3.55 worth it?

[1320']

I don't ever plan to track it or anything...mainly DD and some spirited fun...pretty much 50/50 split of driving. Just trying to figure really if those 3.55s really make the car feel different and/or worth it or are needed.

If you're not planning on tracking it then yeah, 3.55's would make it a very spirited drive and comfortable in day to day driving.

me personally if I were going for absolute best quarter mile times I would buy the 3.55 rear end and then swap in 3.31 gears.

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[Alloy]

I was contemplating this gear swamp as well. I have a base eco AT with 3.15. someone had previously mentioned that the cost involved plus the gear whining noise if it wasn't timed exactly perfect would be an annouing issure. I had wanted to goto the 3.55's. A friend of mine how has the PP eco, stated that his rear diff is steel/iron in the front and aluminum in the rear of the housing....whereas mine is all aluminum.

 

[Spartan]

I was contemplating this gear swamp as well. I have a base eco AT with 3.15. someone had previously mentioned that the cost involved plus the gear whining noise if it wasn't timed exactly perfect would be an annouing issure. I had wanted to goto the 3.55's. A friend of mine how has the PP eco, stated that his rear diff is steel/iron in the front and aluminum in the rear of the housing....whereas mine is all aluminum.

Have you driving his and compared them?

 

[Spartan]

If you're not planning on tracking it then yeah, 3.55's would make it a very spirited drive and comfortable in day to day driving.

me personally if I were going for absolute best quarter mile times I would buy the 3.55 rear end and then swap in 3.31 gears.

Gotcha.

My big thing is that people are saying on here that they feel the 3.15s in the auto make the tranny feel sluggish and the 3.55s really wake it up and you would maybe lose 1 mpg if that.

 

[Alloy]

I'm hoping to. i took him for a ride in mine and he said mine almost felt as peppy as him.....his is stock lol.

 

[15GTBEN]

3.73 would be a terrible gear for the auto...3.31 cars would run it down with ease.

The gearing in the 6R80 is really pretty aggressive and doesn't need or want a ton of gear.

Actually 1st and 6th gear are aggressive in the 6R80 not 2nd-5th.
2nd-5th are less geared than the MT82.

It has been said by Mike Roush after extensive testing that 3.31's in the 6R80 with the 11-14 GT's is the optimal drag race gear, with no real gain going with any more gear.

 

[slythetove]

I don't ever plan to track it or anything...mainly DD and some spirited fun...pretty much 50/50 split of driving. Just trying to figure really if those 3.55s really make the car feel different and/or worth it or are needed.

I don't plan to track either. 3.55 is for fun on the street.

My advice is drive both if you can - you'll know whether it matters to you or not.

 

[Mako_254]

MPG from 8 tanks of ethanol free 93 octane in GT Auto with 3.55

Nice. How's your MPG with the 3.55s?

Tank octane car odo trip1 gal calc
1 - 87 16.3
2 - 93 19.6 0547.6 256.4 14.656 17.5
3 - 93 20.9 0814.2 266.1 14.208 18.7
4 - 93 20.8 1048.7 234.5 12.910 18.2
5 - 93 21.1 1345.6 296.8 15.434 19.2
6 - 93 19.4 1604.2 258.6 14.583 17.7
7 - 93 20.2 1863.1 258.8 13.928 18.6
8 - 93 20.9 2134.7 271.6 14.469 18.8
9 d 93 20.3 2414.4 279.7 15.456 18.1

~33% city (45 mph)
~33% rural (60mph)
~33% hwy (75 mph)

 

[IvanCRF]

Nice. How's your MPG with the 3.55s?

My best ever average was 26.5MPG on a long roadtrip in sixth gear through New Mexico. From there, it is downhill as you have more fun. I bought this thing to have fun.

 

[Mako_254]

Me too!
I did not buy it to save on gas.
:-)

 

[dgc333]

Nice. How's your MPG with the 3.55s?

I have an EB performance package 6spd manual (3.55 gears) with an exhaust and tune. My daily driving 48 mile round trip suburban commute is netting a tank to tank average between 29 and 32 mpg. If I drive it like a little old lady I can get it to 38 mpg, drive it real agressively the mileage drops to 26 mpg.

 

[olaosunt]

I have two 2015's, a base GT M6 with 3.31 gears and a just got a Premium GT A6 with 3.55 gears - why two? Long story.

It may be apples to oranges to some degree due to different gearing ratios of the trannies ,but wow the auto feels a lot faster .....loving it especially in sport/track and the rev matching

It feels so fast,it is hard to imagine what is going to feel like with the Hellion TT

It could also be I have not driven the M6 since December when On3 came to pick it up to use to Fab his TT kit....... Still waiting for prototype peices to return and so he can start testing.

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