Trap speed question
#1
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Car: 92 T/A 'vert
Engine: Mild .040 over L98 4 bolt mains
Transmission: Mostly stock 700R4, 2600 Vigilante
Axle/Gears: LS1 3.42
Trap speed question
After researching online and talking to a few local, diehard gearheads, my 106 MPH trap speed should get me into the 12's albeit just barely. I think I'm leaving pretty well with a 1.70 60'. I do both shifts at about 5200 as while my max HP is up over stock at about 4800 but in typical TPI fashion trails off pretty quickly after that. I was wondering what you more experienced guys would think about holding 1st to about 5500 and locking the T/C after the revs came back a bit in 2nd. My theory is that the big 1-2 step in the 700R4 puts me a little too far down in the torque curve and that the loose Vigilante I have helps with the launch but then slips too much later on in the run. I figured shift at 5500, (which would keep me well above 3000 after the shift), then getting back up closer to peak torque, (3700), and lock the T/C in 2nd. Or would wasting the time wringing the few extra hundred out of first do more harm then good? I'm thinking the T/C lockup is a pretty solid theory but am not too sure about the shift point. Please discuss.
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Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Trap speed question
Back when my car still had 3.27 gears in a 9 bolt, I was running 12.0 at 117 MPH. Gearing was way off. Shifting at around 7000 rpm, I was only crossing the finish line at around 5000. The car was slow off the line but around the 1000 foot mark, it started getting into the powerband and pulled hard from there.
Normally around 12.0, a car should only trap around 110-112.
If properly geared, you should be at your shift point just before or as you cross the finish line for peak performance. Shift points, diff gear and tire size will all determine how well performance is matched going down the track. Something as simple as converter stall speed can change a cars performance. Finding that perfect performance package takes a lot of trial and error.
Normally around 12.0, a car should only trap around 110-112.
If properly geared, you should be at your shift point just before or as you cross the finish line for peak performance. Shift points, diff gear and tire size will all determine how well performance is matched going down the track. Something as simple as converter stall speed can change a cars performance. Finding that perfect performance package takes a lot of trial and error.
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Car: 92 T/A 'vert
Engine: Mild .040 over L98 4 bolt mains
Transmission: Mostly stock 700R4, 2600 Vigilante
Axle/Gears: LS1 3.42
Re: Trap speed question
Well, I trap right at 4800 so I think my gearing is on. I guess I'll just experiment this spring. Thanks.
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Car: 91 Z-28
Engine: 420 sbc
Transmission: T56
Axle/Gears: 12 bolt/4.10 gears
Re: Trap speed question
My old Camaro rs trapped 106 and ran a best of 12.90 with a 1.72 60ft. You've got 12 second potential in your combo for sure. Keep that 60ft low and you'll get there
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Car: 1991 Camaro RS
Engine: BBC 509 Merlin ii 9.6:1 pump gas
Transmission: ATI pro th350 sfi case. TSI 5500 st
Axle/Gears: Strange S60 4:10s
Re: Trap speed question
Keep working on it man. My cars best trap was 13.31@105mph but I had a 1.95 60ft time which was horrible. Had 3.23 gears on the stock 700r4 and its turboed which usually picks up on the top end anyways. My 1/8 mile time was 8.55@82mph
Your trap speeds scream mid 12's so just working on it.
Your trap speeds scream mid 12's so just working on it.
Last edited by fasteddi; 02-03-2013 at 07:20 AM.
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Car: 92 T/A 'vert
Engine: Mild .040 over L98 4 bolt mains
Transmission: Mostly stock 700R4, 2600 Vigilante
Axle/Gears: LS1 3.42
Re: Trap speed question
Well, I was planning on putting the Sumitomos back on and getting a dedicated set of slicks not only for better traction but the BFG DR's after one session at the track and about 3-400 miles are about half gone. And, no, I don't run around doing smoky burn outs and just cleaned them off at the track per BFG's recommendations. I was thinking a 275/50-15 might be the hot set up. The BFGs are 295/35-18. So, they would be a bit narrower but softer with more, (and more flexible), side wall. But, the T/C? I have a pretty mild cam, (213/219, .493/.502, 112). I thought I was almost overstalled as it is. Let's say I can get a 1.6 short time. Is that going to make that big of a difference down track? I need over 2/10ths to see 12's.
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Car: 1984 camaro z28
Engine: sbc 383
Transmission: Th400
Axle/Gears: Moser 9", 4.11 gear
Re: Trap speed question
Not an exact calculation but most people say that a tenth in the 60 foot is about two tenths at the stripe.
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Car: 85 Trans Am
Engine: 383 ci
Transmission: Liberty Geared Tko 600
Axle/Gears: Moser 9" 4.11 gear wavetrac locker
Re: Trap speed question
try a set of the mt et streets before you buy the bfgs again. night and day difference. Our cars like the 275-60r15 version as well.....
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