Tony

The only reason I mentioned Dennis setup is because you want the converter to be able to lock up as it would if it were stock. So you have to make sure you have the correct gear ratio installed to work with the converter. (very different from the old days when you needed a converter if your cam duration was over 300 on a automatic)

Knowing that the top two bolt on cars are automatics with converters & gears one of which is the slower A4 (A6 should be faster because of the gearing) but in this case the lower gearing may be the problem as Dennis car has gone quicker then Theofel 's ....... might as well go for both as Joe suggested.

 

Ragtop get the LS3 If you get the LS2 and save alot of money then it can be added for the mods but the LS3 is a better platform for the same mods...The LS2 are dynoing stock A6 320`mid 330`s and the MANUALS are 350` to 360`s, the LS3`s stock are A6`s 370`s to 380`s and MANUALS 380`s to 390`s.....Thats a tough one because you will probly save a ton on the LS2`s....Also can you correct my mistake

 

Tommy,
Thanks for the info I have talked with Dennis about his setup on the phone many times We shot the bs alot, i wonder if anyone has lefted the stock gears in and just ran the converter? It seems like eveyone with the A6 jumps ship for the 3.15`s and a converter,do you know if anyone has just added a converter to the A6 and lefted the stock gears in

 

Tony
I have not heard of anyone who has installed a converter without also replacing the gears.....best to ask Dave and some of the performance trans shops

 

This compares the effective gearing of the different A6 rears. I put the M6 with Z51 in for comparison. The higher the number the quicker it will accelerate for given amount of torque. A couple observations:

3.15s match up pretty well with Z51 M6 with the advantage of a lower first gear but you'll be turning a few more rpms on the highway.

 

Thanks Ragtop

 

Thanks Tommy, i gonna give Cartek a call tomorrow

 

updated it for ya sorry should have done it to the other post whould have helped see the difference better

it wouldnt change the trans ratios, it would change the final ratios though but i think that is what you are asking and correct me if im wrong

comparing to the Z51 ratios this is what it should feel like is in the rear with
.............2.56........3.15s .........3.42s

1st.........3.47s.........4.26s......... .4.63s
2nd........2.92s..........3.59s......... 3.90s
3rd.........2.74s.........3.37s......... .3.66s
4th.........2.94s.........3.62s......... .3.93s
5th.........3.06s.........3.77s......... .4.09s
6th.........3.01s.........3.70s......... .4.02s
Reverse...2.39s.........2.94s..........3 .19s

 

I have an A6 and thinking about 3.42 or 3.15. I am a rookie at the gear ratio stuff and have a few questions. The vette is my daily driver and i put around 15K miles per year..so dependability is a must.
1) Is the gas mileage significantly difference?
2) can i do gear only...no converter?
3) the gear chart posted above...is the lower the number...the quicker car is taking off from dead stop?

 

The difference will not be huge, especially in town. Average mpg should not go down more than 1, maybe 2 mpg depending upon what percent is highway. This also depends upon how you set your shift points. More agressive shift points can reduce mpg.
Yes
If you are referring to the chart I posted, it is the opposite. For example, a first gear of 12.7 will be faster than a 10.3, assuming you have traction and don't put the tires up in smoke. Likewise, a 6th gear of 1.9 will have lower rpms at cruise than a 2.3 and enjoy better gas mileage and lower engine noise.

 

As far as doing a converter without gears, there are plenty of F-body and C5 with 2.73 gears that put in converters without doing gears. Those cars drove fine with 2800 - 3300 stalls and saw .5 - .7 gains in ET. Given the 4L60e's gears aren't as low as the A6, it is pretty safe to say that a 3000 stall will work just fine in a car with 2.56s and net .4 - .6.

Part of the popularity with gears, besides avoiding the feel of a high stall, was the time it took to get Converter manufacturers to develop and bring high stalls to the market for the A6.

 

Ragtop,

Get the 2008, I have to finance the thing for 5 yrs to make it affordable but the way I look at it the changes and improvements are well worth 10k or so in the difference from a 07. I'll shoot you an email again, we should talk more about our planned purchase.

It's pretty funny to see you posting in the gear/converter posts - just like old times. I definitely consider you a very knowledgeable person in this area and the vette forum can really use your input. I can see a difference in the technical knowledge and years of testing of the LS1 guys vs. the vette crowd.

 

I'll add my opinion on a Converter change. I installed a 3500 stall on my SS Camaro a few years back and had intended to go to the track a couple times a month.

I never actually went to the track more than once or twice over the 3 years and with the 3.23 gearing in my SS, I felt that the 3500 stall with my louder exhaust (Corsa) was a little too much for daily street driving. If I had a 3000 stall I would have been far happier for daily street driving but to each his own. I do know from reading the boards here that Corvette drivers in general are a tiny bit more conservative than the LS1 (Camaro/TransAM) drivers with how tolerant to noise, high rpms, and uncomfortable driving experience they are.

Keep in mind as well that the Corvette is faily light on the back end, adding both gears and a higher stall converter will make traction a very serious problem. If I had an automatic Vette, I would be very torn on what mod to get but I would base it off the transmission I had. If I had an A4 Vette I would give the converter the most weight for overall performance (it would help for the launch and the maintaining rpm's on downshifts at any speed). If I had one of the newer A6's, I would probably just do gears as it would give very nice street manners and still improve performance in every gear. The downshifts at speed are not as big an issue becuase you have 2 more gears and they are closer together.

 

The higher the gear ratio, the higher the effective torque at the rear wheels.

Think of it this way. Going from 3.15 to 3.73 is like adding 60-70 or more foot pounds of engine torque. (I don't know the formula to calculate the exact numbers.)

 

The information I'm giving is based on my LS3-A6. I have DTE 315's with heavy duty output shafts and a Vigalante 2800--3150 Stall converter. The gears were previously installed in my LS2-a6 and worked just fine. This was an upgrade from the original 256's from the factory. After I installed the gears into my LS3 and tranferred some other bolt on's from the LS2 onto the LS3, the LS3 ran a lot stronger. The big difference came with the addition of the Vigalante. WOW!!!! My ET dropped about .5, most noticeable in the first 60 foot. I drive my car daily and didn't want to loose any diiveabilty. When I installed the 315's there wasn't any 342 gears available. I'm not sure what I would have purchased if that choice was given to me. When I drive around town my gas millage is about the same as the factory gears, it just shifts into the next highest gear sooner. On the highway I lost about 3 mpg. My ET at the 1/4 mile amazed me, as well as my 60 foot times. If you are going to change gears, make sure you also change your output shafts at the same time. If your only going to add the converter you should also change your output shafts. I live in South Florida and I have yet to run my car with a DA of less than 2300. Can't wait for some cooler weather and a sticky track. My ET's 11.44 @ 119 mph and a 1.64 60' time. the mods I have are a BPP vortex CAI, Long tube headers , SLP cat back and a tune. The dr's are BFG 345's and need to be replaced soon. Again..... I hope for some better ET's in some cooler weather. I hope some of this info helps you in your decision. GOOD LUCK!

 

What was your 60' with the 3.15s and stock converter?

 

I know the 2008s are nicer, but to go over $50k (vert) is tough for me to swallow on principal. I've even thought about going to coupe to get into an 08; but I'm worried that I'll miss the open feel of a vert and the ease of opening (flip a switch vs. remove and store).

My style is to buy cars that are 1-2 years old and let the depreciation hit incurred by the original owner pay for the mods. Modding is part of the fun of owning. Maybe the thing will be to wait to Fall 2008 and pick up a low mileage 2008 at a fire sale.

 

My LS2 times with my bolt ons, without the gears were 12.5's 119mph with my 60's in the 1.9's. My LS3 with the same mods and 315 gears 11.99@118mph and my 60's were in the 1.8's. With the converter added 11.44 @ 119mph with a 60' of 1.64. A real improvement. The track was not sticky and it was hot and muggy with a DA of 2300. I hope this info helps you.

 

Theofel, Thanks for the info
Ragtop you have been a great help

 

This is what i was looking for