09152007, 11:14 PM  #1 
Basic Member

HowTo: Make Ratios
PLEASE DO NOT EMAIL ME INGAME ABOUT THIS THREAD
Here it goes guys. I'm going to try to explain this the best way I can. First of all, this is not how you make your super fast H2H ratios. This is used as a start off point to base the ratios off of. Once you complete this, you should be able to adjust the ratios little by little until they are perfect for your car. The Formula: RPM After Shift = (Ratio Shift Into / Ratio Shift From) x RPM Before Shift What does this mean? RPM After Shift [equals] Ratio Shift Into [divided by] Ratio Shift From [multiplied by] RPM Before Shift Let me try to explain this a bit. RPM After Shift  The RPM at which you want your needle to drop to after you shift. This is usually the RPM at which you have the MAX torque. Ratio Shift Into  This is the ratio at which you will get to after you shift. This is the unknown variable in the equation. We will be find out how to get this later. Ratio Shift From  This is the ratio at which you shift from. All you have to do here is input the ratio you used on the previous gear. RPM Before Shift  This is the RPM at which you should be shifting every gear. Step #1: Get your MAX horsepower and @ what RPM Get your MAX torque and @ what RPM Get the RPM at which you want to shift at Decide on your 1st gear Step #2: Input your information In this example we will be using my semistock Mustang. MAX 265.72 HP @ 5600RPM MAX 295.06 FTLBS (Torque) @ 4100RPM < "RPM After Shift" Redline is 6200RPM. That is the shift point I want < "RPM Before Shift" 1st Gear = 3.750 < "Ratio Shift From" So this is what we have so far: 4100 = ( ? / 3.750 ) x 6100 So what we have to do now is find out the "?" so we can get each ratio. Step #3: For those younger kids who don't know how to compute this equation I will help you out. Equation: 4100 = ( ? / 3.750 ) x 6100 You want to get rid of the 6100 so you divide 6100 by 6100 and get 1. So meaning if you multiply what's in the parenthesis by 1 you will just get the same number so you don't even have to put the 1. Now you have to divide 4100 by 6100. Your answer is a long decimal. Just round it to the 4th number and you should get .6721 So now we have: .6721 = ? / 3.750 After you divide the "RPM Before Shift" by itself and divide the "RPM After Shift" by the "RPM Before Shift" then the outcome will be the only formula you will need from now on. Step #4: Finally we are on our way of finding our 2nd gear ratio. Now what we have to do is multiply our "Ratios Shift From" by our "RPM After Shift". That would be .6721 x 3.750. Our answer is 2.520. That is now our 2nd gear ratios. Step #5: Now we can figure out the rest of our ratios like this: Remember how we got 2nd gear? Now all you have to do is change 3.750 to 2.520. After you've done 2nd gear then continue with the rest. Just input the previous gear in the spot of "RPM Shift From" 1st gear: 3.750 2nd gear: .6721 x 3.750 = 2.520 3rd gear: .6721 x 2.520 = 1.694 4th gear: .6721 x 1.694 = 1.139 5th gear: .6721 x 1.139 = .766 6th gear: .6721 x .766 = .515 Now as for the Final Drive gear. You are going to have to play with that yourself. Usually you want your last gear finishing at redline. If your gears are too slow and your last gear finishes way before redline then raise up your Final Drive ratio. If they are to fast and your last gear is redlining too soon then simply lower it. Remember this is just how to get a base for ratios. Not ratios for an actual setup. I tried to explain the best I could. If there is anyone who can explain this better than please do. Phusion PLEASE DO NOT EMAIL ME INGAME ABOUT THIS THREAD Last edited by Phusion : 03042011 at 11:47 PM. 
09152007, 11:41 PM  #2 
Basic Member

.. i think i got lost some where at the top i cant remember tho lol

09162007, 12:17 AM  #3 
Basic Member

Let me know what part you need help with. It's a confusing but not impossible to understand. If you read it thoroughly you should be able to get.
Again, just tell me which part confused ya. Phusion 
09162007, 01:04 AM  #4 
Basic Member
Join Date: Feb 2007
Posts: 523

Doesn't even need to be all that lol. Making ratios is based on the max hp of your car and on how you wanna leave. If you wanna rev launch then your first and final need to be alittle lower so you don't spin. To take your Stang if you wanna make it a h2h kinda car. Then you will need to leave on a roll start so you can make the first and final higher in order to leave with nos without spinning. Take practice to make ratios everyone runs and races differently so therefore your ratios will be different.

09162007, 06:31 AM  #5 
Basic Member
Join Date: Feb 2007
Posts: 80

lol
i did everything you said & i was running faster with my stock ratios. 
09162007, 12:45 PM  #6 
Basic Member


09162007, 03:51 PM  #7 
Basic Member

Trust me it works. You might not have put the right numbers in the right spots. If you give me your MAX TORQUE @ RPM, the RPM that you want to shift at, and your first gear ratio then I will be glad to make you a set with this formula. I promise you it works.
Then all you have to do is tweak them a bit. But they should be way better than stock ratios. Phusion 
09162007, 05:19 PM  #8 
Basic Member
Join Date: Aug 2007
Posts: 2

get me started please
i tried what you said but i got a little lost. so here is my stuff and if you can help me wit the first set of ratios than i can do the rest thanks.
i have a evo max 373.47 HP @5600 max 295.06 FtLbs @4100 redline is 7000 1st gear 2.928 2nd 1.950 3rd 1.407 4th 1.031 5th 0.720 6th 0.000 final 4.529 if you can help THANKS 
09162007, 05:48 PM  #9  
Basic Member

Quote:
When you reply I will work on your set. Phusion 

09172007, 05:56 PM  #10 
Basic Member
Join Date: Feb 2007
Posts: 30

Good tuning guide

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