Hello All,

Decided to throw some 5.11s in my car, up from the 4.86.

So in terms of et, will it help, or hurt it?

So in terms of consistency, will it help or hurt?

Ultimate goal is to pick up a little rt, and gain some consistency.

Thanks

I would imagine as long as you have the rpm to play with it should be faster and improve your rt a bit no ?? What's your guess on rpm increase with the change??
We now do quite a bit of 1/8 mile racing yet our cars are both set up for 1/4 mile. I'd love to experiment with some 5.13's

Currently in ideal condition, car crosses at 7100 at 111. Hoping to add 300-400 rpms to that. Engine made peak hp at 7100, so would like to use the back side of the curve more. I would expect it to pick up a little because I would be keeping the rpm closer to pk hp. In the worst conditions I race in, it crosses at 6700-6800. For less than ideal conditions, I probably could get away with more gear. We shall see how it responds.

It'll cross 7350 rpm, I've run 3.90, 4.88, 5.00 with a 1.69 low same weight, same car, 114.50 best mph power in 2400 da best air my car has seen.

You'll notice the converter slip will be 2-3% less than the 4.88, otherwise it would cross -1% 7450 - -0% 7550 rpm.

If you are only coming across at 7100 then it should help with reaction time and ET. My only concern is it may make it harder to hook on less than ideal tracks.

Car has a 1.80 low gear. I have heard that a 1.69 may be faster because it less of an rpm drop on the shift,

Car has been 1.27 sixties, its always hooked well. I am pretty confident I can get the suspension dialed in if it gets a little crazy.

It also slips right at 10%, curious to see how that works out.

Thanks

quote:

Originally posted by banjo:
Car has a 1.80 low gear. I have heard that a 1.69 may be faster because it less of an rpm drop on the shift,

Car has been 1.27 sixties, its always hooked well. I am pretty confident I can get the suspension dialed in if it gets a little crazy.

I think it would, you have excellent sbc power. Momentum

quote:

Originally posted by banjo:
It also slips right at 10%, curious to see how that works out.

Thanks

That's what I came up with, just under 10% based on a 28 diameter x 10' width. Is that a radial or bias?

It'll be 7-8% with the 5.11 gear.

quote:

Originally posted by banjo:
Car has a 1.80 low gear. I have heard that a 1.69 may be faster because it less of an rpm drop on the shift,

Car has been 1.27 sixties, its always hooked well. I am pretty confident I can get the suspension dialed in if it gets a little crazy.

Your car has always worked pretty good.

I run the Mt radial 29.5x10.5 on an 8 inch rim.

Do you think that will be a move in the right direction?

quote:

Originally posted by banjo:
I run the Mt radial 29.5x10.5 on an 8 inch rim.

Do you think that will be a move in the right direction?

Yeah, it'll be good for breaking the beam quicker. Consistency is in the fuel mixture / timing.

It'll be fine, it's a very small adjustment. It'll go a couple two, three hun quicker.

What’s the convertor flash rpm and what does it drop to after launch?

For RT it could possibly be a tic quicker in FB, but not so in TB imho. I believe it’ll run same ET. For consistency it won’t change. I think the lower SLR could be better for consistency. Your convertor and engine tune effects the consistency.

If only going 1/8 and it was me @ 3200, I’d choose 1.58 or 1.64 with a 5.43.

Early last November I went from 4.40 to 5.14 for one pass, and then had the convertor re-stalled for the second time to “finally” get it closer for the very last race event I attended in late November. This change produced some of the results I wanted (more mph on average vs ET) and will be interesting to see how my 2021 season starts with this change. I only compete in 1/8 mile now.

I'm guessing it will hit harder and *might* see .01 in 60'. Otherwise, no difference.

Hits between 5800-6000 depending on condition, drops to 6200-6300 on the shift.

Looking for reaction time off the footbrake, no to worried about off the t brake because I use a box.

Thanks

quote:

Looking for reaction time off the footbrake, no to worried about off the t brake because I use a box.

the more starting line ratio you have the more reaction

I did just opposite with my old Nova and went from 5.90's to 6.1-'s. Mine was because broke one and had other laying there. I remember thinking I could get out and push this thing faster on first pass after change. I think combo has lot to do with result and how good it was or was not originally. Based on my results I think you should gain a tenth plus.

quote:

Originally posted by wideopen231:
Based on my results I think you should gain a tenth plus.

Hey I went from 5.13 to 4.86 and loss almost .2 stands to reason he could pick up close to that.

Now on my brother dragster gear change made almost zero difference, but then every chage we tried made about the same. We changed cams, induction, added vacuum pump and cpl other things car ran almost exact same.

Guess we will find out if he makes the change.