Gotta like those sea level runs. Atco can sure bring out every bit of Superman in a car. With Island closing, I wish it was not two + hours away. That must have been a fun day! Cheryl
Indeed that was very entertaining. Love the sound. So cool you went to the trouble of capturing the moment with an 8mm camera. Thanks for posting! :TU:
Finally stole my daughter's laptop and was able to watch the video! Great run! You said that was shifting at 5k? There was glare on the tach so i couldnt see... The reason I ask is it sounded alot like my 4800 rpm sounds - and alot different than my 5100 rpm sounds. I know these are two very different cars and transmissions..... Thanks for posting!
Hi Walt, was wondering if that was a switch pitch tranny set up? I dare yah to add Toms rockers on it:bla:
Yes, it's a ST400 with the smaller GS converter. I once rebuilt one with B&M parts, but it broke. This one is a junkyard trans with a shift kit. I don't recall if I launched in hi stall or low stall.... I use both depending on traction. I launch from a 1000 idle. Any more and it spins more. Tires are Hoosier Quick times, 275/60-15. 17psi or so. Rhett, In the vid, it sounds like the 1-2 shift was earlier than the 2-3 shift. The gov was set up to shift at 5000. It's a VDO tach, maybe it's accurate. Any body have a critique of this run? what could be better.... shift points, gearing, how much did the wheelspin hurt, etc? Seems to be running well in the traps at 5500, but don't think there's much left. Yeah Bob, roller rockers will help!
I don't know too much about drag racing cause I have never done it on a track, only on the streets. Yeah yeah I know, it's not legal. It was in my younger days. But the wheel spin does hurt ya, if you can get it to hook up you can get your times down a little bit just from that. I can't remember in the video how much of a burnout you did prior to the launch, but typically wheel spin is cause you didn't get the tires hot enough during the burnout to make them sticky. I combination of that plus however long you had to sit between the burnout and launch. If you are rolling through the water box make sure you get a decent burnout in to get the water off the tires good and heat them up well. You can over do a burn out, but doubt you ever would. Takes big horsepower and a extra long burnout to get to that point. I need to watch the video again, but I would say if you could eliminate the amount of wheel spin you had there, that you could probably knock .01 at least off your time, just by not wasting time and distance spinning. Plus the additional push you will get from hooking up instead of the momentum being wasted turning the tires over. Someone with some serious track time could give you a better run down than I can, but this is my personal opinion. Take it for what its worth.
Walt, i didnt see you messing with any switch did you have one or is it on the brake pedal? it looked like you really knew what you were doing with the burn out and at the line you were real calm.:TU: the only thing i was thinking if it pulled that good to 5500 rpm in high that you could shift at 5200-5400 in 1st and 2nd gears.
The switch-pitch switch is mounted on the console next to the shifter. I can hit it with my thumb when my hand is on the shifter. I usually launch in high, then switch to low midway thru first. In the vid, it seems like the 1-2 shift was too early and it slowed a bit. I decided on 5000 more for engine life than performance. Do you think it's maxing out in the traps? It still sounds happy there:grin: 4.11's are enough for me. I'd really like to try some 3.36's to see how those work.... but the Isky cam probably won't like them. Johnny, there a general rule that one tenth in the 60 ft is worth 2 tenths in the 1/4. I think I need to work on the suspension to get better weight transfer to improve traction.....then I can put the v6 hi-stall converter in there and pull a wheelie (or break something!)
All of my suspension work really seemed to pay off well at the top end, if I have any significant wheelspin at all that run is blown.. i'll coast to the end of the track. Weight transfer and rear end height seem to be big factors. My car likes the rear end REAL low... I used to do ok without doing a burnout, but when the weather is cooler (50 degrees or less) heating the tires has helped. The reason I asked about RPM is that both shifts seemed to leave something on the table - maybe 300-400 rpm too early. At least in my car when you've gone beyond where the engine is still making power, you know right away. I use my converter the same way you do - I jump to low stall 3 seconds in... I have a manual control but I have the Bruce Roe controller set to do it automatcally and I like that - it never forgets.....Hell, I've forgotten to shift into second a couple times. I'd ben talking to Tom about trying to Launch in low stall, and then do the high stall process 10-20 feet out. I tried it a few times and it hurt me by a 10th, but it could have been other things at work too.. I'll try it again this spring and see if I get the same result. When is the last time you ran the car at the track?
dont think its maxing out in the traps. the 3-speed and 4.11s are a good combo with your big Isky cam. i looked at your cam card, if you did put the cam in straight up? your at 108 LSA. seems like it likes the tight LSA, pulls low and all the way to at least 5500 rpms.
Walt, did you do any head work? I'm not sure if it's the fact that my Invicta weighs 500lbs or so more that a GS(best case scenario), or that it only has 3.23 gears, but it seems to like it best being shifted at 4700-4800rpms with the Thumpr. Anymore than that and it just doesn't feel like it's pulling as hard.
Rhett, that was my last 1/4 mile run. 1995. I bought 3 more '66's the following year and had my plate full with those! Andy, I did some backyard head work, just port matching and bowl work. I bet my compression is in the low 9's, so I'm surprised it runs as well as it does with that cam.
after watching this amazing video 20 times at least lol. came up with a few things. 1st to 2nd shift was short shifted can hear the motor dog down, maybe another 400-500 rpms higher shift. 2nd to 3rd not bad 100-200 rpm higher shift. the power did come on at a higher rpm, but the 4:11 gears helped a lot, still had a little wheel spin when the power (torque) did come in. most nailheads wont pull that hard after 5200-5300 rpms, but that motor pulled to 5500 rpm with power and sounded like it would go even more. who nows how high but there was still a little left. i use to think and everybody says, you did a big split duration to rev high on a nailhead, not really true after seeing this, a wide LSA to rev high, not really. again it rev high with a 108 LSA. the low .440 lift didnt hurt either for top end, maybe more lift would have helped bottom a little. the 244-244 duration had to be the big reason it pulled so high. it was a fast ramp old school cam (fast ramp not a lot of lift) the new cams are fast ramp lots of lift which is a lot harder on the valve train. maybe with our low flowing heads we dont need a lot of lift. thanks for the video helped keep me going till spring gets here. my post is for entertainment only so no one take it for true facts lol:grin:
Gsgtx, Good points. I listened to it again. Does seem to be pulling goodup top for a 108lsa. Gets me ready for spring to get here to:TU: Played it up loud enough times that my 2 girls and wife are saying "there goes Walt again"..LOL
So do you guys think a split-duration cam with less intake duration, like 230/246 or even 224/236, would be a better choice? Dyno 2003 sims show these cams give much more low-end without losing much up top. Joe, I'll have to look at the Isky's ramp rates. I was thinking they were slow since it's an old design. I plotted a profile of it once upon a time. I agree the 1-2 shift seems early and it slows. Wonder how much a higher shift point would change the et? Here's the comparison. Lower curves are the Isky 310, and the 310 with roller rockers. The upper curves are Comp 'hybrid' cams I made up using their existing lobes.[/IMG]
my mistake its not fast ramp, i was thinking your advertise duration was 291* its really 310* advertised, so 310*-244*@.050=66* not fast ramp at all.
