Diff ratio?
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
Diff ratio?
Hi
i am curious as to whether going from a 2.59:1 diff to say a 3.07:1, or 3.45, or 3.57 would be a huge difference in both acceleration and fuel consumption!
i know of course the shorter the gear ie 3.57:1 will be fast but use the most fuel!
but i am curious as to what is a good medium?
i was thinking of going 3.07:1, but would 3.45:1 be better without alot more fuel usage?
i have seen a 3.07 diff for $365 AUD which i think is pretty cheap!
btw i am in Western Australia!, so it is hard for me to get stuff from the US as they don't want to ship to us
else i would!
thanks
i am curious as to whether going from a 2.59:1 diff to say a 3.07:1, or 3.45, or 3.57 would be a huge difference in both acceleration and fuel consumption!
i know of course the shorter the gear ie 3.57:1 will be fast but use the most fuel!
but i am curious as to what is a good medium?
i was thinking of going 3.07:1, but would 3.45:1 be better without alot more fuel usage?
i have seen a 3.07 diff for $365 AUD which i think is pretty cheap!
btw i am in Western Australia!, so it is hard for me to get stuff from the US as they don't want to ship to us
else i would!thanks
Team Owner
Joined: Dec 2007
Posts: 20,974
Likes: 261
I have had 3.07's and now 2.59's
the difference is a sports car, compared to a 70's car with a v8.
i hate the 2.59's so I bought 3.75's, not installed yet, but I can garuntee you and me I will love them.
I have driven one with 3.54's and it was more fun, but never enough for me.
the difference is a sports car, compared to a 70's car with a v8.
i hate the 2.59's so I bought 3.75's, not installed yet, but I can garuntee you and me I will love them.
I have driven one with 3.54's and it was more fun, but never enough for me.
Team Owner
Joined: Sep 2003
Posts: 25,267
Likes: 2,705
The 3.07 would be an "ideal" swap for many reasons! Availability and price first of all. Based on your location and if the rear is "sound" it's a good maybe "great" find. You would certainly enjoy the "SOTP" experience and economy wouldn't suffer substantially if you kept "your foot out of it"!
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
ok sounds like a good swap then up to 3.07 without hurting the fuel economy too much!
i know we always want more, but would going that bit more like 3.54 be better option in the long run? i would hate to ge the 3.07 and then want more later!
are there 3.45 gears available?
i know we always want more, but would going that bit more like 3.54 be better option in the long run? i would hate to ge the 3.07 and then want more later!
are there 3.45 gears available?
Team Owner
Joined: Sep 2003
Posts: 25,267
Likes: 2,705
Many of the ratio's that are "higher" numerically are done with a "thicker" ring gear which would require the use of your 2.59 carrier. Richmond Gear comes to mind for this type of build. You would need to just be cautious when buying a gear kit for a "higher" numerically gear.
I doubt you'll be disappointed with a 3.07 build!
I doubt you'll be disappointed with a 3.07 build!
Racer
Joined: Nov 2004
Posts: 445
Likes: 0
2.59 to 3.57 would be a relatively "huge" difference. The acceleration would be quite impressive.
If you do many country miles, fuel costs will be noticeable with the higher gears. Around town it won't be so bad...in 80kay zones your trans will jump into o'drive and rpm's drop nicely. In 100kph or higher driving, even in o'drive, the engine is going to spin fairly high, affecting fuel economy.
I have had 2.59's, 2.73's and am now running 3.07 and am loving it....wakens the car up nicely , yet doesn't rev high on the open road...so still has good fuel economy.
Lastly, you can't get too fussy in Oz..! That 3.07 for $365 is a steal...you won't get anything for $365 to fit to your car that will offer the performance gains that will come from that rear gear...
Hope this helps your decision, unless bux don't matter, in which case bigger will be faster and more expensive, but a whole lotta fun...IMO
If you do many country miles, fuel costs will be noticeable with the higher gears. Around town it won't be so bad...in 80kay zones your trans will jump into o'drive and rpm's drop nicely. In 100kph or higher driving, even in o'drive, the engine is going to spin fairly high, affecting fuel economy.
I have had 2.59's, 2.73's and am now running 3.07 and am loving it....wakens the car up nicely , yet doesn't rev high on the open road...so still has good fuel economy.
Lastly, you can't get too fussy in Oz..! That 3.07 for $365 is a steal...you won't get anything for $365 to fit to your car that will offer the performance gains that will come from that rear gear...
Hope this helps your decision, unless bux don't matter, in which case bigger will be faster and more expensive, but a whole lotta fun...IMO
Pro
Joined: May 2006
Posts: 637
Likes: 0
That´s cool, I´m in Sweden and my 91 A4 with 2,59 runs 2000 rpm´s (on tach) at 120 kph/75 mph.
Maybe the km´s shrink when colder...
Or my tach is off, who knows...
Edit, reread and saw 3.07´s in prev post...
Time to start reading posts I guess...
Or isn´t it more of a difference then 10 km´s at same rpm???
Anyone know of a way to calculate something like this???
Maybe the km´s shrink when colder...
Or my tach is off, who knows...
Edit, reread and saw 3.07´s in prev post...
Time to start reading posts I guess...
Or isn´t it more of a difference then 10 km´s at same rpm???
Anyone know of a way to calculate something like this???
Last edited by vette079; Sep 6, 2009 at 01:42 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
7 Bolt-On Upgrades From Extreme Online Store to Level Up Your C6 Corvette
Pouria Savadkouei
How Likely Are These Five 2027 Corvette Rumors to Be True?
Brett Foote
9 Best Corvettes You Can Buy for Half Price (& 1 You Should NEVER Buy!)
Joe Kucinski
8 Very Best Corvettes of Amelia Island 2026
Joe Kucinski
Top 10 WORST Corvette Engineering Failures of All Time!
Joe Kucinski
10 Records the C8 Corvette Generation Has SMASHED (& 1 Glaring Failure)
Joe Kucinski
7 Wildest Corvette Concepts Ever Made
Brett Foote
Racer
Joined: May 2005
Posts: 497
Likes: 1
From: Casa Grande Az
Hi
i am curious as to whether going from a 2.59:1 diff to say a 3.07:1, or 3.45, or 3.57 would be a huge difference in both acceleration and fuel consumption!
i know of course the shorter the gear ie 3.57:1 will be fast but use the most fuel!
but i am curious as to what is a good medium?
i was thinking of going 3.07:1, but would 3.45:1 be better without alot more fuel usage?
i have seen a 3.07 diff for $365 AUD which i think is pretty cheap!
btw i am in Western Australia!, so it is hard for me to get stuff from the US as they don't want to ship to us else i would!
thanks
i am curious as to whether going from a 2.59:1 diff to say a 3.07:1, or 3.45, or 3.57 would be a huge difference in both acceleration and fuel consumption!
i know of course the shorter the gear ie 3.57:1 will be fast but use the most fuel!
but i am curious as to what is a good medium?
i was thinking of going 3.07:1, but would 3.45:1 be better without alot more fuel usage?
i have seen a 3.07 diff for $365 AUD which i think is pretty cheap!
btw i am in Western Australia!, so it is hard for me to get stuff from the US as they don't want to ship to us
else i would!thanks
I did the swap a year ago and it pretty much feels like a totally different car.
It will depend however on what motor you have in your car as well. Mine is a LT1 , if yours is not then what I said above may not apply.
Drifting
Joined: Feb 2008
Posts: 1,267
Likes: 27
From: Texas
That´s cool, I´m in Sweden and my 91 A4 with 2,59 runs 2000 rpm´s (on tach) at 120 kph/75 mph.
Maybe the km´s shrink when colder...
Or my tach is off, who knows...
Edit, reread and saw 3.07´s in prev post...
Time to start reading posts I guess...
Or isn´t it more of a difference then 10 km´s at same rpm???
Anyone know of a way to calculate something like this???
Maybe the km´s shrink when colder...
Or my tach is off, who knows...
Edit, reread and saw 3.07´s in prev post...
Time to start reading posts I guess...
Or isn´t it more of a difference then 10 km´s at same rpm???
Anyone know of a way to calculate something like this???
2000rpm with 2.59 at 75 seem high unless they are VERY low in the 20xx
Ill be going with 3.54 gears when i swap to D44 and built 700r4
need it to withstand a 427 stroked 400 later down the road with alot of nitrous. Plan ahead
Pro
Joined: May 2006
Posts: 637
Likes: 0
at 71mph my car just changes from 20xxrpm to 21xxrpm with 3.07 and OD.
2000rpm with 2.59 at 75 seem high unless they are VERY low in the 20xx
Ill be going with 3.54 gears when i swap to D44 and built 700r4
need it to withstand a 427 stroked 400 later down the road with alot of nitrous. Plan ahead
2000rpm with 2.59 at 75 seem high unless they are VERY low in the 20xx
Ill be going with 3.54 gears when i swap to D44 and built 700r4
need it to withstand a 427 stroked 400 later down the road with alot of nitrous. Plan ahead
Drifting
Joined: Feb 2008
Posts: 1,267
Likes: 27
From: Texas
Race Director
Joined: Jan 2005
Posts: 10,641
Likes: 13
From: Slidell Louisiana
That´s cool, I´m in Sweden and my 91 A4 with 2,59 runs 2000 rpm´s (on tach) at 120 kph/75 mph.
Maybe the km´s shrink when colder...
Or my tach is off, who knows...
Edit, reread and saw 3.07´s in prev post...
Time to start reading posts I guess...
Or isn´t it more of a difference then 10 km´s at same rpm???
Anyone know of a way to calculate something like this???
Maybe the km´s shrink when colder...
Or my tach is off, who knows...
Edit, reread and saw 3.07´s in prev post...
Time to start reading posts I guess...
Or isn´t it more of a difference then 10 km´s at same rpm???
Anyone know of a way to calculate something like this???
Best calculator ive found and I've been using it for YEARS http://www.f-body.org/gears/
I use the 93-97 A4 as a base line (same tranny I just enter my gear ratio and tires)
Racer
Joined: May 2005
Posts: 497
Likes: 1
From: Casa Grande Az
Best calculator ive found and I've been using it for YEARS http://www.f-body.org/gears/
I use the 93-97 A4 as a base line (same tranny I just enter my gear ratio and tires)
I use the 93-97 A4 as a base line (same tranny I just enter my gear ratio and tires)
Wow you guys with 2.59s are good for 240mph in OD at 5700RPM .. in your C4
O to have the road , horsepower , tires , and nuts to do that
Pro
Joined: May 2006
Posts: 637
Likes: 0
Well, checked it and it´s doing 2000 rpm at 120 km/74-75 mph.
Checked it through the digital read out in the AC controller/display.
At 2000 rpm on the analog gauge it showed 79-80 on the C68 display.
Makes 2000 rpm if I have to believe the calculation in the FSM.
Value on display multiplied with 25.
Checked it through the digital read out in the AC controller/display.
At 2000 rpm on the analog gauge it showed 79-80 on the C68 display.
Makes 2000 rpm if I have to believe the calculation in the FSM.
Value on display multiplied with 25.
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
Sorry i have not been on for awhile!
thanks for all the comments, i think i will eventually go with the 3.07 gears! when money allows
most of my driving is around the 60-70km/h speeds, while every now and then i get up to 90 and 100km/h!
I have a 90 model so an L98 engine! which has good low down torque anyway, so it should be alot better with that diff!
Do you guys drive in D or keep it so it stays in 3rd(auto cars of course)?
the car shop guy i bought it from said to drive it in 3rd and only select O/D when going 80 plus! i assume as it keeps the revs up and doesn't bog down!
thanks for all the comments, i think i will eventually go with the 3.07 gears! when money allows
most of my driving is around the 60-70km/h speeds, while every now and then i get up to 90 and 100km/h!
I have a 90 model so an L98 engine! which has good low down torque anyway, so it should be alot better with that diff!
Do you guys drive in D or keep it so it stays in 3rd(auto cars of course)?
the car shop guy i bought it from said to drive it in 3rd and only select O/D when going 80 plus! i assume as it keeps the revs up and doesn't bog down!
