Gear gurus. right ratios for all around performance.
12-17-2013, 09:11 PM
#1
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Gear gurus. right ratios for all around performance. Car is a miata that im building a tube chassis for. This will be my first very fast car. (Faster than 12 seconds) The goal for the car is to street drive it but be able to take it to a drag strip, auto cross and road course and do well at all of it. Shooting for weight of 2500.
Largest tire I can fit is a 335 35 17.
Rear is a for 9 with comp engineering housing. Currently has 3.73 Im guessing that I need to go with 3.23 or 3.08
Engine 370 L92 twin s366 turbos 700 to 1000 rwhp hoping for.
I hope thats all the info needed.
T56 magnum will be the trans.
Question is there are 3 different 1st gear ratios to choose from.
2.62 2.71 2.92
My guess is the 2.62 would be best because of weight but with what rear gear?
Largest tire I can fit is a 335 35 17.
Rear is a for 9 with comp engineering housing. Currently has 3.73 Im guessing that I need to go with 3.23 or 3.08
Engine 370 L92 twin s366 turbos 700 to 1000 rwhp hoping for.
I hope thats all the info needed.
T56 magnum will be the trans.
Question is there are 3 different 1st gear ratios to choose from.
2.62 2.71 2.92
My guess is the 2.62 would be best because of weight but with what rear gear?
12-18-2013, 03:25 PM
#3
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I have been running 3.55 rear gears with the stock T56 2.66 first gear.
My car is nothing like what you are building, but in my opinion I would leave the 3:73 rear gear. In my opinion the 2.92 first would be the best for what you are doing. I think that this would have a better chance of hooking up. From what I have done, a taller first gear and tall rear gears like 3.08 and numerically lower tend to spin the tires with hard launches with high horsepower and light weight cars like yours, and this combo is harder to feather the throttle to get it to hook up again. You will not be in first very long with this combo before shifting to second, and that will be about the time the boost is on tap. Could be scary!
Sounds like a ton of fun regardless of what gears you end up with.
Good luck.
My car is nothing like what you are building, but in my opinion I would leave the 3:73 rear gear. In my opinion the 2.92 first would be the best for what you are doing. I think that this would have a better chance of hooking up. From what I have done, a taller first gear and tall rear gears like 3.08 and numerically lower tend to spin the tires with hard launches with high horsepower and light weight cars like yours, and this combo is harder to feather the throttle to get it to hook up again. You will not be in first very long with this combo before shifting to second, and that will be about the time the boost is on tap. Could be scary!
Sounds like a ton of fun regardless of what gears you end up with.
Good luck.
12-18-2013, 03:48 PM
#4
use this calculator http://www.tremec.com/calculadora.php and enter your 411 to get RPM with a particular gear.
given the very low weight of your car the 3:73's may be good, especially if you go with the 2.92 1st gear.
My slicks are a 26" tall tire but my street tires are a 27". Whatever tire height you will use, enter that in the calculator with the other 411 and determine what gear ratio works best for your use
I have the 2.66 1st gear T56 and run 4:10's...but have a car that weighs twice what yours does
given the very low weight of your car the 3:73's may be good, especially if you go with the 2.92 1st gear.
My slicks are a 26" tall tire but my street tires are a 27". Whatever tire height you will use, enter that in the calculator with the other 411 and determine what gear ratio works best for your use
I have the 2.66 1st gear T56 and run 4:10's...but have a car that weighs twice what yours does
12-18-2013, 03:48 PM
#5
use this calculator http://www.tremec.com/calculadora.php and enter your 411 to get RPM with a particular gear.
given the very low weight of your car the 3:73's may be good, especially if you go with the 2.92 1st gear.
My slicks are a 26" tall tire but my street tires are a 27". Whatever tire height you will use, enter that in the calculator with the other 411 and determine what gear ratio works best for your use
I have the 2.66 1st gear T56 and run 4:10's...but have a car that weighs twice what yours does
given the very low weight of your car the 3:73's may be good, especially if you go with the 2.92 1st gear.
My slicks are a 26" tall tire but my street tires are a 27". Whatever tire height you will use, enter that in the calculator with the other 411 and determine what gear ratio works best for your use
I have the 2.66 1st gear T56 and run 4:10's...but have a car that weighs twice what yours does
12-18-2013, 09:16 PM
#6
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3.23 would be 164 at 6800 rpm
3.73 would be 146. Wouldnt the 3.73s make me possibly go for 5th in the 1/4? I dont have the slightest clue how fast this thing will go In the 1/4.I would think low 9s are possible with car.
With the 3.23s it would allow me to go with the closer ratio OD gears and still get good mile race speeds. Thoughts?
3.73 would be 146. Wouldnt the 3.73s make me possibly go for 5th in the 1/4? I dont have the slightest clue how fast this thing will go In the 1/4.I would think low 9s are possible with car.
With the 3.23s it would allow me to go with the closer ratio OD gears and still get good mile race speeds. Thoughts?
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12-19-2013, 11:21 AM
#8
Car is going to be a challenge to hook in a straight line let alone coming out of corners, it's going to be a handful for sure! I'd suggest going for a ride in a NA LS Miata before considering TT if you're serious about it wanting it to be anything more than a drift car
What clutch do you plan on running?
What clutch do you plan on running?
12-19-2013, 12:05 PM
#9
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the car has been together already once with a 347 Ford. It put down 375 to the wheels. But was still independent rear suspension. New setup will have much more tire. A 3 link with a frame mounted Watts link. I have no idea on clutch. I'm sure it will be some form of a street twin.
12-20-2013, 11:06 AM
#10
the car has been together already once with a 347 Ford. It put down 375 to the wheels. But was still independent rear suspension. New setup will have much more tire. A 3 link with a frame mounted Watts link. I have no idea on clutch. I'm sure it will be some form of a street twin.
12-20-2013, 01:29 PM
#12
I think if you can hook up it should go 8's
3.25 for a 9" and 3.31 gears for an 8.8" would be my choice. You want to gear it for finishing in 4th in the 1/4.
With good dual valve springs and lightweight valves (not truck valves) that should rev well past 7K if you want to. Morel link bar lifters will allow for more safely margin.
My buddy revs his to 7800rpm with Morels, medium size hydraulic cam, stock crank, 4.065" bore, $600 rods, $800 pistons, ported LS3 heads/dual springs, LS3 intake, GTS76 single turbo. 950rwhp. He runs a T56 and 3.31 gear 8.8" Cobra IRS out back.
If you can keep that cool on a road course I will be blown away! You may need multiple radiators. Definitely some Depends and big brakes.
There is a local Miata with n/a LS1 making around 400rwhp and it weighs approx 2100lbs. Widebody setup, front splitter, big rear wing, full cage, T56, 8.8" IRS rear dedicated road race car. It is a mean lil SOB
Only thing I don't like about the Miatas is the short wheel base and limited tire you can fit under them. I'm sure you are taking care of the latter part.
Are you doing an aluminum block for the final setup?
3.25 for a 9" and 3.31 gears for an 8.8" would be my choice. You want to gear it for finishing in 4th in the 1/4.
With good dual valve springs and lightweight valves (not truck valves) that should rev well past 7K if you want to. Morel link bar lifters will allow for more safely margin.
My buddy revs his to 7800rpm with Morels, medium size hydraulic cam, stock crank, 4.065" bore, $600 rods, $800 pistons, ported LS3 heads/dual springs, LS3 intake, GTS76 single turbo. 950rwhp. He runs a T56 and 3.31 gear 8.8" Cobra IRS out back.
If you can keep that cool on a road course I will be blown away! You may need multiple radiators. Definitely some Depends and big brakes.
There is a local Miata with n/a LS1 making around 400rwhp and it weighs approx 2100lbs. Widebody setup, front splitter, big rear wing, full cage, T56, 8.8" IRS rear dedicated road race car. It is a mean lil SOB
Only thing I don't like about the Miatas is the short wheel base and limited tire you can fit under them. I'm sure you are taking care of the latter part.
Are you doing an aluminum block for the final setup?
Last edited by gnx7; 12-20-2013 at 01:43 PM.
12-20-2013, 06:41 PM
#13
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9 inch will be in the rear. It currently has 3.73s in it. Rear tire size is 335 35 17. Yes I would hate to shift 5 in the 1/4. I just want the car to perform well at any type of event I go to. Thats the cool thing about turbos. You can pull boost or add it accordingly. Iron block are all I like to use.
12-21-2013, 12:09 PM
#14
http://www.f-body.org/gears/
12-21-2013, 12:32 PM
#15
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Hoosiers are what I have. Thats what im using for mock up. 3.23/3.25 sounds like the right for 1/4 mile. But then what trans gear set would work optional? Man I really hope this thing scares the **** outta me! Lol
