting the wheels up, and losing time in the 1st part of the run.
Check your 60ft, 330ft and 1/8 mile time to mine and my guess is this is where you are losing time although you have faster speed across line.

Mine was

60ft = 2.2558 sec
330ft = 6.1135 sec
1/8 mile = 9.3363 @ 77.07mph
1000ft = 12.0659 @ 89.98mph
1/4 mile = 14.3771 @ 97.35mph
well it does spin wheels from start all the way up to 3rd...too much torque to put to the ground I suppose...but anyway this means if I was to make a proper start then I would be below 14.3 which is really unbeliavable for me...
I know next to nothing about standing quarter miles, drag racing etc....
... so excuse me if I'm talking sh!te, but I don't think the terminal velocity is necessarily directly linked to standing quarter times; to give an extreme example an F1 car could accelerate to 90mph in a couple of secs (?) and stay at that speed to the standing quarter, resulting in a stupidly quick time but lower terminal velocity.
It's about power curves and gearing, no?:)
 

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I know next to nothing about standing quarter miles, drag racing etc....
... so excuse me if I'm talking sh!te, but I don't think the terminal velocity is necessarily directly linked to standing quarter times; to give an extreme example an F1 car could accelerate to 90mph in a couple of secs (?) and stay at that speed to the standing quarter, resulting in a stupidly quick time but lower terminal velocity.
It's about power curves and gearing, no?:)
Well I assume that we all try to achieve the best possible time and we all aim to keep the car within optimal rpms for as much time as possible so your comparison is not exactly correct :)
I think that it's all about who has more hp for more time in the run....which essentially brings us to terminal speed, yes there are other factors like gear changes, weight of course, wheel spin etc but it still seems strange to me...
 

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Well I assume that we all try to achieve the best possible time and we all aim to keep the car within optimal rpms for as much time as possible so your comparison is not exactly correct :)
Like I said, the F1 example was an extreme one to show that a high acceleration early on with lower terminal velocity can give a quicker quarter mile time.
The power curve/gearing combination of the GTV versus your car might be an example of this.
:)
 

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Discussion Starter #19
The time seems about right mate as I only have a decat and custom induction kit so more a less standard as well.
 

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Hi

Lots of factors. Get smartly off the line and you will reduce you time and increase your terminal speed, but how much of either it another question.

Light weight helps with acceleration, but also reduces grip. So if traction is a major problem you probably lose out from less weight (and that is before we get into fwd / rwd weight distribution effects).

Similarly, lower gearing means more torque at the wheels, so better acceleration in a particular gear but having to change up to the next gear (which probably has far less torque at the wheels) far earlier. Again, if you can't get the power down then you are gaining nothing from the lower gearing.

Power curve can help in 1st gear, but after that you will be around peak power so won't care. You only need to be using the revs to keep around peak torque when launching. If the torque curve is fairly flat then you can be fully off the clutch early on, but if it is a peaky little bugger (like a 125 2 stroke bike) then you need to abuse the clutch like mad to keep the revs high.

Never really tried to measure standing quarters in a car (plenty on bikes). Do have a Driftbox which can measure them accurately if anyone around Staffs wants to have a play.

All the best

Keith
 
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