Has this been done? 273's

[cobra101]

Has anyone put in 273 gears in the rear end? 300.00 mod and pretty sure my MPG should go from 20-21MPG HWY to 24-25MPG HWY.

25MPG with 500+ HP = Unheard of, at least by me or anyone i know, or anyone they know.


Plus with a whipple, you may get 24MPG with close to 700 BHP.

Obviously, the one doing it would NOT care about 1/4 miles. I do believe there is enough boost and power there at 520 BHP to pull the gear off. Especially if it was a whipple at 680 BHP. The 6 speed is such a close ratio anyways, I think it would work.

Anyways, just seems like the best of both worlds.

Ok, Go ahead, let the ragging begin LMAO

 

[BIGV]

I didn't buy the cobra for gas mileage so if I change gears it will be 3.90's.

 

[SLEEPERSTATUS]

I didn't buy the cobra for gas mileage so if I change gears it will be 3.90's.

:lol::rockon::thumbsup:

 

[cobra101]

Well derr, tell me something I don't know. I already know basically ALL that do change the gear, change to the lower gear. And yes, I did not buy my car for the mileage either. And if I wanted 35+ MPG I will and am getting another car. BUT that good mile car will not have 700HP. I dont go to the track and think 700HP even with 273 gears will still be pretty fast

 

[68_GT]

did you mean 327's ?? those used to be stock on GTs Stangs ? I think 308's wer a choice also. Not sure about 273's ? but holy cow with a t56 you'd probably finish a 1/4 mile in 2nd gear lol

 

[Sniperdog]

I actually have 3.27's in mine.., and took a road trip @80-85 got 22.4 mpg.,. still hauls the mail :thumbsup:

 

[IronTerp]

Yeah, I think 2.73's kind of defeat the purpose of the car. Is the gas mileage worth the reduction in torque multiplication? Turbocharged 4 cyclider would be a better platform for that approach IMO.

 

[cobra101]

Can a turbo 4 cyclinder make 500-700 BHP easily?

Cool deal sniper, good to hear it still hauls, but you do have the blower swap and gobs of power. I am sure it hauls arse. Do you think lower would affect it much? Do you find the wheels break loose more or less often with the lower gear? Same?

I am fairly certain with a blower swap and gobs of power it would haul arse with 273's, still! I had 273s (HWY gear) in my 1985 GT and it was fast enough with 230HP (5 speed). 308's would be good too, but 273's will really show the MPG improvement. And yes, you would think there would definitely be one less shift in a 1/4 run. I think it would be very DD/street friendly too. SOP feel would be interesting, longer in each gear and longer WHINES!

We'll have to wait and see. Great info.

 

[mu22stang]

How much highway driving do you do? This may not do much if you aren't on the highway a good portion of the time.

 

[03cobra#694]

How much highway driving do you do? This may not do much if you aren't on the highway a good portion of the time.

You were reading my mind!

 

[ROADSTR6]

2.73's were stock in the old five speed 5.0 cars. 3.08's were in the AOD's and in cop cars as well.

 

[Digital]

HP doesnt really matter if your never in your power band or have zero tq. A 400awhp subaru is going to spank the shit out of your 700rwhp 2.73 gear car.

 

[Posi]

2.73 = No 4th, 5th, or 6th gear pulls!!!!!!!!!!!:lol:

 

[evil04svtcobra]

i think in the turbo cobra section i've read about turbo cobra guys and some 2.8kb guys going with higher gears like 2.73 and 2.97(i think)

helps them at the track.

i have stock 3.55 gears, and i've pulled off 24mpg a couple times on my trip to st. louis last summer.

 

[cobra101]

HP doesnt really matter if your never in your power band or have zero tq. A 400awhp subaru is going to spank the shit out of your 700rwhp 2.73 gear car.

Problem is I dont have a 400awhp car nor the money to buy one. Zero TQ, I didn't realize the changed gear was going to turn the TQ form near 550ish to zero, my mistake. It probably would be slower than a civic with that rear end gear. 700Hp will feel like 200 LMAO, I don't think so.

Enough with the racing crap. THIS IS NOT A RACING MOD. We all know it will not be as fast as if it had the stock 355 or higher. If I wanted to spank that subaru piece of crap I would keep my gears or go higher.

The fact is, does anyone know of ANY car EVER that got 24 MPG+ with 700BHP? Anyone who knows anyone who knows anyone who knows ANYONE who ever got that type of efficiency? Closest thing I can think might come close is a twin turbo supra of old. With the right gear that may do it but I don't much bout their MPG stock or Heavily modded. Granted maybe no one ever seen it because USUALLY people work so hard to get that power they rface and want every bit of gear they can get. With the cobra easy power mods, it may be appealing to some

Fact is, if it is possible and even easy then who cares if it is a bit slower on the track than a normally geared counter part. 700HP on the street is mean either way!

 

[Sniperdog]

Can a turbo 4 cyclinder make 500-700 BHP easily?

Cool deal sniper, good to hear it still hauls, but you do have the blower swap and gobs of power. I am sure it hauls arse. Do you think lower would affect it much? Do you find the wheels break loose more or less often with the lower gear? Same?

I am fairly certain with a blower swap and gobs of power it would haul arse with 273's, still! I had 273s (HWY gear) in my 1985 GT and it was fast enough with 230HP (5 speed). 308's would be good too, but 273's will really show the MPG improvement. And yes, you would think there would definitely be one less shift in a 1/4 run. I think it would be very DD/street friendly too. SOP feel would be interesting, longer in each gear and longer WHINES!

We'll have to wait and see. Great info.

When Hermann tuned it, he said if hooked up better than he was used to at that power level, and since the gears went in with the blower,., I don't have any before and after with that setup :shrug: but its pretty cool 0-60 in first gear, and when on hwy, @ 65-70, droping to second gear rip someone a new one :thumbsup:

 

[Sniperdog]

Problem is I dont have a 400awhp car nor the money to buy one. Zero TQ, I didn't realize the changed gear was going to turn the TQ form near 550ish to zero, my mistake. It probably would be slower than a civic with that rear end gear. 700Hp will feel like 200 LMAO, I don't think so.


The fact is, does anyone know of ANY car EVER that got 24 MPG+ with 700BHP? Anyone who knows anyone who knows anyone who knows ANYONE who ever got that type of efficiency? Closest thing I can think might come close is a twin turbo supra of old. With the right gear that may do it but I don't much bout their MPG stock or Heavily modded. Granted maybe no one ever seen it because USUALLY people work so hard to get that power they rface and want every bit of gear they can get. With the cobra easy power mods, it may be appealing to some

Fact is, if it is possible and even easy then who cares if it is a bit slower on the track than a normally geared counter part. 700HP on the street is mean either way!

I think if I was on the hwy going speed limit,. I would get @24 mpg :shrug:

 

[twhitey]

If thats what your into. Its not for me

 

[68_GT]

2.73 = No 4th, 5th, or 6th gear pulls!!!!!!!!!!!:lol:

excellent point that high gear would be a lot more load added to the engine = higher engine temps = boom

 

[c6zhombre]

thats a bad idea with a 3800lb+ car. if anything, i'd go 3.90s and probably improve your city mileage with the fact you could lug around in 4th and 5th gear alot without fear of bogging the car down. these t56 1-4 ratios are already steep versus the old t45/3650 tranny