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-   -   Need help on shifting by time?? (https://www.racingjunk.com/forums/showthread.php?t=31949)

hammertime 04-10-2012 06:25 AM


Originally Posted by SPEEDNEEDS1
Can't say if it is under tired or not but I think it is. I see every one else running a 16.5-17x33's and some with 34.5's. I have access to all of the 17x33.5 and 34.5's that I could ever use, but I have no 16" wheels. The car runs really well for what it is. The track that I have been running it at has several dragsters and most there have 565's with BB3 cylinder heads and we run the same et, so I figure that mine is running ok. I understand that the big tire will slow me down, but I ran with a few guy's that ran this same D2070 tire that I have and had 4.72-4.73 time slips like they was ran off of a coping machine. My car only moved .002 from the 330 to the 660 all weekend. Still ran 4.85 to 4.88 and 1.065-1.086.

My converter was not set up for a dragster, was set up for my 2600lbs door car and it is a 8". Any ideas if this is what the problem is.....

Id venture to say them cars going 4.70s with the same tire have almost the same 60ft as you going a tenth slower ?

Do you know anything about where the converter flash stalls and fallback rpm is ? Sounds to me like you have a lot of wheel speed which makes me think the converter is on the tight side. With a smaller tire you need something a bit looser (6400ish) and more forgiving. From what your saying its good after the shift but from launch to that point its moving around, pull timing, looser converter or bigger tire would all help.

Example of how to calm them down at the hit, [email protected] last weekend first pass in my new car, I set the converter upto flash at 6750 and fallback just over 6900. Very loose, deadly and big mph. My 60ft was 1.088-1.090

shawnp 04-10-2012 07:20 AM

David is correct. Loose as a goose gets your down the track where you want to be. We are normally a 1.10-1.11 60 ' using a 34.5 tire and run 4.77-4.80 range at 145 mph. Unless you are looking to quick race and squeeze every ounce of ET out of your combo, loosen that converter and get the bigger tire on it. That thing will hook on an ice rink and repeat all day long.

SPEEDNEEDS1 04-10-2012 05:37 PM

I have talked to the guy's at hughes and they said that the converter will work fine, but if they had known it was going in a dragster when they built it I would be .4-.5 hundreths faster in e.t., and .2-.3 slower in 60 ft. I am sending it back to them next week.

My brother and I have been running this car together the last two weekends and I know that its kinda dumb now, but after talking to him last night he has been putting 6.0lbs of air in the hoosiers and goodyears. I feel certian that is not right. I am trying 4.75-5.0 this weekend.

When I have it shifting at 2.200 "7500" it falls back to 6500 if that helps.

SPEEDNEEDS1 04-10-2012 05:40 PM

On the shock setting, it is all of the way loose, then 4 clicks tight. Havent moved it either way yet, I need to go to test n tune and try looser and tighter just to see what happens.

hammertime 04-10-2012 08:24 PM

6lbs isnt that far out of line but 5-5.25 will likely be where you end up at.
Whats the #s on the converter, I am fimilar with hughes stuff. 6500 after the shift is a good spot to be though, big tire is the next option, remember not all cars are the same and if you get the option to barrow some bigger rims and tires from someone you should do it, what works on one will not work on the other. What did you say you were launch rpm was ?

Tigthen that shock up a few clicks also, thats on the soft side.

roadkill2 04-11-2012 08:52 AM


Originally Posted by SPEEDNEEDS1
I have talked to the guy's at hughes and they said that the converter will work fine, but if they had known it was going in a dragster when they built it I would be .4-.5 hundreths faster in e.t., and .2-.3 slower in 60 ft. I am sending it back to them next week.

My brother and I have been running this car together the last two weekends and I know that its kinda dumb now, but after talking to him last night he has been putting 6.0lbs of air in the hoosiers and goodyears. I feel certian that is not right. I am trying 4.75-5.0 this weekend.

When I have it shifting at 2.200 "7500" it falls back to 6500 if that helps.

Tuning the converter to your car's weight and Engine/tire combination will help immensly.

On the tire thing. Goodyears are sensitive to both air and heat . . at least in my experience. A quarter of pound of air, one way or another has a fair amount of effect. Goodyears also like a little heat in them, somewhere around 110, 120 if you can get it and keep it while staging.

Hoosiers, on the other hand, will work really well on a specific setting. Once you find the air pressure the tire likes, leave it alone. An acquaintence running an Undercover 4 Link, 560+ BBC has 5.5# of air and it seems to hook up good. Track conditions, or even track temp doesn't seem to have much effect on them. Big Burnouts are actually detrimental to their performance . . We stage with about 90-95 on a 90 track (average) and they work really well. Personally, I wouldn't use a Goodyear on a tugboat . . but that's just me . . Also, on the Hoosiers, it takes about a half pound of air to make a difference. And you'll know right away, because, like I said, Hoosiers (at least in my experience) are kind of "one setting" Tires . .

shawnp 04-11-2012 10:14 AM

With the Hoosiers on our old Nelson car that was hardtail/front suspended we ran 33.5's with 5.25-.5.5 on the air pressure. Current swingarm car with 582 we run 6.0's in the 34.5's. Now changing to the aluminum block that may or maynot change for this year.

SPEEDNEEDS1 04-11-2012 06:05 PM

launch is at 4800 and goes to around 6400-6500 as soon as the trans brake releases. It hits the tire really hard. I accidently left the three step switch on one pass and left wide open and it slowed down...... I no longer use the three step switch, just try to keep it under 7000 in burnout.

hammertime 04-11-2012 08:13 PM


Originally Posted by SPEEDNEEDS1
launch is at 4800 and goes to around 6400-6500 as soon as the trans brake releases. It hits the tire really hard. I accidently left the three step switch on one pass and left wide open and it slowed down...... I no longer use the three step switch, just try to keep it under 7000 in burnout.

Have you tried to launch lower ? Sure seems like you have a lot of wheel speed.

roadkill2 04-12-2012 05:57 AM


Originally Posted by hammertime

Originally Posted by SPEEDNEEDS1
launch is at 4800 and goes to around 6400-6500 as soon as the trans brake releases. It hits the tire really hard. I accidently left the three step switch on one pass and left wide open and it slowed down...... I no longer use the three step switch, just try to keep it under 7000 in burnout.

Have you tried to launch lower ? Sure seems like you have a lot of wheel speed.

Dunno. If he has tire shake, it's usually because one doesn't have enough "Wheelspeed" to maintain the wrinkle and tire shape. If you can "Drive through it" that usually means that it's very minor and you're just "on the Edge" of tire distortion.

But . . I don't know of anyone who runs Hoosiers that have "Tire Shake" to any degree, unless they have too heavy a car for the sidewall design. On the other hand Goodyears will shake if they have too low an air pressure for the wheel speed being applied . . Sometimes, with Goodyears, an eighth of a pound will make a difference. not so much with Hoosiers . .

Basically, shake still goes back to the sidewall wrinkle and the fine line between grip and wheelspeed . . My opinion, anyway . .

I think I'd try launching at 5000, just for more data, and to see if the shake will go away . . Watch those RPMs in the water. The water box has killed more BBCs than all the races they've been in put together . . We keep our burnouts to 6500. If you can't clean and warm a tire with that, 7 grand won't do it either!


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