gear ratios

I am going to make a gear change after breaking my 4.86 gears last year and just wanted some opinions.

I know there are a lot on here that think the higher gears are better because of big torque #'s. I have ran 4.86 and 4.30's in the 1/8 and have found the 4.86 to be quicker in the 1/8 mile. I have also ran out to 1000 ' with 4.86 and et 6.665 @ 7600 rpm so this has me leaning towards changing to 5.13 gears.

I think I can cover the 1/8 mile with them , and I don't expect big mph #'s with the p-51's , I mean 135-138mph I think is good for a door car in the 1/8 mile . If you get up into the 140-145 mph range its going to take upwards of 1100 hp to do it.

What do you guys think ?

Never know till you try, just make adjustments to keep the nose on the ground.

A little squirt of giggle gas goes a long way.......

Steeper gear will help a converter thats on the loose side, but that said one will run harder with a tighter converter and a higher numerical gear in the 1/8th anyway.

Just have to try every possibility.

dfree383 wrote:A little squirt of giggle gas goes a long way.......

Hush your mouth! No No No!

I really don't think it would pick up more rpm with 5:13 gears than it would going out to 1000 ' with 4.86's. I have seen consistent gains of 2 numbers of et for 1 number of 60' .

Squirt away Freeloader that is the easy way out lol .

Ms mustang is gonna have to come to the realization that Ky either needs a squirt of nos or a big big new engine

MsKYMustang wrote:

dfree383 wrote:A little squirt of giggle gas goes a long way.......

Hush your mouth! No No No!

Don't be sceer'd.....

I love the easy way out!

KY JELLY wrote: Ms mustang is gonna have to come to the realization that Ky either needs a squirt of nos or a big big new engine

I vote for big engine!

richter69 wrote:Steeper gear will help a converter thats on the loose side, but that said one will run harder with a tighter converter and a higher numerical gear in the 1/8th anyway.

Just have to try every possibility.

This is the direction I have went with mine and so far it works.

MsKYMustang wrote:

KY JELLY wrote: Ms mustang is gonna have to come to the realization that Ky either needs a squirt of nos or a big big new engine

I vote for big engine!

Their you go Randy.... Momma say's bigger is better !!!! and you now have permission !!!!

MsKYMustang wrote:

KY JELLY wrote: Ms mustang is gonna have to come to the realization that Ky either needs a squirt of nos or a big big new engine

I vote for big engine!

X2

dfree383 wrote:

MsKYMustang wrote:

KY JELLY wrote: Ms mustang is gonna have to come to the realization that Ky either needs a squirt of nos or a big big new engine

I vote for big engine!

Their you go Randy.... Momma say's bigger is better !!!! and you now have permission !!!!

yes that is good news , but I am not done with this p-51 engine yet

just doing the math my car is 11% quicker et wise from the 1/8 to the 1000' timers than from the 330 timers to the 1/8 with 4.86 gears. A 2-3 % improvement to the 1/8 would be great.

A legal nhra pro stock car is about 14.5% quicker , but that is geared for 1/4 and 10,000rpm+ exotic parts got to keep that in mind.

If your 4.86's are the big pinion gears, do you have the parts on hand to make the swap over to the small pinion 5.13's? If you have all the parts already you might as well give the steeper 5.13 gear a try just for shits & grins.

A 5.13/5.14 gear might ET better than the 4.86 in the 1/8 mile NA, but with more torque (some nitrous added or a bigger motor), I'm thinking the 4.86 (or smaller) might ET better.

How close is the current converter choice to being "dead nuts" perfect? Or is it a little on the loose/tight side for this engine combo?

A small block gear in that package? I'd guess I'm missing something.

it may ET better and not change mph any.the low gear will make it harder to get off the line,kinda like haven a 3speed in it.you already 60' very good.

Randy,

When I asked this same question a year ago I got the opposite for an answer. I went from 488 to 430 and my car picked up a little. I remember Keith Fulp saying the same for his car when he went to a higher gear. It could be the HP difference between our machines. Mine is not a high HP engine and may like the gear better. I've since wondered if 513 would not help me 60' better. My 60's are not good for what I have and I do not know why. The best ever was 1.34 this summer when it ran a 6.11 at 114. I wonder if a 513 would lower the 60 to say 1.29 or 1.30 and pick up a tenth on the run. I run almost exclusive 1/8 th but would love to make a 1/4 race sometime. I'm real curious what your car will do with the 513 in it. Good luck.

Kerry

I think a lot of it depends on if your car can manage the extra torque off the line , but I see very little almost no difference in finish line rpm between 4:86 and 4:30. I think my 60' is better than it should be but my mph is with in reason for the et I am running.

It just a matter of whether I want to spend the $ for the gears to see its only money

"but I see very little almost no difference in finish line rpm between 4:86 and 4:30."
Looks like a conv. issue to me.

KY JELLY wrote:I think a lot of it depends on if your car can manage the extra torque off the line , but I see very little almost no difference in finish line rpm between 4:86 and 4:30. I think my 60' is better than it should be but my mph is with in reason for the et I am running.

It just a matter of whether I want to spend the $ for the gears to see its only money

it could make a 5.01 turn into a 4.99 so i vote to spend the money!

Lem Evans wrote:"but I see very little almost no difference in finish line rpm between 4:86 and 4:30."
Looks like a conv. issue to me.

could be but a converter only acts on what is put on it from either end , if you keep hp/tq the same and have less resistance it should do what it has , produce better 60 times and quicker et

What's that gotta do with finish line rpm?

knrclark wrote:Randy,

When I asked this same question a year ago I got the opposite for an answer. I went from 488 to 430 and my car picked up a little. I remember Keith Fulp saying the same for his car when he went to a higher gear. It could be the HP difference between our machines. Mine is not a high HP engine and may like the gear better. I've since wondered if 513 would not help me 60' better. My 60's are not good for what I have and I do not know why. The best ever was 1.34 this summer when it ran a 6.11 at 114. I wonder if a 513 would lower the 60 to say 1.29 or 1.30 and pick up a tenth on the run. I run almost exclusive 1/8 th but would love to make a 1/4 race sometime. I'm real curious what your car will do with the 513 in it. Good luck.

Kerry

i went from 4.86 to 4.30 and lost hardly any 60',made about 1mph,and crossed at a little less rpm.ran the same ET.when the gear is in the ballpark,it's a way to fine tune.some times i think it's a way to "make use"of the converter you have.

Lem Evans wrote:What's that gotta do with finish line rpm?

the engine is the boss on whether the rpm is right or not at a 1000' it seems happy with 4:86. It takes 1.83 seconds from 330- 660 and 1.61 seconds from 660-1000.

Randy,
Wanna try a set of big Pinion 4:71's ............. I gotta set setting here. You got a 10 bolt pos-a-traction out of a S-10 right ??? Seriuosly I do have a set, won't cost you anything but shipping to try them.