The best mod for a RC

Nowwhat

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As I have gone through this wonderful learning curve that is making things go faster....there is one universal mod that will absolutley make RCs come alive for a reasonable cost...

and that is the 4.88 gears....the 4.56s are just toooo tall for a 6 speed with a 31.5" tall tire....and the 4.88s are good to 120 mph at the track.....

Hell the vipers come with crazy tall gears for mpg claims and emission standards...
 
Lots of variables to consider though Mike. 4.88s may be the best mod for a realitively stock RC on stock rubber. However, Even the tallest drag radial in 17" size is only 30" tall, which means the 4.56 gear would be more optimum for a truck running that tire.

If you are using the 29" tall 18" drag radial the 4.10 gears are probably optimum.

AND if you are putting down over 550 rwhp all of these ratio optimums will probably change.
 
AH bro, Nowwhat is probably trying to get me to order the 4.88's so my crap will run outta gear in the 1/4, for the nats.
 
ViperTruck2933 said:
Lots of variables to consider though Mike. 4.88s may be the best mod for a realitively stock RC on stock rubber. However, Even the tallest drag radial in 17" size is only 30" tall, which means the 4.56 gear would be more optimum for a truck running that tire.

If you are using the 29" tall 18" drag radial the 4.10 gears are probably optimum.

AND if you are putting down over 550 rwhp all of these ratio optimums will probably change.


There are always variales.....let's see...

1) with a 30" tall DR and 4.88s...you have enough gear for 116mph
2) If you are making enough power to trap higher than 116...you have out grown drag radials
3) 4.10 on a 30" tall tire are good to 138mph....:dontknow: 134 on a 29"
 
Nowwhat said:
There are always variales.....let's see...

1) with a 30" tall DR and 4.88s...you have enough gear for 116mph
2) If you are making enough power to trap higher than 116...you have out grown drag radials
3) 4.10 on a 30" tall tire are good to 138mph....:dontknow: 134 on a 29"
So are you saying that 4.88s are optimum until you break over 116 mph?

Some guys who ran the 18" X 29" tall drag radial on a NA setup claimed they were running out of 4th gear before hitting the traps. :dontknow:

Shifting into 5th gear before the traps = not good.
 
Silver had done some calculations on this awhile back!! If memory serves me, top end in 4th with 4:88's at 6000 rpm is around 110??

Couldn't find the post but that seems about right

I will agree that the 4:88's woke up the truck tremendously!!!
 
Marc T said:
Silver had done some calculations on this awhile back!! If memory serves me, top end in 4th with 4:88's at 6000 rpm is around 110??

Couldn't find the post but that seems about right

I will agree that the 4:88's woke up the truck tremendously!!!


4.88's on stock tires....ie 31.5 at 6000 rpm = 122mph.....that is fricken fast....:D
 
ViperTruck2933 said:
So are you saying that 4.88s are optimum until you break over 116 mph?

Some guys who ran the 18" X 29" tall drag radial on a NA setup claimed they were running out of 4th gear before hitting the traps. :dontknow:

Shifting into 5th gear before the traps = not good.



the nitto 555r come in 2 series....one is 26.4" tall the other almost 29....some guys bought the 26.4"....tires....man that is just too short for several reasons...

I am saying 99.5% of your driving will not be at the track therefore 4.88s....once you hit the track get the taller tire....and again 4.88s...
 
Won't traction be an issue with a blower, NOS or both with 4.88 gears... Not too mention even on the street just using the blower. The tendency I have seen from board members is to stay with 4:10's with blower?

Just being a curious troll...
 
Where are you getting your speed #'s? Im coming up with these assuming no slippage, 6000RPM, 31.5" tire (stock) and a 1:1 4th gear:

4.11: 136.8
4.56: 123.3
4.88: 115.2

Using the 29.5 tall M+H Drag Radial I get:

4.11: 128.1
4.56: 115.5
4.88: 107.9

Im swapping Tim (vipertruck) for his 4.10's (that may be a first) because he is staying all motor and I plan to do a turbo setup. Turbos like load, plus its going to trap big MPH, so the 4.10s are better for me and the 4.56's would be better for him. I think my truck may be a little lazy around town compared to now with the 4.56's, but on the bottle, I would bet it would run the same or better #'s.

EDIT: Also keep in mind a QC will most likely not be able to acheive these MPH's because of convertor slippage. Nowwhat was your truck staying in 3rd with the 4.56's on your 121MPH pass? What height tire were you running?
Justin
 
Nowwhat said:
As I have gone through this wonderful learning curve that is making things go faster....there is one universal mod that will absolutley make RCs come alive for a reasonable cost...

and that is the 4.88 gears....the 4.56s are just toooo tall for a 6 speed with a 31.5" tall tire....and the 4.88s are good to 120 mph at the track.....

Hell the vipers come with crazy tall gears for mpg claims and emission standards...

What I did something right for once:dontknow: ....:D

I couldnt agree anymore!!!! Truck feels way snappier around town and overall just lighter. I love them.

patrick
 
dialing in your gearing is definately crucial to 1/4 mile performance. I'm spraying a 150 shot with 4.10's on the M&H DR's and am at about 5,400 RPM in 4th @116mph through the traps. I think with 456's and the nostalgia slick would be ideal.....but don't have the $ and want to see what'll happen with this setup.
 
Nowwhat said:

Well one of our calculators is incorrect LOL. According to Rice Eater post, my calculator comes up with 115.3 @ 5400RPM, and yours is coming up with 122.5. I dont think either is correct for his post, as your timeslip is averaging your MPH for the last 66 feet at the track, so he is literally running 118 or so as he goes through the traps. We need an unbiased 3rd calculator to settle this!
Justin
 
A RC with 4.88 and street tires is useless from a drag racing standpoint. The best option for a RC to drag race would be an automatic out of a Cummins powered Dodge truck from 1989. It has an overdrive,same guts as a 727 automatic,convertors available,same bell housing bolt pattern,transbrake available.
 
best mod....add two more doors and back seat for late night bar parking lot discussion with multiple ladies
 
JMB Justin said:
Well one of our calculators is incorrect LOL. According to Rice Eater post, my calculator comes up with 115.3 @ 5400RPM, and yours is coming up with 122.5. I dont think either is correct for his post, as your timeslip is averaging your MPH for the last 66 feet at the track, so he is literally running 118 or so as he goes through the traps. We need an unbiased 3rd calculator to settle this!
Justin

I went through it with the formulas and the calculator Mike is referring to is flawed.

I also went back and checked the "Speed in Gears" thread that I started long ago. I believe it's incorrect also. What I did was use the data from Car and Driver and just extrapulated it out from their numbers. I believe their numbers may be in error.

Hopefully I will have a day off sometime in the future so I can sit down and come up with the real numbers based on transmission/rearend ratios and tire size so it will be done with.
 
Silverback said:
I went through it with the formulas and the calculator Mike is referring to is flawed.

I also went back and checked the "Speed in Gears" thread that I started long ago. I believe it's incorrect also. What I did was use the data from Car and Driver and just extrapulated it out from their numbers. I believe their numbers may be in error.

Hopefully I will have a day off sometime in the future so I can sit down and come up with the real numbers based on transmission/rearend ratios and tire size so it will be done with.


Silver doesnt make mistakes:dontknow: :dontknow: "say it iznt so"!!!!!:D :D


patrick
 

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