Forced Induction Supercharger/Turbocharger

Best gear ratio for FI car

Thread Tools
 
Search this Thread
 
Old 12-01-2011, 11:11 PM
  #1  
Registered User
Thread Starter
 
lymlyt96's Avatar
 
Join Date: Dec 2010
Location: Bay area,Ca.
Posts: 361
Best gear ratio for FI car

I wanted to know what rear gear ratio the high boost guys are running and if the setup is for street or track. Right now I have a stock 10 bolt with 3:42's that's perfectly fine on the street but I have a 9 inch with 3:70's that needs to be built. I'm gonna put that in when I get all my other projects for the car knocked out but wanted to get some opinions from experience which gearset would be best.
lymlyt96 is offline  
Old 12-02-2011, 09:29 AM
  #2  
rwb
Registered User
 
rwb's Avatar
 
Join Date: Feb 2001
Location: Ks,USA
Posts: 197
Re: Best gear ratio for FI car

Manual or Auto?? If it's a manual 6sp and you are running big DR's you can run 4:10's like I am. My speed at 70mph is 2200rpms if you are running an Auto run no higher than 3:73's or you will be screaming down the highway.
rwb is offline  
Old 12-02-2011, 02:46 PM
  #3  
Registered User
 
LT1 POWR's Avatar
 
Join Date: Apr 2005
Location: Colorado Springs, CO
Posts: 1,830
Re: Best gear ratio for FI car

I can tell you that 4.11's in a 4L60E are horrible. 1st and 2nd gear are useless even with 27" slicks and I can't cruise too much over 55 or 60mph. They were supposed to be 3.73's which I think is still too much. If I were to do a gear change, I'd probably do something in the 3.20-3.40 range.
LT1 POWR is offline  
Old 12-02-2011, 04:40 PM
  #4  
Registered User
 
Kevin Blown 95 TA's Avatar
 
Join Date: Oct 2001
Posts: 2,685
Re: Best gear ratio for FI car

I have a 3.42 but I think I could go less. Some of that is because of the ridiculous 1st gear in the 4L60E. Last time at the track I trapped at 126 and was at the top of 3rd gear, which isn't too bad. I don't use slicks and don't get good traction, but I don't have a drag car, either. I am considering a Gear Vendors OD if I can prove to myself that the electronics will work. Then if that works and maybe go with a 3.08 gear.
Kevin Blown 95 TA is offline  
Old 12-02-2011, 06:57 PM
  #5  
Registered User
Thread Starter
 
lymlyt96's Avatar
 
Join Date: Dec 2010
Location: Bay area,Ca.
Posts: 361
Re: Best gear ratio for FI car

I have a 6spd and on my last setup N/A I had 4:10's and even with 400rwhp 1st and 2nd were useless on the street. I should be seeing the track often next season but this is mainly going to be a street car so I want to be able to cruise around and enjoy the ride. With that being said should I be looking for somethin more like a 3:08 or would the 3:70's be fine, I'm pretty sure the power is gonna be there to make up for the lack of gearing on the track but I figure if I wanna turn it into a street strip car I can just get another third member with 4:11's and swap it out when its GO time.
lymlyt96 is offline  
Old 12-07-2011, 11:37 AM
  #6  
Registered User
 
DirtyDaveW's Avatar
 
Join Date: Dec 1999
Location: Upstate New York,USA
Posts: 1,791
Re: Best gear ratio for FI car

My initial setup was 4.10's with the turbo. Kinda helped with any turbo lag on the street but I never raced at the track with that setup.

I then opted for 3.55's (I have a Ford/GM 8.8 hybrid differential) and it's great for an all around street car. Not much fun at the strip though since the 275 Nitto DR's either spin or bog. I sometimes drive long distances in the car with the 3.55's and it seems like it's at a fast idle at 75mph

I have a TH350 to put in it after I get the torque converter restalled to 4,000. I'll know how well the combo works at the strip next Spring.
DirtyDaveW is offline  
Old 12-13-2011, 12:54 AM
  #7  
Registered User
Thread Starter
 
lymlyt96's Avatar
 
Join Date: Dec 2010
Location: Bay area,Ca.
Posts: 361
Re: Best gear ratio for FI car

Thanks for the info guys after reading what you have to say I think I'm leaning more towards having this an all around fun street car and when or if I do hit the track I'll have a race setup ready.
lymlyt96 is offline  
Old 12-13-2011, 10:05 PM
  #8  
Registered User
 
dizwiz24's Avatar
 
Join Date: Mar 2009
Posts: 125
Re: Best gear ratio for FI car

i heard once that 4.10 gears (w/ a 6spd) makes a forced induction car slower at the quarter.

it does this because you end up with an extra shift and with every shift you 'blow off' or waste your boost.

Not sure if this was urban legend or truth.

3.45:1 to 3.73:1 (w/ 6spd) seems like the best rear end ratio to have.
dizwiz24 is offline  
Old 12-14-2011, 09:38 AM
  #9  
Registered User
 
Sparkz28ss's Avatar
 
Join Date: Nov 2004
Location: ..behind you with a butter knife
Posts: 977
Re: Best gear ratio for FI car

3.42. ....... Let that boost work for you
Sparkz28ss is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
ChrisFrez
CamaroZ28.Com Podcast
1
12-21-2014 09:47 PM
ChrisFrez
CamaroZ28.Com Podcast
1
12-15-2014 03:09 PM
tds1213
General 1967-2002 F-Body Tech
1
11-27-2014 12:55 PM
USAirman93
General 1967-2002 F-Body Tech
4
11-24-2014 03:37 PM
chevroletfreak
LT1 Based Engine Tech
202
07-04-2005 05:00 PM



Quick Reply: Best gear ratio for FI car



All times are GMT -5. The time now is 04:19 AM.