3.73 vs. 4.10

[biminiLX]

I've been finalizing a mod plan for the current goals and have been spending time on a drag calculator site (Wallace Racing - Calculate Rear Gear Ratio for given MPH, RPM and Trans Gear Ratio).

Most opinion here says 3.73s for the street, but even my conservative estimates on the calculators show it wanting a 4.10 gear minimum.

I'd appreciate some real world input on best ratio.

Looking to run 135-140mph at the drag strip with a 28.74" 315/35/20 DR.
Would drive on that tire daily and the goal is to drive it to the track and run solid mid/high 10s.

I've driven on drag radials daily before and this car will only see rain if I get caught in it, so I know what I'm getting into.

Would also likely put a 28" bias-ply ET Street or full slick on it, but that would be close to the same 28.75-29" with growth anyway.
Thanks, J
:beer:

 

[BOD89LX]

So are you looking for drag strip only best gear or drag strip/street race best gear? I hope to get back to the drag strip soon without the clutch protection and stock gears. I will say on the street the 3:31's work great for dig or roll race( unless its against a GTR) and the 130 ish in 3rd and then having 4th to 170 plus is hard to beat. For the track maybe go with a 26" tall tire to get good use out of 4 th.

 

[biminiLX]

So are you looking for drag strip only best gear or drag strip/street race best gear? I hope to get back to the drag strip soon without the clutch protection and stock gears. I will say on the street the 3:31's work great for dig or roll race( unless its against a GTR) and the 130 ish in 3rd and then having 4th to 170 plus is hard to beat. For the track maybe go with a 26" tall tire to get good use out of 4 th.

To me the best gear is what will let me hit the goals at the strip.
The 26" tire for the strip isn't a bad idea, but I don't want to fit hooking a short tire, a 28" would be musch easier.
-J

 

[rancid]

I know a lot of people love 3.73's but I honestly think 4.10's get a bad wrap. I had them in my 2000GT with an aluminum driveshaft and a TKO transmission and loved that car at the track and for a DD with interstate driving.

Birddoc is the only one to my knowledge that has had both sets in this particular car and he has given his recommendation in a couple threads. If I still have mine when the warranty is up I will do 4.10's then go down to 3.73's afterwards if it is too much. I would rather have too steep of a gear and have to swap for that reason than to because "what if" then go backwards anyways a third time.

I believe lethal is still using the stock gears and running 9's at the track. Not sure what Evolution did with their's.

 

[BIRDDOC]

4.10's in currently. Bottom line is there is no better gear for the strip than the 4.10. Especially when the tire is close to 29 inches (growing 28 inch slick/28.9 inch DR). I'm finishing about 6600-6800 rpm's across the line with total engine effort and efficiency.

I do think the 3.73's have better manners on the street. After this season I may slow down at the strip with my Shelby. If I do that 3.73's are going back in.

 

[shetheri]

J

I have 3.73's in mine and I usually lean to the conservative side when it comes to gearing. However, with this car, I believe that the 4.10's would be very good for both street and strip. I still feel that even with the 3.73's it could use more gear, that could be because I am running a 28.7" tire as well.

 

[USV8PWR]

So are you looking for drag strip only best gear or drag strip/street race best gear? I hope to get back to the drag strip soon without the clutch protection and stock gears. I will say on the street the 3:31's work great for dig or roll race( unless its against a GTR) and the 130 ish in 3rd and then having 4th to 170 plus is hard to beat. For the track maybe go with a 26" tall tire to get good use out of 4 th.

To me the best gear is what will let me hit the goals at the strip.
The 26" tire for the strip isn't a bad idea, but I don't want to fit hooking a short tire, a 28" would be musch easier.
-J

I agree with BOD89LX...I'd personally stay with the 3:31's and do a 13-6 kit from Van or similar from Lethal. I really don't understand the point of 3:73's, unless all you plan to do is drag race the car. I mean not only would it be that much more difficult to launch properly on the street...the car would not fare nearly as well in a roll race at say 70MPH to 130MPH. My favorite part of this car is how quick it is on the highway. I raced a 2012 Ferrari 458 Spyder the other day and he could not pull away at all; sure a lot of that is the insane power these cars make stock...but some of it also has to do with the gearing.

 

[masonh]

I don't have any real world experience with either in the new Shelby as I still have the 3.31 in mine, but i do have a set of 27" drag radial that I put on to go to the track, which helps just a little.

It's always tougher trying to build for great drag strip runs and some streetability for daily driving. If you want the best gear for 1/4" possible I would say order a 4.30 from Motive, but if you want a great daily driver gear then I wouldn't go higher than 3.73.

I think you have another option as well that Motive makes. They have a 3.90 which might be a nice compromise. I also read that they have some lightweight yet still very strong ring and pinion kits that are supposed to shave a little time for the serious racer. I guess in theory they spin up a little quicker. They may have shaved some tenths off some nascar dudes but i can't imagine them helping a 4000lb drag car out much.

 

[Fastfish420]

Im glad someone started this thread because I am in the same boat.My car has 300 miles on it and I already have Vans 13-6 kit plus a 10% lower pulley and am running 100 octane race tune from Lund..Im a drag racer at heart and I think the 4.10 would be the gear to go with and I think it would be ok for the street also..but I love the manners of the 3.31 also.I plan on taking my car to the track soon and want to run the 20 in M/T 305 DR.I think the 3.31 would be ok to make the car less violent off the starting line.I guess i should just try it and see what happens?

 

[biminiLX]

4.10's in currently. Bottom line is there is no better gear for the strip than the 4.10. Especially when the tire is close to 29 inches (growing 28 inch slick/28.9 inch DR). I'm finishing about 6600-6800 rpm's across the line with total engine effort and efficiency.

I do think the 3.73's have better manners on the street. After this season I may slow down at the strip with my Shelby. If I do that 3.73's are going back in.

Thanks Mark, I know we've discussed this before, now I'm getting ready to pull the trigger.

When you say better manners--what differences did you notice on the street?
I will be running around with 700-750rwhp and the 315/35/20 tall DR full time.
I love your track wheels but what street tire do you use?
-J

 

[biminiLX]

J

I have 3.73's in mine and I usually lean to the conservative side when it comes to gearing. However, with this car, I believe that the 4.10's would be very good for both street and strip. I still feel that even with the 3.73's it could use more gear, that could be because I am running a 28.7" tire as well.

Thanks, that's what I'm thinking to, but the calculators don't give me real world experience.
I did a 4.30 gear in my NA '01 Cobra and never thought it was too much, so don't fear the gear can be true.
I'm more concerned about using 3.73s and loosing top-eng MPH on the strip because its under the peak HP at the traps.
Maybe if we get together (still hoping for Woodward dream cruise) I can feel it in person.
I have been thinking 3.73 all along, but everyone and myself seems to forget that's a TALL tire and makes the 3.73 act more like a 3.55.
-J

 

[biminiLX]

Im glad someone started this thread because I am in the same boat.My car has 300 miles on it and I already have Vans 13-6 kit plus a 10% lower pulley and am running 100 octane race tune from Lund..Im a drag racer at heart and I think the 4.10 would be the gear to go with and I think it would be ok for the street also..but I love the manners of the 3.31 also.I plan on taking my car to the track soon and want to run the 20 in M/T 305 DR.I think the 3.31 would be ok to make the car less violent off the starting line.I guess i should just try it and see what happens?

Yep, those are some reasons I made this thread.
If you go to the track now with the extra power and 3.31s, you'll cross the traps in 4th but well under peak power.
Still, I'd say try it and see and let us know.
How tall are those MT 305?

I don't see the difference in 3.73 or 4.10 hurting street traction with a tall DR. I won't be doing much street racing anyway.
As far as the roll racing/highway goes, it depends on the speed ranges as 4.10s could help
Tough call.
-J

 

[KsE]

Went from 3.73 to 4.10's....I love the 4.10's. The car with drag radials is a nasty ride on the street.

 

[BIRDDOC]

Thanks Mark, I know we've discussed this before, now I'm getting ready to pull the trigger.

When you say better manners--what differences did you notice on the street?
I will be running around with 700-750rwhp and the 315/35/20 tall DR full time.
I love your track wheels but what street tire do you use?
-J

Manners wise the 4.10 "buck" some with stop and go traffic. It takes more concentration to shift smooth (although it's not that bad). Also, if your going to roll race at all you loss a lot of your top end (120+). In the end if you goal is 1/4 mile times their acceptable on the street if you have the right tires.

My setup is True Forged 20x11 Super Sports with MT ET Street II's (305/35/20). The MT actually work stellar on the street and am very happy with them. It's still hard to get 1st gear traction but with clutch modulation and warm tires you can put it down in 2nd decent (with controlled spin). 3rd gear will dead hook even when cold outside if the tires are warmed up. W/O the MT's I have no confidence on the street as I'll go sideways (unanticipated sometimes and dangerous)at 60+ MPH with stock level tires.

 

[Fastfish420]

Yep, those are some reasons I made this thread.
If you go to the track now with the extra power and 3.31s, you'll cross the traps in 4th but well under peak power.
Still, I'd say try it and see and let us know.
How tall are those MT 305?

I don't see the difference in 3.73 or 4.10 hurting street traction with a tall DR. I won't be doing much street racing anyway.
As far as the roll racing/highway goes, it depends on the speed ranges as 4.10s could help
Tough call.
-J

Im pretty sure there 29 inches tall..

 

[biminiLX]

Went from 3.73 to 4.10's....I love the 4.10's. The car with drag radials is a nasty ride on the street.

Perfect that's the real world experience I was hoping for.
What mods/power level is your car at? Which drag radial?



BIRDDOC: Thanks again, I'm not sure how much roll racing I will do.
I really just enjoy cruising it on the street and some mixed aggressive driving for stress relief :burnout:
I just want it to perform well when I take it to the strip.
-J
:beer:

 

[03cobra#694]

4.10s until u make 800rwhp then 3.73s will be faster ....

 

[biminiLX]

4.10s until u make 800rwhp then 3.73s will be faster ....

Well, I've been meaning to call you on advice, so there's my answer.
My instinct is to go 4.10s with the tall tire, I will start there.
Hope things are well man.
-J
:beer:

 

[masonh]

I have been thinking 3.73 all along, but everyone and myself seems to forget that's a TALL tire and makes the 3.73 act more like a 3.55.

I think for every inch in tire diameter you will gain/lose approximately .1 of gear ratio. I forget the exact number, but I would say that with a 28.7" tire you would be closer to 3.65 that 3.55.

4.10 would put you real close to 4.0

 

[carguy19]

I wish motorsport would make a 3.90 ratio so I could do that and not worry about it being noisy. I dont trust motive or richmond