2 questions(weight, shift points)
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Racer
Joined: Oct 2001
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From: Bradenton Fl
2 questions(weight, shift points)
First question does anyone know how much an 86 with iron heads weighs? trying to figure out how much hp I have
Second where should I be shifting at I usually shift at about 4800 rpms but after looking at the dyno graph in my owners manual it looks like I should shift at round 42-43 rpms thanks for any answers
[Modified by daddydahlin, 11:02 PM 9/17/2002]
Second where should I be shifting at I usually shift at about 4800 rpms but after looking at the dyno graph in my owners manual it looks like I should shift at round 42-43 rpms thanks for any answers
[Modified by daddydahlin, 11:02 PM 9/17/2002]
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Re: 2 questions(weight, shift points) (daddydahlin)
I usually shift at about 48K rpms but after looking at the dyno graph in my owners manual it looks like I should shift at round 42-43k rpms thanks for any answers
Just me personally...I usually shift @ 3500-4000 rpm except on on ramps of course...I LOVE on ramps :blueangel:
Thread Starter
Racer
Joined: Oct 2001
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From: Bradenton Fl
Re: 2 questions(weight, shift points) (DRAGRACR)
Thats what I thouht I should start shifting at, trying to learn the car as much about the car as possible want to get the most out before the headers go on.
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From: SE NY
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Re: 2 questions(weight, shift points) (daddydahlin)
Curbe weight of the '86 base Vette coupe was ~3,240lbs.
To calculate your launch weight (approximately) subtract 6lb/gal of fuel below a full tank and add your body weight. So, if for example, you launch with 1/3 tank of fuel and weigh say 180lbs you would launch at about 3,340lbs ==3,240 - (20 * 6 * 2 / 3) + 180) = 3,240 - 80 + 180.
This should give a rough estimate of CHP, good enough for comparisons anyway.
You could install select weights and/or springs from a B&M Governor Recal. Kit (P/N 20248) to adjust the WOT shift points.
But, actually, 4,800rpm doesn't sound bad and may even become a little low as you increase air flow, especially at higher RPM.
As mentioned, the optimum time slip data is obtained by shifting beyond the HP peak, so as to maximize the area under the power curve. For example, my current dyno plot is only 20hp higher than to one on my site and data shows I shoud be shifting at about 5,600-5,700rpm.
To calculate your launch weight (approximately) subtract 6lb/gal of fuel below a full tank and add your body weight. So, if for example, you launch with 1/3 tank of fuel and weigh say 180lbs you would launch at about 3,340lbs ==3,240 - (20 * 6 * 2 / 3) + 180) = 3,240 - 80 + 180.
This should give a rough estimate of CHP, good enough for comparisons anyway.
You could install select weights and/or springs from a B&M Governor Recal. Kit (P/N 20248) to adjust the WOT shift points.
But, actually, 4,800rpm doesn't sound bad and may even become a little low as you increase air flow, especially at higher RPM.
As mentioned, the optimum time slip data is obtained by shifting beyond the HP peak, so as to maximize the area under the power curve. For example, my current dyno plot is only 20hp higher than to one on my site and data shows I shoud be shifting at about 5,600-5,700rpm.
Thread Starter
Racer
Joined: Oct 2001
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From: Bradenton Fl
Re: 2 questions(weight, shift points) (65Z01)
when it revs over 5100 it starts to bog down, so maybe 4800 isn't to high, I guess I need to start spending more time at the track to find where it runs best at I think I can get another tenth out of some maybe some cool weather would help
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Re: 2 questions(weight, shift points) (daddydahlin)
You guys have to keep in mind that the built in tach has a certain amount of lag based on the display update frequency...in otherwords, heavy acceleration can accelerate the engine 500 RPM's past what the tachometer reads...so you think 4800 RPM is the 1-2 shift, where if you had a real tach you might see 5300-5500 RPM's. Of course, in steady traffic driving, it will read correct as it updates every half second or so.
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: 2 questions(weight, shift points) (daddydahlin)
It seems to me that it updates much faster than every half second. I can't even read the numbers when I rev it, I have to go by the bar.. which worries me. I know how the speedo can be off also, takes awhile to react.
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Re: 2 questions(weight, shift points) (daddydahlin)
daddydahlin, that shounds a little low, but I expect you've been running in 90+ teps and launching with high coolant temps too.
In better weater you could build 10-15hp more.
In better weater you could build 10-15hp more.