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.

 

Cant hurt to try it. In my experience locking never improved my et's. my buddy who tunes lsx trucks and cars says it has improved on some of his so it depends. I didnt find my sweetspot on my two motors

 

i'd been 12.3-12.4 at 108 on a 1.62 sixty...keep working at it man!

 

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.

 

Well, I trap right at 4800 so I think my gearing is on. I guess I'll just experiment this spring. Thanks.

 

My heavy 4th gen will trap almost 109 ant it ran a 12.8 with a crappy 1.9 60.

 

What are your 1/8 mile numbers?

 

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

 

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.

 

My 99 has been 12.75 at 106.9 on low 1.8x 60 and has been as good as 12.15 at 111 on a 1.66 60 ft. My bolt on l98 went 12.95 and 12.99 at 103.8 on 1.70-1.71 60's

 

My old 305 went 12.38@108 on a 1.62 sixty

 

Let's hope the 5.3L is faster matt

 

Probably not

 

8.3X @ 79-80

Yeah. My goal was 12's so a 12.99 and I could die happy!

 

I'd say sticky tires and a looser stall would get you there.

 

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.

 

Not an exact calculation but most people say that a tenth in the 60 foot is about two tenths at the stripe.

 

You said peak torque was 3700....you try to pick a converter close to peak torque for best et.

 

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.....