Quarter Mile Gear Selection

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MobileCustoms said:
I'm not real smart on all of this stuff, but based on what you said about fun, retirement and bracket racing in the 1/4 mile VS 1/8th, I'd lean towards the most consistent ET setup you can get while making sure you don't blow it all to Hell. -More time at the strip and less time and money on rebuilding broken stuff. With all that torque, I'd think 3.91 or 4.10 gears would be the sweet spot. But like I said, I ain't schooled in racing.
Sounds like a great retirement though!
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Post of the year right here^^^^^^^!!!

I was roflmaopmgo when I read something between “consistent ET and not blowing it all to hell”!

Perfecto!
 
RustyRatRod said:
My 2 cents says to use the lowest numerical gear set you think the engine will pull. But I'm pretty conservative. I don't like spinnin stuff to the moon, because I'm always on a budget and if I blow something all to pieces, it's gonna be a long time comin before I can build something else. Plus, with a 512, you could run some impressive times with a 3.23 gear, so there's THAT. I'm sure you can stand more than that, it was just an example. I think I'd try a 4.10 and possibly even a 3.91......but with that tall tire, the 3.91 might not be enough.
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I agree, I would run a 3.54 with a 28 inch tire
 
Great discussion. I've been wondering about all of this myself. My friend just started drag racing and he's like PBR and cant tell me his RPM at the trap. I get it. Especially if your fender racing.
 
Syleng1 said:
I’ll be the first to ask:

How the heck do you build that big and elaborate of and engine and not know what gears your running? The whole system works as a package not ala-cart.

First thing my engine builder asked was gears, mt or auto and tire height and weight of the car. Just saying.
Syleng1
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Oh I don't know. Sometimes it pays to swap around. If it was mine, I'd try the 3.91 after the 4.10 just to see what happens.
 
Just stopping here to wait for the "we don't race dyno's" crowd.

The best way to know what gear you need is by doing math. In order to have accurate numbers for the equation you need to know where the engine makes peak hp and how well it carries the power band.

I am thinking you will be close to 6500 rpm max with that cam unless it is unusually long duration with a wide (112, 114) LSA.

If I were tring to shoot in the middle (6800ish) I'd look at a 10.5x29.5 stiff wall slick. MT p/n 3062.
 
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Syleng1 said:
I’ll be the first to ask:

How the heck do you build that big and elaborate of and engine and not know what gears your running? The whole system works as a package not ala-cart.

First thing my engine builder asked was gears, mt or auto and tire height and weight of the car. Just saying.
Syleng1
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The last things you buy on a race car are the torque converter (power band dependent), shocks (ride height dependent) and gears .

In my experience you can get pretty close to your intended powerband by providing factual information to an experienced cam grinder/engine builder.
 
I kinda lucked out with gearing on my car. My Duster has a 4.88 rear gear in it and a 14-32 slick. When I started running 9.30’s my old 408 was winging higher than I needed it to or wanted it to. I was kicking around going to a 4.30 and boom within months the 4 tracks that I frequent all switched my class over to 1/8 mile. All is good now. Not sure what I would do now if I had to buy a new set. I guess I should give that some thought. I wish I had a Ford 9 inch as I have at least 3-4 carriers
 
No matter what gear you decide, the torque converter will play a key factor on what your trap RPM will be. Just be prepared to make potential changes after the car gets going down the track and you get usable data to work from. Whose converter are you using? I know you said 5,000 stall but I’m curious who produced it.
 
This note is probably late, cause the o.p. has already said he's going with the 4.10, but.....
The case break is at 4.10/4.56
If you have a 4.56 carrier, you are stuck with 4.56 on up (4.56, 4.88, 5.14, etc)
If you have the 4.10 carrier, you can use Dr. Diffs 3.23, 3.54, 3.73 (no 3.91s for a dana that I know of) and 4.10s, AND! you can get thick 4.56 or 4.88 to use with the 4.10 down carrier.
So, for maximum versatility and gear choice, the 4.10 down carrier is a no-brainer.
 
...and for what it's worth... I bought an aluminum 9"center for my big port big block car......with 4.10s, to replace the 3.50s that is in it.
I'll record the difference in what it runs, and the difference in weight. And finish line rpm.
Gonna be interesting!
 
Great thread and it has me thinking........................4 speed with 4.88's and don't want to blow it up crossing the line too high RPM :rofl: :rofl:
 
pittsburghracer said:
I kinda lucked out with gearing on my car. My Duster has a 4.88 rear gear in it and a 14-32 slick. When I started running 9.30’s my old 408 was winging higher than I needed it to or wanted it to. I was kicking around going to a 4.30 and boom within months the 4 tracks that I frequent all switched my class over to 1/8 mile. All is good now. Not sure what I would do now if I had to buy a new set. I guess I should give that some thought. I wish I had a Ford 9 inch as I have at least 3-4 carriers
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You got a good 9" track lock unit? lol
 
33IMP said:
That would be an eighth-mile-only car, if it was mine. (For what it's worth, I think I might be in the minority, but I LIKE eighth mile!)

Edit: I LOVE eighth mile.
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I've tried to get into it. Just never have. I will say it is a better representation of red light to red light street racin though.
 
RustyRatRod said:
I've tried to get into it. Just never have. I will say it is a better representation of red light to red light street racin though.
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I like the fact that it is so much safer for old guys like me, to do 100, instead of 135, and imo, the second half of the 1/4 is just boring and hard on the car. The starting line, the 60 ft, the gear changes, and the finish line is what's important, and you get all that in an eighth too, without having to beat the car up in high gear.
 
33IMP said:
I like the fact that it is so much safer for old guys like me, to do 100, instead of 135, and imo, the second half of the 1/4 is just boring and hard on the car. The starting line, the 60 ft, the gear changes, and the finish line is what's important, and you get all that in an eighth too, without having to beat the car up in high gear.
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Sounds a lot safer for my car as well. The last time I raced 1/4 mile was in the 80's, never really thought about 1/8th. Now with this car and everything invested, it makes pretty good sense.................. :thumbsup: :thumbsup:

I knew this was a good thread.
 
33IMP said:
I like the fact that it is so much safer for old guys like me, to do 100, instead of 135, and imo, the second half of the 1/4 is just boring and hard on the car. The starting line, the 60 ft, the gear changes, and the finish line is what's important, and you get all that in an eighth too, without having to beat the car up in high gear.
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You make some great points. I have an 1/8 mile track under an hour away. If it wasn't a place to get shot or stabbed, I might go.
 
71Demon528 said:
I won’t even run 1/4 mile if they offer it. 1/8 is way better and way safer.
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Not to mention, the program can run much faster (especially on t-n-t nights).

It's a good thing that I like 1/8th. Nearest 1/8 is twenty minutes. Nearest 1/4, not counting pomona (f#@k nhra) is four hours.
 
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