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-   -   Jerico 4 spd ratio? (https://classracer.com/classforum/showthread.php?t=48324)

L79racer 07-12-2013 07:04 PM

Jerico 4 spd ratio?
 
Whats a good ratio for a 550 hp motor with 4.56 rear gears at 3000lbs? I know its a little vague.

Dinsdale 07-13-2013 12:10 AM

Re: Jerico 4 spd ratio?
 
You need to call Jerico and be a little (actually a lot) less vague. Any other advice at this point is pure speculation and pretty much useless.

tj310 07-13-2013 08:46 AM

Re: Jerico 4 spd ratio?
 
30 x 9 tires ? smallblock ? we switched from a 3.25 first with a 5.57 rear to 2.75 x 6.0 ,similar results . If I were buying new 3.08 ---Trevor

james schaechter 07-13-2013 09:56 AM

Re: Jerico 4 spd ratio?
 
The standard Jerico ratio that you see is typically a 3.19 low. If you don't have adequate hook, maybe 3.08 or even less, but only if you are working around less then ideal set up like a street strip car or small tire combo that does not work well. Clutch plays a big role. 4.56? Low rpm engine or street strip? If you can't hook the low gear and adapt the ratios to compensate, get a gear set that is easier to upgrade. Make sure the forst gear set is 33/15 and work with Scott at Jerico to pick the rest. If you plan on ramping up the car to handle the more traditional race ratios, it makes a difference. If you do it right, you can then change only main drive gears to go to a 3.19. If you pick some weird ones, it gets expensive because you have to choose a whole set.

Run to Rund 07-13-2013 10:44 AM

Re: Jerico 4 spd ratio?
 
After a discussion with Scott on my fairly similar combination, I got 3.08, 1.93, 1.34 iirc.

L79racer 07-14-2013 11:41 AM

Re: Jerico 4 spd ratio?
 
Quote:

Originally Posted by james schaechter (Post 390572)
The standard Jerico ratio that you see is typically a 3.19 low. If you don't have adequate hook, maybe 3.08 or even less, but only if you are working around less then ideal set up like a street strip car or small tire combo that does not work well. Clutch plays a big role. 4.56? Low rpm engine or street strip? If you can't hook the low gear and adapt the ratios to compensate, get a gear set that is easier to upgrade. Make sure the forst gear set is 33/15 and work with Scott at Jerico to pick the rest. If you plan on ramping up the car to handle the more traditional race ratios, it makes a difference. If you do it right, you can then change only main drive gears to go to a 3.19. If you pick some weird ones, it gets expensive because you have to choose a whole set.

Thanks for the replies, Its a 383 small block chevy. I will be shifting at 7200 and should be going through the traps about the same. Probably a 29x9 tire. Once its done If needed might go to 4.88. It will be a 4 link so hooking should not be a problem. Clutch will be a ram adjustable. I see a lot have the 3.08 1.93 1.34. If you go to a 3.19 what do you bring second and third to?

james schaechter 07-14-2013 09:10 PM

Re: Jerico 4 spd ratio?
 
http://www.jericoperformance.com/charts.htm

This lists the chart on gears. How much power and how much weight. What RPM do you plan on finishing at?

The reason I ask is that your shift rpm doesn't seem to match your gear selection. Not saying you are wrong. Just need more info. If youhave the power and torque to run a lot of mph, then maybe you need a 2.90 something first gear. If not and you can't handle the rpm on the other end, maybe reconsider the shift rpm also?

L79racer 07-14-2013 09:48 PM

Re: Jerico 4 spd ratio?
 
Quote:

Originally Posted by james schaechter (Post 390778)
http://www.jericoperformance.com/charts.htm

This lists the chart on gears. How much power and how much weight. What RPM do you plan on finishing at?

The reason I ask is that your shift rpm doesn't seem to match your gear selection. Not saying you are wrong. Just need more info. If youhave the power and torque to run a lot of mph, then maybe you need a 2.90 something first gear. If not and you can't handle the rpm on the other end, maybe reconsider the shift rpm also?

Why doesnt my shift point match gear selection? I used to run a Nash 5 speed then switch to a glide. Its been 9.92 at over 134 mph at 2900lbs.. With that Mph and a 29" tire it was going through the traps around 7000 plus or minus a few rpms. I dont want to be going through the traps over 7200.

james schaechter 07-23-2013 09:35 AM

Re: Jerico 4 spd ratio?
 
The short tire at 134 answers the question. The detail in the last post is helpful. Definately not set up for best e t so that makes it pretty easy to choose. It depends on if you have any future plans to change the car. Sounds like the car has more than enough power to run 3.08 or even like a 2.93 or so. Only you have enough info to decide, but it would be good to discuss the ratios with Scott at Jerico so you don't pick something odd that is hard to change later. Good Luck!

jscamaro1 07-24-2013 07:01 PM

Re: Jerico 4 spd ratio?
 
Seems to me you would be going the wrong way with the first gear. With that rear gear and small tire I would want a 3.19 way before a 2.93 or 3.08. Clutch setup might be tricky with not much ratio in the trans or rear end.

Ever call G-force?


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