I plan on rebuilding my diff. and swapping in a 4.10 for my stock 3.08. I was wondering what the rpm increase will be.
3.08 to 4.10 question
- Thread starter kr8zstang
- Start date
for my 3.73's 60mph is at 2000rpm, so 4.10's will be at about 2200rpm, your probabvly doing 1600 right now?
5.0 Nostalgia
10 Year Member
When I had 4.10's in my 96, it was at about 2,500 at 65mph. The 3.73's in my 89 produce similar results to mob, though I am using 16 inch wheels.
Yeah, the engine isn't turning much at 60. Most of the racing i do is 45-100 mph roll-ons. Is the 4.10 a good choice for this, or would i be better off with a 3.55?
Dont go 3.55 trust me youll regret it, gears wont be much of a FEELING impact, you will notice it but it wont be insane, go with 3.73's, you will notice the rpm's and it will pull nice in every gear. If you dont mind spending alittle more for gas and shifting alot more go with 4.10's. Unless you have an automatic and then definatly go 4.10's and dont look back.
and for 45-100mph racing 4.10's will get it up there very nice but you will be turning ALOT of rpms at 100mph and youll probably have to shift into 5th gear if you want to keep climbing.
and for 45-100mph racing 4.10's will get it up there very nice but you will be turning ALOT of rpms at 100mph and youll probably have to shift into 5th gear if you want to keep climbing.
You will have alittle left in 4th gear, I go 99mph down the track and get into 4th about 3/4 down the track, maybe turn about 3k? at the line, idk id have to check, ive really never gone past 100mph in my car and only gone that at the track
willys1
Active Member
Thats kind of a generic chart,its close,but not exact. I have 410's in my AOD. Believe it or not my 373's were 2 tenths faster at the track..Granted,410's are a total blast for around town driving,makes everyday driving alot more fun!
They limit you on the highway though unless you dont mind revving your motor and getting crappy gas mileage. I have my motor set up to breathe better now at higher RPM's (Thumper Heads,1.7 RR's,and soon added cobra intake and catted X-pipe) Im gonna get to the track in March see how it runs.But Im pretty sure Im gonna put the 373's back in. For better highway mileage and 1/4 mile ET's!! If you have a 5spd theres no way I'd put 410's in!!
The old rule of thumb is 373's in a 5spd is the same as 410's in an AOD.JMO
They limit you on the highway though unless you dont mind revving your motor and getting crappy gas mileage. I have my motor set up to breathe better now at higher RPM's (Thumper Heads,1.7 RR's,and soon added cobra intake and catted X-pipe) Im gonna get to the track in March see how it runs.But Im pretty sure Im gonna put the 373's back in. For better highway mileage and 1/4 mile ET's!! If you have a 5spd theres no way I'd put 410's in!!The old rule of thumb is 373's in a 5spd is the same as 410's in an AOD.JMO
Michael Yount
Mustang Master
The chart's helpful but there's a pretty easy way to figure this. Any speed, any gear --- the change in engine speed is simply the engine speed you're seeing on your tach (assuming it's accurate --- a big assumption if it's a stock Stang tach) X the ratio of the gears you're changing to -- 4.10/3.08. So, if you're cruising down the highway in 5th at 1800 rpm with 3.08's, when you put the 4.10's in the new rpm will be 1800 X 4.10/3.08 = 2396, or 2400 rpm. It's just simple ratios.
Blake - what rear tire size was the chart based on?
Blake - what rear tire size was the chart based on?
willys1
Active Member
Michael Yount said:
Blake - what rear tire size was the chart based on?[/QUOTE]
This is what I was referring to when I said it was generic!!
rd
Founding Member
The rpm at any given speed will be 4.1/3.08 x whatever it is right now with the tire size you have. Plain old ratio. Tire size is the most annoying number to find or figure out accurately.
Its best to just bite the bullet and crunch the numbers.
My 82 runs about 2500 at 45 mph with about a 26 in tall BFG 275-50-15 Drag Radial, with 4.10 gears. So 90 is 5000, and 104 at the finish line is about 5700. Allowing for converter slippage, and the stock tach, it seems to finish at 6000-6100.
Its best to just bite the bullet and crunch the numbers.
My 82 runs about 2500 at 45 mph with about a 26 in tall BFG 275-50-15 Drag Radial, with 4.10 gears. So 90 is 5000, and 104 at the finish line is about 5700. Allowing for converter slippage, and the stock tach, it seems to finish at 6000-6100.
Michael Yount
Mustang Master
willys - that's why I provide the formula.....instead of just saying 'it's generic'.....
It's actually not generic -- it's for just one tire height, otherwise it's not accurate.
It's actually not generic -- it's for just one tire height, otherwise it's not accurate.
willys1 said:
Well, the X-pipe puts a new factor in there, but if you have before dyno (I know you have track data) and are going to get after dyno/track data - I'd love to hear the results on the intake switch.
willys1
Active Member
Im pretty curious to see the results also..Im looking for a dyno in my area.Tom the closest dyno's are at some really good Mustang shops,Larocco's,Crazy Horse,and a few others,but they are wayyyy south for me.2 hours minimum. Im pretty sure theres a Turbo shop not too far away with a dyno.I just have to find them which shouldnt be hard.tmoss said:
LOL,,Mr Yount you gotta lighten up!!
Similar threads
